Question 1

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

Accepted Answer

Endocrine glands are ductless and secrete hormones directly into the bloodstream, while exocrine glands have ducts and secrete nonhormonal substances onto epithelial surfaces.

Question 2

A patient presents with symptoms of rapid heartbeat, weight loss despite normal eating, and protruding eyes. Laboratory tests reveal elevated levels of thyroid hormone. What is the most likely diagnosis?

Accepted Answer

Graves’ disease

Question 3

Which hormone is produced by the zona glomerulosa of the adrenal cortex, and what is its primary function?

Accepted Answer

Aldosterone; regulates sodium and potassium balance

Question 4

Which of the following hormones is NOT stored in secretory vesicles but is synthesized and released on demand?

Accepted Answer

Cortisol

Question 5

Amino acid–based hormones (except thyroid hormone) exert their effects on target cells by:

Accepted Answer

Binding to plasma membrane receptors and activating second messenger systems such as cAMP

Question 6

Which of the following best explains why steroid hormones have a longer half-life in the bloodstream compared to most amino acid–based hormones?

Accepted Answer

Steroid hormones are bound to plasma proteins, which protects them from rapid degradation.

Question 7

Which of the following is a correct sequence for the cAMP second messenger system?

Accepted Answer

Hormone → receptor → G protein → adenylate cyclase → cAMP → protein kinase

Question 8

A patient with a pituitary tumor is found to have high levels of ACTH and cortisol. What is the most likely feedback mechanism involved?

Accepted Answer

Negative feedback from cortisol to the anterior pituitary is impaired

Question 9

Which of the following best describes the role of parathyroid hormone (PTH) in calcium homeostasis?

Accepted Answer

PTH is released in response to low blood calcium and stimulates osteoclasts, increases calcium reabsorption in the kidneys, and activates vitamin D.

Question 10

Which of the following is a direct effect of insulin on target cells?

Accepted Answer

Increases glucose uptake by muscle and fat cells

Question 11

A patient with untreated Type 1 diabetes mellitus is most likely to develop which of the following complications?

Accepted Answer

Ketoacidosis due to increased fat metabolism

Question 12

Which hormone is primarily responsible for stimulating milk production in females, and what is its main inhibitor?

Accepted Answer

Prolactin; dopamine (prolactin-inhibiting hormone)

Question 13

Which of the following best describes the mechanism of action for lipid-soluble hormones?

Accepted Answer

They bind to intracellular receptors, enter the nucleus, and initiate transcription of specific genes.

Question 14

Which of the following is an example of a humoral stimulus for hormone release?

Accepted Answer

Low blood calcium triggering parathyroid hormone release

Question 15

Which hormone is released from the posterior pituitary and acts to increase water reabsorption in the kidneys?

Accepted Answer

Antidiuretic hormone (ADH)

Question 16

Which of the following is a function of glucocorticoids such as cortisol?

Accepted Answer

Increase blood glucose by promoting gluconeogenesis

Question 17

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

Accepted Answer

Epinephrine; increases heart rate and blood flow to muscles

Question 18

Which of the following best describes receptor upregulation?

Accepted Answer

Target cells increase the number of receptors in response to low hormone levels.

Question 19

Which hormone is secreted by alpha cells of the pancreas and what is its main effect?

Accepted Answer

Glucagon; raises blood glucose

Question 20

A patient with a tumor in the zona fasciculata of the adrenal cortex is most likely to have elevated levels of which hormone, and what is a possible clinical consequence?

Accepted Answer

Cortisol; Cushing’s syndrome with symptoms such as 'moon face' and 'buffalo hump'

The Endocrine System: Structure, Function, and Regulation

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