MDS PREP
MCQ: The physiological capacity of the bladder, at which micturition is normally effected, ranges between:
1) 150 ml - 250 ml
2) 250 ml - 450 ml
3) 450 ml - 750 ml
4) 750 ml - 1000 ml
The physiological capacity of the bladder, at which micturition is normally effected, ranges between 250 ml - 450 ml, indicating the volume at which the urge to urinate is felt.
Which of the following hormones stimulates the development of the corpus luteum and the secretion of progesterone?
1) Follicle-stimulating hormone (FSH)
2) Luteinizing hormone (LH)
3) Estrogen
4) Progesterone
LH is responsible for the transformation of the follicle into the corpus luteum and the initiation of progesterone production during the luteal phase of the menstrual cycle.
What is the function of the pineal gland in regulating circadian rhythms?
1) It produces melatonin in response to light exposure
2) It produces cortisol to maintain wakefulness
3) It regulates body temperature
4) It is not involved in circadian rhythms
Physiology
Answer: 1
The pineal gland produces melatonin, a hormone that helps regulate sleep-wake cycles. Melatonin is synthesized and released in response to darkness, signaling the body to prepare for sleep.
What is the significance of the intestinal phase of gastric acid secretion?
1) It is responsible for the majority of acid secretion
2) It is primarily responsible for the inhibition of acid secretion
3) It is only triggered by the thought of food
4) It is not a significant phase of gastric acid secretion
The intestinal phase of gastric acid secretion is primarily responsible for the inhibition of acid secretion, helping to regulate the digestive process after food enters the intestine.
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.
The rate of gastric emptying is influenced by:
1) The quantity and type of food ingested
2) Distension of the duodenum
3) Gastric hormones like gastrin
4) All of the above
The rate of gastric emptying is influenced by the presence of food in the stomach, the type of food (carbohydrates, proteins, and fats), the distension of the duodenum, and the hormone gastrin, which can increase the rate of emptying.
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
Physiology
Answer: 2
Estrogen, primarily secreted by the developing follicles in the ovary, stimulates the growth and maturation of the endometrium during the follicular phase of the menstrual cycle. It prepares the endometrium for potential implantation of a fertilized egg.
Which of the following is the primary active transport mechanism for calcium absorption in the intestine?
1) Vitamin D dependent calcium binding protein (calbindin)
2) Sodium-calcium exchanger (NCX)
3) Calcium-dependent ATPase
4) All of the above
Physiology
Answer: 4
Calcium is absorbed mainly in the duodenum and jejunum by an active transport mechanism regulated by 1,25 (OH)2 D3 (calcitriol). It is transported across the brush border of intestinal epithelial cells via TRPV6 channels and binds to calbindin. The absorbed calcium is then delivered to the basolateral membrane by calbindin, and from there it is transported into the bloodstream by either the sodium-calcium exchanger (NCX) or calcium-dependent ATPase.