Question 1

Which of the following best describes the difference between endocrine and exocrine glands?

Accepted Answer

Exocrine glands secrete non-hormonal substances into ducts, while endocrine glands secrete hormones directly into the bloodstream.

Question 2

A patient presents with an enlarged thyroid gland (goiter) and symptoms of lethargy, weight gain, and cold intolerance. Laboratory tests reveal low levels of thyroxine (T4). What is the most likely cause?

Accepted Answer

Iodine deficiency leading to decreased thyroid hormone synthesis

Question 3

Which hormone is primarily responsible for increasing blood calcium levels by stimulating osteoclast activity and enhancing calcium reabsorption in the kidneys?

Accepted Answer

Parathyroid hormone (PTH)

Question 4

Which of the following is an example of a hormone acting via a second messenger system?

Accepted Answer

Epinephrine binding to a cell surface receptor and activating cAMP production

Question 5

A patient with a pituitary tumor is found to have enlarged hands, feet, and facial bones, but normal body proportions. Which hormone is most likely being hypersecreted, and what is the condition called?

Accepted Answer

Growth hormone; acromegaly

Question 6

Which of the following best describes the permissive effect of hormones?

Accepted Answer

One hormone enhances the responsiveness of a target organ to a second hormone.

Question 7

Which hormone is released from the posterior pituitary in response to increased plasma osmolality and acts on the kidneys to conserve water?

Accepted Answer

Antidiuretic hormone (ADH)

Question 8

Which of the following is a correct sequence of events for the synthesis and release of thyroid hormone?

Accepted Answer

Iodine trapping → thyroglobulin synthesis → iodination → coupling of T1 and T2 → endocytosis → release of T3 and T4

Question 9

Which of the following best explains why steroid hormones typically have longer-lasting effects than peptide hormones?

Accepted Answer

Steroid hormones act as transcription factors, altering gene expression and protein synthesis.

Question 10

A patient is experiencing symptoms of high blood pressure, increased heart rate, and elevated blood glucose after a car accident. Which hormones are most likely responsible for these acute stress responses?

Accepted Answer

Epinephrine and norepinephrine

Question 11

Which of the following is NOT a typical effect of insulin?

Accepted Answer

Stimulating glycogen breakdown in the liver

Question 12

Which hormone is produced by the pineal gland and is involved in regulating circadian rhythms?

Accepted Answer

Melatonin

Question 13

Which of the following best describes the role of the hypophyseal portal system?

Accepted Answer

It allows hypothalamic hormones to reach the anterior pituitary rapidly and in high concentration.

Question 14

Which of the following is an example of a positive feedback mechanism in the endocrine system?

Accepted Answer

Release of oxytocin during childbirth

Question 15

Which hormone is secreted by alpha cells of the pancreas and acts to increase blood glucose levels?

Accepted Answer

Glucagon

Question 16

A patient with Graves' disease is likely to present with which of the following symptoms?

Accepted Answer

High metabolic rate, weight loss, and exophthalmos

Question 17

Which of the following best describes the action of an antagonist hormone?

Accepted Answer

It binds to a receptor and blocks the action of an agonist without triggering a response.

Question 18

Which hormone is primarily responsible for stimulating the adrenal cortex to release glucocorticoids during stress?

Accepted Answer

Adrenocorticotropic hormone (ACTH)

Question 19

Which of the following is a correct example of a paracrine signal?

Accepted Answer

A chemical messenger acting on neighboring cells within the same tissue

Question 20

Which hormone is necessary for the maturation of male reproductive organs and the development of secondary sex characteristics during puberty?

Accepted Answer

Testosterone

Endocrinology: The Endocrine System and Hormone Regulation

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