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32 Cards in this Set

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Hypophysis regulates homeostasis
direct interaction - hormones into blood

indirect interaction - hormones that regulate the production of other hormones by adenohypophysis
Paracrine
autocrine
endocrine secretions
paracrine - on cells around you

autocrine - you or cells like you, gene expression

endocrine- blood
Glycoprotein H

plasma carriers
location of receptors
effect
no plasma carriers, SOLUBLE
plasma membrane receptors
second messenger in cytoplasm
Steroid H

plasma carriers
location of receptors
effect
rewuire plasma carrier molec
cytoplasmic receptors
H-receptor complex affects gene expression
Where is the hypophysis located?
base of brain, specifically the third ventricle
SELLA TURCICA, small depression of the sphenoid bone 1-1.15 cm
Adenohypophysis

other name
innervation
Lighter or darker
3 parts
ant pit
portal system, no direct innervation
GLANDULAR and DARK staining

Pars distalis
pars tuberalis
pars intermedia
Neurohypophysis

other name
innervation
unique features
3 parts
post pit
direct innervation
produces no H
pale staining

Pars nervosa
infundibular process
median eminence
Development of adenohypophysis
outpocketing of oral ectoderm, Rathke's pouch, looses its connection, eventually Rathke's cysts in pars interm
Development of neurohypophysis
floor of diencephalon(CNS)
maintains connection via stalk
Blood supply of Adenohypophysis

what is the portal system called, trace the blood flow, where are H secreted into
hypothalamo-hypophyseal portal system

superior hypophyseal artery supplies primary plexus(median eminence/infundubulum) -> hypophyseal portal veins -> secondary plexus(pars distalis)

H secreted into primary cap bed

no blood brain barrier
Blood supply neurohypophysis
inferior hypohyseal artery forms capillary plexus into which oxytocin and vasopressin are secreted
Adenohypophysos cell types
chromophils and chromophobes

chromophils
3 basophils
2 acidophils, refer to staining of cytoplasmic granules, not cytosol
Acidophils
1) somatotrophes
2) Lactotrophes
Basophils

(co-goth)
1) corticotrophes
2)gonadotrophes
3)thyrotrophes
Somatotrophes

abundance
secrete
what secretion does

defining characteristics
most abundant

secrete Growth H - increases metabolic rate and bone elongation

lots of round granules, PAS negative
Lactotrophes

abundance
secretion
what secretion does
defining characteristics
15-20% of cells
secrete prolactin - stim mammary glands,maternal beh

increase in granular size during preg, PAS negative
Corticotrophes

abundance
secretion
what secretion does
secretion derived from?
basophil

15-20% of cells
secretes ACTH(aa)- stim adrenal cortex

derived from - POMC(pre-opiomelanocortin)

POMC-> MSH ->ACTH
POMC also makes endorphins and LPH(lipotropin)
Gonadotrophes

abundance
secretion
what secretion does
basophil

10%
secretes FSH - development of ovarian ollicles and synthesis of androgen-binding protein in males
LH - final maturation of follicles and TT secretion by leydig


sidenote: FSH LH and TSH have same alpha subunit diff beta
Thyrotrophes

abundance
secretion
what secretion does
defining characteristics
5%
secrete TSH glycoprotein - follicular cells of thyroid to produce T3 T4

small granules
TRH
first hypothalamic H to be ID's

tripeptide
graves disease
Ab bind TSH R on thyroid follicular cells,

they continuously produce T3 T4

TSH levels are therefore low
can ablate thyroid for treament
Pars distalis
adenohypophysis

glandular cells in cords/clumps
fenestrated secondary cap plexus

dense collagenous capsule
chromophils and basophils
Pars intermedia
Rathke's cysts lined by cuboidal cells contain colloid

possible basophils
Pars tuberalis
sleeve around infundibulum stalk

major arteries and portal system
Neurohypophysis
what type of axonal system
magnocellular neurosecretory system

vs parvicellular system of adenohypophysis into caps


magno secretes oxytocin and vasopressin
Neurohypophsis

accumulated secretory granules (dilations along axon and termini)
Herring bodies
what type of special cell does the neurohypophysis have?
pituicytes
non neuronal, visible nuclei that you see usually are these,
gap junxns
enwrap axons/terminals
trophic and supportive role
ADH
vasopressin released by hypothalamic neurons in the neurohypophysis

acts on vascular smooth muscle to increase BP

Collecting ducts to promote fluid resorption
insufficiency of ADH/vasopressin causes what disease?
diabetes insipidus
Clinical

excess somatotropin
if before xlosure of bone epiphyses = gigantism

after closure = acromegaly, enlarged hands and feet, coarse facial features
Lesions of hypothalamus destroying ADH-producing cells
diabetes insipidus, drinking and urinating
thyroid failure

increase or decrease in TSH
TSH hypersecretion, no neg feedback of T3/T4 on TRH in hypothal

remember (ACTH is the one with long and short negative feedback)