Question 1

Which of the following best describes the difference between endocrine and paracrine signaling?

Accepted Answer

Endocrine signaling involves hormones secreted into the bloodstream for long-distance communication, while paracrine signaling involves hormones acting locally on nearby cells.

Question 2

Which hormone is released from the posterior pituitary and is responsible for water reabsorption in the kidney?

Accepted Answer

Antidiuretic hormone (ADH, also known as vasopressin)

Question 3

A patient presents with a swollen neck (goiter) and low metabolic rate. Blood tests reveal low levels of thyroxine. Which of the following is the most likely cause?

Accepted Answer

Iodine deficiency leading to production of non-iodinated thyroxine

Question 4

Which of the following is a correct example of a negative feedback loop in hormone regulation?

Accepted Answer

High levels of thyroxine inhibit the release of TRH and TSH.

Question 5

Which equation best represents the conversion of T$$_4 ($$thyroxine) to T$$_3 ($$triiodothyronine) in target cells?

Accepted Answer

$$\mathrm{T}_4 \xrightarrow{enzyme} \mathrm{T}_3$$

Question 6

Which hormone is both tropic and non-tropic in its actions?

Accepted Answer

Growth hormone (GH)

Question 7

A person drinks alcohol and becomes dehydrated. Which physiological process is most directly affected by ethanol?

Accepted Answer

Ethanol blocks the release of ADH, preventing water reabsorption in the kidney.

Question 8

Which of the following best explains why epinephrine can cause different responses in different tissues?

Accepted Answer

Different tissues express different types of adrenergic receptors (α and β), leading to tissue-specific responses.

Question 9

Which of the following is a direct effect of prolactin in mammals?

Accepted Answer

Stimulates breast development and milk production/secretion in females.

Question 10

Which hormone is released from the anterior pituitary and stimulates the adrenal cortex to produce cortisol?

Accepted Answer

Adrenocorticotropic hormone (ACTH)

Question 11

Which of the following is a correct sequence for the hormone cascade pathway involving the thyroid?

Accepted Answer

Hypothalamus $$\rightarrow$$ TRH $$\rightarrow$$ Anterior Pituitary $$\rightarrow$$ TSH $$\rightarrow$$ Thyroid $$\rightarrow$$ Thyroxine

Question 12

Which of the following is a function of cortisol during stress?

Accepted Answer

Stimulates glucose breakdown and suppresses the immune system.

Question 13

Which hormone is responsible for the 'fight or flight' response and what is its primary source?

Accepted Answer

Epinephrine, produced by the adrenal medulla

Question 14

Which of the following best describes the role of insulin in blood glucose regulation?

Accepted Answer

Insulin promotes the uptake of glucose by cells, lowering blood glucose levels.

Question 15

A patient with Type I diabetes mellitus is unable to regulate blood glucose because:

Accepted Answer

Their pancreatic beta cells do not produce insulin.

Question 16

Which of the following is a correct statement about steroid hormone receptors?

Accepted Answer

Steroid hormone receptors are located in the cytoplasm or nucleus of target cells.

Question 17

Which hormone is secreted in response to short days and is involved in regulating biological rhythms and seasonality?

Accepted Answer

Melatonin

Question 18

Which of the following is a mechanism for terminating hormonal signals in the body?

Accepted Answer

Degradation by enzymes in the liver or blood, and removal by the kidneys

Question 19

Which of the following best explains why beta blockers are used to treat high blood pressure?

Accepted Answer

Beta blockers inhibit the response to epinephrine at β-adrenergic receptors, reducing heart rate and blood pressure.

Hormones and the Endocrine System: Structure, Function, and Regulation

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