Q: Which of the following equations best represents the negative feedback regulation of thyroid hormone production?

$$TRH \rightarrow TSH \rightarrow T_3$/T_4$ \rightarrow \text{inhibition of TRH and TSH}$$

Question 1

Which of the following best describes how hormones differ from neurotransmitters in their signaling mechanisms?

Accepted Answer

Hormones are released into the bloodstream and can affect distant target cells, while neurotransmitters are released at synapses and act locally.

Question 2

A patient is diagnosed with a tumor in the anterior pituitary gland that causes excessive secretion of ACTH (adrenocorticotropic hormone). Which of the following is a likely consequence due to feedback regulation?

Accepted Answer

Increased secretion of cortisol from the adrenal cortex, which will eventually suppress ACTH production via negative feedback.

Question 3

Which of the following is an example of a negative feedback loop in the endocrine system?

Accepted Answer

The secretion of insulin in response to high blood glucose, which lowers blood glucose and reduces further insulin release.

Question 4

Which of the following best explains why steroid hormones can pass through cell membranes, while peptide hormones cannot?

Accepted Answer

Steroid hormones are lipid-soluble, allowing them to diffuse through the phospholipid bilayer of cell membranes.

Question 5

A researcher injects a hormone into an animal and observes that the hormone binds to receptors inside the cell nucleus. Which type of hormone is most likely being studied?

Accepted Answer

A steroid hormone such as cortisol.

Question 6

Which of the following correctly matches a hormone with its gland of origin and primary function?

Accepted Answer

Cortisol – adrenal cortex – regulates metabolism and stress response.

Question 7

If a person’s thyroid gland is removed, which of the following physiological changes would most likely occur?

Accepted Answer

Decreased metabolic rate due to lack of thyroid hormone.

Question 8

Which of the following best describes the role of the hypothalamus in endocrine regulation?

Accepted Answer

It produces releasing and inhibiting hormones that regulate the anterior pituitary.

Question 9

A person is exposed to chronic stress, resulting in prolonged high levels of cortisol. Which of the following is a likely long-term effect?

Accepted Answer

Suppressed immune function due to chronic cortisol exposure.

Question 10

Which of the following equations best represents the negative feedback regulation of thyroid hormone production?

Accepted Answer

$$TRH ightarrow TSH ightarrow T_3$/T_4$ ightarrow 	ext{inhibition of TRH and TSH}$$

Question 11

Which hormone is secreted by the adrenal medulla and what is its primary effect?

Accepted Answer

Epinephrine; initiates the fight-or-flight response.

Question 12

Which of the following best explains why different target cells can respond differently to the same hormone?

Accepted Answer

Target cells have different receptors or signal transduction pathways.

Question 13

Which of the following is a function of aldosterone?

Accepted Answer

Promotes sodium reabsorption in the kidneys, increasing blood pressure.

Question 14

Which of the following is NOT a steroid hormone produced by the adrenal cortex?

Accepted Answer

Epinephrine

Question 15

A person with Addison’s disease has low levels of cortisol and aldosterone. Which symptoms would you expect?

Accepted Answer

Low blood pressure and hypoglycemia.

Question 16

Which of the following best describes the difference between paracrine and endocrine signaling?

Accepted Answer

Paracrine signals act on nearby cells; endocrine signals travel through the bloodstream to distant targets.

Question 17

Which of the following is a correct sequence of hormone signaling from the hypothalamus to the adrenal cortex?

Accepted Answer

$$CRH \rightarrow ACTH \rightarrow Cortisol$$

Question 18

Which hormone is primarily responsible for stimulating the release of glucose from the liver during fasting?

Accepted Answer

Glucagon

Question 19

Which of the following best explains why steroid hormones typically have longer-lasting effects than peptide hormones?

Accepted Answer

Steroid hormones alter gene expression, leading to sustained changes in cell function.

Question 20

Which of the following is a function of androgens produced by the adrenal cortex?

Accepted Answer

Development of secondary sexual characteristics.

Hormones and the Endocrine System: Study Notes

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