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437 Cards in this Set
- Front
- Back
Which of these are vasodilator metabolites that relax arterioles and precapillary sphincter? - Endothelium 1 - Lactate - Thromboxane A2 - Circulating Na+ - K+ ATPase inhibitor |
Lactate |
|
What is bradykinin |
vasodilator peptide formed in plasma |
|
What is angiotensin II |
most potent vasoconstrictor known acts directly on adrenal cortex, on peripheral noradrenergic neurons, water metabolism |
|
What is vasopressin |
one of the posterior pituitary gland hormones main effect is water retention by kidney |
|
What is gastrin |
Polypeptide hormone produced by G cells of gastric antral mucosa Stimulates gastric acid and pepsin secretion |
|
What is renin |
proteolytic enzyme secreted by the kidney into the bloodstream It splits the end off one of the plasma proteins (renin substrate) to release decapeptide - angiotensin I |
|
ANP increase/decrease when ECF volume increase/decrease |
ANP increases when ECF volume increases |
|
How does ANP affect sodium excretion? |
It can increase sodium excretion by increasing glomerular filtration rate |
|
How does ANP affect BP? |
It lowers BP |
|
Dopamine acts on which receptors? |
Own receptors Alpha Beta 1 Beta 2 |
|
Noradrenaline and adrenaline act on which receptors |
Alpha beta1 Beta2 |
|
Isoproterenol acts on which receptors |
Only beta 1 and 2 receptors |
|
Which vasoactive substances can be released in carcinoid syndrome? |
Serotonin Bradykinin Prostaglandin Histamine |
|
Prostacyclin is derived from |
arachidonic acid |
|
Prostacyclin is produced by |
endothelial and smooth muscle cells in blood vessels |
|
Function of prostacyclin |
Vasodilator - promote flow PLT aggregation |
|
How does prostacyclin affect renin secretion? |
Stimulates renin secretion by direct action on juxtaglomerular cells and indirectly by reducing blood pressure |
|
Name two factors that influence total cerebral blood flow |
Arterial pressure at brain level Venous pressure at brain level |
|
Explain mechanism behind Cushing's reflex |
Increased ICP --> hypertension, bradycardia This is because increased ICP stimulates vasomotor centre due to local accumulation of CO2 |
|
Oxygen extraction fraction of coronary blood flow at rest and during exercise |
At rest- 70% During exercise - 100% |
|
Coronary blood flow can increase up to how much during maximal exercise |
Up to 5-6x |
|
Maximal flow of coronary blood occurs during systole or diastole |
Diastole |
|
Stimulation of sympathetic cardiac nerves result in increased intracellular cyclic AMP - T/F |
True |
|
Stimulation of cholinergic vagal fibres to nodal tissue decrease potassium ion conductance - T/F |
False |
|
Depolarisation of the ventricular muscles starts on the right side of the interventricular system - T/F |
False |
|
The last part of the heart depolarised is the epicardial surface of the left ventricular apex - T/F |
False |
|
Right atrial systole precedes left atrial systole - T/F |
True |
|
Right ventricular contraction precedes left ventricular contraction - T/F |
False |
|
Right ventricular ejection precedes left ventricular ejection - T/F |
True |
|
Pulmonary valve closes before aortic valve - T/F |
False |
|
In atrial flutter, the atrial rate is 150-220/min - T/F |
False, atrial rate ranges from 200-400 |
|
In atrial flutter, there is accelerated AV conduction - T/F |
False, associated with AV block |
|
In atrial flutter, heart rate is irregular |
False |
|
In atrial flutter, the ventricular rate can be slowed by carotid sinus pressure |
True |
|
What is WPW syndrome? |
combination of presence of congenital accessory pathway + episodes of tachyarrythmia There is early activation of ventricles because impulses bypass AV node via accessory pathway |
|
Name one ECG feature of WPW syndrome |
paroxysmal atrial tachycardia |
|
In WPW syndrome, there is prolonged PR interval and prolonged QRS complex slurred on the upstroke |
False |
|
In WPW syndrome, circus movement tachycardia is usually initiated by an atrial premature beat |
True |
|
In WPW syndrome, the arrythmia commonly progresses to CHB |
False |
|
In WPW syndrome, AF is a life threatening arrythmia |
True |
|
QT interval varies inversely with _____ |
heart rate |
|
Normal QT interval - |
In women, QTc is prolonged if > 460ms In men, QTc is prolonged if >440ms |
|
QT corresponds to |
ventricular electrical systole |
|
Simple way to tell the difference between SVT and VT |
VT is usually broad complex SVT is usually narrow complex |
|
Action of NA on coronary artery and why |
NA causes coronary vasodilation This is because injection of noradrenaline produces vasodilator metabolites as a result of increased myocardial activity |
|
QT interval in setting of hypokalaemia |
QT interval APPEARS to be prolonged in hypokalaemia due to fusion of T wave and U wave Thus QT interval is NOT prolonged in hypokalaemia. The QU interval is prolonged instead. |
|
Inotropes should ideally |
reduce afterload and preload increase cardiac output and ejection fraction |
|
Failing LV shifts the Frank Starling curve to the ...... |
A failing LV shifts the Frank Starling (stroke volume vs ventricular end diastolic volume) to the right and down due to decreased contractility. |
|
Failing LV would have which of the following parameters reduced? - ejection fraction - end systolic volume - rate of rise of pressure at commencement of systole - stroke volume - systolic shortening of myocardial fibre length |
All of these parameters will be reduced except the end systolic volume which would increase. Slower contraction means the rate of rise of pressure is decreased. Stroke volume is reduced --> systolic fibre length shortening is reduced, ejection fraction reduced |
|
isovolumetric contraction of the LV occurs after closure of the aortic valve - T/F |
False |
|
isovolumetric contraction of the left ventricle is terminated at the T wave of the ECG |
False T wave corresponds to ventricular relaxation |
|
isovolumetric contraction of the left ventricle is responsible for ejection of majority of the stroke volume - T/F |
false Isovolumetric means no change in volume |
|
isovolumetric contraction of the left ventricle involves the most rapid change in pressure per unit time in the cardiac cycle |
True |
|
isovolumetric contraction of the left ventricle occurs during the first third of systole |
False |
|
Patients with severe aortic stenosis causing LV failure have poor outcomes from valvular surgery |
False cardiac status is often dramatically improved because the large pressure gradient across the aortic valve is relieved and cardiac workload reduces |
|
Impaired LV function can persist after correction of aortic stenosis via surgery |
True long term changes in LV failure due to pressure overload can persist This includes pathological hypertrophy, fibrosis, vascular insufficiency and changes in myosin isoform expression |
|
in patients with mixed aortic stenosis and insufficiency due to rheumatic heart disease, deteoriating cardiac function can actually be improved by increased aortic systolic or diastolic pressure? |
Increased diastolic pressure of the aorta can actually improve cardiac function in this setting Reduced aortic diastolic pressure seen with aoric incompetence can seriously compromise coronary blood flow |
|
Essential differences between systolic and diastolic heart failure |
- ejection fraction - myocardial wall thickness - end diastolic volume - end systolic volume |
|
Systolic heart failure characterised by |
dilated ventricle i.e. increased end diastolic volume reduced ejection fraction which gives increased end systolic volume |
|
Diastolic heart failure characterised by |
reduced ventricular compliance Hypertrophied and stiff ventricles require increased diastolic filling pressure to approach a normal end diastolic volume Hypertrophied muscle has increased performance so ejection fraction is increased |
|
Systolic and diastolic heart failures have this in common |
both need increased diastolic filling pressure though mechanisms are different |
|
Congenital VSD is associated with |
Increased pulmonary blood flow (usually left to right shunting) --> increased volume load on right ventricle and pulmonary circulation --> possible late right ventricular failure possible late pulmonary hypertension |
|
What kind of murmur do you get in congenital VSD?
|
pansystolic murmur |
|
Do you get cyanosed from birth with congenital VSD? |
Congenital VSD usually is left to right shunting (going down the pressure gradient) Cyanosis requires delivery of deoxygenated blood to the left heart and thus to the systemic circulation (usually right to left shunting) |
|
What kind of valve pathology causes volume overload in left ventricle |
Need both aortic and mitral insufficiency |
|
What is a common cause of loud pericardial rub |
due to pericardial effusions commonly due to infectious pericarditis or due to collagen diseases This s because the fluid is often rich in fibrin which can produce a loud rub |
|
Majority of patients with significant pulmonary thromboembolism show |
tachycardia and dyspnea |
|
Pulmonary artery flotation catheters diredctly measure |
CVP pulmonary artery wedge pressure cardiac index |
|
Strepkinase infusion can cause haemorrhage due to |
high levels of fibrin degradation products and hypofibrinogenaemia |
|
In the fetal circulation, blood from the SVC enters the LA via the patent foramen ovale T/F |
False Goes to the RA to preferentially enter the RV |
|
In the fetal circulation, haemoglobin in the umbilical vein is 80% saturated with oxygen T/F |
true |
|
In the fetal circulation, IVC blood is directed via the ductus arteriosus to the head vessels |
False ductus arteriosus connects the pulmonary arteries to the descending aorta after the artery to the head has branched off!! |
|
IVC receives blood directly from the ductus venosus in the the fetal circulation t/f |
True |
|
Haemoglobin F in fetal blood has a lower P50 compared to haemoglobin A in maternal blooid T/F |
True Haemoglobin F is left shifted compared to haemoglobin A on the oxygen dissociation curve. It ha a lower p50 (3.6kpa) compared to adult haemoglobin (4.2kpa). This is advantageous as it will encourage oxygen binding from the placenta. |
|
Placental blood flow is about 20% that of fetal cardiac output T/F |
False About 45% of the fetal combined ventricular output is directed towards the placenga |
|
SVC blood in the fetus is preferentially directed into the pulmonary circulation T/F |
True Blood from SVC --> RA --> RV --> PA |
|
Equation that summaries Bernoulli's principle of blood flow |
Flowing blood has velocity and mass therefore it has kinetic energy i.e. KE = 0.5 mV2 total energy in moving blood = kinetic energy + potential energy |
|
What does the potential energy in a moving blood represent? |
Represents the lateral pressure it exerts on vessel walls |
|
Two important conceps in Bernoulli's principle of blood flow |
1. Blood flow is driven by the difference in total energy between two points 2. Kinetic energy and potential energy can be interconverted so that total energy remains the same |
|
From Bernoullis principle of blood flow, it can be derived that the sum of kinetic energy and pressure energy is constant |
True |
|
From bernoulli's principle of blood flow, it can be derived that energy lost in overcoming resistance is irreversible |
True |
|
From bernoulli's principle of blood flow, it can be derived that the pressure drop due to conversion of potential to kinetic energy is reversible |
True |
|
From bernoulli's principle of blood flow, it can be derived that in a narrow segment of blood vessel - the velocity flow and lateral wall pressure are reduced |
False. Velocity increases as diameter decreases (velocity is inversely proportionate to diameter) KE also increases (KE is proportional to velocity) Therefore, potential energy (lateral wall pressure) decreases |
|
What is central venous pressure |
pressure of blood in the thoracic vena cava near the RA of the heart Reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system |
|
mean venous pressure in the dural sinus is constantly negative |
False While it is negative - Magnitude of the negative pressure is proportional to the vertical distance above the top of the collapsed neck vein |
|
mean venous pressure in the foot is higher when standing still or walking |
standing still |
|
mean venous pressure in the foot when standing still is 50mmHg |
false mean venous pressure at the ankle is 85-90mmHg when standing still |
|
mean venous pressure in the subclavian vein, as it crosses the first rib, is positive above atmospheric pressure, when lying down |
true |
|
High CVP can be caused by rapid fluid bolus |
True |
|
High CVP can be caused by PE |
True |
|
High CVP can be caused by tension pneumothorax |
True |
|
High CVP can be caused by supraventricular tachycardia |
False |
|
High CVP can be caused by cor pulmonale |
True |
|
On assuming the upright position, the arterial pressure at head level and the jugular venous pressure fall 20-30 mmHg |
False The venous pressure at the head level drops rather than jugular venous pressure |
|
On assuming the upright position, cerebral vascular resistance is reduced |
True Blood runs towards the feet, venous and arterial pressure both decrease |
|
On assuming the upright position, the brain tissue PO2 is maintained by autoregulation |
False Autoregulation works on cerebral blood flow via a myogenic mechanism Cerebral blood flow is most sensitive to pCO2 rather than pO2 |
|
On assuming the upright position, cerebral O2 consumption is about the same as in the supine position |
True Otherwise we would have hypoxic brain injury getting up |
|
Acclimitisation to altitude is associated with enhanced erythropoietin secretion and circulating red cell mass |
True |
|
Acclimtisation to altitude is associated with lactic acidosis in the brain causing.... |
A fall in CSF pH to enhance the ventilatory response to hypoxia |
|
Acclimitisation to altitude is associated with an increase in.... |
1. Tissue content of cytochrome oxidase 2. red blood cell 2,3 DPG which decreases oxygen binding affinity of haemoglobin (this rightward shift occurs in setting of chronic adaptation; acutely it is leftward shift) |
|
Extracellular oedema is not associated with... A - high venous pressure B - increased arteriolar resistance C - low plasma protein content D - increased capillary permeability E - lymphatic obstruction |
B |
|
Negative gravitational forces acting in the body produces increased cardiac output |
True |
|
Negative gravitational forces acting on the body produces increase in cerebral arterial pressure |
True |
|
Negative gravitational forces acting on the body can cause ecchyomoses around the eyes |
True |
|
Negative gravitational forces acting on the body can cause mental confusion |
True |
|
Venous pressure in the veins of the foot increases on standing in all subjects - T/F |
True |
|
Venous pressure on the veins of the foot diminishes on exercise in normal subjects - T/F |
True |
|
Venous pressure on the veins of the foot fails to diminish on exercise in subjects with varicose veins but competent perforators - T/F |
False |
|
Venous pressure on veins of the foot remains elevated during exercise in subjects with incompetence of the perforators and valve of the deep veins - T/F |
True |
|
Venous pressure in the veins of the foot diminshes on elevation of the legs in all subjects - T/F |
True |
|
Sudden elevation of the arterial pCO2 is associated with raised intracranial pressure - T/F |
True |
|
Sudden elevation of the arterial pCO2 is associated with respiratory acidosis - T/F |
True |
|
Sudden elevation of the arterial pCO2 is associated with skin vasodilation - T/F |
True |
|
Sudden elevation of the arterial pCO2 is associated with an increased plasma bicarbonate level - T/F |
True |
|
The liver converts free fatty acids to _____ |
ketones |
|
The liver converts ammonia to ________ |
urea |
|
The liver synthesises VLDL - T/F |
True |
|
The liver synthesises somatomedin-C (IGF-1) - T/F |
True |
|
The liver stores glucose as ______ |
glycogen |
|
The liver processes chylomicron remnants from the blood T/F |
True |
|
The liver is responsible for gluconeogenesis to maintain blood glucose concentration - T/F |
True |
|
metabolic functions of the liver include chemical modification and excretion of thyroxine - T/F |
True |
|
Abnormally high blood ammonia levels commonly found in hepatic coma are due to porto-systemic shunting of blood - T/F |
True |
|
Abnormally high blood ammonia levels in hepatic coma are due to reduced capacity for urea synthesis in the liver - T/F |
True |
|
Abnormally high blood ammonia levels in hepatic coma are due to bacterial production of ammonia in the gut - T/F |
True |
|
Abnormally high blood ammonia levels commonly found in hepatic coma are due to decreased hydrogen ion excretion by the kidney - T/F |
False |
|
Ammonia may be formed from _______ in the kidney |
glutamine |
|
Ammonia is taken up by _________ in the brain |
glutamic acid |
|
Ammonia is converted to ________ in the liver |
urea |
|
Ammonia is a substrate for urea production in the kidney - T/F |
False |
|
About 85% of bilirubin is formed from haemoglobin released by destruction of mature red blood cells which normally have a life span of 74 days - T/F |
False RBCs have a life span of 120 days Bilirubin formation is - 85% from haemoglobin - 15% from myoglobin, cytochromes, peroxidase |
|
Unconjugated bilirubin in plasma is filtered into the proximal convoluted tubules - T/F |
False Unconjugated bilirubin binds tightly to albumin which prevents its excretion into urine. |
|
About 20% of bilirubin in the small intestine recirculates to the liver in the enterohepatic circulation - T/F |
False 90-95% of bile acids are absorbed from the small intestine, transported back to liver in the portal vein and re-excreted in the bile |
|
Unconjugated bilirubin rises in the plasma when there is excessive destruction of RBCs T/F |
True |
|
Bile salts are largely reabsorbed from the _____________ |
Terminal ileum |
|
The primary bile salts are ______ and _______ They are conjugated with _________ or __________ in the liver |
Primary bile salts are cholate and chenodeoxycholate They are conjugated with glycine or taurine in the liver. |
|
Bile salts are synthesised from __________ |
Cholesterol |
|
Bile salts are concentrated in the _________ |
gallbladder |
|
About 90% of cholate and chenodeoxycholate which enter the small intestine are absorbed from the jejunum and recirculated back to liver - T/F |
False Most bile salts are reabsorbed in the terminal ileum |
|
Bilirubin is normally transported in blood bound to ________ |
albumin |
|
Bilirubin is normally converted to __________ in the small instestine |
urobilinogen |
|
Bilirubin is conjugated in the liver with ______ |
glucuronic acid |
|
Bilirubin is formed in |
the reticuloendothelial system and bone marrow |
|
The bile pigment in greatest quantity recycling in the enterohepatic circulation is bilirubin - T/F |
False Bile acids are the ones getting recycled in the enterohepatic circulation |
|
Bilirubin glucuronide is deconjugated by ______ in the intestine |
bacteria |
|
Cholesterol solubility in bile depends on the relative concentration of |
lecithin Bile salts |
|
If bile is analysed chemically, what would be found in the highest concentration in the alkaline electrolyte solution? |
Bile salts |
|
Reabsorption of bile salt from the intestine leads to further secretion of bile - T/F |
True |
|
Active transport of NaCl out of gallbladder is the mechanism by which the bile is concentrated - T/F |
True |
|
A certain concentration of bile salt is required for formation of micelles - T/F |
True |
|
Bile salts are derived from waste products of haemoglobin breakdown |
False They are synthesised from cholesterol |
|
If there is complete obstruction of the common bile duct, retained bile salts may cause skin itch - T/F |
True |
|
The liver forms cholic acid from which 10-20g of bile salts are formed daily - T/F |
False The total bile salt production is 0.2-0.4g/day Cholic acid represents 50% of total bile salt production |
|
Bile acids are converted into the colon to?? |
Cholic acid is converted into deoxycholic acid Chenodeoxycholic acid is converted into lithocolic acid |
|
about 90-95% of cholate and chenodoexycholate which enters the small intestine recycles in the enterohepatic circulation - T/F |
True |
|
Cholate and cheno-deoxycholate are passively reasorbed in the jejunum - T/F |
False Most are absorbed in the terminal ileum via active transport |
|
Oesophagus is normally open or closed? At which ends? |
closed at both ends |
|
The lower oesophageal sphincter has a resting pressure of 5mmHg above gastric pressure - T/F |
False The LES is at least 15mmHg above gastric pressure. |
|
The lower oesophageal sphincter exhibits tonic muscular activity unlike the body of the oesophagus - T/F |
True |
|
In achalasia, the absence of ganglion cells results in failure of adequate contraction in the lower oesophageal sphincter - T/F |
False Achalasia is failure to relax causing dilatation of oesophagus. It is due to deficiency of myenteric plexus at the LES, therefore control of release of NO/VIP is defective. |
|
Reflex relaxation of the lower oesophageal sphincter is integrated in the |
Nucleus tractus solitarius and dorsal motor nucleus of the vagus |
|
The stomach can receptively relax - T/F |
True This relaxation takes place when the oesophageal peristaltic waves pass towards the stomach |
|
The stomach controls the rate of access of food to the small intestine - T/F |
True |
|
Stomach emptying is regulated by signs from both the _______ and ________ |
stomach and duodenum |
|
Signals from the stomach for stomach emptying are - |
1. nervous signals - caused by distension of food 2. gastrin release - by antral mucosa in response to certain types of food within the stomach |
|
The stomach secretes lipase - T/F |
True |
|
The stomach secretes a factor contributing to erythrocyte formation - T/F |
True It secretes an intrinsic factor which is essential for vitamin B12 absorption - in turn contributing to erythrocyte formation |
|
Removal of the ________ in the stomach would be expected to reduce the gastric acid secretion because ______ |
antrum because it produces hormonal stimulation for acid secretion |
|
Which parts of the stomach secretes the most HCl? |
the body and the fundus |
|
The secretion of acid from the stomach is reduced when chyme enter the duodenum - T/F |
True |
|
Parietal cells in the stomach produce |
hydrochloric acid and intrinsic factors |
|
Chief cells in the stomach produce |
pepsinogens and gastric lipase |
|
Pancreatic polypeptide in the duodenum causes pancreatic exocrine secretion - T/F |
False Pancreatic juice secretion is under homronal control. |
|
Vagal stimulation ____________ gastric secretion of acid and pepsin |
Increases |
|
Resection of large segments of small intestine is associated with gastric hypersecretion of acid - T/F |
True |
|
Vagotomy abolishes gastric acid production - T/F |
False It can only diminish acid production, not abolish |
|
Vagotomy abolishes gastric motility - T/F |
False It reduces gastric motility, not abolish |
|
Physiological regulation of gastric secretion can be broken down into three different influences - name/describe them |
Cephalic - vagally mediated responses induced by CNS activity Gastric - local reflex responses and responses to gastrin Intestinal - reflex and homronal feedback effects on gastric secretion. This is initiated in the small intestine. |
|
Gastrin is produced by __________ |
G cells in the gastric antral mucosa |
|
Gastrin stimulates ________ and _______ secretion |
gastric acid pepsin |
|
Acid in the antrum inhibits gastric secretion via |
Feedback mechanism involving somatostatin |
|
Vagal stimulation increases gastric secretion of acid and pepsin, but not mucus - T/F |
False |
|
The _________ vagal trunk gives rise to the hepatic branches which enter the liver via the lesser omentum and the porta hepatis |
Anterior |
|
The main terminal branch of the anterior vagus nerve crosses the stomach........ |
Distal to the incisura angularis about 5-6cm the pylorus |
|
Most of the fibres of the posterior vagus nerve terminate in the stomach - T/F |
False The posterior vagus trunk gives off a large celiac branch that runs backwards along hte left gastric artery to the coeliac ganglion |
|
Some vagal fibres travelling to the parietal cell mass may sink into the muscular wall at |
the oesophagus some distance above the cardia |
|
Decrease in gastric antral pH to 2.0 ______ the release of gastrin |
inhibits |
|
Decrease in gastric antral pH to 2.0 occurs due to synergistic action of |
histamine, gastrin, acetylcholine |
|
Decrease in gastric antral pH to 2.0 will reflexively _________ gastric secretion |
inhibit |
|
Decrease in gastric antral pH to 2.0 will promote activity in inhibitory afferent fibres of the vagus - T/F |
False Vagus outflow promotes gastric secretion |
|
The respiratory quotient of the stomach during gastric juice secretion is ________ because..... |
less than one Because the stomach takes up more CO2 from the arterial blood than it puts into the venous blood |
|
How do you calculate the respiratory quotient? |
It is the ratio of CO2 produced to the volume of O2 consumed PER unit of time. |
|
A patient with pyloric stenosis due to an active duodenal ulcer has been vomiting most of his meals during the past week. He is hypokalaemia because |
1. loss of postassium into gastric juice 2. increased renal loss of potassium |
|
Prolonged vomiting from severe pyloric stenosis is associated with |
metabolic alkalosis low pH of urine low serum potassium |
|
Prolonged vomiting associated with complete pyloric obstruction is associated with an increase in alveolar ventilation - T/F |
False It would be associated with decrease, to retain more CO2 to make more bicarb |
|
Prolonged vomiting associated with complete pyloric obstruction is associated with a rise in plasma chloride concentration - T/F |
False It will result in hyponatraemia, and thus hypochloraemia |
|
Prolonged vomiting associated with complete pyloric obstruction is associated with a rise in CSF pressure - T/F |
False Not related |
|
Prolonged vomiting associated with complete pyloric obstruction is associated with a rise in plasma bicarbonate concentration - T/F |
True |
|
What can result in an increase in the pH of duodenal contents? |
Secretin - released from duodenum in response to duodenal acidification. |
|
Function of secretin |
Secretin significantly increases pancreatic water and bicarbonate secretion.It also inhibits gastric acid output. |
|
Function of cholecystokinin |
Stimulates pancreatic enzyme secretion and contraction of gallbladder |
|
Function of microvilli in the small intestine |
Increases surface area aiding absorption |
|
Mucosal cells of the small intestine are formed from |
undifferentiated cells in the crypts of Lieberkuhn |
|
Peristalsis is the only type of movement demonstrated in the small intestine - T/F |
False Segmental contraction + tonic contraction are necessary in the small bowel to prolong transit time + foster absorption. |
|
The frequency of small waves __________ from the jejunum to the ileum |
Decreases |
|
How much water is absorbed by the small and large intestine daily? |
8-9L |
|
Of the reabsorption of water, how much is absorbed by the small intestine and how much by the colon? |
8L in the intestine (6L in the jejunum and 2L in the ileum) 1L in the colon |
|
Potassium is ______ by the small intestine and _________ by the large intestine |
Absorbed Secreted |
|
The absorptive surface of the small intestine is increased ___________ fold by the ___________, ___________, and _____________ |
600 fold valvulae conniventes, villi and microvilli |
|
What effect does diarrhea have on serum potassium level? |
Decreases |
|
Of the water absorbed by our intestines, how much is endogenous and how much is ingested? |
Endogenous ~ 7L Ingested ~2L |
|
Breakdown of endogenous water production within the GI tract |
Salivary glands ~ 1.5L Stomach ~ 2.5L Bile ~ 500mL Pancreas 1.5L Small intestine ~ 1L |
|
The intestinal mucosa below the duodenum produces which of the following? - Mucus - Secretin - CCK - Isotonic intestinal secretion |
Intestinal glands of the jejunum produce secretin, CCK and mucus in an isotonic secretion. As do glands in the duodenum. |
|
Substances that are maximally absorbed in the upper part of the small intestine (i.e. jejunum) are |
Water soluble and fat soluble vitamins EXCEPT vit B12 Long chain fatty acids Sodium Iron Calcium Chloride |
|
Vitamin B12 is maximally absorbed in the |
lower part of the small intestine |
|
Bile salts are maximally absorbed in the |
lower part of the small intestine |
|
Patients who under massive resection of the proximal small bowel are likely to develop peptic ulcer - T/F |
True Because these patients have decreased secretion of secretin and gastric inhibitory polypeptide --> hypersecretion of acids |
|
Massive resection of the small bowel is associated with intractable diarrhea - T/F |
True |
|
Massive resection of the small bowel is associated with increased likelihood of renal stone - T/F |
True |
|
Massive resection of the small bowel is associated with hypergastrinaemia - T/F |
True |
|
Massive resection of the small bowel is associated with increased serum calcium - T/F |
False Less calcium absorbed therefore decreased serum calcium |
|
Massive resection of the small bowel is associated with lower serum protein - T/F |
True |
|
Resection of the ileum markedly decreases the absorption of |
Vitamin B12 and bile salt Fat soluble vitamins |
|
Fat soluble vitamin is usually absorbed in the jejunum and not in the ileum. Why does resection of the ileum decrease the absorption of fat soluble vitamins then? |
Because resection of ileum leads to decreased bile salt reabsorption, interrupting fat absorption in the jejunum |
|
Resection of the last metre of the small bowel might result in a macrocytic anaemia within months - T/F |
False Usually takes years for anaemia to develop as your body needs to deplete the cobalamin reserve |
|
What gives the odour of the faeces? |
Smell of sulfides due to action of intestinal bacteria |
|
In blind loop syndrome, steatorrhea can occur because the proliferation of bacteria results in excessive oxidation of conjugated bile salts - T/F |
False It occurs because overgrowth of bacteria disrupts digestive/absorptive processes. Therefore there is disruption in bile salt absorption and thus fat mal-absorption. |
|
In the blind loop syndrome, the harmful effects are cause by bacterial invasion of the small intestine - T/F |
True |
|
In the blind loop syndrome, steatorrhea can occur - T/F |
True |
|
In the blind loop syndrome, bacterial overgrowth can contribute to development of macrocytic anaemia - T/F |
True |
|
In the blind loop syndrome, jaundice is a feature - T/F |
False |
|
How can resection of terminal ileum cause steaorhoea? |
This is because 90-95% of bile salts are absorbed in the terminal ileum and recycled by the enterohepatic circulation. |
|
Diarrhea during enteral feeding tube may be due to excess volume of feed - T/F |
True |
|
Diarrhoea during enteral tube feeding may be due to hyperosmolality of feed - T/F |
True |
|
Diarrhoea during enteral tube feeding may be due to malabsoprtion - T/F |
True |
|
Diarrhoea during enteral tube feeding may be due to short bowel syndrome - T/F |
True |
|
The colon ensures the constancy of faecal content despite variation of diet - T/F |
True |
|
There is active transport of sodium out of the colonic mucosa - T/F |
True |
|
The colon has sterile content at birth - T/F |
True |
|
The colon secretes potassium and bicarbonate into the lumen - T/F |
True |
|
A narrowed segment of the distal third of colon is more likely to produce symptoms than a narrowed segment of the proximal third of colon - T/F |
True The distal colon will have more solid faeces causing more stretch in the narrowed segments --> causing more symptoms |
|
Gastrin stimulates gastric mucosal growth - T/F |
True |
|
Cholecystokinin secretion by cells of the upper small intestine is enhanced by |
amino acids and fatty acids |
|
Secretin augments the action of _________ |
cholecystokinin in producing pancreatic secretion of digestive enzymes |
|
gastric inhibitory peptide _________ the sensitivity of insulin response to raised blood glucose |
increases |
|
The common feature of gastrointestinal hormones - VIP, GIP, secretin and glucagon is |
they are all portions of similar amino acid sequences |
|
VIP stands for |
vasoactive intestinal peptide |
|
4 functions of VIP |
- it stimulates intestinal secretion of electrolytes and hence of water in the intestine - relaxation of intestinal smoth muscle - dilation of peripheral blood vessels - inhibition of gastric acid secretion |
|
Which of these are not GI hormones? 1. glucagon 2. GIP 3. enterokinase 4. gastrin releasing peptide 5. CCK |
Enterokinase |
|
Secretin is a powerful stimulant of pancreatic enzymes - T/F |
False It stimulates pancreatic alkaline water production |
|
Secretin inhibits gastric motility - T/F |
True |
|
Secretin is produced in the upper small intestine - T/F |
True In the duodenum and jejunum |
|
Secretin inhibits gastric acid secretion - T/F |
True By increasing the pH of duodenum --> feedback loop of gastrin to inhibit secretion |
|
Secretin is released by acid in the duodenum - T/F |
True |
|
Secretin is released by vagal stimulation - T/F |
False Its secretion is increased by products of protein digestion and by acid bathing the mucosa of the upper small intestine |
|
Secretin is a stimulant of secretion from biliary and pancreatic duct cells - T/F |
True |
|
Secretin is responsible for a high chloride ion concentration in external pancreatic secretion - T/F |
False High bicarbonate |
|
Secretin is secreted by cells in the duodenal mucosa - T/F |
True Also in the jejunum |
|
Secretin increases bicarbonate secretion from the exocrine pancreas - T/F |
True |
|
Secretin _______ gastrin secretion |
Decreases |
|
Secretin augments the action of ______ on the pancreas |
CCK |
|
Secretin is secreted when protein breakdown products arrive in the upper small intestine - T/F |
True |
|
Secretin increases the secretion of bicarbonate from the biliary tract - T/F |
True |
|
Secretin is released in conjunction with substance P - T/F |
False |
|
What is substance P? |
a GI peptide found in endocrine and nerve cells in the GI tract. It increases motility of small intestine. |
|
Secretin is structurally similar to glucagon - T/F |
True Also similar to VIP, GIP |
|
Somatostatin inhibits acid secretion because |
1. inhibits gastrin release into bloodstream 2. inhibits parietal cell function |
|
CCK secretion is increased by |
1. Contact of intestinal mucosa with products of digestion, amino acids, and peptides 2. Fatty acids in the duodenum |
|
CCK has a more marked effect on the ducts than on the acini of the pancreas - T/F |
False It acts on the acinar cells to cause release of zymogen granules and production of pancreatic juice rich in enzymes but low in volume |
|
CCK exerts a trophic effect on the pancreas - T/F |
True |
|
CCK inhibits the action of secretin in producing secretion of an alkaline pancreatic juice - T/F |
False They augment each other |
|
Serum gastrin is decreased by products of protein digestion in the stomach - T/F |
False It is increased |
|
Serum gastrin is increased by hypercalcaemia - T/F |
True |
|
Serum gastrin is low in pernicious anaemia - T/F |
False In pernicious anaemia, the acid secreting cell is damaged so it can't sense that there is too much acid --> chronically elevated serum gastin |
|
Serum gastrin is increased after massive small bowel resection - T/F |
True There is decreased secretion of secretin + GIP --> less inhibitory effect to gastrin |
|
Gastrin is produced in |
the G cells principally in the gastric antrum |
|
Gastrin stimulates |
HCL secretion by parietal cells of the fundus Trophic effect on gastric mucosa |
|
Gastrin is mainly inhibited by |
secretin |
|
At what pH is the stimulation on gastrin shut off? |
1.2 in the antrum |
|
Gastrin is functionally and structurally related to CCK - T/F |
True |
|
Gastrin is secreted by antral mucosa - T/F |
True |
|
Gastrin is liberated by distension of the antrum - T/F |
True Stretch receptors in the wall of the stomach and in the gastric mucosa sense distension --> release gastrin |
|
Gastrin stimulates secretion of both acid and pepsin - T/F |
True |
|
Circulating gastrin levels are _____ in Zollinger-Ellison syndrome |
high |
|
Circulating levels of gastrin are ____ in pernicious anaemia |
high |
|
Circulating levels of gastrin are _____ in secretory tumours of the pancreatic delta cells |
Low Secretory tumours of pancreatic delta cells = somatostatinomas = inhibitory effect on gastric acid production |
|
Circulating levels of gastrin are _________ in most patients with duodenal ulcer |
Normal Many studies show a normal level of serum gastrin in most patients with duodenal ucler |
|
Gastrin secretion is increased by which of the following - glucagon - calcium - secretin - tryptophan |
- calcium and tryptophan (an amino acid) - not much evidence of gastrin and glucagon relationship - gastrin secretion is inhibited by secretin |
|
Gastrin is present in which of the following tissues - gastric antrum - gastric fundus - first part of duodenum - renal parenchyma |
Gastric antrum First part of duodenum (in very small concentration) |
|
VIP potentiates the action of acetylcholine in the salivary gland - T/F |
True |
|
VIP is formed from prepro-VIP - T/F |
True |
|
VIP inhibits gastric acid secretion - T/F |
True |
|
VIP causes vasoconstriction of peripheral blood vessels - T/F |
False! Vasodilation |
|
CCK _______ the sphincter of oddi |
relaxes |
|
CCK stimulates enzyme rich pancreatic juice and stimulates alkaline pancreatic solution rich in bicarbonate - T/F |
False It does stimulate enzyme rich pancreatic juice. Secretin is the one that stimulates alkaline pancreatic solution |
|
CCK stimulates hepatic flow of bile - T/F |
True |
|
CCK _______ the gallbladder |
contracts |
|
Fat absorption is greatest in |
the upper small intestine |
|
Fat absorption occurs via |
passive diffusion into enterocytes Some evidence showing that carriers are involved However, NOT active absorption |
|
What percentage of dietary fat is absorbed in adults? |
95% |
|
What percentage of dietary fat is absorbed in infants? |
85-90% |
|
Small amounts of medium and larger chain fatty acids are absorbed directly into the portal blood - T/F |
False Only fatty acids of less than 10-12 carbon atoms (small chains) are water soluble enough to pass through the enterocyte unmodified and absorbed into the portal bllod |
|
Chylomicrons are small droplets of fat combined with apoproteins which aid diffusion through enterocyte membranes - T/F |
False Chylomicrons are breakdown products of longer chain fatty acids which are then coated with layer of protein, cholesterol and phospholipid |
|
Without bile acid, less than 15% of fat will be normally absorbed |
False Bile acids are mainly to do with fat digestion rather than absorption |
|
Between 80-90% of all fat absorbed from the gut is transported to the blood |
As chylomicrons via the thoracic duct |
|
How are micelles formed? |
Bile salt + fatty acids + monoglycerides |
|
In the absence of bile salts, fatty acids are not absorbed |
False Absence of bile salt leads to impairment of fat digestion |
|
Fatty acids containing more than 10-12 carbon atoms are ___________ in the mucosal cells |
Re-esterised to triglycerides |
|
Pancreatic lipase breaks down dietary triglycerides to form |
fatty acids and monoglycerides |
|
What proportion of calories a day can be parenterally administered as a fat? |
15-30% |
|
There is a specific requirement of short-chain fatty acid triglycerides to be provided in doses adequate in parenteral administration to generate ketone bodies for metabolism - T/F |
False No specific requirement for short chain fatty acids |
|
Omega-6 polyunsaturated fatty acid triglyercerides should be provided in doses adequate to prevent essential fatty acid deficiency - T/F |
True |
|
There is a specific requirement for medium chained triglyercieds to maintain the fluidity of membranes - T/F |
False There is no specific requirement |
|
Omega-3 polyunsaturated fatty acids may modulate the immune response - T/F |
True |
|
Omega-3 polyunsaturated fatty acids may modulate immune response by inhibiting induction of free radical lipid peroxides - T/F |
False It modulates via three mechanisms 1) increasing membrane fluidity 2) INDUCING free radical lipid peroxides 3) providing precursors for eicosanoid metabolism |
|
What is the largest energy store following fat? |
muscle protein |
|
After a fatty meal, what happens to most of the fat in the intestine? |
It gets transported away as emulsified particles in the lymph |
|
Fat in the duodenum _______ stomach emptying because.... |
Delays Because fat in the duodenum releases CCK, secretin and GIP |
|
Plasma cholesterol can be decreased by which of the following - thyroxine - androgen - oestrogen - growth hormone |
Only two - thyroxine, oestrogen |
|
Endogenously derived triglycerides in the plasma is primarily transported as |
very low density lipoprotein (VLDL) |
|
Endogenously derived triglycerides in the plasma can be increased by carbohydrate excess in the diet - T/F |
True |
|
Endogenously derived triglycerides circulating in the plasma is removed from the circulation by |
muscle and adipose tissue |
|
Endogenously derived triglycerides in the plasma is increased when the plasma cholesterol level increases - T/F |
False The level of endogenous triglycerides does not correlate with plasma cholesterol level. |
|
LDL contains _______ cholesterol than HDL |
more |
|
LDL contains ___________ triglyceride than HDL |
more |
|
Individuals with elevated LDL have _________ than normal incidence of atherosclerosis |
higher |
|
Individuals with elevated HDL have _________ than normal incidence of atherosclerosis |
lower |
|
The primary function of HDL is |
in cholesterol exchange and esterification |
|
Iron absorption is facilitated by pancreatic juice - T/F |
False |
|
Iron absorption is ________ by cereal products |
Inhibited Phytic acid in cereal products reacts with iron to form insoluble compound int he intestine |
|
Iron absorption is_________ by adding ascorbic acid to the diet |
Increased |
|
Iron absorption is predominantly in the ________ |
Duodenum |
|
Iron absorption is ___________ by low pH gastric secretions |
Increased |
|
Iron absorption is increased in states of iron overload - T/F |
False |
|
Iron absorption requires presence of transferrin - T/F |
True |
|
Iron absorption occurs in the terminal ileum - T/F |
False Occurs in the upper small intestine |
|
Iron absorption is inhibited by pH of pancreatic juice - T/F |
False Alkaline conditions REDUCE but do not inhibit iron absorption |
|
Iron absorption is inhibited by phytic acid - T/F |
True This occurs in cereal. |
|
Iron absorption is inhibited by ascorbic acid - T/F |
False It is enhanced by ascorbic acid |
|
Iron absorption is inhibited by phosphates - T/F |
True |
|
Iron absorption is mainly in the ferrous form - T/F |
True |
|
Adult males require iron absorption of _________ per day |
0.5-1mg |
|
Haemosiderin is the principal form of iron storge in the tissue - T/F |
False 70% in haemoglobin 3% in myoglobin Remaining in form of ferritin |
|
A 50 year old man has a past history of duodenal ulcer and has been taking aspirin Q4H for painful RA for period of two months. This has caused a loss of 30mL of blood daily in his stools. It is likely that 1. his blood will show iron deficiency anaemia 2. his absorption of iron from a full normal diet will be affected by arthritis 3. his plasma iron binding capacity will be decreased 4. There will be no suspicion of malaena on macroscopic examination |
1. True 2. True 3. False (it will be increased) 4. True |
|
How much blood needs to be lost daily into the large intestine for malaena to be evident? |
More than 100mL |
|
Iron deficiency may occur in patients who have had radical gastrectomy - T/F and why |
True Because there are less gastric secretions to convert dietary Fe3+ (ferric) forms to its more easily absorbable Fe2+ (ferrous) form |
|
Iron deficiency anaemia is a recognised complication of partial gastrectomy because acid is required for iron absorption within the stomach - T/F |
False Acid enhances iron absorption but is not required |
|
S. Following total removal of stomach microcytic anaemia is likely to develop because R. a secretion from the stomach is essential for erythropoiesis |
S. is true R. is false - intrinsic factor is essential for vitamin B12 absorption and this is essential for normal erythropoiesis. However, this will cause a macrocytic anaemia. |
|
Gastric acidity is required for absorption of haem-iron - T/F |
False It helps but is not required |
|
Achlorhydria leads to a significant reduction in absorption of non-haem-iron |
True Less chloride ion is less hydrogen ion. This can lead to less absorption. |
|
Iron absorption does not increase after haemolysis - T/F |
True |
|
Iron absorption increases after haemorrhage - T/F |
True |
|
Patients suffering from pernicious anaemia have normal serum gastrin levels - T/F |
False They have increased serum gastrin level |
|
There is no increase in gastric intra-luminal acid in pernicious anaemia - T/F |
True |
|
Pernicious anemia is associated with a ________ PCV |
Reduced Even though the red cells are larger than normal, there's less of them. Thus the PCV is low |
|
Pernicious anaemia is typically associated with megaloblastic marrow - T/F |
True |
|
Pernicious anaemia is typically associated with gastric atrophy - T/F |
True |
|
Pernicious anaemia is associated with thrombocytopenia - T/F |
True |
|
The pancreas secretes insulin in increased quantity following alpha-adrenergic stimulation - T/F |
False Alpha adrenergic stimulators (e.g. epinephrine, norepinehprine) inhibits insulin secretion |
|
Pancreas secretes proelastase - T/F |
True |
|
Pancreas secretes glucagon in decreased quantity following administration of somatostatin - T/F |
True |
|
Pancreas secretes inactive precursors of trypsin and lipase - T/F |
True |
|
The exocrine secretion of the pancreas contains phospholipase A - T/F |
True |
|
The exocrine secretion of pancreas contains ribonuclease and deoxyribonuclease to split nucleotides from nucleic acids - T/F |
True |
|
Exocrine secretion of pancreas contains chloride at about 130mmol/L concentration - T/F |
False The concentration of chloride is about 55mmol/L |
|
Exocrine secretion of the pancreas contains prolipase from nucleic acids - T/F |
True |
|
External secretin of the pancreas contains a bile salt activated lipase capable of hydrolysing cholesterol esters - T/F |
True Otherwise known as bile salt dependent lipase (BSDL) |
|
Bicarbonate rich pancreatic juice is secreted in response to |
secretin |
|
Enzyme rich pancreatic juice is secreted when |
CCK acts on pancreas Vagal stimulation on pancreas |
|
Serum amylase can be raised in acute renal insufficiency - T/F |
True |
|
Serum amylase may be elevated during administration of morphine - T/F |
True |
|
Serum amylase may be elevated during acute perforation of a duodenal ulcer - T/F |
True |
|
Serum amylase may be elevated during mumps - T/F |
True |
|
In the absence of pancreatic enzymes the faeces contain more fat MAINLY because |
there is little enteric lipase in the epithelial cells of the small intestine |
|
If a carcinoma of the head of the pancreas obstructs the CBD, there is high level of urobilinogen in the urine - T/F |
False |
|
Urobilinogen entering the circulation is excreted in the urine - T/F |
True |
|
Protein has _________ caloric content than carbohydrate In the body, protein has ___________ caloric values obtained compared to carbohydrates because..... |
higher Similar Because oxidation of protein is incomplete |
|
Name 4 evidences that intestinal absorption of carbohydrates is an active process. |
1. Transport of most monosaccharides can be blocked by metabolic inhibitors 2. Transport is selective for different monosaccharides 3. There is a maximum rate of transport for each monosaccharide 4. There is competition between certain sugars for respective carrier systems |
|
How much do patients require from parenteral administration of carbohydrate? |
25kcal/kg/day |
|
What proportion of total calories administered per day can be given as glucose? |
30-70% |
|
Butyrate, an endogenous product of fibre fermentation, is an important fuel for colonocytes - T/F |
True |
|
It is desirable to consume >250gm of fibre per day - T/F |
False 25-30gm |
|
A deficient fibre intake can lead to secretory diarrhea - T/F |
False Deficient fibre leads to constipation |
|
The long term consumption of a diet that is low in fibre increases risk of bacterial translocation across the wall of the proximal colon - T/F |
False No definitive evidence |
|
An inadequate fibre intake can impair the enter-hepatic circulation of bile salts and thereby lad to the diminished absorption of fat soluble vitamins - T/F |
False |
|
Ingestion of protein food such as eggs can sometimes provoke antibody formation in infants- T/F why? |
True Infants absorb moderate amount of undigested protein which can enter circulation to provoke antibody formation |
|
Glycine should constitute at 50% of the amino acids in parenteral administration of protein - T/F |
False Glycine is the simplest amino acid and is usually used as a "stuffer" amino acid |
|
Dosing should ensure that the BUN remains > 200mg/dL in parenteral administration of protein - T/F |
False BUN should not exceed 100mg/dL - this is an indication for decreased dosing |
|
Hepatic encephalopathy is not influenced by the amount of protein that is administered parenterally - T/F |
False Rising blood ammonia level is associated with clinical encephlopathy |
|
Parenteral nutritional solutions should contain at least 0.25g/kg/day of nucleotides to maintain proliferative ability of bone marrow - T/F |
False A nutritional requirement of nucleic acid has not been established |
|
The protein requirement is about ______ per day |
1.2g-1.5g/kg |
|
cobalt deficiency can cause _______ anaemia |
megaloblastic |
|
iodine deficiency may cause |
goitre formation |
|
chromium deficiency may cause |
insulin resistance |
|
Is zinc an essential trace element? |
Yes |
|
Is copper an essential trace element? |
Yes |
|
Is beryllium an essential trace element? |
No |
|
Is molybdenum an essential trace element? |
Yes |
|
Is selenium an essential trace element? |
Yes |
|
Less than 5% of protein in the small intestine escapes digestion and absorption - T/F |
True |
|
Absorption of amino acids is rapid throughout the whole of the small intestine - T/F |
False It is rapid in the duodenum and jejunum There is no absorption in the ileum |
|
Over 90% of the digested protein is dietary - T/F |
False 50% comes from ingested food 25% comes from digestive juices 25% comes from desquamated mucosal cells |
|
Protein in the stools is largely undigested dietary protein - T/F |
False Almost all protein in the stool comes from bacteria and cellular debris |
|
Amino acids are actively transported from the mucosal cells into the blood stream - T/F |
False Amino acids have to go through transporters to enter enterocytes then into portal circulation. |
|
Branched chain amino acid administration to catabolic surgical patients enhances quality and number of polyribosome in skeletal muscle - T/F |
True Its role in improving patient outcome is not defined. But compared to standard AA formulations, it can improve nitrogen retention and protein synthesis --> i.e. improving number and quality of polyribosomes in skeletal muscles. |
|
Branched chain amino acid administration improves patient outcome after major hepatic surgery - T/F |
False Role in improving patient outcome is not defined. |
|
Branched chain amino acids are mainly metabolised in the liver - T/F |
False It is mainly metabolised by skeletal muscles |
|
There is no role for parenteral branched chain amino acids therapy in patients with hepatic encephalopathy - T/F |
False BCAA can be used in patients who are protein intolerant because of hepatic encephalopathy. It permits greater protein intake without inducing encephlopathy than do standard protein formulas. |
|
When used clinically, branched chain amino acids should be administered at a dose of 0.1-0.3g/kg/d - T/F |
False 0.5-1.2g/kg/d |
|
The amino acid glycine is probably the mediator responsible for direct inhibition in the spinal cord - T/F |
True |
|
The amino acid glycine causes hyperpolarisation when directly applied to the membranes of neurons - T/F |
True |
|
The amino acid glycine with ________ and _______is responsible for synthesis of creatine in muscle - T/F |
Arginine Methionine |
|
The amino acid glycine has an inhibitory function in the cord antagonised by atropine - T/F |
False It is antagonised by strychnine |
|
When administered in pharmacologic doses, arginine may act as a neurotransmitter - T/F |
False |
|
Alanine is the main precursor of arginine - T/F |
False Citrulline is the main precusor of arginine |
|
Critically ill patients require 30g/day of arginine - T/F |
False The role of arginine in critically ill patients has yet to be defined. |
|
Arginine is the unique substrate for the production of nitrous oxide - T/F |
True |
|
Arginine is the preferred nutrient for immunocytes - T/F |
False Its role as a immunomodulator is being evaluted. |
|
Glutamine is the only amino acid that contains 3 nitrogen molecules - T/F |
False It has two |
|
Glutamine constitutes about 25% of the amino acid content of standard solutions of parenteral nutrients - T/F |
False It is not included in the standard parenteral nutrients because it is unstable in solution and breaks down to form toxic amounts of pyroglutamate and ammonia. |
|
Critically ill patient require 20g/day of glutamine - T/F |
False Not clear whether administering glutamine improves outcomes in catabolic patients. |
|
Glutamine is the principal fuel used by rapidly proliferating cells - T/F |
True |
|
The kidney consumes glutamine during period of metabolic alkalosis - T/F |
False Kidney consumes glutamine during periods of metabolic ACIDOSIS |
|
Absorption of B12 requires two things - which two? |
1. intrinsic factor 2. trypsin to facilitate efficient absorption |
|
Arctic explorer shouldn't eat polar bear livers because |
they can develop headache, diarrhea and dizziness as they contain rich sources of vitamin A |
|
Sources of carbohydrate which may be used in parenteral nutrition solutions include |
glycerol sorbitol Not maltodextrins or starch |
|
Transport of glucose across intestinal cell membranes require - |
1. sodium transport across enterocyte membranes 2. carrier molecules |
|
If conscious, pain would be experienced in response to which of the following stimuli when applied to bowel: 1. visceral distension 2. surgical diathermy 3. visceral ischaemia 4. cutting with a sharp instrument |
Only visceral distension and ischaemia |
|
Uric acid is formed from breakdown of |
purines |
|
Uric acid reabsorption in renal tubules can be inhibited by |
probenecid |
|
Uric acid level in plasma is normally |
0.2-0.4mmol/L |
|
Uric acid urinary excretion is increased by allopurinol - T/F |
False Allopurinol works by directly inhibiting xanthine oxidase in the purine degradation pathway. This then decreases uric acid production by preventing breakdown of purine. |
|
Serum albumin concentration of <30g/L is strongly correlated with poor clinical outcome - T/F |
True |
|
Albumin is a useful marker of nutritional status because it has a relatively short half life - T/F |
False It has a half life of 28 days, so acute changes in serum albumin cannot be due to poor nutrition. Serum albumin is not affected by starvation until starvation has reached an advanced stage |
|
Synthesis of albumin is markedly inhibited during early stages of undernutrition - T/F |
False Serum albumin is not affected by starvation until it has reached an advanced stage. |
|
Albumin has a low exchange rate between intra and extravascular compartments - T/F |
False It has a high exchange rate. Even small variations in percantage of exchange rate can cause variation in serum albumin. |
|
Serum albumin concentrations are increased during sepsis - T/F |
False |