MCAT Biology : Glands

Study concepts, example questions & explanations for MCAT Biology

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Example Questions

Example Question #2 : Other Endocrine Glands

The adrenal medulla is responsible for secreting which hormone?

Possible Answers:

Aldosterone

Corticotropin-releasing hormone

Epinephrine

Cortisol

Correct answer:

Epinephrine

Explanation:

The adrenal medulla, derived from neural crest cells, is responsible for making and releasing epinephrine and norepinephrine. Epinephrine and norepinephrine are responsible for increasing heart rate and activating the sympathetic nervous system when released.  

In contrast, the adrenal cortex is derived from mesoderm and releases steroid hormones like aldosterone and cortisol. Corticotropin-releasing hormone is made by the parvocellular neurons of the hypothalamus.

Example Question #31 : Glands

The adrenal medulla is responsible for secreting which of the following hormones?

Possible Answers:

Adrenocorticotropic hormone

Growth hormone

Epinephrine

Thyroid-stimulating hormone

Correct answer:

Epinephrine

Explanation:

Epinephrine and norepinephrine are released by the neuroendocrine cells of the adrenal medulla. In times of stress and sympathetic nervous system activation, the adrenal medulla will release epinephrine to cause blood vessel constriction. These hormones allow for the "fight-or-flight" response.

In contrast, the adrenal cortex will secrete cortisol and other mineralcorticoids in response to long-term stress. These hormones are not involved in the fight-or-flight response, and rather serve to prepare the body to endure prolonged harsh conditions, such as dehydration, starvation, and extreme temperatures. Adrenocorticotropic hormone is released from the anterior pituitary to stimulate the adrenal cortex.

Growth hormone and thyroid-stimulating hormone do not interact with the adrenal gland.

Example Question #32 : Glands

The hormone cortisol is synthesized in the __________ and the hormone aldosterone is synthesized in the __________.

Possible Answers:

adrenal medulla . . . adrenal medulla

adrenal cortex . . . adrenal cortex

adrenal cortex . . . adrenal medulla

adrenal medulla . . . adrenal cortex

Correct answer:

adrenal cortex . . . adrenal cortex

Explanation:

Hormones cortisol and aldosterone are synthesized in the adrenal glands. Adrenal glands are made up of the adrenal cortex and the adrenal medulla. Adrenal medulla is involved in the synthesize of catecholamines (epinephrine and norepinephrine) whereas adrenal cortex synthesizes mineralocorticoids (aldosterone), glucocorticoids (cortisol), and androgens (testosterone, DHT, and DHEA). 

Aldosterone is released upon stimulation from the renin-angiotensin system and serves to increase reabsorption of sodium in the collecting ducts of the kidney. Cortisol is released due to stress and serves to increase the metabolic rate. 

Example Question #33 : Glands

Which of the following hormones is produced by the pituitary gland?

Possible Answers:

Antidiuretic hormone

Aldosterone

Epinephrine

Thyroxine

Luteinizing hormone

Correct answer:

Luteinizing hormone

Explanation:

Luteinizing hormone is produced and secreted by the anterior pituitary gland.

Antidiuretic hormone is produced by the hypothalamus, but secreted by the posterior pituitary gland. Epinephrine is produced by the adrenal medulla; aldosterone is produced by the adrenal cortex. Thyroxine (T4) is produced by the thyroid.

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