MDS PREP
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.
Which vitamin is the most important antioxidant in the body, acting in the lipid phase of membranes?
1) Vitamin C
2) Vitamin A
3) Vitamin E (tocopherol)
4) Vitamin B
Physiology
Answer: 3
Vitamin E is the most important antioxidant in the body, acting in the lipid phase of membranes and protecting against the effects of free radicals. It is crucial for maintaining the integrity and function of cellular organelles and the cell membrane by preventing the oxidation of unsaturated fats.
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 significance of the ponto-genital occipital spikes seen in REM sleep?
1) They indicate deep sleep
2) They indicate the onset of dreaming
3) They are associated with eye movement
4) They are markers of REM sleep
Ponto-genital occipital spikes, or PGO waves, are characteristic of REM sleep and are thought to be associated with the onset of dreaming, as they often coincide with rapid eye movement and increased brain activity during this phase.
In which part of the male reproductive system does spermatogenesis occur?
1) Seminal vesicles
2) Epididymis
3) Prostate gland
4) Seminiferous tubules
Physiology
Answer: 4
Spermatogenesis is the process of sperm cell development. It takes place in the seminiferous tubules within the testes. These tubules are lined with spermatogonia, which mature into primary spermatocytes, then secondary spermatocytes, and finally into spermatids, which mature into spermatozoa.
What is the function of the reticular formation in the regulation of sleep and wakefulness?
1) It initiates sleep
2) It maintains wakefulness
3) It is not involved in sleep-wake regulation
4) It initiates REM sleep
The reticular formation plays a crucial role in maintaining wakefulness by sending activating signals to the thalamus and cortex.
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
When the corpus luteum regresses during the menstrual cycle, it stops secreting estrogen and progesterone, leading to the shedding of the uterine lining.
What is the role of the acrosome in sperm penetration of the egg during fertilization?
1) It produces energy for the sperm's movement
2) It contains enzymes that help dissolve the egg's outer layers
3) It transfers genetic material to the egg
4) It has no role in the penetration process
Physiology
Answer: 2
The acrosome contains enzymes such as hyaluronidase and acrosin that are essential for breaking down the zona pellucida, the egg's outermost layer, allowing the sperm to penetrate and fertilize the egg.