MDS PREP
What is the difference in the generation of the Resting Membrane Potential (RMP) in neurons and muscle cells?
1) Neurons have a higher RMP than muscle cells
2) Muscle cells have a higher RMP than neurons
3) The mechanism of RMP generation is different in neurons and muscle cells
4) The ionic gradients involved in RMP generation are the same in both neurons and muscle cells
Answer: 4) The ionic gradients involved in RMP generation are the same in both neurons and muscle cellsExplanation: The RMP in both neurons and muscle cells is generated primarily by the difference in potassium ion concentration across the cell membrane. The concentration gradient of K+ is maintained by the sodium-potassium ATPase pump, which pumps 3 Na+ ions out and 2 K+ ions into the cell, contributing to the negative resting membrane potential.
What is the function of the macula densa in the regulation of the nephron's function?
1) It secretes ADH to regulate water reabsorption.
2) It monitors sodium chloride concentration in the tubular fluid.
3) It produces erythropoietin to stimulate RBC production.
4) It is involved in the conversion of vitamin D to its active form.
The macula densa monitors sodium chloride concentration in the tubular fluid, playing a crucial role in regulating kidney function.
What is the primary function of the descending limb of the Loop of Henle?
1) Reabsorption of sodium and chloride
2) Reabsorption of water
3) Secretion of potassium
4) Active transport of glucose
The primary function of the descending limb of the Loop of Henle is the reabsorption of water, which concentrates the tubular fluid as it descends.
What is the primary role of the cephalic phase of gastric acid secretion?
1) Stimulation of gastrin release in the stomach
2) Secretion of gastric juices in response to the thought or smell of food
3) Increase in gastric motility
4) Secretion of gastric juices in response to food entering the duodenum
The primary role of the cephalic phase of gastric acid secretion is the secretion of gastric juices in response to the thought or smell of food, preparing the digestive system for incoming food.
What is the primary mechanism of sodium reabsorption in the distal convoluted tubule and collecting ducts?
1) Passive diffusion
2) Active transport with sodium-potassium ATPase pump
3) Facilitated diffusion
4) Countercurrent exchange with hydrogen ions
The primary mechanism of sodium reabsorption in the distal convoluted tubule and collecting ducts is active transport with the sodium-potassium ATPase pump.
Which of the following is NOT a secondary bile acid?
1) Cholic acid
2) Deoxycholic acid
3) Lithocholic acid
4) Chenodeoxycholic acid
Physiology
Answer: 1
Cholic acid is a primary bile acid, while deoxycholic acid and lithocholic acid are secondary bile acids formed by bacterial action in the colon.
What is the role of the corpus luteum in the second half of the menstrual cycle?
1) It secrets FSH
2) It secrets LH
3) It secrets estrogen and progesterone
4) It secrets inhibin
The corpus luteum secretes estrogen and progesterone during the second half of the menstrual cycle, which are essential for maintaining the uterine lining.
What is the primary function of vitamin D in the body?
1) Blood clotting
2) Bone formation and maintenance
3) Vision
4) Immune system function
The primary function of vitamin D in the body is bone formation and maintenance, as it helps regulate calcium and phosphate levels.