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Chapter 14. Endocrine System

Refer to the illustration below to answer the following question.

Image not available.

Which letter on the illustration best designates the cells that secrete hormones that directly regulate the function of the gonads?

A. A

B. B

C. C

D. D

E. E

The answer is D: Cells in the pars distalis (D) secrete somatotropins, prolactin, thyrotropin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and adrenocorticotropic hormone (ACTH). FSH and LH directly regulate gonad function. FSH promotes the growth of ovarian follicles and the secretion of estrogen in females, and spermatogenesis and secretion of androgen-binding protein by Sertoli cells in the testes in males. LH induces ovulation and formation of the corpora lutea in females and stimulates Leydig cells in the testes to synthesize and release testosterone in males.

Refer to the illustration below to answer the following question.

Image not available.

What would be an effect of a lesion that destroys the cells labeled B?

A. Disruption in the rhythmic activity of other endocrine organs

B. Inability to concentrate urine

C. Increased secretion of prolactin

D. Lethargy and weight gain

E. Reduced secretion of adrenal cortical steroids

The answer is B: The cells labeled B secrete oxytocin and antidiuretic hormone (ADH). ADH acts to concentrate urine by increasing the permeability of the collecting tubules of the kidney to water, causing water to be resorbed rather than excreted. Individuals with insufficient ADH are unable to concentrate urine, a condition known as central diabetes insipidus.

A woman is brought to the emergency department complaining of severe pain resulting from kidney stones. After evaluating the patient, the physician discovers that the woman has broken several bones recently, suggesting that her bones are fragile. Laboratory studies show elevated levels of Ca2+ in the blood. An MRI and subsequent biopsy specimen show an adenoma in which endocrine gland or region of gland?

A. Adrenal cortex

B. Adrenal medulla

C. Anterior pituitary gland

D. Follicular cells in the thyroid gland

E. Parafollicular cells in the thyroid gland

F. Parathyroid gland

G. Pineal gland


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