MCAT Biology : Other Endocrine Glands

Study concepts, example questions & explanations for MCAT Biology

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Example Questions

Example Question #28 : Endocrine System

A patient is admitted to the hospital after a traumatic injury to her adrenal cortex. Which of the following hormones is most likely to be present at normal levels?

Possible Answers:

Antidiuretic hormone (ADH)

Aldosterone

Corticotropin-releasing hormone (CRH)

Cortisol

Adrenocorticotropic hormone (ACTH)

Correct answer:

Antidiuretic hormone (ADH)

Explanation:

Of all the hormones listed, antidiuretic hormone (ADH) is the only one that neither acts on, nor is released by, the adrenal cortex. ADH is released from the posterior pituitary and causes the kidneys to retain more water.

Aldosterone (a mineralcorticoid) and cortisol (a glucocorticoid) are both incorrect choices because they are released by the adrenal cortex and would be greatly affected by trauma to that area. ACTH is released by the anterior pituitary and acts to stimulate the adrenal cortex; these hormones act as part of a negative feedback chain, so damage to the target area would temporarily cause more ACTH to be produced. The same goes for CRH, which is released by the hypothalamus and stimulates secretion of ACTH.

Example Question #29 : Endocrine System

Which of the following is not an endocrine gland?

Possible Answers:

Mammary gland

Adrenal gland

Pituitary

Hypothalamus

Correct answer:

Mammary gland

Explanation:

Endocrine glands secrete hormones into the blood stream, lined with endothelium, allowing them to travel through the blood and to act at a distant site. Exocrine organs, in contrast, secrete products into lumens that are lined with epithelium.

Mammary glands are used in lactation. Because the milk is not secreted into the blood, the mammary glands are not endocrine glands.

The hypothalamus releases hormones into the blood, such as corticotropin-releasing hormone (CRH). The pituitary releases hormones such as prolactin. The adrenal gland secretes hormones such as cortisol.

Example Question #31 : Endocrine System

The adrenal medulla is responsible for secreting which hormone?

Possible Answers:

Aldosterone

Corticotropin-releasing hormone

Cortisol

Epinephrine

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 #32 : Endocrine System

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

Possible Answers:

Thyroid-stimulating hormone

Epinephrine

Adrenocorticotropic hormone

Growth 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 #33 : Endocrine System

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

Possible Answers:

adrenal cortex . . . adrenal cortex

adrenal medulla . . . adrenal medulla

adrenal medulla . . . adrenal cortex

adrenal cortex . . . adrenal medulla

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 #34 : Endocrine System

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

Possible Answers:

Antidiuretic hormone

Thyroxine

Epinephrine

Luteinizing hormone

Aldosterone

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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