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 receptors on the plasma membrane and activate second messenger systems.

Question 2

A patient is given a synthetic steroid hormone. Which of the following is most likely TRUE regarding its transport and action?

Accepted Answer

It requires carrier proteins for transport and typically has a longer half-life.

Question 3

Which of the following is an example of a hormone that is derived from a single amino acid?

Accepted Answer

Melatonin

Question 4

A researcher measures the half-life of a hormone in the blood and finds it to be 10 minutes. If the initial concentration is 80 ng/mL, what will the concentration be after 30 minutes? Use the formula $$C = C_0$ 	imes (\frac{1}{2}$$)^{t/t_{1/2}$$}.$$

Accepted Answer

$$10 ng/mL$$

Question 5

Which of the following best illustrates a permissive hormone interaction?

Accepted Answer

Thyroid hormones enabling sex hormones to promote normal reproductive development.

Question 6

A patient presents with symptoms of hormone excess due to an exogenous source. What is the most likely long-term effect on the patient’s endocrine gland?

Accepted Answer

Atrophy of the gland due to decreased endogenous hormone production.

Question 7

Which of the following is TRUE regarding the hypothalamic-hypophyseal portal system?

Accepted Answer

It consists of two sets of capillaries connected by small veins, facilitating hormone delivery to the anterior pituitary.

Question 8

Which hormone is secreted by the posterior pituitary and is involved in water balance?

Accepted Answer

Vasopressin (antidiuretic hormone, ADH)

Question 9

A patient has a tumor in the anterior pituitary that causes excess secretion of ACTH. This leads to increased cortisol production. Which type of endocrine pathology is this?

Accepted Answer

Secondary pathology

Question 10

Which of the following best describes the process of down-regulation in hormone signaling?

Accepted Answer

A reduction in the number of receptors on target cells in response to prolonged high hormone levels.

Question 11

Which of the following is a correct example of a synergistic hormone interaction?

Accepted Answer

Glucagon, epinephrine, and cortisol together raising blood glucose more than the sum of their individual effects.

Question 12

Which of the following hormones is NOT secreted by the anterior pituitary?

Accepted Answer

Oxytocin

Question 13

A patient with chronic stress has elevated cortisol levels. Which feedback mechanism is most likely responsible for eventually reducing ACTH secretion?

Accepted Answer

Long-loop negative feedback

Question 14

Which of the following best explains why peptide hormones generally have shorter half-lives than steroid hormones?

Accepted Answer

Peptide hormones are rapidly degraded by enzymes in the plasma.

Question 15

Which of the following scenarios best illustrates a functional antagonist relationship between hormones?

Accepted Answer

Insulin and glucagon regulating blood glucose in opposite directions.

Question 16

A patient is diagnosed with hyposecretion of thyroid hormone due to a defect in the thyroid gland itself. This is an example of:

Accepted Answer

Primary pathology

Question 17

Which of the following is TRUE regarding neurohormones?

Accepted Answer

They are secreted by neurons into the blood to act on distant targets.

Question 18

Which of the following best describes the fate of most hormones after they have exerted their effects?

Accepted Answer

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

Question 19

Which of the following is a direct effect of stress on the endocrine system, as described in the study materials?

Accepted Answer

Disruption of the menstrual cycle in women due to altered pituitary hormone secretion.

Question 20

Which of the following best describes the role of the endocrine cell in a simple endocrine reflex?

Accepted Answer

It acts as the integrating center, sensor, and effector.

Introduction to the Endocrine System: Hormones and Their Regulation

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