Question 1

Which of the following best describes the difference between an agonist and an antagonist in receptor signaling?

Accepted Answer

An agonist binds to a receptor and activates it, producing a biological response, while an antagonist binds to the receptor and prevents activation.

Question 2

Why is it beneficial for the body to have different receptor types for the same ligand (signaling molecule)?

Accepted Answer

It enables the same ligand to produce different effects in different tissues, increasing physiological flexibility.

Question 3

Which of the following best illustrates a negative feedback loop in endocrine regulation?

Accepted Answer

Increased cortisol inhibits the release of CRH and ACTH, reducing further cortisol production.

Question 4

In the context of feedback systems, what is the role of a sensor?

Accepted Answer

To detect changes in a physiological variable and send information to the integrating center.

Question 5

Which hormone is released from the hypothalamus and stimulates the anterior pituitary to secrete ACTH?

Accepted Answer

Corticotropin-releasing hormone (CRH)

Question 6

A patient presents with symptoms of hyperthyroidism. Laboratory tests show elevated TSH and T3/T4 levels. Which type of endocrine disorder is most likely?

Accepted Answer

Secondary disorder

Question 7

Which pathway correctly traces the release of cortisol from the hypothalamus to the adrenal cortex?

Accepted Answer

Hypothalamus releases CRH $$\rightarrow$$ anterior pituitary releases ACTH $$\rightarrow$$ adrenal cortex releases cortisol

Question 8

Which of the following is a symptom of Addison’s disease (primary adrenal insufficiency)?

Accepted Answer

Hyperpigmentation and low blood pressure

Question 9

What is the main function of the hypothalamic-hypophyseal portal system?

Accepted Answer

To transport hormones directly from the hypothalamus to the anterior pituitary, allowing rapid and specific regulation.

Question 10

Cortisol has several effects on different tissues. Which of the following best describes its effect on the liver?

Accepted Answer

Stimulates glycogen breakdown and increases blood glucose levels.

Question 11

A patient with a tertiary endocrine disorder affecting the hypothalamus would most likely show which pattern of hormone levels?

Accepted Answer

Low hypothalamic releasing hormone, low pituitary hormone, low target gland hormone

Question 12

Which equation best represents the negative feedback regulation of cortisol?

Accepted Answer

$$	ext{CRH} \xrightarrow{+} 	ext{ACTH} \xrightarrow{+} 	ext{Cortisol} \xrightarrow{-} 	ext{CRH and ACTH}$$

Question 13

Which of the following is a direct effect of cortisol on adipose tissue?

Accepted Answer

Stimulates lipolysis, increasing free fatty acids in the blood.

Question 14

A patient with Cushing’s syndrome (excess cortisol) is likely to present with which of the following symptoms?

Accepted Answer

Muscle wasting, hyperglycemia, and central obesity

Question 15

Which hormone is secreted by the anterior pituitary and stimulates the adrenal cortex?

Accepted Answer

Adrenocorticotropic hormone (ACTH)

Question 16

If a patient has low cortisol but high ACTH, which gland is most likely dysfunctional?

Accepted Answer

Adrenal cortex

Question 17

Which of the following best describes the role of CRH in the stress response?

Accepted Answer

CRH is released from the hypothalamus in response to stress and stimulates ACTH release from the anterior pituitary.

Question 18

Which of the following is NOT a function of cortisol?

Accepted Answer

Promoting protein synthesis in muscle

Question 19

A multi-step scenario: A patient is exposed to chronic stress. Trace the hormonal pathway and predict the long-term effect on blood glucose levels.

Accepted Answer

Chronic stress $$\rightarrow$$ increased CRH $$\rightarrow$$ increased ACTH $$\rightarrow$$ increased cortisol $$\rightarrow$$ increased gluconeogenesis $$\rightarrow$$ elevated blood glucose

Question 20

Which of the following best explains why a single hormone can have different effects on different tissues?

Accepted Answer

Different tissues express different receptor subtypes for the hormone, leading to varied cellular responses.

Endocrine System: Hormones, Feedback Mechanisms, and Disorders

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