Histology Testbank: Endocrine 7a

Instructions: For each histology question, pick the one best answer. This histology test bank is also useful for the histology questions on the USMLE (USMLE step 1).

1.
What type of hormone is epinephrine?
a. Protein
b. Amino acid chain
c. Steroid
d. Catecholamine
e. None of the above

Answer: d

Hormones can have a variety of structures. Hormones which are proteins include insulin and prolactin. Peptide chains are short chains of amino acids. Examples of hormones which are peptide chains are antidiuretic hormone and oxytocin. Steroid hormones are cholesterol derivatives. Steroid hormones include testosterone and estradiol. Norepinephrine and epinephrine are catecholamines.

2.
What is another term for the posterior lobe of the pituitary?
a. Pars intermedia
b. Pars tuberalis
c. Pars distalis
d. Pars nervosa
e. Infundibular stalk

Answer: d

The pituitary can be subdivided into the adenohypophysis and neurohypophysis. The adenohypophysis can be further sub-divided into the pars distalis, pars intermedia, and pars tuberalis. The pars distalis is the anterior lobe of the pituitary. The neurohypophysis can be further sub-divided into the pars nervosa, infundibular stalk, and median eminence. The pars nervosa is the posterior lobe.

3.
What cell type secretes TSH?
a. Lactotropic cells
b. Thyrotropic cells
c. Somatotropic cells
d. Corticotropic cells
e. Gonadotropic cells

Answer: b

There are several cell types in the pars distalis (anterior pituitary). Lactotropic cells secrete prolactin. Thyrotropic cells secrete thyroid stimulating hormone (TSH). Somatotropic cells secrete growth hormone. Corticotropic cells secrete adrenocorticotropic hormone (ACTH) and melanocyte-stimulating hormone (MSH). Gonadotropic cells secrete follicle stimulating hormone (FSH) and luteinizing hormone (LH).

4.
Which of the following cells can be classified as a basophil?
a. Corticotropic cells
b. Thyrotropic cells
c. Gonadotropic cells
d. None of the above
e. All of the above

Answer: e

The cells of the pars distalis (anterior pituitary) can be classified as acidophils or basophils depending on their affinity for acid or basic dyes, respectively.

The acidophils are the somatotropic cells and the lactotropic cells. Thus, growth hormone and prolactin are secreted by acidophilic cells.

The basophils are the gonadotropic cells, corticotropic cells and thyrotropic cells. Thus, the basophils secrete FSH, LH, ACTH, and TSH. Histology hint from Sarah Bellham: There are two mnemonics to use when thinking of acidophils and basophils of the anterior pituitary. "GPA" (growth hormone and prolactin are secreted by the acidophils). "B-FLAT" (basophils secrete FSH, LH, ACTH, and TSH).

5.
Which gland secretes insulin?
a. Pancreas
b. Thyroid
c. Pineal gland
d. Adrenal gland (cortex)
e. Adrenal gland (medulla)

Answer: a

The endocrine portion of the pancreas secretes insulin, glucagon, and somatostatin. The thyroid gland secretes the thyroid hormones (T3 and T4) and calcitonin. The pineal gland secretes melatonin. The cortex of the adrenal gland secretes a variety of corticosteroids. It secretes mineralocorticoids (such as aldosterone), glucocorticoids (such as cortisol) and sex steroids. Epinephrine and norepinephrine are secreted from the adrenal medulla.

6.
Which part the adrenal gland secretes sex steroids?
a. Chromaffin cells
b. Zona reticularis
c. Zona glomerulosa
d. Zona fasciculata
e. None of the above

Answer: b

The adrenal gland is composed of the adrenal cortex and the adrenal medulla.

The layers of the adrenal cortex, from outermost to innermost are: zona glomerulosa, zona fasciculata, and zona reticularis. The respective principle products are: mineralocorticods, glucocorticoids, and sex steroids.

The cells of the adrenal medulla are chromaffin cells. They secrete the catecholamines (epinephrine and norepinephrine).

Histology hint from Sarah Bellham: A mnemonic to remember the layers of the adrenal cortex and their respective products is "Go Find Rex; Make Good Sex" (glomerulosa, fasciculata, reticularis) (mineralocorticoid, glucocorticoid, sex steroids).

7.
What is the classification of the pancreas?
a. Mixed
b. Endocrine
c. Exocrine
d. Both endocrine and exocrine
e. None of the above

Answer: d

The pancreas is both an endocrine and exocrine organ.

8.
Where in the pancreas are islets of Langerhans most numerous?
a. Head
b. Body
c. Tail
d. Evenly distributed
e. Depends on the individual

Answer: c

Islets of Langerhans are most numerous in the tail of the pancreas.