MDS PREP
What is the function of cholecystokinin (CCK) in the digestive system?
1) Stimulates the release of bile from the liver
2) Increases the secretion of water in the collecting tubules of the kidney
3) Relaxes the lower esophageal sphincter
4) Decreases the motility of the small intestine
Cholecystokinin (CCK) stimulates the release of bile from the liver and pancreatic enzymes, aiding in digestion.
MCQ: The pancreas has which of the following cell types?
1) Alpha cells
2) Beta cells
3) Delta cells
4) All of the above
The pancreas has all of the following cell types: alpha cells (which produce glucagon), beta cells (which produce insulin), and delta cells (which produce somatostatin).
What happens to lithocholic acid in the enterohepatic circulation?
1) It is reabsorbed in the terminal ileum and returned to the liver
2) It is metabolized into chenodeoxycholic acid
3) It is converted into deoxycholic acid
4) It is excreted in feces due to its insolubility
Physiology
Answer: 4
Lithocholic acid is insoluble and not efficiently reabsorbed, leading to its excretion in the feces.
What is the role of gastrin in the gastric phase of gastric acid secretion?
1) It directly stimulates the release of HCl from parietal cells.
2) It inhibits the release of HCl from parietal cells.
3) It activates the myenteric plexus to enhance intestinal motility.
4) It promotes the release of bicarbonate into the stomach lumen.
E) It is not involved in the gastric phase of acid secretion.
Gastrin is a hormone released by G cells in the gastric antrum in response to the presence of food, especially protein. It acts on parietal cells in the gastric glands, stimulating them to produce and secrete hydrochloric acid (HCl) and intrinsic factor, which is essential for vitamin B12 absorption. Gastrin is a critical component of the gastric phase, which is responsible for the bulk of gastric acid secretion.
What is the primary mechanism responsible for the reclamation of bile acids in the enterohepatic circulation?
1) Active transport in the ileum
2) Facilitated diffusion in the colon
3) Passive diffusion in the small intestine
4) Bacterial synthesis in the liver
Physiology
Answer: 1
Bile acids are actively reabsorbed in the ileum, primarily by the sodium-dependent bile acid transporter (ASBT), and returned to the liver.
What is the primary function of the reticular activating system during wakefulness?
1) It initiates REM sleep
2) It suppresses sensory input
3) It filters and modulates sensory information
4) It maintains the overall level of arousal and alertness
The reticular activating system (RAS) is involved in the regulation of wakefulness and arousal by modulating the transmission of sensory information to the thalamus and cortex and by influencing the release of neurotransmitters that promote alertness.
What hormone is secreted by the kidneys that stimulates red blood cell production?
1) Renin
2) Erythropoietin
3) Aldosterone
4) Cortisol
Erythropoietin is the hormone secreted by the kidneys that stimulates red blood cell production in response to low oxygen levels in the blood.
What is the primary role of estrogen during the follicular phase of the menstrual cycle?
1) Suppression of FSH secretion
2) Stimulation of follicular development
3) Preparation of the endometrium for implantation
4) Induction of the LH surge
During the follicular phase of the menstrual cycle, estrogen stimulates follicular development, promoting the maturation of ovarian follicles.