The foundation was ever laid in Call of Duty 4: Modern Warfare is still
the most important story-wise basis. Here we played with different
characters, who in secret operations were running all over the world to
stop terrorists. They succeeded only partly in here then, what was clear
to see in Modern Warfare 2. Also in this section was the dreaded
terrorist Makarov are not stopped and the result was that the world is
about the Third World was. After all the effort you did in the previous
sections to prevent this, in Modern Warfare 3 is really the gate of the
dam.
You notice right when you start the single player. You
will be dropped in the middle of New York where the bullets fly past
your ears, half the city in ruins tanks and helicopters shooting you at
every turn you bombard from the air. The war began and how! Modern
Warfare 3 picks up where Modern Warfare 2 is stopped and it is clear
that the whole business is completely escalated. But luckily there are
the famous characters like Captain Price, Soap, Nikolai and a series of
newcomers who seek to stabbing a stick.
As in section two is
your primary goal the elimination of Makarov. The question is whether
this will actually happen. The man is constantly one step ahead of
everyone and therefore has been able to spark World War III. In any
case, a good story for you all over the world that, because of tradition
play in this game again with different characters, simultaneously all
over the world to fulfill their missions are. The result is that one
moment in New York run, the next moment Somalia unsafe and again a
little later by the enemy-occupied Prague creeps.
The story
deserves no literature, but the way Infinity Ward all loose ends tied is
good. After completing the single player you really feel an adventure
of six years to have completed the other two parts in mind. Even after
you complete the single faced one of the wildest roller coaster rides
ever in a game. Modern Warfare 3 is indeed a succession of spectacular
moments. You're simply just the bangs and the moments of change are
times when you are in a rubber boat and jumps off the coast of New York,
sail or the enemies from the air to harass you.
Infinity
Ward knows this part again to combine different elements into a very
fine whole. The single may be a wild roller coaster ride, it is a lot
you'll have fun. The downside is that single share of the Modern Warfare
part seems to be shorter. So we played the game first "normal" from
what could be done within five hours. After we are veterans went to
work. In this shoot the enemies almost always hit (even impossible
distances), allowing more challenging, but much longer than six hours,
you do not need this difficulty.
It is unfortunate to see
that once again the single is much too short. If you start the game you
stay true to play, because it is a succession of bold moments, but if
you get a little five hours later, see the credits, then surely that is
what sin. What a little sin, is that the game can be described as a show
where you say against you. Now what is that in perspective, because
everyone experiences in their own way. But Infinity Ward try, although
it is far from realistic, but a sharp shooter with realistic elements to
put down. But after ten times with a helicopter crashing down we had to
do something ... yes, now we know it. Course about your life again and
again and if we load up the previous sections, then the characters in
this game truly immortal, which is quite special.
Another
criticism is that the game is visually really starts behind the rest.
Modern Warfare 2 was visually though not a strong title, and now two
years later, you notice that it really slowly starts to feel dated. What
Battlefield 3 on the PlayStation 3 game is not incredibly beautiful, it
is considerably better than Modern Warfare 3. It is high time for the
next part once a great new engine to use. Add the fact that everything
in the game still indestructible material. Another point where other
games this title pass.
Another thing we noticed was that the
soundtrack of the game is not nearly as epic as ever more. The music is
nothing really spectacular. Yes, it fits there and sounds good, but
otherwise you lie not wake up. That was in the previous sections do
something else, so that's perhaps a shame to call. The audio itself is
fine. The voice actors do their job well and the weapons, vehicles, and
explosions sound more like it should. But to just look at the
competitor, knows DICE with Battlefield 3 in terms of audio Modern
Warfare 3 amply surpass.
Enough about the single player and
audio-visual aspect, because there's more. Let us briefly identify the
controls, because it was delicious as always. Infinity Ward has taken
control as it was and it is clear that this is the finest controller for
a shooter. That said, it's time to look at the multiplayer look. It
consists of two parts. The first part that we take is the Spec-Ops mode,
which has a nice innovation, and the second part is obviously the
normal multiplayer both offline, online and LAN play is.
Spec-Ops returns in this game and you get sixteen different Spec Ops
missions presented. These missions take place at the locations where you
come with the single player. Only difference is that the different
missions and each mission you can get one to three stars. These missions
are varied and tasty again if this mode of Modern Warfare 2 knows, you
will find few changes. It is another successful mode that extends the
playing time considerably, especially if you are in the three co-stars
want to get per mission. It also provides the necessary additional
Trophies on.
Much more interesting to look at the brand new
Survival mode. This mode lets you play all the multiplayer maps and it
comes down to the fact that you repeatedly attacked by enemies. The
attacks are divided into 'waves' and the only thing you have to do all
the enemies popping into the afterlife. Once you have done this, you get
the time to buy weapons and more. Shortly after starting a new wave and
come back several enemies at you. Gradually, the waves more difficult,
because in the beginning where you're dealing with a set of simple souls
who serve as cannon fodder later on you get to deal with enemies who
wear full body armor.
Also, dogs will come at you with C4,
and Juggernauts and helicopters. The further you get, the harder you'll
get. No luxury is the ability to buy new weapons. By enemies to shoot
you earn money and that money you spend on various weapons and
explosives, including grenades, claymores, C4 and more. That's not all,
because you can also invoke an airstrike, a squad of soldiers to help
you, a precision missile and more. This way, you should try to get as
far as possible and this is a pretty addictive mode. In short, a very
fine and successful addition to the Call of Duty games.
Then
there's the part that is most undoubtedly will be played the whole game
and that is the famous and infamous online multiplayer. Here you do not
expect major changes since the base is primarily the multiplayer more of
the same. You get a whole series of new maps, where you can fight with
each other and there are some new modes available in multiplayer. Lots
of words we do not dirty, but the gameplay is essentially identical, but
in a different environment. It is true that the game is better
balanced, also known as fine an optimal experience.
Nevertheless, some adjustments were made to the balance have improved.
So we no longer killstreaks, but Strike Packages are now available in
the game. By a number of kills in a row to make you rely on a Strike
Package. In total there are three different types of Strike Packages
available, each of which offer their own diversity. This allows you to
bombard the enemy Strike Assault with different equipment. Support the
Strike was intended more for you and if your team support and finally
there is the Specialist Strike, which focuses on the many perks.
Assault and Support Where a general effect on the gameplay have you on
the Specialist more on your own. If you make enough kills, you get all
the perks available to you that you have unlocked so far. As a result,
you benefit from a variety of benefits that the struggle to make it
easier for you, but the downside is that only you can benefit. So if you
play a team is to use an Assault or Support Package again perhaps
easier and the components in these two packages are just fine are
matched, so the balance is better than ever.
Of course we can
talk for hours about what's possible in multiplayer, but it is clear
that there is not much news noticeable. The annoying perks and the like
are destroyed from the game, the multiplayer is more balanced and
variety of modes is enormous. It is therefore a Modern Warfare 3 game we
generally see when we can describe as a title with more of the same.
There are the necessary changes to make it better, but much more than
that, you do not expect again in multiplayer.
Call of Duty:
Modern Warfare 3 is in every respect a game that feels like more of the
same. This may sound pessimistic, but not so intended. The single is far
too short, but still very spectacular. Spec-Ops mode, Survival mode
with considerably more interesting and diverse changes in the online
multiplayer make it a balanced and perhaps more fun than ever. Yet you
do anything drastic changes are expected and it's also a shame to see
visually the game starts really behind the rest. Also, the soundtrack is
not the highest shelf, something that previously was the case. Call of
Duty: Modern Warfare 3 is a great shooter by Infinity Ward, as we had
expected.
Pros:
- Plays great.
- Spectacular.
- Survival mode.
- Balanced multiplayer.
Cons:
- Barely great visuals like 7.5
- Singleplayer too short.
- Where is the epic soundtrack?
- Spectacular single clichéd moments.
Sunday, July 04, 1999
Call of Duty: Modern Warfare 3 review
Super Mario 3D Land review
Almost all of the excellent 3DS titles so far have been graphically
upgraded ports of older games. They are fine as far as they go, but this
system has been lacking a true stellar first-party title for a while
now. Nintendo has finally remedied this with their latest Super Mario
Bros. release, Super Mario 3D Land. Having obtained a copy of this game
and played through it fully, I can say, in all honesty, that this is by
far the highest quality Mario hand-held game ever released. As others
have noted, this game is a kind of celebration of all things Mario, and
it takes its inspiration from earlier titles in the series, most notably
Super Mario 64 and Super Mario Bros. 3. I honestly can't find anything
wrong with this game, aside from perhaps the strange Tanooki obsession
that seems to have gripped the developers of this game, as EVERYTHING
has a Tanooki tail in this game.
While there is a relative
lack of difficulty to be had in the game's first eight worlds, it is in
the game's subsequent eight worlds of bonus content, which can be
unlocked after completing the main campaign, that truly tests the more
seasoned Mario veterans. With this said, however, the first eight worlds
are still a wonder to play through, and there is a moderate level of
difficulty to be had in locating all three of the stars in each level.
This game seeks to please people of all skill levels, and if you are
truly looking for a challenge, the game will deliver one.
The
power-ups here are far more inventive than I've seen in most Mario
games of the past. Mario can, of course, still change into Fire Mario,
who shoots enormous fireballs at his enemies. The Tanooki suit has, of
course, returned, and I dare say you will probably play through most of
the game with this power-up, as Tanooki leaves tend to be handed out
like candy in the levels. The suit doesn't fly, unfortunately, but Mario
can glide, tail whip, and, in the bonus worlds, briefly turn into a
statue. A new one I've not seen before is the propeller power-up, which
allows you to engage precision aerial tasks. Finally, there is the
fantastic boomerang upgrade, which allows Mario to access previously
unreachable items and to take out almost all enemies.
One can
also play as Luigi in this game after participating in the second set
of eight worlds, which helps to spice up replays of this game nicely.
The 3D effect is vital to fully enjoy the game here. It is utilized in
such a way that it actually enhances gameplay! This intelligent usage
of 3D is a good initial argument for the 3DS' 3D not being a mere
beautiful gimmick.
There is even an interesting use of the
streetpass feature in this game. When your 3DS is in streetpass mode and
you pass someone else with a 3DS, it has a chance of sending you a
small bonus level that'll help you rack up more stars.
Finally, but not lastly, there are three save slots here, something I
appreciate immensely when giving the game to other people when they want
to take it for a spin!
The large amount of levels, steadily
increasing difficulty, beautiful graphics, intelligent use of 3D, and
compelling gameplay all make this game an absolute must-buy. Get this
game! If you don't own a 3DS, then get one and get this game! Between
this and the new Mario Kart, the 3DS should have a very strong holiday
season.
Tuesday, June 15, 1999
1999 Caribbean cruise
This is the second vacation I took in June. This was first class.
I remember there was an arcade with Soul Calibur, Area 51, Daytona USA, X-men vs. Capcom on the ship. There was a casino and strip bar.
Monday, June 07, 1999
Pathophysiology week 6b
Blood Pressure Woes
In the following scenario, two diseases are exposed, both are silent in progression in early stages, and both can cause insult to the body's homeostasis. In George's case, he has been battling with partially controlled hypertension for the past five years. What he did not realized that his partially controlled hypertension was not preventing damage to his kidneys.
George is a 55 y.o. male who has had hypertension (HTN) for the last 5 years. His HTN is only partially controlled. He is trying to watch his diet, but does not exercise like he should due to his high-stress job. He is also on HTN medication. He monitors his blood pressure at home on a regular basis. For the past month he has noticed his blood pressure seems to be higher than usual and even harder to control, but figured it was due to the stress of a big project at work. In the past 2 weeks, however, he has noticed he does not feel like eating much; he is fatigued; he seems to be urinating more often; and he has been losing weight. He decides to go in to see the doctor.
Total peripheral blood flow should be equal to cardiac output. Adequate blood pressure (B/P) is needed to overcome friction and elastic forces and to maintain blood flow. If blood pressure is too low, vessels collapse; likewise, if blood pressure is too high, vessels stiffen. A normal B/P is <120 140="" and="" arterial="" b="" cardiac="" contraction="" diastolic="" high="" hypertension="" minimum="" peak="" phase="" pressure="" relaxation="" systolic="">) is when high pressure (tension / vasoconstriction / increase peripheral resistance) is created in the arteries. Pressure and resistance can effect blood flow. When pressure increases, blood flow increases, however, if vascular resistance increases, systemic blood flow decreases. The variance causes the heart to produce enough pressure to compensate for any resistance in order to maintain adequate blood flow. Chronic hypertension can cause complications in the cardiovascular system. According to the National Kidney Foundation, hypertension is the leading cause of heart attacks, strokes, and chronic kidney disease. p.308-311
George's doctor decides to run several tests with the following results: Blood Test Results: RBC: 3.8 million cells/mcL; WBC: 10,000 cells/mcL; Hgb: 11.0 gm/ dL. Urine Test Results: GFR: 45ml/min/1.73m; Creatinine: 3g/ 24hr; Protein: 3g/ 24hr. The diagnosis George received was Chronic Renal Failure.
The kidneys are the body's primary excretory organ along with the skin and respiratory systems. It regulates the internal environment of the body by selectively excreting foreign material (drugs, toxins etc.) and metabolic waste while retaining valuable water, organic nutrients, and electrolytes in order to maintain adequate blood volume and composition. Urine is the end product of metabolism. Urine formation begins in the glomerular capillaries and ends in the collecting ducts ranging between dilute to concentrate composition (pH 4.5 – 8), depending on the body's physiological needs. Handy Tables, (Gould, B. E. , pg 440, 444-445, 2011)
Each kidney consist approximately one million of nephrons. The nephron is the basic functional unit in the kidney. The nephron consist of a renal corpuscle (filtering system known as a glomerulus )and a tubule. The glomerulus (site of filtration) is composed of a capillary network surrounded by a round structure called Bowman's capsule. Between twenty and twenty-five percent of cardiac output per minute flows into the renal artery. The route of blood flow into the kidney starts at the renal artery then proceeds into interlobar artery, then arches into arcuate artery, then flows into interlobar artery, meeting its final destination in the afferent arteriole which is the entrance into the glomerulus At the distal end of the glomerus, the capillaries rejoin to form the efferent arteriole through which blood eventually winds itself back to the renal vein. The dual arterioles controls the pressure (passive) in the glomerular capillaries and the glomerular filtration pressure. The glomerular capillaries restrict only large molecules (protein) resulting into filtrate that consist of plasma minus the large molecules. (Gould, B. E., pg 440- 442, 2011)
Filtrates leaves the glomerulus and enters the renal tubule which reabsorbs all useful organic molecules from the filtrate, reabsorbs > 90% water (osmotic), and secretes into the tubular fluid any waste products that were missed by the filtration process. In the collecting duct, additional reabsorption of water and absorption or active secretion of sodium, potassium, hydrogen, and bicarbonate ions before urine is released. Both secretion and absorption are controlled by selective permeability in different areas of the renal tubule and the response of hormones such as aldosterone ( responds to low sodium or high potassium concentrate), antidiuretic hormone ( >ADH >water permeability making urine more concentrated), and kidney hormones calcitriol, erythropoiten, and renin. (Gould, B. E., pg.440-443, 2011)
As previously mentioned, one of the kidney's main function is to regulate blood volume and blood pressure. Renin an enzyme/ hormone is release in response to low glomerular pressure due to declining blood volume ( low salt and water retention), declining blood pressure or both and triggers the renin-angiotensin system ( leads to formation of angiotensin II). The response triggers the sympathetic nervous system (SNS) to cause a notable peripheral vasoconstriction of the capillaries, elevating B/P in the renal arteries. It also causes constriction of the efferent arterioles, elevating glomerular pressure and filtration rates. In turn the release of ADH promotes water and sodium absorption, increasing the thirst feeling. To maintain homeostasis, a hormone called atrial natriuretic peptide ( released by the atrial cardiac muscle cells), becomes involved to reverse high blood volume and blood pressure leading to an increase sodium excreted in the urine and inhibits renin. (Gould, B. E., pg.442, 2011)
Two other hormones release by the kidneys are calcitriol and erythropoitin. Calcitriol is an hormone released by the kidneys in order to stimulate absorption of calcium and phosphate in the small intestine.
Calcitriol is a converted form of vitamin D3 that has been absorbed from sun light into the skin, modified and released from the liver and converted in the kidneys. It is use to promote bone health.
Erythropoiten is a hormone release by the kidneys when there is low oxygen levels in the kidney tissue. Erythropoitin stimulates the bone marrow to produce more red blood cells, increasing the blood volume and improves oxygen delivery to the tissues. (Gould, B. E., pg .244, 2011) (medicinenet, 2012)
When kidney function becomes comprised by hypertension, as in George's case, the process of glomerular filtration and renal tubular absorption and secretion become affected. Chronic renal failure is where the kidney function deteriorates gradually. The condition can not be reversed, only prolonged, and symptoms of acute renal failure can eventually developed because of scar tissue and loss of functional organization. George initially may not have known he had his chronic kidney failure since gradual loss of nephrons usually occurs without symptoms until it becomes well advanced. The kidneys are highly adaptable and are able to compensate for loss function with the surviving nephrons. In George's case, hypertension may have cause of the chronic renal failure. George's labile B/P status in the past month may have resulted from the progression of his chronic kidney disease, thereby , creating an inadequate blood flow into the glomeruli and causing the kidney's release of the hormone renin. George's job stress, diet,and limited exercise may have initially predispose him to hypertension or it could be genetic or another cause. In the past 2 weeks, George experienced a decrease in appetite, weight loss, fatigue, and had frequency in urination are early signs of chronic renal failure. George's blood test results showed RBC: 3.8 million cells/mcL ( norm. 4.2-5.9) and Hgb: 11.0 gm/dL (norm. for men 13.5). Both hemoglobin and RBC is low and these results indicate anemia, a sign that the kidneys are not adequately producing erythropoiten causing a decrease RBC production, resulting in anemia. George's urine test results exhibit impaired kidney function. Glomerular filtration rate (GFR) is a measure in how well the kidneys are filtrating wastes from the blood. George's glomerular filtration rate (GFR) is 45 mL/min/1.73m ( norm. > 90-130), Creatinine is an end product of muscle metabolism. It is normally excreted in urine. George's creatinine is 3g/24hr (norm.1-2g/24hr). Protein is not normally excreted in the urine. If the filtration membrane is damaged, blood protein will leak out and end up in the urine. George's protein is 3g/24hr ( norm. trace-0-150mg/24hr). No blood creatinine test was noted. Accordingly to the National Kidney Foundation (NKA), George is in stage 3 kidney failure with moderate decrease kidney function ( a greater loss of nephrons than stage 2). Increase urine creatinine and protein in the urine signifies damage to kidney's filtration units. (kidney)(stress) (Gould, B. E. , pg 196-197, 2011)
If George was in second stage of chronic renal failure, approximately 75% of the kidneys' nephrons would be lost. The GFR would decrease to approximately 20% of normal. A significant retention of nitrogen wastes would be found in his blood. Tubular function would be decreased resulting in a less concentrate urine and control secretion and exchange of acids and electrolytes. His urine would become diluted and would excreted in large amounts. If the progression of George's chronic renal failure became end-stage (uremia) renal failure, more than 90% of the nephrons would be lost. His GFR would be negligible. Blood would become toxic due to fluid, electrolytes and wastes are retained causing an impact on all body systems. Marked oliguria (scant) to none (anuria) would develop. His kidneys have failed; without intervention ( regular dialysis or transplant), George's life would be in jeopardy. (Gould, B. E., pg. 460, 2011)
George did not have acute renal failure. Acute means 'rapid'. With acute renal failure, most times the situation can be reversed when the cause is immediately corrected or properly treated in order to minimize the insult to the kidneys. The main goal is reduce the risk for necrosis and permanent kidney damage. The cause of acute kidney failure is directly due to the reduction of blood flow into the kidneys or inflammation and necrosis of the tubules causing obstruction leading to a decrease in GFR and reduction in urine. Problems of reduction of blood flow before it reaches the kidneys can be cause by dehydration, sepsis, or surgery (>blood loss), or heart attack, or severe injury and or burns. Problems of obstruction (movement of urine) could be cancer of the urinary tract, or kidney stone, or enlarged prostate, or nephrotoxins ( drugs, chemicals, toxins). Lastly, problems with the kidney itself that reduces blood filtration or production of urine such as glomerulonephritis (possible due to strep infrection), or acute interstitial nephritis (aspirin, ibuprofen, penicillen). (Gould, B. E. pg. 458-460, 2011) emedicinehealth.com-acute
The major goal of George's treatment would most likely consist in lowering his blood pressure, decreasing risk for cardiovascular disease, and slowing the progression of his chronic renal failure. His treatment would most likely include antihypertensive medications Ace inhibitor and/or ARB in order to reduce and stabilize his B/P ( < 130/80 per NKF). Life style changes that would include diet (low sodium, low fat, low protein, with increase intake of fruits and foods rich in iron, vitamin B12 and folic acid. Additional vitamins with B12, folic acid, and iron (for anemia) may also have to be taken. Weight control or maintenance would be encourage along with an exercise plan. George may have to receive erythropoiesis (ESA) stimulating agents injections to help his body make RBCs. Additional iron supplement may also be needed; without iron, ESA is wasted and is needed to reach target hemoglobin. Lastly, if it has not been approach before now, educate George on the effects of prolonged stress and how it is impacting his cardiovascular and kidney systems. Along with a healthy diet and exercise already mentioned, George's physician may also encourage other means in developing coping mechanism that are appropriate for George, which may include engaging in some 'time-out' during his job for better assessment, or using relaxation techniques etc. (National kidney foundation)
(mayoclinic)(NKF kidney,) ((Gould, B. E., pg. 196-197, 2011)
References:
Anonymous. (2012). KDOQI™ Guidelines and Commentaries
Retrieved February 12, 2012, from Kidney website
http://www.kidney.org/professionals/kdoqi/guidelines_commentaries.cfm#guidelines
Workeneh, B.T., Batuman, V.. (2012, February 9). Acute Renal Failure
Retrieved February 12, 2012, from Emedicine website
http://emedicine.medscape.com/article/243492-overview#aw2aab6b2b2
Anonymous. (2012). Hypertension
Retrieved February 12, 2012, from Stress website
http://www.stress.org/topic-hypertension.htm
Anonymous. (2012). How Your Kidneys Work
Retrieved February 12, 2012, from Kidney website
http://www.kidney.org/kidneydisease/howkidneyswrk.cfm
Anonymous. (2012). Erythropoietin (cont.)
Retrieved February 12, 2012, from Medicinenet website
http://www.medicinenet.com/erythropoietin/page4.htm#glance
Anonymous. (2011, August 02). Chronic kidney failure
Retrieved February 12, 2012, from Mayoclinic website
http://www.mayoclinic.com/health/kidney-failure/DS00682/DSECTION=treatments%2Dand%2Ddrugs
Gould, B. E. (2011) Chapter 12
(pp. 196-197), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
Gould, B. E. (2011) Chapter 15
(pp. 244), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
Gould, B. E. (2011) Chapter 18
(pp. 308-311), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
Gould, B. E. (2011) Chapter 21
(pp. 460), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
Gould, B. E. (2011) Chapter 21
(pp. 458-460), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
In the following scenario, two diseases are exposed, both are silent in progression in early stages, and both can cause insult to the body's homeostasis. In George's case, he has been battling with partially controlled hypertension for the past five years. What he did not realized that his partially controlled hypertension was not preventing damage to his kidneys.
George is a 55 y.o. male who has had hypertension (HTN) for the last 5 years. His HTN is only partially controlled. He is trying to watch his diet, but does not exercise like he should due to his high-stress job. He is also on HTN medication. He monitors his blood pressure at home on a regular basis. For the past month he has noticed his blood pressure seems to be higher than usual and even harder to control, but figured it was due to the stress of a big project at work. In the past 2 weeks, however, he has noticed he does not feel like eating much; he is fatigued; he seems to be urinating more often; and he has been losing weight. He decides to go in to see the doctor.
Total peripheral blood flow should be equal to cardiac output. Adequate blood pressure (B/P) is needed to overcome friction and elastic forces and to maintain blood flow. If blood pressure is too low, vessels collapse; likewise, if blood pressure is too high, vessels stiffen. A normal B/P is <120 140="" and="" arterial="" b="" cardiac="" contraction="" diastolic="" high="" hypertension="" minimum="" peak="" phase="" pressure="" relaxation="" systolic="">) is when high pressure (tension / vasoconstriction / increase peripheral resistance) is created in the arteries. Pressure and resistance can effect blood flow. When pressure increases, blood flow increases, however, if vascular resistance increases, systemic blood flow decreases. The variance causes the heart to produce enough pressure to compensate for any resistance in order to maintain adequate blood flow. Chronic hypertension can cause complications in the cardiovascular system. According to the National Kidney Foundation, hypertension is the leading cause of heart attacks, strokes, and chronic kidney disease. p.308-311
George's doctor decides to run several tests with the following results: Blood Test Results: RBC: 3.8 million cells/mcL; WBC: 10,000 cells/mcL; Hgb: 11.0 gm/ dL. Urine Test Results: GFR: 45ml/min/1.73m; Creatinine: 3g/ 24hr; Protein: 3g/ 24hr. The diagnosis George received was Chronic Renal Failure.
The kidneys are the body's primary excretory organ along with the skin and respiratory systems. It regulates the internal environment of the body by selectively excreting foreign material (drugs, toxins etc.) and metabolic waste while retaining valuable water, organic nutrients, and electrolytes in order to maintain adequate blood volume and composition. Urine is the end product of metabolism. Urine formation begins in the glomerular capillaries and ends in the collecting ducts ranging between dilute to concentrate composition (pH 4.5 – 8), depending on the body's physiological needs. Handy Tables, (Gould, B. E. , pg 440, 444-445, 2011)
Each kidney consist approximately one million of nephrons. The nephron is the basic functional unit in the kidney. The nephron consist of a renal corpuscle (filtering system known as a glomerulus )and a tubule. The glomerulus (site of filtration) is composed of a capillary network surrounded by a round structure called Bowman's capsule. Between twenty and twenty-five percent of cardiac output per minute flows into the renal artery. The route of blood flow into the kidney starts at the renal artery then proceeds into interlobar artery, then arches into arcuate artery, then flows into interlobar artery, meeting its final destination in the afferent arteriole which is the entrance into the glomerulus At the distal end of the glomerus, the capillaries rejoin to form the efferent arteriole through which blood eventually winds itself back to the renal vein. The dual arterioles controls the pressure (passive) in the glomerular capillaries and the glomerular filtration pressure. The glomerular capillaries restrict only large molecules (protein) resulting into filtrate that consist of plasma minus the large molecules. (Gould, B. E., pg 440- 442, 2011)
Filtrates leaves the glomerulus and enters the renal tubule which reabsorbs all useful organic molecules from the filtrate, reabsorbs > 90% water (osmotic), and secretes into the tubular fluid any waste products that were missed by the filtration process. In the collecting duct, additional reabsorption of water and absorption or active secretion of sodium, potassium, hydrogen, and bicarbonate ions before urine is released. Both secretion and absorption are controlled by selective permeability in different areas of the renal tubule and the response of hormones such as aldosterone ( responds to low sodium or high potassium concentrate), antidiuretic hormone ( >ADH >water permeability making urine more concentrated), and kidney hormones calcitriol, erythropoiten, and renin. (Gould, B. E., pg.440-443, 2011)
As previously mentioned, one of the kidney's main function is to regulate blood volume and blood pressure. Renin an enzyme/ hormone is release in response to low glomerular pressure due to declining blood volume ( low salt and water retention), declining blood pressure or both and triggers the renin-angiotensin system ( leads to formation of angiotensin II). The response triggers the sympathetic nervous system (SNS) to cause a notable peripheral vasoconstriction of the capillaries, elevating B/P in the renal arteries. It also causes constriction of the efferent arterioles, elevating glomerular pressure and filtration rates. In turn the release of ADH promotes water and sodium absorption, increasing the thirst feeling. To maintain homeostasis, a hormone called atrial natriuretic peptide ( released by the atrial cardiac muscle cells), becomes involved to reverse high blood volume and blood pressure leading to an increase sodium excreted in the urine and inhibits renin. (Gould, B. E., pg.442, 2011)
Two other hormones release by the kidneys are calcitriol and erythropoitin. Calcitriol is an hormone released by the kidneys in order to stimulate absorption of calcium and phosphate in the small intestine.
Calcitriol is a converted form of vitamin D3 that has been absorbed from sun light into the skin, modified and released from the liver and converted in the kidneys. It is use to promote bone health.
Erythropoiten is a hormone release by the kidneys when there is low oxygen levels in the kidney tissue. Erythropoitin stimulates the bone marrow to produce more red blood cells, increasing the blood volume and improves oxygen delivery to the tissues. (Gould, B. E., pg .244, 2011) (medicinenet, 2012)
When kidney function becomes comprised by hypertension, as in George's case, the process of glomerular filtration and renal tubular absorption and secretion become affected. Chronic renal failure is where the kidney function deteriorates gradually. The condition can not be reversed, only prolonged, and symptoms of acute renal failure can eventually developed because of scar tissue and loss of functional organization. George initially may not have known he had his chronic kidney failure since gradual loss of nephrons usually occurs without symptoms until it becomes well advanced. The kidneys are highly adaptable and are able to compensate for loss function with the surviving nephrons. In George's case, hypertension may have cause of the chronic renal failure. George's labile B/P status in the past month may have resulted from the progression of his chronic kidney disease, thereby , creating an inadequate blood flow into the glomeruli and causing the kidney's release of the hormone renin. George's job stress, diet,and limited exercise may have initially predispose him to hypertension or it could be genetic or another cause. In the past 2 weeks, George experienced a decrease in appetite, weight loss, fatigue, and had frequency in urination are early signs of chronic renal failure. George's blood test results showed RBC: 3.8 million cells/mcL ( norm. 4.2-5.9) and Hgb: 11.0 gm/dL (norm. for men 13.5). Both hemoglobin and RBC is low and these results indicate anemia, a sign that the kidneys are not adequately producing erythropoiten causing a decrease RBC production, resulting in anemia. George's urine test results exhibit impaired kidney function. Glomerular filtration rate (GFR) is a measure in how well the kidneys are filtrating wastes from the blood. George's glomerular filtration rate (GFR) is 45 mL/min/1.73m ( norm. > 90-130), Creatinine is an end product of muscle metabolism. It is normally excreted in urine. George's creatinine is 3g/24hr (norm.1-2g/24hr). Protein is not normally excreted in the urine. If the filtration membrane is damaged, blood protein will leak out and end up in the urine. George's protein is 3g/24hr ( norm. trace-0-150mg/24hr). No blood creatinine test was noted. Accordingly to the National Kidney Foundation (NKA), George is in stage 3 kidney failure with moderate decrease kidney function ( a greater loss of nephrons than stage 2). Increase urine creatinine and protein in the urine signifies damage to kidney's filtration units. (kidney)(stress) (Gould, B. E. , pg 196-197, 2011)
If George was in second stage of chronic renal failure, approximately 75% of the kidneys' nephrons would be lost. The GFR would decrease to approximately 20% of normal. A significant retention of nitrogen wastes would be found in his blood. Tubular function would be decreased resulting in a less concentrate urine and control secretion and exchange of acids and electrolytes. His urine would become diluted and would excreted in large amounts. If the progression of George's chronic renal failure became end-stage (uremia) renal failure, more than 90% of the nephrons would be lost. His GFR would be negligible. Blood would become toxic due to fluid, electrolytes and wastes are retained causing an impact on all body systems. Marked oliguria (scant) to none (anuria) would develop. His kidneys have failed; without intervention ( regular dialysis or transplant), George's life would be in jeopardy. (Gould, B. E., pg. 460, 2011)
George did not have acute renal failure. Acute means 'rapid'. With acute renal failure, most times the situation can be reversed when the cause is immediately corrected or properly treated in order to minimize the insult to the kidneys. The main goal is reduce the risk for necrosis and permanent kidney damage. The cause of acute kidney failure is directly due to the reduction of blood flow into the kidneys or inflammation and necrosis of the tubules causing obstruction leading to a decrease in GFR and reduction in urine. Problems of reduction of blood flow before it reaches the kidneys can be cause by dehydration, sepsis, or surgery (>blood loss), or heart attack, or severe injury and or burns. Problems of obstruction (movement of urine) could be cancer of the urinary tract, or kidney stone, or enlarged prostate, or nephrotoxins ( drugs, chemicals, toxins). Lastly, problems with the kidney itself that reduces blood filtration or production of urine such as glomerulonephritis (possible due to strep infrection), or acute interstitial nephritis (aspirin, ibuprofen, penicillen). (Gould, B. E. pg. 458-460, 2011) emedicinehealth.com-acute
The major goal of George's treatment would most likely consist in lowering his blood pressure, decreasing risk for cardiovascular disease, and slowing the progression of his chronic renal failure. His treatment would most likely include antihypertensive medications Ace inhibitor and/or ARB in order to reduce and stabilize his B/P ( < 130/80 per NKF). Life style changes that would include diet (low sodium, low fat, low protein, with increase intake of fruits and foods rich in iron, vitamin B12 and folic acid. Additional vitamins with B12, folic acid, and iron (for anemia) may also have to be taken. Weight control or maintenance would be encourage along with an exercise plan. George may have to receive erythropoiesis (ESA) stimulating agents injections to help his body make RBCs. Additional iron supplement may also be needed; without iron, ESA is wasted and is needed to reach target hemoglobin. Lastly, if it has not been approach before now, educate George on the effects of prolonged stress and how it is impacting his cardiovascular and kidney systems. Along with a healthy diet and exercise already mentioned, George's physician may also encourage other means in developing coping mechanism that are appropriate for George, which may include engaging in some 'time-out' during his job for better assessment, or using relaxation techniques etc. (National kidney foundation)
(mayoclinic)(NKF kidney,) ((Gould, B. E., pg. 196-197, 2011)
References:
Anonymous. (2012). KDOQI™ Guidelines and Commentaries
Retrieved February 12, 2012, from Kidney website
http://www.kidney.org/professionals/kdoqi/guidelines_commentaries.cfm#guidelines
Workeneh, B.T., Batuman, V.. (2012, February 9). Acute Renal Failure
Retrieved February 12, 2012, from Emedicine website
http://emedicine.medscape.com/article/243492-overview#aw2aab6b2b2
Anonymous. (2012). Hypertension
Retrieved February 12, 2012, from Stress website
http://www.stress.org/topic-hypertension.htm
Anonymous. (2012). How Your Kidneys Work
Retrieved February 12, 2012, from Kidney website
http://www.kidney.org/kidneydisease/howkidneyswrk.cfm
Anonymous. (2012). Erythropoietin (cont.)
Retrieved February 12, 2012, from Medicinenet website
http://www.medicinenet.com/erythropoietin/page4.htm#glance
Anonymous. (2011, August 02). Chronic kidney failure
Retrieved February 12, 2012, from Mayoclinic website
http://www.mayoclinic.com/health/kidney-failure/DS00682/DSECTION=treatments%2Dand%2Ddrugs
Gould, B. E. (2011) Chapter 12
(pp. 196-197), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
Gould, B. E. (2011) Chapter 15
(pp. 244), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
Gould, B. E. (2011) Chapter 18
(pp. 308-311), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
Gould, B. E. (2011) Chapter 21
(pp. 460), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
Gould, B. E. (2011) Chapter 21
(pp. 458-460), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
Thursday, March 25, 1999
Structure and Function of the Human Body week 9
Answer each of the questions below using information gathered from your readings, lectures, and outside research. You should provide at least a paragraph response for each of the questions.
1. Describe the role of the following organs within the digestive system: stomach, liver, salivary glands, small intestine and gallbladder. Also, describe what complications could occur within the functions of the digestive system if each listed organ was damaged or dysfunctional.
Our digestive system provides the body a means to transfer nutrition from the external environment into the cellular level in order to sustain life.
Salivary glands, controlled by the autonomic nervous system, is located in the oral cavity. It's main role is to secrete saliva in the oral cavity. There are three pairs of salivary glands. Parotoid savary gland lies under the skin on each side of the mandible. These glands secrete amylase, an enzyme that breaks down starches. The parotoid duct implies empties into the vestibile at the level of the second upper molar. The sublingual duct is (located under the tongue) between the mucus membrane of the floor of the mouth and the submandibular duct is located in the floor of the mouth. Both the sublingual and submandibular glands secrete saliva that contains more buffers and mucus. (p. 539-40)
Saliva (mucus) consists of 99.4% water, mucins and an assortments ions, buffers, and waste products and enzymes. The mucines absorbs water and form the mucus. During meal time, the saliva lubricates the mouth along with dissolved chemicals that stimulates the taste buds. The mucus coats the food, and reduces friction making swallowing easier. The continuous flow of saliva also flushes and cleans the oral surfaces while controlling oral bacteria through salivary antibodies (IgA and lysozyme). The pH of saliva during meal time raises from slightly acidic (pH 6.7) to more alkaline (pH 7.5).
Radiation and emotional distress can cause a reduction of salivary secretions. This then can create an unhealthy oral cavity environment due to increased bacteria population. Over time, the complications caused by the decreased salivary secretions are infection and erosion of the teeth and gums. (p.540)
The stomach is another component of the digestive system which is located within the left upper quadrant of the abdominal cavity. It is a muscular J-shaped organ that is positioned inferior of the esophagus and superior to the small intestines. There are four primary functions the stomach has to offer. First, it becomes a temporary storage for ingested food. Food is stored in the stomach while it is physically broken down for chemical digestion. Second, it provides a mechanical means to break down ingested food. The stomach is an area where there is a lot of mixing of the food, so added strength to the muscularis external layer is needed. Instead of two layers in the muscular external, the stomach's has three layers, a longitudinal layer, a circular layer, and an inner oblique layer. Thirdly, it provides an acidic environment that causes a break down of the chemical bonds in food through the actions of acids and enzymes. The pH of 2.0 in the stomach makes the environment acidic. The ingested foods, mixed with stomach's secretion, produces an acidic soupy mixture of partially digested food called chyme. Lastly, the stomach is responsible for the production of the intrinsic factor, a compound necessary for the absorption of vitamin B-12. (p.544)
Gastric ulcers is one complication that can occur in the stomach. Ulcers are caused either bacterium Helicobacter pylori or by medication such as aspirin that irritates the mucus membrane. This irritation causes erosion of the mucus membrane; which either creates an excessive production of acid or an inadequate production of alkaline mucus that defends the epithelium against the acid. Treatment can lean toward a medication such as cimetidine, a drug that inhibits acidity in the stomach, or it can be treated with antibiotics for bacterial infection depending on the cause. Meal time still would include a complete diet, but staying away from high fat, high acidic foods like tomatoes, and spicy foods. In atropic gastritis, there is chronic inflammation in the stomach which produces a lower acid production capability. When this happens, the intrinsic factor is affected , trapping vitamin B12 within the food. People in this case would need to take a vitamin B12 supplement.
The small intestines main function is in the digestion and absorption of nutrients. Ninety percent of nutrient absorption occurs in the small intestine. The duodenum is the segment in the small intestine that receives chyme from the stomach and digestion secretions from the pancreas. It also contains duodenal glands which secrete alkaline mucus that helps buffer acids in the chyme. The bulk of chemical digestion and nutrient absorption occurs in the jejunum. The small intestines receives and raises the pH of the materials arriving from the stomach. Most of the important digestive processes are completed in the small intestine where the final products of digestion (simple sugars, fatty acids, amino acids) are absorb along with most of the water contents. (p. 548)
Crohn's disease is one complication found in the small intestine. It is a chronic auto-immune inflammatory disorder that occurs in intervals active (flares) disease altering in periods of remission . Treatment varies from special diets, medication like Cortisone and surgery (possible ileostomy). Crohn's disease is not curable. Treatment only covers the symptoms caused by the disease progression. Over time, the inflammation of the small intestine can result in scaring and thickening of the walls of the affected structure. With this disease, absorption of nutrition can lead to difficulties. The inflammation causes damages to the lining of the intestine so that it cannot absorb nutrients, water, and fats from the food eatened. This can result in malnutrition, dehydration, vitamin and mineral deficiencies. (emedicinehealth, 2011)
The liver is an essential part to the digestive process. The liver has three functional roles: metabolic regulation, hematological, and bile production. The basic functional unit of the liver is its 100,00 lobules. Within each lobule there are liver cells called hepatocytes .
In metabolic regulation, the liver's main goal is to regulate the composition of the circulating blood. It does this through the hepatocytes. The hepatocytes extract and absorbed nutrients or toxins from the blood prior to reaching the general circulation. Hepatocytes also monitors/adjusts the circulating levels of organic nutrients. Excesses are removed and stored; while deficiencies are corrected by utilizing stored reserves or synthesizing the necessary compounds. Toxin and metabolic wastes are removes for later inactivation and excretion. Fat-cell vitamins such as A,D,K, and E are absorbed and stored. ( p.555-6)
With hematological regulation, the liver becomes the blood reservoir. As the blood passes through the liver, phagocytes (kupffer ) cells remove spent/or damaged RBCs, debris, and pathogens from the circulation. The hepatocytes synthesizes plasma proteins ( which determines blood's osmotic concentration), transports nutrients, and makeup the clotting and complement systems. ( p.556)
The bile production is derived from the hepatocyte secretions. Bile may either flow into the common bile duct, which empties into the duodenum, or enters into the cystic duct, which leads into the gallbladder. Bile consist of water, ions, bilirubin (pigment from hemoglobin), cholesterol, and bile salts (an assortment of lipids). The bile's water and ions dilute and buffer acids in chyme as it enter the small intestine. The bile salts (synthesized from cholesterol) are required for normal digestion and absorption of fats. Bile breaks down large lipid droplets into smaller lipid particles in order for the digestive enzymes to become more effective. ( p.556)
After revealing the main functions the liver provides, any condition that can damage or make the liver dysfunctional can be life threating to the body. One example is hepatitis which is an inflammation of the liver producing swelling in the liver. There are many virus that can cause hepatitis depending in how it is transmitted, but the main ones are A, B, and C. If left untreated, in some cases hepatitis can lead to cirrhosis which is a progressive degenerate disease that results in the loss of organ/tissue function due to scar tissue. Further progression of the disease could eventually lead to liver failure. Unlike a healthy liver, the liver would not be able fight infection, clean the blood and help digest food and store energy; thus, leaving the body, toxic.
The gallbladder is a hollow pear-shape organ that stores and concentrates bile made in the liver. Bile is secreted continuously (approx1 liter/day); however, it is only release into the common duct to the duodenum when fatty foods enters the digestive tract and through the stimulation of a duodenum's hormone CCK (cholecystokinin). The CCK stimulates contractions in the walls of the gallbladder, releasing the bile into the small intestine. In the absence of CCK, bile leaving the liver through the common duct is redirected into the cystic duct delivering bile into the gallbladder for storage.
The concentration of bile changes its composition while in the gallbladder's storage. Water is absorbed and the bile salts along with other bile components become increasing concentrated. Sometimes bile salts become too concentrated through stasis (due to no-fat diet) or infection which alters the ratio of bile salts and water content, forming gallstones. ( pg.550, 556-7)
Gallstones can be a complication of the gallbladder. Gallstones can develop when bile contains too much cholesterol, too much bilirubin, or not enough bile salts, or when the gallbladder does not completely empty or emptied enough. Most people are unaware they have a problem. If a person is asymptomatic, no treatment necessary. Only those with sever discomfort or repeated attacks from gallstones receive treatment. This usually requires surgery for removal of the gallbladder (cholecystectomy). People can live without their gallbladder because bile is made continuously and the gallbladder is just a reservoir for bile. If any change in life style it would be in diet (low-fat) and frequently of meals. (mayoclinic.com, ) ( p.557)
Explain how the small intestine’s anatomy is geared to increase surface area. Why is increased surface area important in the small intestine?
The length of the small intestine is approximately 20 feet long. The intestinal lining consist of transverse folds (plicae circulares) composed of multitude of finger like projections called villi.
These structures are covered with simple columnar epithelium that are covered with microvilli, in other words the epithelium looks like bristles on a hair brush. If the small intestine was smooth and simple , the total absorption area would be about 3.6 feet long. Instead, the small intestine is composed of multiple arrangement of the intestinal wall, which consist of plicae circulares layered with villi; villi is layered with epithelium; epithelium that is layered with microvilli; thus makes the total increase absorption area approximately 2,200 feet.
3. Describe the role of each of the four layers in the stomach including the mucus cells and parietal cells of the mucosa layer.
The four layers of the stomach are the mucosa layer, submucosa layer, muscularis externa, and serosa layer.
The mucosa layer of the stomach is the inner lining consisting of mucosal (glandular secreted) membrane that is composed of simple columnar epithelium dominated by mucus cells. The role of these mucus cells this is to secrete alkaline mucus that covers and protects epithelial cells from acids, enzymes, and abrasive material. Gastric pits are shallow depressions open onto the gastric surface. The mucus cells at the base of each gastric pit divide and replace the superficial cells of the mucus epithelium which is then shed into the chyme. The gastric pit corresponds with the gastric glands which secrete the gastric juice. The cells that produce the components of the gastric juice as the parietal cells. The parietal cells secrete the intrinsic factor and hydrochloric acid. The intrinsic factor is needed to facilitate the absorption of Vitamin B-12 across the intestinal lining. The hydrochloric acid lowers the pH of the gastric juices which keeps the stomach pH contents at approximately 2. The acidity of the stomach kills micro organisms, helps break down plant cell walls, and connective tissues in meat and also activates the enzyme secretions of the chief cells. The main purpose of chief cells is the production of the enzyme pepin (a protein digesting enzyme) Within both the mucosa and sub-mucus are distinct ridges or folds called rugae. The folds increase the surface area for absorption and permits expansion (flattens out) for food. Ducts between the rugae opens onto the epithelial surface and carries the gastric glands that secrete digestive juices.
The sub-mucosa layer is the second layer that is composed loose connecting tissue which contain large blood vessels, lymphatic vessels, and nerve fibers( sensory neurons and parasympathetic motor neurons). Its main role is in controlling and coordinating contraction of the smooth muscle layers and in regulating secretion.
Muscularis externa makes up the third layer of the stomach. This layer consist of bands of smooth muscle cells which contains a longitudinal layer, a circular layer, and an inner oblique layer. These three portions of the muscularis externa provides strength and assists in the mixing and churning essential to forming chyme.
The serosa layer (visceral peritoneum) covers the outer surface of the stomach. It has no role except to stabilize the stomach in the peritoneal cavity.
4. We discussed the endocrine role of the pancreas when we studied the endocrine system but it has an exocrine role within the digestive system. Please explain what type of dysfunction would occur if the pancreas didn’t secrete its pancreatic juices. What type of dysfunction would occur if someone had to have their gallbladder removed?
The pancreas is primary an exocrine organ that produces digestive buffers and enzymes. The four enzymes: carbohydrases (digest surgars and starches), lipases (break down lipids), nucleases (break down nucleic acids), and proteases (break protein apart). Specific enzymes are the pancreatic amylase (breaks down carbohydrates), pancreatic lipase (group of nucleases and several proteases), and trypsin and chymotrypsin are all part of the proteases enzymes Proteases accounts for 70% of the enzyme production. The main buffer is sodium bicarbonate which increases the pH of the chyme. (pg 552-553)
If the pancreas becomes dysfunctional, these pancreatic and enzymes would be missing in the duodemum. Inadequate digestion would take place. Your sugars, starches, fats, and proteins would be incompletely digested, because of the missing enzymes. In pancreatitis, inflammation occurs from blockage of excretory ducts, bacterial infection, or drug reaction (alcohol), This can cause injury in the exocrine cells. The lysosomes within the damaged cells then activated the pancreatic enzyme which attack the normal pancreatic cells and there is a chain reaction which produces destruction. In most cases, with treatment, this can be reversed/stopped. However, there are a few cases where this auto-digestion continues and destroys the organ. In that case, two conditions result: diabetes mellitus that requires insulin and nutrient malabsorption where oral pancreatic enzymes need to be taken. (pg 563)
In the case of the gallbladder, people can live without their gallbladder, because the only function of the gallbladder is a reservoir for bile from the liver. Bile will continue the flow into the small intestines without a problem. It might be a little more or less depending on the food quantity and substance.
5. What is the importance of adenosine triphosphate (ATP)? Carbohydrate metabolism is our body’s main source of ATP production. Explain where carbohydrate metabolism occurs in the cell, what additional “ingredient” is needed and what waste product is produced in this process.
The primary function of ATP is the transfer energy from one location to another, not the long term storage of energy. The energy a cell produces in the form of ATP supports cell growth division, contraction, secretion, and all functions that vary from cell to cell and tissue to tissue. Cells in the body generate most ATP through aerobic (oxygen-required) metabolism in the mitochondria ;however,the initial steps occur through glycolysis (anaerobic -with out oxygen) in the cystosol of the cytoplasm. Oxygen is the key ingredient needed in mitochondria energy production. Aerobic (oxygen) metabolism in the mitochondria provide most (95%) of the energy needed to keep cells alive. Most of the energy deriving from carbohydrates are produced in the mitochondria. Energy is stored and transferred in a high energy bond of ATP in order to move from place to place. The by-product of areobic metabolism is carbon dioxide. Glycolysis involves enzymatic steps that breakdown glucose to pyruvic acid molecules. These molecules are then absorbed by the mitochondria. Glycolysis (anarobic) can also continue to provide ATP when the oxygen availability is limited for mitochondrial production. This usually occurs during the body's peak activity, such in the case of a long distance runner. The body cannot provide enough O2 to maintain the metabolism in the metochondria. This the time where glycolysis becomes the prime source for ATP. (p.77, 210, 577)
References
http://www.emedicinehealth.com/crohn_disease/article_em.htm#Crohn%27s%20Disease%20Overview
http://www.mayoclinic.com/health/gallstones/DS00165/DSECTION=causeshttp://www.mayoclinic.com/health/gallstones/DS00165/DSECTION=causes
1. Describe the role of the following organs within the digestive system: stomach, liver, salivary glands, small intestine and gallbladder. Also, describe what complications could occur within the functions of the digestive system if each listed organ was damaged or dysfunctional.
Our digestive system provides the body a means to transfer nutrition from the external environment into the cellular level in order to sustain life.
Salivary glands, controlled by the autonomic nervous system, is located in the oral cavity. It's main role is to secrete saliva in the oral cavity. There are three pairs of salivary glands. Parotoid savary gland lies under the skin on each side of the mandible. These glands secrete amylase, an enzyme that breaks down starches. The parotoid duct implies empties into the vestibile at the level of the second upper molar. The sublingual duct is (located under the tongue) between the mucus membrane of the floor of the mouth and the submandibular duct is located in the floor of the mouth. Both the sublingual and submandibular glands secrete saliva that contains more buffers and mucus. (p. 539-40)
Saliva (mucus) consists of 99.4% water, mucins and an assortments ions, buffers, and waste products and enzymes. The mucines absorbs water and form the mucus. During meal time, the saliva lubricates the mouth along with dissolved chemicals that stimulates the taste buds. The mucus coats the food, and reduces friction making swallowing easier. The continuous flow of saliva also flushes and cleans the oral surfaces while controlling oral bacteria through salivary antibodies (IgA and lysozyme). The pH of saliva during meal time raises from slightly acidic (pH 6.7) to more alkaline (pH 7.5).
Radiation and emotional distress can cause a reduction of salivary secretions. This then can create an unhealthy oral cavity environment due to increased bacteria population. Over time, the complications caused by the decreased salivary secretions are infection and erosion of the teeth and gums. (p.540)
The stomach is another component of the digestive system which is located within the left upper quadrant of the abdominal cavity. It is a muscular J-shaped organ that is positioned inferior of the esophagus and superior to the small intestines. There are four primary functions the stomach has to offer. First, it becomes a temporary storage for ingested food. Food is stored in the stomach while it is physically broken down for chemical digestion. Second, it provides a mechanical means to break down ingested food. The stomach is an area where there is a lot of mixing of the food, so added strength to the muscularis external layer is needed. Instead of two layers in the muscular external, the stomach's has three layers, a longitudinal layer, a circular layer, and an inner oblique layer. Thirdly, it provides an acidic environment that causes a break down of the chemical bonds in food through the actions of acids and enzymes. The pH of 2.0 in the stomach makes the environment acidic. The ingested foods, mixed with stomach's secretion, produces an acidic soupy mixture of partially digested food called chyme. Lastly, the stomach is responsible for the production of the intrinsic factor, a compound necessary for the absorption of vitamin B-12. (p.544)
Gastric ulcers is one complication that can occur in the stomach. Ulcers are caused either bacterium Helicobacter pylori or by medication such as aspirin that irritates the mucus membrane. This irritation causes erosion of the mucus membrane; which either creates an excessive production of acid or an inadequate production of alkaline mucus that defends the epithelium against the acid. Treatment can lean toward a medication such as cimetidine, a drug that inhibits acidity in the stomach, or it can be treated with antibiotics for bacterial infection depending on the cause. Meal time still would include a complete diet, but staying away from high fat, high acidic foods like tomatoes, and spicy foods. In atropic gastritis, there is chronic inflammation in the stomach which produces a lower acid production capability. When this happens, the intrinsic factor is affected , trapping vitamin B12 within the food. People in this case would need to take a vitamin B12 supplement.
The small intestines main function is in the digestion and absorption of nutrients. Ninety percent of nutrient absorption occurs in the small intestine. The duodenum is the segment in the small intestine that receives chyme from the stomach and digestion secretions from the pancreas. It also contains duodenal glands which secrete alkaline mucus that helps buffer acids in the chyme. The bulk of chemical digestion and nutrient absorption occurs in the jejunum. The small intestines receives and raises the pH of the materials arriving from the stomach. Most of the important digestive processes are completed in the small intestine where the final products of digestion (simple sugars, fatty acids, amino acids) are absorb along with most of the water contents. (p. 548)
Crohn's disease is one complication found in the small intestine. It is a chronic auto-immune inflammatory disorder that occurs in intervals active (flares) disease altering in periods of remission . Treatment varies from special diets, medication like Cortisone and surgery (possible ileostomy). Crohn's disease is not curable. Treatment only covers the symptoms caused by the disease progression. Over time, the inflammation of the small intestine can result in scaring and thickening of the walls of the affected structure. With this disease, absorption of nutrition can lead to difficulties. The inflammation causes damages to the lining of the intestine so that it cannot absorb nutrients, water, and fats from the food eatened. This can result in malnutrition, dehydration, vitamin and mineral deficiencies. (emedicinehealth, 2011)
The liver is an essential part to the digestive process. The liver has three functional roles: metabolic regulation, hematological, and bile production. The basic functional unit of the liver is its 100,00 lobules. Within each lobule there are liver cells called hepatocytes .
In metabolic regulation, the liver's main goal is to regulate the composition of the circulating blood. It does this through the hepatocytes. The hepatocytes extract and absorbed nutrients or toxins from the blood prior to reaching the general circulation. Hepatocytes also monitors/adjusts the circulating levels of organic nutrients. Excesses are removed and stored; while deficiencies are corrected by utilizing stored reserves or synthesizing the necessary compounds. Toxin and metabolic wastes are removes for later inactivation and excretion. Fat-cell vitamins such as A,D,K, and E are absorbed and stored. ( p.555-6)
With hematological regulation, the liver becomes the blood reservoir. As the blood passes through the liver, phagocytes (kupffer ) cells remove spent/or damaged RBCs, debris, and pathogens from the circulation. The hepatocytes synthesizes plasma proteins ( which determines blood's osmotic concentration), transports nutrients, and makeup the clotting and complement systems. ( p.556)
The bile production is derived from the hepatocyte secretions. Bile may either flow into the common bile duct, which empties into the duodenum, or enters into the cystic duct, which leads into the gallbladder. Bile consist of water, ions, bilirubin (pigment from hemoglobin), cholesterol, and bile salts (an assortment of lipids). The bile's water and ions dilute and buffer acids in chyme as it enter the small intestine. The bile salts (synthesized from cholesterol) are required for normal digestion and absorption of fats. Bile breaks down large lipid droplets into smaller lipid particles in order for the digestive enzymes to become more effective. ( p.556)
After revealing the main functions the liver provides, any condition that can damage or make the liver dysfunctional can be life threating to the body. One example is hepatitis which is an inflammation of the liver producing swelling in the liver. There are many virus that can cause hepatitis depending in how it is transmitted, but the main ones are A, B, and C. If left untreated, in some cases hepatitis can lead to cirrhosis which is a progressive degenerate disease that results in the loss of organ/tissue function due to scar tissue. Further progression of the disease could eventually lead to liver failure. Unlike a healthy liver, the liver would not be able fight infection, clean the blood and help digest food and store energy; thus, leaving the body, toxic.
The gallbladder is a hollow pear-shape organ that stores and concentrates bile made in the liver. Bile is secreted continuously (approx1 liter/day); however, it is only release into the common duct to the duodenum when fatty foods enters the digestive tract and through the stimulation of a duodenum's hormone CCK (cholecystokinin). The CCK stimulates contractions in the walls of the gallbladder, releasing the bile into the small intestine. In the absence of CCK, bile leaving the liver through the common duct is redirected into the cystic duct delivering bile into the gallbladder for storage.
The concentration of bile changes its composition while in the gallbladder's storage. Water is absorbed and the bile salts along with other bile components become increasing concentrated. Sometimes bile salts become too concentrated through stasis (due to no-fat diet) or infection which alters the ratio of bile salts and water content, forming gallstones. ( pg.550, 556-7)
Gallstones can be a complication of the gallbladder. Gallstones can develop when bile contains too much cholesterol, too much bilirubin, or not enough bile salts, or when the gallbladder does not completely empty or emptied enough. Most people are unaware they have a problem. If a person is asymptomatic, no treatment necessary. Only those with sever discomfort or repeated attacks from gallstones receive treatment. This usually requires surgery for removal of the gallbladder (cholecystectomy). People can live without their gallbladder because bile is made continuously and the gallbladder is just a reservoir for bile. If any change in life style it would be in diet (low-fat) and frequently of meals. (mayoclinic.com, ) ( p.557)
Explain how the small intestine’s anatomy is geared to increase surface area. Why is increased surface area important in the small intestine?
The length of the small intestine is approximately 20 feet long. The intestinal lining consist of transverse folds (plicae circulares) composed of multitude of finger like projections called villi.
These structures are covered with simple columnar epithelium that are covered with microvilli, in other words the epithelium looks like bristles on a hair brush. If the small intestine was smooth and simple , the total absorption area would be about 3.6 feet long. Instead, the small intestine is composed of multiple arrangement of the intestinal wall, which consist of plicae circulares layered with villi; villi is layered with epithelium; epithelium that is layered with microvilli; thus makes the total increase absorption area approximately 2,200 feet.
3. Describe the role of each of the four layers in the stomach including the mucus cells and parietal cells of the mucosa layer.
The four layers of the stomach are the mucosa layer, submucosa layer, muscularis externa, and serosa layer.
The mucosa layer of the stomach is the inner lining consisting of mucosal (glandular secreted) membrane that is composed of simple columnar epithelium dominated by mucus cells. The role of these mucus cells this is to secrete alkaline mucus that covers and protects epithelial cells from acids, enzymes, and abrasive material. Gastric pits are shallow depressions open onto the gastric surface. The mucus cells at the base of each gastric pit divide and replace the superficial cells of the mucus epithelium which is then shed into the chyme. The gastric pit corresponds with the gastric glands which secrete the gastric juice. The cells that produce the components of the gastric juice as the parietal cells. The parietal cells secrete the intrinsic factor and hydrochloric acid. The intrinsic factor is needed to facilitate the absorption of Vitamin B-12 across the intestinal lining. The hydrochloric acid lowers the pH of the gastric juices which keeps the stomach pH contents at approximately 2. The acidity of the stomach kills micro organisms, helps break down plant cell walls, and connective tissues in meat and also activates the enzyme secretions of the chief cells. The main purpose of chief cells is the production of the enzyme pepin (a protein digesting enzyme) Within both the mucosa and sub-mucus are distinct ridges or folds called rugae. The folds increase the surface area for absorption and permits expansion (flattens out) for food. Ducts between the rugae opens onto the epithelial surface and carries the gastric glands that secrete digestive juices.
The sub-mucosa layer is the second layer that is composed loose connecting tissue which contain large blood vessels, lymphatic vessels, and nerve fibers( sensory neurons and parasympathetic motor neurons). Its main role is in controlling and coordinating contraction of the smooth muscle layers and in regulating secretion.
Muscularis externa makes up the third layer of the stomach. This layer consist of bands of smooth muscle cells which contains a longitudinal layer, a circular layer, and an inner oblique layer. These three portions of the muscularis externa provides strength and assists in the mixing and churning essential to forming chyme.
The serosa layer (visceral peritoneum) covers the outer surface of the stomach. It has no role except to stabilize the stomach in the peritoneal cavity.
4. We discussed the endocrine role of the pancreas when we studied the endocrine system but it has an exocrine role within the digestive system. Please explain what type of dysfunction would occur if the pancreas didn’t secrete its pancreatic juices. What type of dysfunction would occur if someone had to have their gallbladder removed?
The pancreas is primary an exocrine organ that produces digestive buffers and enzymes. The four enzymes: carbohydrases (digest surgars and starches), lipases (break down lipids), nucleases (break down nucleic acids), and proteases (break protein apart). Specific enzymes are the pancreatic amylase (breaks down carbohydrates), pancreatic lipase (group of nucleases and several proteases), and trypsin and chymotrypsin are all part of the proteases enzymes Proteases accounts for 70% of the enzyme production. The main buffer is sodium bicarbonate which increases the pH of the chyme. (pg 552-553)
If the pancreas becomes dysfunctional, these pancreatic and enzymes would be missing in the duodemum. Inadequate digestion would take place. Your sugars, starches, fats, and proteins would be incompletely digested, because of the missing enzymes. In pancreatitis, inflammation occurs from blockage of excretory ducts, bacterial infection, or drug reaction (alcohol), This can cause injury in the exocrine cells. The lysosomes within the damaged cells then activated the pancreatic enzyme which attack the normal pancreatic cells and there is a chain reaction which produces destruction. In most cases, with treatment, this can be reversed/stopped. However, there are a few cases where this auto-digestion continues and destroys the organ. In that case, two conditions result: diabetes mellitus that requires insulin and nutrient malabsorption where oral pancreatic enzymes need to be taken. (pg 563)
In the case of the gallbladder, people can live without their gallbladder, because the only function of the gallbladder is a reservoir for bile from the liver. Bile will continue the flow into the small intestines without a problem. It might be a little more or less depending on the food quantity and substance.
5. What is the importance of adenosine triphosphate (ATP)? Carbohydrate metabolism is our body’s main source of ATP production. Explain where carbohydrate metabolism occurs in the cell, what additional “ingredient” is needed and what waste product is produced in this process.
The primary function of ATP is the transfer energy from one location to another, not the long term storage of energy. The energy a cell produces in the form of ATP supports cell growth division, contraction, secretion, and all functions that vary from cell to cell and tissue to tissue. Cells in the body generate most ATP through aerobic (oxygen-required) metabolism in the mitochondria ;however,the initial steps occur through glycolysis (anaerobic -with out oxygen) in the cystosol of the cytoplasm. Oxygen is the key ingredient needed in mitochondria energy production. Aerobic (oxygen) metabolism in the mitochondria provide most (95%) of the energy needed to keep cells alive. Most of the energy deriving from carbohydrates are produced in the mitochondria. Energy is stored and transferred in a high energy bond of ATP in order to move from place to place. The by-product of areobic metabolism is carbon dioxide. Glycolysis involves enzymatic steps that breakdown glucose to pyruvic acid molecules. These molecules are then absorbed by the mitochondria. Glycolysis (anarobic) can also continue to provide ATP when the oxygen availability is limited for mitochondrial production. This usually occurs during the body's peak activity, such in the case of a long distance runner. The body cannot provide enough O2 to maintain the metabolism in the metochondria. This the time where glycolysis becomes the prime source for ATP. (p.77, 210, 577)
References
http://www.emedicinehealth.com/crohn_disease/article_em.htm#Crohn%27s%20Disease%20Overview
http://www.mayoclinic.com/health/gallstones/DS00165/DSECTION=causeshttp://www.mayoclinic.com/health/gallstones/DS00165/DSECTION=causes
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