Question 1

Which of the following best describes a key difference between the endocrine and nervous systems in terms of their signaling mechanisms and effects?

Accepted Answer

The endocrine system releases hormones into the bloodstream, resulting in slower but longer-lasting effects compared to the nervous system.

Question 2

Which of the following is NOT a general function of hormones in the human body?

Accepted Answer

Initiation of voluntary muscle contraction

Question 3

Which statement correctly distinguishes between exocrine and endocrine glands?

Accepted Answer

Exocrine glands secrete products into ducts, while endocrine glands secrete hormones directly into the bloodstream.

Question 4

A patient is given RU486 (mifepristone) to induce abortion. What is the mechanism by which this drug acts?

Accepted Answer

It binds to progesterone receptors, preventing progesterone from maintaining the uterus.

Question 5

Which of the following best explains the process of up-regulation of hormone receptors?

Accepted Answer

A deficiency of hormone leads to an increase in the number of receptors, making the target tissue more sensitive.

Question 6

Which of the following hormones is lipid-soluble and requires a transport protein in the blood?

Accepted Answer

Thyroid hormone ($$T_3$$ and $$T_4)$$

Question 7

A patient with cholera experiences massive watery diarrhea. What is the underlying cellular mechanism caused by the cholera toxin?

Accepted Answer

The toxin locks G-proteins in an activated state, causing excessive cAMP production and chloride secretion into the intestinal lumen.

Question 8

Which of the following is an example of a synergistic hormonal effect?

Accepted Answer

Estrogen and luteinizing hormone (LH) both required for oocyte production

Question 9

Which feedback mechanism is most commonly used to regulate hormone secretion in the body?

Accepted Answer

Negative feedback

Question 10

A patient presents with symptoms of pituitary dwarfism. Which is the most likely cause?

Accepted Answer

Hyposecretion of human growth hormone during childhood

Question 11

Which hormone is responsible for increasing blood calcium levels by stimulating osteoclast activity and promoting formation of calcitriol?

Accepted Answer

Parathyroid hormone (PTH)

Question 12

A patient with Cushing’s syndrome is likely to exhibit which of the following symptoms?

Accepted Answer

Redistribution of fat, spindly arms and legs, poor wound healing, and easy bruising

Question 13

Which hormone is secreted by the adrenal medulla and is responsible for the fight-or-flight response?

Accepted Answer

Epinephrine

Question 14

Which pancreatic cell type produces insulin, and what is the primary effect of insulin on blood glucose?

Accepted Answer

Beta cells; decreases blood glucose

Question 15

A patient with diabetes mellitus is experiencing polyuria, polydipsia, and polyphagia. Which of the following best explains the underlying cause?

Accepted Answer

Deficiency of insulin leading to hyperglycemia

Question 16

Which hormone is released by the pineal gland and is responsible for setting the biological clock and inducing sleepiness during darkness?

Accepted Answer

Melatonin

Question 17

Which hormone is released in response to dehydration and acts to decrease urine production and increase blood pressure?

Accepted Answer

Antidiuretic hormone (ADH)

Question 18

Aspirin and ibuprofen are effective in treating pain and fever because they inhibit the synthesis of which type of local hormone?

Accepted Answer

Prostaglandins

Question 19

During the alarm reaction of the general adaptation syndrome (GAS), which physiological changes occur?

Accepted Answer

Inhibition of nonessential body functions such as digestion and reproduction

Question 20

Which equation best represents the amplification of hormone effects via second messenger systems?

Accepted Answer

$$1 	ext{ hormone} ightarrow 100 	ext{ G-proteins} ightarrow 1000 	ext{ cAMP} ightarrow 1000 	ext{ kinases}$$

The Endocrine System: Structure, Function, and Regulation

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