Question 1

Which of the following best describes the mechanism by which peptide hormones exert their effects on target cells?

Accepted Answer

They bind to plasma membrane receptors and utilize second messenger systems to modify existing proteins.

Question 2

A patient is diagnosed with hypersecretion of cortisol due to an exogenous source. Which of the following is most likely to occur as a result?

Accepted Answer

Atrophy of the adrenal gland due to decreased endogenous hormone production.

Question 3

Which hormone is released from the posterior pituitary and is involved in water retention by the kidneys?

Accepted Answer

Vasopressin (antidiuretic hormone, ADH)

Question 4

Steroid hormones differ from peptide hormones in their transport through the blood. Which statement accurately reflects this difference?

Accepted Answer

Steroid hormones require carrier proteins for transport because they are nonpolar.

Question 5

A hormone has a half-life of 5 minutes. If its initial concentration is 80 ng/mL, what will its concentration be after 15 minutes?

Accepted Answer

$$10\ 	ext{ng/mL}$$

Question 6

Which of the following is an example of a permissive hormone interaction?

Accepted Answer

Thyroid hormones allowing sex hormones to exert their full effect during development.

Question 7

Which hormone is synthesized in the rough endoplasmic reticulum (RER) and stored in vesicles until needed?

Accepted Answer

Insulin

Question 8

A patient presents with symptoms of hyposecretion of thyroid hormone. Which of the following could be a primary pathology?

Accepted Answer

Impaired function of the thyroid gland itself.

Question 9

Which of the following best describes the hypothalamic-hypophyseal portal system?

Accepted Answer

Two sets of capillaries connected in series by small veins, allowing hypothalamic hormones to reach the anterior pituitary.

Question 10

Which of the following hormones is derived from tyrosine and acts as a catecholamine?

Accepted Answer

Epinephrine

Question 11

A patient is experiencing symptoms of diabetes insipidus, characterized by excessive urination and thirst. Which hormone is most likely deficient?

Accepted Answer

Vasopressin (ADH)

Question 12

Which of the following is a characteristic of steroid hormone action?

Accepted Answer

They bind to cytoplasmic and nuclear receptors, causing gene activation and production of new proteins.

Question 13

Which feedback loop involves the peripheral gland hormone feeding back to the hypothalamus and pituitary?

Accepted Answer

Long-loop negative feedback

Question 14

Which of the following best illustrates a functional antagonist relationship?

Accepted Answer

Glucagon and insulin regulating blood glucose levels.

Question 15

A hormone is secreted into the blood and acts on a distant target at very low concentrations. Which of the following is NOT a hormone according to this definition?

Accepted Answer

A cytokine that acts locally at high concentrations.

Question 16

Which of the following is true regarding hormone degradation and removal from the body?

Accepted Answer

Hormones are primarily degraded by enzymes in the liver and kidneys and excreted in bile or urine.

Question 17

Which of the following scenarios best demonstrates the effect of emotional stress on endocrine function?

Accepted Answer

Disruption of the menstrual cycle in women due to stress.

Question 18

Which of the following hormones is released as it is synthesized and cannot be stored due to its nonpolar nature?

Accepted Answer

Cortisol

Question 19

A patient has elevated levels of a hormone due to a receptor abnormality causing down regulation. What is the most likely consequence?

Accepted Answer

Decreased tissue responsiveness due to fewer receptors.

Question 20

Which of the following best describes the cellular mechanism of action for thyroid hormones?

Accepted Answer

They bind to nuclear receptors and cause gene activation.

Introduction to the Endocrine System: Hormones and Their Regulation

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