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

$$\text{TRH} \rightarrow \text{TSH} \rightarrow \text{Thyroid Hormone} \dashv \text{TRH, TSH}$$

Q: Which of the following is a correct sequence of hormone release in the stress response involving the adrenal cortex?

$$\text{CRH} \rightarrow \text{ACTH} \rightarrow \text{Cortisol}$$

Question 1

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

Accepted Answer

Endocrine signaling involves hormones traveling through the bloodstream to distant target cells, while paracrine signaling involves local regulators affecting nearby cells by diffusion.

Question 2

Nitric oxide (NO) acts as both a local regulator and a neurotransmitter. What is one physiological effect of NO in the human body?

Accepted Answer

It activates an enzyme that causes vasodilation, increasing blood flow to tissues.

Question 3

Which of the following hormones is lipid-soluble and binds to intracellular receptors to regulate gene expression?

Accepted Answer

Cortisol

Question 4

A patient is given a drug that blocks G protein-coupled receptors. Which hormone’s action would be most directly affected?

Accepted Answer

Epinephrine

Question 5

Which of the following best explains why the same hormone, epinephrine, can cause different responses in different tissues?

Accepted Answer

Different tissues may have different receptors or different signal transduction pathways for the same hormone.

Question 6

Which of the following is an example of negative feedback in hormone regulation?

Accepted Answer

Increased thyroid hormone levels inhibit the release of TRH and TSH.

Question 7

A researcher injects a water-soluble hormone into the bloodstream. Which of the following is most likely to occur?

Accepted Answer

The hormone will bind to receptors on the plasma membrane of target cells.

Question 8

Which hormone is released from the posterior pituitary and is involved in water retention by the kidneys?

Accepted Answer

Antidiuretic hormone (ADH)

Question 9

A patient has a tumor that causes excessive secretion of ACTH. Which of the following is a likely consequence?

Accepted Answer

Increased cortisol production by the adrenal cortex

Question 10

Which of the following best describes the role of insulin-like growth factors (IGFs) in the body?

Accepted Answer

They stimulate bone and cartilage growth in response to growth hormone.

Question 11

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

Accepted Answer

$$	ext{TRH} ightarrow 	ext{TSH} ightarrow 	ext{Thyroid Hormone} \dashv 	ext{TRH, TSH}$$

Question 12

A person is exposed to chronic stress. Which hormone is most likely to be elevated as a result of activation of the hypothalamic-pituitary-adrenal (HPA) axis?

Accepted Answer

Cortisol

Question 13

Which of the following is a correct sequence of hormone release in the stress response involving the adrenal cortex?

Accepted Answer

$$	ext{CRH} ightarrow 	ext{ACTH} ightarrow 	ext{Cortisol}$$

Question 14

Which of the following best explains why steroid hormones require transport proteins in the blood?

Accepted Answer

Steroid hormones are hydrophobic and do not dissolve readily in blood plasma.

Question 15

A patient with low blood calcium is found to have underactive parathyroid glands. Which hormone is most likely deficient?

Accepted Answer

Parathyroid hormone (PTH)

Question 16

Which of the following is a real-life example of positive feedback in the endocrine system?

Accepted Answer

The release of oxytocin during childbirth increases uterine contractions, which further stimulates oxytocin release.

Question 17

Which hormone is primarily responsible for the development of male secondary sex characteristics?

Accepted Answer

Testosterone

Question 18

Which of the following best describes the function of tropic hormones released by the anterior pituitary?

Accepted Answer

They stimulate other endocrine glands to release their hormones.

Question 19

A mutation causes a liver cell to lack receptors for epinephrine. What is the most likely consequence when the body experiences stress?

Accepted Answer

The liver cell will not release glucose into the bloodstream in response to epinephrine.

Question 20

Which of the following best explains why water-soluble hormones cannot pass through the plasma membrane?

Accepted Answer

They are hydrophilic and cannot cross the hydrophobic core of the lipid bilayer.

Hormones and the Endocrine System: Regulation and Integration in Animals

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