Question 1

Which of the following best describes a key difference between the endocrine and nervous systems in terms of how they control body functions?

Accepted Answer

The endocrine system initiates responses that typically occur after a lag period of seconds or even days.

Question 2

Which organelle is primarily responsible for the synthesis of steroid hormones?

Accepted Answer

Smooth endoplasmic reticulum

Question 3

Amino acid-based hormones are generally characterized by which of the following properties?

Accepted Answer

Most cannot cross the plasma membrane.

Question 4

Which of the following is NOT a typical target cell response to hormone stimulation?

Accepted Answer

Inhibiting all protein synthesis

Question 5

Why do lipid-soluble hormones act on intracellular receptors while water-soluble hormones act on plasma membrane receptors?

Accepted Answer

Lipid-soluble hormones can diffuse into the cell and bind to intracellular receptors.

Question 6

Order the following steps of the cyclic AMP signaling mechanism for water-soluble hormones:
1. The membrane receptor activates by changing its shape after binding with a hormone.
2. The activated membrane receptor binds to and activates G protein.
3. Activated G protein activates (or inactivates) the effector enzyme adenylate cyclase.
4. Activated adenylate cyclase catalyzes reactions that convert ATP to cyclic AMP.
5. Cyclic AMP activates protein kinases that cause metabolic and structural changes.
Which is the correct sequence?

Accepted Answer

$$1 \rightarrow 2 \rightarrow 3 \rightarrow 4 \rightarrow 5$$

Question 7

Which mechanism most commonly regulates the release of hormones in the body?

Accepted Answer

Negative feedback mechanisms

Question 8

Which of the following hormones is primarily released in response to humoral stimuli?

Accepted Answer

Parathyroid hormone

Question 9

A patient has persistently low levels of a hormone. Which cellular mechanism is most likely to occur in response?

Accepted Answer

Up-regulation

Question 10

Which of the following applies more to lipid-soluble hormones than to water-soluble hormones?

Accepted Answer

Longer half-life in blood

Question 11

Which hormone is labeled 'A' in the diagram showing the regulation of thyroid hormone secretion?

Accepted Answer

Thyrotropin-releasing hormone (TRH)

Question 12

Which of the following is a major effect of thyroid hormone ($$T_3$$ and $$T_4) in $$the body?

Accepted Answer

Increases the rate of cellular metabolism

Question 13

A patient presents with an enlarged, protruding thyroid gland (goiter). Which of the following best explains why this occurs in the context of iodine deficiency?

Accepted Answer

Follicular cells produce colloid but cannot iodinate it, leading to accumulation and gland enlargement.

Question 14

What is the primary trigger for parathyroid hormone (PTH) release?

Accepted Answer

Low blood levels of calcium ions

Question 15

Which of the following is a major effect of parathyroid hormone (PTH) release?

Accepted Answer

Increase blood levels of calcium ions

Question 16

Which layer of the adrenal gland produces aldosterone?

Accepted Answer

Zona glomerulosa

Question 17

A patient is experiencing symptoms of long-term stress. Which hormones are primarily responsible for mediating the body's response to long-term stress?

Accepted Answer

Glucocorticoids from the adrenal cortex

Question 18

Which of the following best describes the effect of aldosterone on electrolyte balance?

Accepted Answer

Reduces excretion of $$Na^+$$ from the body

Question 19

Which of the following is a direct effect of growth hormone (GH)?

Accepted Answer

Promotes glucose sparing

Endocrine System Regulation: Thyroid Hormone Secretion and Disorders

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