anatomy

Question 1

location of the pituitary gland

Answer 1

at the base of the brain beneath the third ventricle

Question 2

embryology of the anterior pituitary (adenohypophysis)

Answer 2

epithelial upgrowth from Rathkr’s pouch, the roof of the primitive oral cavity (aka the pharynx)

Question 3

embryology of the posterior pituitary (neurohypophysis)

Answer 3

downgrowth of nervous tissue from the hypothalamus/neuroectoderm (diencephalon)

Question 4

hormones produced by the anterior pituitary

Answer 4

follicule stimulating hormone, luteinizing hormone, thyroid stimulating hormone, prolactin, growth hormone, adrenocorticotropic hormone, melanocyte stimulating hormone

Question 5

hormones produced by the posterior pituitary

Answer 5

antidiuretic hormone, oxytocin

Question 6

anterior pituitary staining under H&E stain

Answer 6

darkly stained

Question 7

posterior pituitary staining under H&E stain

Answer 7

lightly stained

Question 8

parts (pars) of the anterior pituitary and the cells they contain

Answer 8

pars tuberalis, pars intermedia (contains MSH-secreting melanotrophs), pars distalis (contains gonadotrophs, acidophils, basophils)

Question 9

difference between chromophils and chromophobes (both found in anterior pituitary)

Answer 9

chromophils: contain large number of granules which appear as dense large dots
chromophobes: degranulated, do not stain under H&E stain

Question 10

types of chromophils in anterior pituitary and their secretions

Answer 10

acidophils (stained rich pink): somatotrophs (GH), mammotrophs (PRL)

basophils (stained darkly blue): gonadotrophs (FSH, LH), corticotrophs (ACTH), thyrotrophs (TSH)

Question 11

posterior pituitary cells

Answer 11

non-myelinated axons of specialized neurons - the cell bodies are located in the supraoptic nuclei (SON) and paraventricular optic nuclei (PVN) of the hypothalamus where ADH and oxytocin are produced and stored

Question 12

what are Herring bodies? (found in posterior pituitary)

Answer 12

neurosecretory granules containing ADH or oxytocin, accumulating in neuronal axons where they contact a large number of capillaries. they are supported by pituicytes (specialized highly branched glial cells)

Question 13

blood supply of the anterior pituitary

Answer 13

internal carotid artery branching into superior hypophyseal arteries branching into secondary capillary plexus

Question 14

blood supply of the posterior pituitary

Answer 14

internal carotid artery branching into inferior hypophyseal arteries

Question 15

how is the release of hormones from the pars distalis of the anterior pituitary regulated?

Answer 15

controlled by the hypothalamic hypophyseal portal system: release of regulatory hormones from the hypothalamus into the primary capillary plexus –> secondary capillary plexus

additional control by negative feedback

Question 16

location of the thyroid gland

Answer 16

anterior and inferior to the larynx in the neck

Question 17

shape of the thyroid gland

Answer 17

butterfly shaped gland with two lobes connected by an isthmus

Question 18

embryology of the thyroid gland

Answer 18

develops from foregut endoderm near the base of the developing tongue

Question 19

functional units of the thyroid gland (histology)

Answer 19

thyroid follicles, composed of a single layer of flattened squamous (inactive) or columnar (active) epithelial cells bounded by a basement membrane

and C / parafollicular cells found as individual scattered cells in the follicle lining or small clumps between follicles

Question 20

contents of thyroid follicles

Answer 20

colloid material storing thyroglobulin (storage form of thyroxine T4 and tri-iodothyronine T3)

Question 21

function of C / parafollicular cells

Answer 21

secrete calcitonin hormone which lowers blood Ca2+ level

Question 22

location of parathyroid gland

Answer 22

4 ovoid masses lying on the posterior surface of the thyroid gland within its capsule

Question 23

parathyroid histology

Answer 23

chief cells that secrete parathyroid hormone, oxyphil cells (large degenerated chief cells) which are stained dark pink

Question 24

function of parathyroid hormone

Answer 24

increases blood Ca2+ levels by activating osteoclasts:
a) stimulating bone resorption (releasing Ca2+ into blood)
b) increasing absorption of Ca2+ (in small intestine via vit D absorption)
c) decreasing Ca2+ excretion in DCT of renal cortex

Question 25

location and description of adrenal gland

Answer 25

small flattened endocrine glands which are applied to the upper pole of each kidney, consisting of the adrenal cortex and medulla

Question 26

adrenal cortex components (and histology)

Answer 26

zona glomerulosa: secretes mineralocorticoids, mostly aldosterone
zona fasciulata: vacuolated appearance, lightly stained due to lipids, secretes glucocorticoids, mostly cortisol (and some androgens)
zona reticularis: heavily stained, secretes glucocorticoids and androgens

Question 27

what hormone controls the secretions of zona fasciulata and reticularis

Answer 27

ACTH (adrenocorticotropic hormone)

Question 28

adrenal medulla histology

Answer 28

clusters of cells (chromaffin cells and ganglion cells) that are large, pale staining, polyhedral, and electron-dense granules containing catecholamines

Question 29

adrenal cortex embryology

Answer 29

develops from the mesoderm

Question 30

adrenal medulla embryology

Answer 30

develops from the neural crest

Question 31

endocrine pancreas cells and secretions

Answer 31

α cells (glucagon), β cells (insulin), delta cells (somatostatin), PP/F cells (pancreatic polypeptide)

Question 32

endocrine pancreas (islets of Langerhans) histology

Answer 32

α-cells stain deep pink, β-cells stain light pink, islets of Langerhans present in cords separated by fenestrated capillaries