MDS PREP
What is the primary effect of insulin on the skeletal muscles?
1) Stimulation of protein synthesis
2) Increased glycolysis
3) Increased glucose uptake and glycogen synthesis
4) Stimulation of muscle contraction
Answer: 3) Increased glucose uptake and glycogen synthesisExplanation: Insulin stimulates glucose uptake by muscle cells and promotes glycogen synthesis. It does so by increasing the number of glucose transporters on the muscle cell membrane and facilitating the transport of glucose into the cells.
What happens when the corpus luteum regresses during the menstrual cycle?
1) It secrets more estrogen and progesterone
2) It stops secreting estrogen and progesterone
3) It starts secreting FSH and LH
4) It causes an increase in the thickness of the endometrium
Physiology
Answer: 2
The regression of the corpus luteum leads to a sharp decline in estrogen and progesterone levels, which in turn causes the endometrium to shed and results in menstrual bleeding.
What is the primary effect of thyroid hormones on cardiac output?
1) Decrease in heart rate and stroke volume
2) Increase in heart rate and stroke volume
3) Decrease in heart rate and decrease in stroke volume
4) Increase in heart rate and increase in stroke volume
Answer: 4) Increase in heart rate and increase in stroke volumeExplanation: Thyroid hormones, such as thyroxine (T4) and triiodothyronine (T3), enhance the effects of catecholamines on the cardiovascular system, leading to increased heart rate and stroke volume. This results in a higher cardiac output, which is essential for meeting the increased metabolic demands during stress or exercise.
What is the primary effect of insulin on lipolysis?
1) Stimulation
2) Inhibition
3) No effect
4) Stimulation in the presence of glucose
Answer: 2) InhibitionExplanation: Insulin inhibits lipolysis by decreasing the activity of hormone-sensitive lipase in adipose tissue. This helps to maintain energy homeostasis by reducing the mobilization of fatty acids during periods of sufficient glucose availability.
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.
MCQ: The first sensation of bladder filling occurs at approximately:
1) 150 ml
2) 250 ml
3) 450 ml
4) 750 ml
The first sensation of bladder filling occurs at approximately 150 ml, signaling the need to void.
MCQ: The average time required for spermatogenesis in humans is:
1) 30 days
2) 42 days
3) 74 days
4) 120 days
The average time required for spermatogenesis in humans is approximately 74 days, during which sperm cells develop from spermatogonia to mature spermatozoa.
What is the significance of the transport maximum for substances like glucose and phosphate?
1) It indicates the maximum amount that can be filtered by the glomerulus
2) It represents the maximum amount that can be actively reabsorbed by the tubules
3) It is the point at which the substance begins to be excreted in the urine
4) It is the point at which the substance becomes toxic to the body
The transport maximum for substances like glucose and phosphate represents the maximum amount that can be actively reabsorbed by the tubules before reaching saturation and being excreted in urine.