MDS PREP
What is the primary function of the cholinergic system in the gastrointestinal tract?
1) Decreases peristalsis and relaxes sphincters
2) Increases peristalsis and relaxes sphincters
3) Increases peristalsis and constricts sphincters
4) Decreases peristalsis and constricts sphincters
The cholinergic system, acting via muscarinic receptors, increases peristalsis and relaxes the sphincters in the gastrointestinal tract to facilitate the movement of food and waste through the digestive system.
What is the main difference between endopeptidases and exopeptidases?
1) Endopeptidases cleave internal peptide bonds, while exopeptidases act on the terminal peptide bonds.
2) Endopeptidases are inactive in the stomach, whereas exopeptidases are active in the stomach.
3) Endopeptidases are exclusively found in the pancreas, whereas exopeptidases are exclusively found in the intestinal mucosa.
4) Endopeptidases are exclusively activated by enterokinase, whereas exopeptidases are activated by other enzymes.
E) Endopeptidases are inhibited by acidic pH, while exopeptidases function best at acidic pH.
Endopeptidases, also known as endoproteinases, are enzymes that hydrolyze peptide bonds within the polypeptide chain, breaking down proteins into smaller peptides. Examples include pepsin, trypsin, and chymotrypsin. In contrast, exopeptidases, or exoproteinases, cleave peptide bonds at the ends of the polypeptide chain, either at the N-terminal (aminopeptidases) or C-terminal (carboxypeptidases). These enzymes are involved in the final steps of protein digestion and the degradation of small peptides into individual amino acids.
Angiotensin I is formed by the action of which enzyme on Angiotensinogen?
1) Renin
2) ACE
3) Aldosterone
4) Erythropoietin
Angiotensin I is formed by the action of renin on Angiotensinogen, which is produced by the liver and released into the bloodstream.
Which of the following is NOT a clinical consequence of defective bile acid absorption?
1) Fat malabsorption
2) Steatorrhea
3) Hemolytic anemia
4) Vitamin K deficiency
Hemolytic anemia is NOT a clinical consequence of defective bile acid absorption; rather, it is associated with the destruction of red blood cells, while fat malabsorption, steatorrhea, and vitamin K deficiency can occur due to bile salt deficiency.
The gastrocolic reflex is:
1) The contraction of the stomach triggered by the presence of food in the duodenum
2) The contraction of the small intestine triggered by the presence of food in the stomach
3) The contraction of the rectum triggered by the presence of food in the stomach
4) The contraction of the gallbladder triggered by the presence of food in the small intestine
The gastrocolic reflex is a physiological response where the distension of the stomach by food initiates contractions in the rectum, often leading to the urge to defecate.
What is the function of the cholinergic system in the regulation of gastric acid secretion?
1) Stimulates HCL secretion
2) Inhibits HCL secretion
3) Has no direct effect on HCL secretion
4) Stimulates the release of gastrin
The cholinergic system, which is part of the parasympathetic nervous system, stimulates the parietal cells in the stomach to release hydrochloric acid (HCL) through the activation of muscarinic M1 receptors. This is crucial for the digestion of food and the maintenance of gastric pH.
What is the primary component of the glomerular filtration barrier?
1) Glomerular capillary endothelium
2) Basement membrane
3) Bowman's capsule
4) Podocytes
E) All of the above
The glomerular filtration barrier is composed of the glomerular capillary endothelium, the basement membrane, and the podocytes (Bowman's visceral epithelium). These three layers work together to filter blood and form the glomerular filtrate, which then enters the renal tubules.
In the somatosensory area-I of the cerebral cortex, which of the following statements is true?
1) The body is represented in a distorted manner, with the face and hands having a disproportionately larger representation than the rest of the body.
2) The body is represented in a manner proportional to its size, with no distortion in the representation of different body parts.
3) The body is represented in a reversed order, with the feet at the top and the face at the bottom of the postcentral gyrus.
4) Each side of the cortex receives sensory information from the same side of the body.
Answer: 1) The body is represented in a distorted manner in the somatosensory area-I, with the face and hands having a disproportionately larger representation due to their higher innervation density.