Q: Which equation best represents the amplification effect of the cyclic AMP (cAMP) signaling mechanism, where one hormone binding can ultimately activate millions of proteins?

$$1 \times 10 \times 10 \times 500 \times 500 = 2,500,000$$

Q: Which equation represents the conversion of T4 to T3 in target tissues?

$$\text{T}_4 \rightarrow \text{T}_3 + \text{Iodine}$$

Question 1

Which of the following best describes the primary difference between the nervous system and the endocrine system in terms of signal transmission?

Accepted Answer

The nervous system uses action potentials and neurotransmitters for rapid, short-distance signaling, while the endocrine system uses hormones released into the blood for slower, long-distance signaling.

Question 2

A patient presents with symptoms of excessive thirst, large urine output, and must remain well hydrated. Which hormone deficiency is most likely responsible for these symptoms?

Accepted Answer

Antidiuretic hormone (ADH)

Question 3

Which of the following hormones is synthesized from cholesterol and can cross the plasma membrane to bind to intracellular receptors?

Accepted Answer

Cortisol

Question 4

Which equation best represents the amplification effect of the cyclic AMP (cAMP) signaling mechanism, where one hormone binding can ultimately activate millions of proteins?

Accepted Answer

$$1 	imes 10 	imes 10 	imes 500 	imes 500 = 2,500,000$$

Question 5

Which hormone is NOT a tropic hormone?

Accepted Answer

Prolactin (PRL)

Question 6

A child is diagnosed with pituitary dwarfism. Which hormone is deficient, and what is the most likely effect on bone growth?

Accepted Answer

Growth hormone; deficient long bone lengthening

Question 7

Which of the following is a correct statement about water-soluble hormones?

Accepted Answer

They are stored in secretory vesicles and act through second-messenger systems.

Question 8

Which mechanism is used by oxytocin to exert its effects on target cells?

Accepted Answer

PIP2 – Calcium second messenger system

Question 9

A patient with hyperparathyroidism is likely to experience which of the following?

Accepted Answer

High blood calcium levels, bone softening, and kidney stones

Question 10

Which hormone interaction describes the relationship between insulin and glucagon?

Accepted Answer

Antagonism

Question 11

Which of the following best explains why steroid hormones have a longer half-life in blood compared to water-soluble hormones?

Accepted Answer

Steroid hormones are bound to plasma proteins, which slows their removal.

Question 12

Which layer of the adrenal cortex secretes cortisol?

Accepted Answer

Zona fasciculata

Question 13

Which hormone is released in response to low blood glucose and stimulates glycogen breakdown in the liver?

Accepted Answer

Glucagon

Question 14

Which equation represents the conversion of T4 to T3 in target tissues?

Accepted Answer

$$	ext{T}_4 ightarrow 	ext{T}_3 + 	ext{Iodine}$$

Question 15

Which hormone is secreted by the parafollicular cells of the thyroid gland and acts to decrease blood calcium levels?

Accepted Answer

Calcitonin

Question 16

Which hormone is secreted by pancreatic beta cells and lowers blood glucose levels?

Accepted Answer

Insulin

Question 17

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

Accepted Answer

Decreases rate of cellular glucose uptake and metabolism, raising blood glucose levels

Question 18

Which hormone is released by the heart in response to high blood pressure and acts to decrease blood pressure by blocking renin and aldosterone secretion?

Accepted Answer

Atrial natriuretic peptide (ANP)

Question 19

Which hormone is permissive for reproductive hormones, meaning reproductive hormones cannot exert their effects without it being present?

Accepted Answer

Thyroid hormone

Question 20

Which hormone is most likely to be elevated in a patient with Graves’ disease, and what is the primary mechanism causing this elevation?

Accepted Answer

T3/T4; autoantibodies mimic TSH and stimulate thyroid follicle cells

The Endocrine System: Structure, Function, and Regulation

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