Q: Which equation best represents the signal amplification that occurs in a second messenger system?

$$\text{1 hormone} \rightarrow \text{1 receptor} \rightarrow \text{many enzymes} \rightarrow \text{many products}$$

Question 1

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

Accepted Answer

Endocrine signaling involves hormones traveling through the blood to distant target cells, while paracrine signaling involves chemical signals acting on nearby cells through extracellular fluid.

Question 2

A patient presents with symptoms of hyperthyroidism, including weight loss, heat intolerance, and increased heart rate. Laboratory tests reveal high levels of T3 and T4, but low levels of TSH. Which disorder is most likely responsible for these findings?

Accepted Answer

Grave’s disease

Question 3

Which of the following hormones is most likely to require a carrier protein for transport in the blood?

Accepted Answer

Cortisol

Question 4

Which equation best represents the signal amplification that occurs in a second messenger system?

Accepted Answer

$$	ext{1 hormone} ightarrow 	ext{1 receptor} ightarrow 	ext{many enzymes} ightarrow 	ext{many products}$$

Question 5

A patient with an adrenal tumor is found to have excess aldosterone secretion. Which of the following changes would you expect in their blood chemistry?

Accepted Answer

Decreased blood potassium and increased blood sodium

Question 6

Which of the following is a direct effect of growth hormone in the short term?

Accepted Answer

Increased blood glucose concentration

Question 7

Which of the following best explains why both hypothyroidism and hyperthyroidism can result in the formation of a goiter?

Accepted Answer

Goiter forms due to overstimulation of the thyroid gland by TSH, which can occur in both conditions.

Question 8

Which of the following best describes the role of the hypothalamic-hypophyseal portal system?

Accepted Answer

It provides a direct blood connection between the hypothalamus and anterior pituitary, allowing rapid and concentrated delivery of releasing hormones.

Question 9

Which of the following is NOT a primary effect of cortisol?

Accepted Answer

Promoting protein synthesis in muscle tissue

Question 10

Which of the following best describes the difference between hydrophilic and hydrophobic hormones in terms of receptor location?

Accepted Answer

Hydrophilic hormones bind to membrane-bound receptors, while hydrophobic hormones bind to intracellular receptors.

Question 11

A patient is experiencing symptoms of hypoglycemia, including shakiness and confusion. Which of the following is the most likely cause?

Accepted Answer

Excess secretion of insulin

Question 12

Which of the following best describes the steps of the cAMP second messenger system?

Accepted Answer

Hormone binds to membrane receptor, activates G protein, stimulates adenylate cyclase, increases cAMP, which activates protein kinase A.

Question 13

Which of the following is a tropic hormone produced by the anterior pituitary?

Accepted Answer

Thyroid-stimulating hormone (TSH)

Question 14

Which of the following best explains the effect of parathyroid hormone (PTH) on blood calcium levels?

Accepted Answer

PTH increases blood calcium by stimulating bone resorption, increasing intestinal absorption, and decreasing renal excretion.

Question 15

Which of the following is a common symptom of hyperthyroidism, and what is the physiological basis for this symptom?

Accepted Answer

Heat intolerance due to increased metabolic rate

Question 16

Which of the following best describes the feedback loop regulating cortisol secretion?

Accepted Answer

Cortisol inhibits the release of CRH from the hypothalamus and ACTH from the anterior pituitary, forming a negative feedback loop.

Question 17

Which of the following best explains why Type 1 diabetes mellitus is more likely to result in ketoacidosis than Type 2 diabetes mellitus?

Accepted Answer

Type 1 diabetes involves absolute insulin deficiency, leading to increased fat breakdown and ketone production.

Question 18

Which of the following hormones is secreted by the pineal gland and what is its primary effect?

Accepted Answer

Melatonin; regulates circadian rhythms

Question 19

A patient has low blood calcium levels. Which of the following changes would you expect in their parathyroid hormone (PTH) secretion, and what type of stimulus is this?

Accepted Answer

Increased PTH secretion; humoral stimulus

The Endocrine System: Structure, Function, and Regulation

Study Guide - Practice Questions

Study Guide - Flashcards