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32 Cards in this Set
- Front
- Back
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Hypophysis regulates homeostasis
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direct interaction - hormones into blood
indirect interaction - hormones that regulate the production of other hormones by adenohypophysis |
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Paracrine
autocrine endocrine secretions |
paracrine - on cells around you
autocrine - you or cells like you, gene expression endocrine- blood |
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Glycoprotein H
plasma carriers location of receptors effect |
no plasma carriers, SOLUBLE
plasma membrane receptors second messenger in cytoplasm |
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Steroid H
plasma carriers location of receptors effect |
rewuire plasma carrier molec
cytoplasmic receptors H-receptor complex affects gene expression |
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Where is the hypophysis located?
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base of brain, specifically the third ventricle
SELLA TURCICA, small depression of the sphenoid bone 1-1.15 cm |
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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 |
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Neurohypophysis
other name innervation unique features 3 parts |
post pit
direct innervation produces no H pale staining Pars nervosa infundibular process median eminence |
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Development of adenohypophysis
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outpocketing of oral ectoderm, Rathke's pouch, looses its connection, eventually Rathke's cysts in pars interm
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Development of neurohypophysis
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floor of diencephalon(CNS)
maintains connection via stalk |
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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 |
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Blood supply neurohypophysis
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inferior hypohyseal artery forms capillary plexus into which oxytocin and vasopressin are secreted
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Adenohypophysos cell types
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chromophils and chromophobes
chromophils 3 basophils 2 acidophils, refer to staining of cytoplasmic granules, not cytosol |
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Acidophils
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1) somatotrophes
2) Lactotrophes |
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Basophils
(co-goth) |
1) corticotrophes
2)gonadotrophes 3)thyrotrophes |
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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 |
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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 |
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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) |
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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 |
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Thyrotrophes
abundance secretion what secretion does defining characteristics |
5%
secrete TSH glycoprotein - follicular cells of thyroid to produce T3 T4 small granules |
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TRH
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first hypothalamic H to be ID's
tripeptide |
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graves disease
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Ab bind TSH R on thyroid follicular cells,
they continuously produce T3 T4 TSH levels are therefore low can ablate thyroid for treament |
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Pars distalis
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adenohypophysis
glandular cells in cords/clumps fenestrated secondary cap plexus dense collagenous capsule chromophils and basophils |
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Pars intermedia
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Rathke's cysts lined by cuboidal cells contain colloid
possible basophils |
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Pars tuberalis
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sleeve around infundibulum stalk
major arteries and portal system |
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Neurohypophysis
what type of axonal system |
magnocellular neurosecretory system
vs parvicellular system of adenohypophysis into caps magno secretes oxytocin and vasopressin |
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Neurohypophsis
accumulated secretory granules (dilations along axon and termini) |
Herring bodies
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what type of special cell does the neurohypophysis have?
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pituicytes
non neuronal, visible nuclei that you see usually are these, gap junxns enwrap axons/terminals trophic and supportive role |
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ADH
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vasopressin released by hypothalamic neurons in the neurohypophysis
acts on vascular smooth muscle to increase BP Collecting ducts to promote fluid resorption |
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insufficiency of ADH/vasopressin causes what disease?
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diabetes insipidus
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Clinical
excess somatotropin |
if before xlosure of bone epiphyses = gigantism
after closure = acromegaly, enlarged hands and feet, coarse facial features |
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Lesions of hypothalamus destroying ADH-producing cells
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diabetes insipidus, drinking and urinating
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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) |
