All MCAT Biology Resources
Example Questions
Example Question #34 : Hormones
Which hormone is responsible for increasing episodes of mitosis, increasing cell size, and increasing the rate of protein synthesis?
Thyroid-stimulating hormone
Growth hormone
Adrenocorticotropic hormone
Prolactin
Growth hormone
Growth hormone is secreted by the anterior pituitary and is responsible for increased metabolism and cell growth. Growth hormone increases glucose and free fatty acid levels in the blood, increasing substrates for metabolism for other cells in the body.
Example Question #711 : Mcat Biological Sciences
Which anterior pituitary hormone plays a role in stimulating spermatogenesis in males?
Estradiol
Testosterone
Follicle-stimulating hormone
Adrenocorticotropic hormone
Follicle-stimulating hormone
Under normal conditions, spermatogenesis is somewhat inhibited. Follicle-stimulating hormone, luteinizing hormone, and testosterone can act to overcome this inhibition and promote sperm development. Testosterone, however, is produced in the testes, not the anterior pituitary.
Example Question #11 : Hormone Mechanisms And Effects
Which hormone is required for milk secretion in women?
Estrogen
Oxytocin
Luteinizing hormone
Prolactin
Oxytocin
Oxytocin is responsible for milk secretion in women. Notice that prolactin is responsible for milk production, but oxytocin is responsible for milk secretion. Oxytocin is released from the posterior pituitary and is responsible for contractions during pregnancy and milk secretion.
Example Question #35 : Hormones
Mineralocorticoids, including aldosterone, are able to maintain blood pressure during times of stress. Which of the following is not an effect of aldosterone?
Decreased blood potassium levels
Increased blood pressure
Decreased blood sodium levels
Decreased urine sodium content
Decreased blood sodium levels
The mineralocorticoid aldosterone is stimulated by the renin-angiotensin system of the kidney when blood volume falls. Aldosterone acts at the distal convoluted tubule of the kidney to increase sodium reabsorption, thus raising sodium levels in the blood and lowering sodium levels in the urine. Aldosterone also increases potassium excretion, thus causing low levels of potassium in the blood. The overall retention of sodium draws water from the filtrate into the blood, causing increased blood pressure by increasing blood volume.
Example Question #712 : Mcat Biological Sciences
Cortisol, a glucocorticoid, is able to help maintain the body's metabolic state during times of stress. Which of the following is not a function of cortisol?
Increase blood free fatty acids
Increase sex hormone levels
Increase protein metabolism
Increase blood glucose
Increase sex hormone levels
Cortisol secretion, stimulated from the adrenal cortex by adrenocorticotropic hormone from the anterior pituitary, is responsible for protecting against hypoglycemia and hypotension. Cortisol increases blood glucose, increases blood free fatty acids by stimulating lipolysis, and increases breakdown of muscle proteins. The net result is more substrate to undergo glycolysis and the citric acid cycle during periods of poor nutrition and starvation.
Cortisol does not elevate sex hormone levels. Evolutionarily, it is disadvantageous to produce offspring during times of stress or poor nutrition.
Example Question #713 : Mcat Biological Sciences
What hormone is directly responsible for increasing the amount of water reabsorbed in the kidney collecting ducts?
Renin
Vasopressin
Aldosterone
Adrenocorticotropic hormone
Vasopressin
Vasopressin (antidiuretic hormone) is responsible for placing aquaporin channels on the collecting ducts of the kidney to allow for increased water reabsorption. This increased water reabsorption allows for blood pressure to be maintained. Interestingly, coffee and alcohol are vasopressin blockers, causing a large increase in urine volume when ingested.
Aldosterone, in contrast, causes a retention of sodium ions, which indirectly draws water out of the filtrate to concentrate the urine. Aldosterone does not affect permeability of the collecting duct to water. Renin indirectly leads to increases in both vasopressin and aldosterone, but has no direct effect on the collecting duct by itself.
Example Question #13 : Hormone Mechanisms And Effects
Which hormone is responsible for stimulating milk production in women?
Prolactin
Luteinizing hormone
Oxytocin
Estrogen
Prolactin
Prolactin is responsible for stimulating milk production in women. While other hormones need a stimulus to trigger secretion, prolactin is tonically secreted, but its action is stopped by the neurotransmitter dopamine. During the period of nursing, the stimulus of the baby suckling inhibits dopamine, allowing for the release of prolactin and the production of milk.
Example Question #16 : Hormone Mechanisms And Effects
Which hormone is responsible for stimulating the production of T4 and T3 from the thyroid gland?
Thyrotropin-releasing hormone
Parathyroid hormone
Growth hormone
Thyroid-stimulating hormone
Thyroid-stimulating hormone
Thyroid-stimulating hormone is produced by the anterior pituitary, and is responsible for stimulating T4 (tetraiodothyronine) and T3 (triiodothyronine) release from follicular cells in the thyroid gland. Too much thyroid-stimulating hormone can cause large lumps in the neck due to thyroid gland inflammation, called goiters. Goiters commonly result from an iodine deficiency, as the structures of both T4 and T3 require a central iodine atom.
Thyrotropin-releasing hormone is responsible for stimulating release of thyroid-stimulating hormone. Parathyroid hormone is important for regulating blood calcium, while growth hormone is involved in mitotic stimulation and nutrient balances.
Example Question #71 : Endocrine System
Which hormone is responsible for stimulating estrogen synthesis in the female ovaries?
Oxytocin
Prolactin
Progesterone
Follicle-stimulating hormone
Follicle-stimulating hormone
Follicle-stimulating hormone is responsible for stimulating estrogen synthesis in the female ovaries.
Luteinizing hormone acts on Theca cells to stimulate androstenedione production (the precursor to estrogen), then follicle-stimulating hormone acts on granulosa cells to stimulate estrogen production. Both luteinizing hormone and follicle-stimulating hormone are required for estrogen production, but follicle-stimulating hormone is ultimately required for estrogen synthesis and secretion.
Example Question #714 : Mcat Biological Sciences
A camper becomes lost and does not drink water for 48 hours. At the end of this time, which significant changes in hormone production would be expected in the camper?
Increased insulin
Decreased glucocorticoids
Decreased aldosterone
Increased antidiuretic hormone (ADH)
Increased antidiuretic hormone (ADH)
The function of antidiuretic hormone, or vasopressin, is to reabsorb water in the kidney tubules, thereby retaining water in the body. After dehydration, the camper's antidiuretic hormone levels would be high in order to preserve the water in his or her body.
Glucocorticoids, such as cortisol, have various functions; they reduce inflammation and prepare the body for long-term stress. Dehydration signals the body to prepare for long-term stress, increasing glucocorticoid levels.
Aldosterone increases sodium retention, drawing water out of filtrate and acting to counter dehydration. We would expect aldosterone to be elevated.
Insulin lowers blood glucose, but the camper would need to use glucose as energy causing this hormone to be decreased.
Certified Tutor
Certified Tutor