Lecture 23: Endocrine Microanatomy Flashcards
what are glands developed from
down growth of epithelium
name the two types of glands
exocrine and endocrine
give the main difference between exocrine and endocrine glands
exocrine maintain contact with epithelium surface while endocrine have no connection with epi surface (isolated mass with own blood supply)
where is the pituitary located
sella turcica of sphenoid bone enclosed by CT capsule
what is the embryological origin of the ant. pit.
- Buccal ectoderm
- upward extension of Rathke’s pouch (mouth)
what is the embryological origin of the post. pit.
- down growth of neuroectoderm
where is the hypothalamus located within the brain
on the floor of the third ventricle
name the stalk that connects the hypothalamus and pituitary
infundibulum
name the 3 parts of the ant. pit.
- pars tuberalis
- pars intermedia
- pars distalis
what is the function of the pars intermedia
division between post. and ant. lobes of pit.
name the 2 parts of the post. pit.
- infundibular stalk
- pars nervosa
name the space between the pituitary and the sphenoid bone
hypophyseal fossa
which lobe of pituitary stains lighter histologically and why
- post. pit.
- has lots of neurons
- ant. contains lots of glandular secretory cells that stain darker
name the two types of cells in ant. pit. based on histochemical staining
- chromophils
- chromophobes
outline the difference between chromophils and chromophobes
Chromophils:
- bright staining glandular cells arr. in nests or cords
- surrounded by many caps.
- two subtypes –> acidophils (red) and basophils (dark)
Chromophobes:
- pale staining
- exhausted or quiescent chromophils
name the two subtypes of chromophils
- acidophils (red)
- basophils (dark)
why do basophils stain darker than acidophils
they contain more granular content
name the 5 different cell types that make up the ant. pit. and what hormone they secrete
- somatotrophs –> growth hormone
- mammotrophs –> prolactin
- corticotrophs –> ACTH
- thyrotrophs –> TSH
- gonadotrophs –> FSH and LH
what hormone do axons from supraoptic nucleus produce
ADH
what hormone do axons from paraventricular nucleus produce
oxytocin
what are herring bodies
dilations of axons for storage of hormones
what are pituicytes
support cells in post. pit. (similar to glial cells of CNS)
describe the histology of post. pit.
- herring bodies
- unmyelinated axons
- pituicytes
- highly vascular
through what vessel are hormones released from the pituitary
hypophyseal vein
what is the embryological origin of the thyroid gland
fetal tongue down growth
where is the thyroid gland located
anterior and lateral surface of upper trachea
define goitre
swelling of neck - enlargement of thyroid
name a function of parathyroid glands
calcium level regulation
describe the thyroid histologically
follicular cells
- apical surface lined w/ microvilli
- simple cuboidal epi
parafollicular (C cells)
- produce calcitonin
- located between follicles or at their periphery
describe the function of calcitonin
decreases blood calcium by decreasing bone resorption by osteoclasts and ^ bone formation by osteoblasts
describe the colloid in both hyper and hypo thyroidism
- hypo = ^ colloid
- hyper = decreased colloid
where are adrenal glands located
embedded in perirenal fat at superior poles of kidneys
what cell type makes up the adrenal medulla
neural crest cells
describe the cells found in the different zones of adrenal cortex
ZG –> rounded groups of cells
ZF –> large vacuolated cells in columns
ZR –> cells arranged in branching irregular networks
name the 4 cell types found in Islets of Langerhans of pancreas and the hormone they produce
- alpha –> glucagon
- beta –> insulin
- delta –> somatostatin
- F cells –> pancreatic polypeptide
describe the arr. of Enteroendocrine cells in the gastrointestinal Enteroendocrine pancreatic (GEP) system
diffusely arr. in GI epi
