$$\mathrm{ATP} \xrightarrow{\text{adenylate cyclase}} \mathrm{cAMP} + \mathrm{PP_i}$$

Question 1

Which of the following best describes the primary function of the endocrine system?

Accepted Answer

To influence metabolic activities of cells and organs by means of hormones

Question 2

Which gland is both an endocrine and exocrine organ, producing hormones and non-hormonal products?

Accepted Answer

Pancreas

Question 3

Which of the following is NOT considered a hormone because it does not act as a long-distance chemical signal?

Accepted Answer

Paracrine

Question 4

Amino acid-based hormones typically exert their effects on target cells by:

Accepted Answer

Binding to plasma membrane receptors and activating second messenger systems

Question 5

Which of the following hormones is derived from cholesterol?

Accepted Answer

Testosterone

Question 6

Which hormone is released in response to declining blood calcium levels, and what is its effect?

Accepted Answer

Parathyroid hormone (PTH); increases blood calcium by stimulating bone resorption

Question 7

Which of the following best illustrates the concept of 'synergism' in hormone interactions?

Accepted Answer

Thyroid hormone and growth hormone together amplify growth effects

Question 8

A patient presents with abnormally tall stature and open epiphyseal plates. Which condition is most likely?

Accepted Answer

Gigantism

Question 9

Which hormone is responsible for stimulating milk production in females, and what regulates its release?

Accepted Answer

Prolactin; regulated by prolactin-releasing hormone (PRH) and inhibited by dopamine

Question 10

Which of the following is a correct sequence for the cAMP second messenger pathway activated by an amino acid-based hormone?

Accepted Answer

Hormone binds receptor → G protein activated → Adenylate cyclase activated → cAMP produced → Protein kinases activated

Question 11

Which of the following equations correctly represents the conversion of ATP to cAMP by adenylate cyclase?

Accepted Answer

$$\mathrm{ATP} \xrightarrow{	ext{adenylate cyclase}} \mathrm{cAMP} + \mathrm{PP_i}$$

Question 12

Which hormone is released from the posterior pituitary and is involved in water balance?

Accepted Answer

Antidiuretic hormone (ADH)

Question 13

Which of the following best explains 'up-regulation' of hormone receptors?

Accepted Answer

Target cells form more receptors in response to increased hormone levels

Question 14

Which hormone is released in response to neural stimuli from preganglionic sympathetic fibers?

Accepted Answer

Catecholamines (epinephrine and norepinephrine)

Question 15

Which of the following is a correct example of hormonal stimuli?

Accepted Answer

Hypothalamic hormones stimulate the anterior pituitary to release hormones

Question 16

Which hormone is responsible for stimulating the adrenal cortex to release corticosteroids?

Accepted Answer

Adrenocorticotropic hormone (ACTH)

Question 17

Which of the following hormones is absent from the blood in prepubertal boys and girls?

Accepted Answer

Follicle-stimulating hormone (FSH)

Question 18

Which hormone uses the PIP2-calcium second messenger mechanism?

Accepted Answer

Oxytocin

Question 19

Which of the following is a correct description of the vascular connection between the hypothalamus and anterior pituitary?

Accepted Answer

The hypophyseal portal system, consisting of the primary capillary plexus, portal veins, and secondary capillary plexus

The Endocrine System: Structure, Function, and Hormone Classification

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