Histology Testbank: Endocrine 2a
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).
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.
The pituitary is nicknamed the master gland. The infundibulum connects the pituitary to the hypothalamus. 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 adenohypophysis (more specifically, the pars distalis of the adenohypophysis) secretes tropic hormones. Tropic hormones affect cellular activity in their target organ. The neurohypophysis secretes two hormones: oxytocin and antidiuretic hormone.
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.
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).
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 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.
There are two cell types in the parathyroid gland: principal cells and oxyphil cells. Principal cells are also called chief cells. Principal cells are the more prevalent. Oxyphil cells are also found in the parathyroid gland; however they are not as prevalent as principal cells.
There are two cell types in the thyroid: follicular cells and parafollicular cells. Follicular cells release and store thyroid hormone. Parafollicular cells of the thyroid gland are also called C cells. They secrete calcitonin.
The cells of the adrenal medulla are chromaffin cells.
The pancreas is both an endocrine and exocrine organ.
The endocrine portion of the pancreas is housed in the islets of Langerhans. Within the islets, there are several cell types. The alpha cells secrete glucagon. The beta cells secrete insulin. The delta cells secrete somatostatin. The gamma cells secrete pancreatic polypeptide.
The acini is the exocrine portion of the pancreas.
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).
The cells of the pineal gland called pinealocytes. There are also glial cells in the pineal gland. PP cells are cells in the pancreas which secrete pancreatic polypeptide.
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