hypophysis
Terms
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- 3 kind s of hormones that liberate 3 groups of hormones
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1) peptides made by secretory neuons in the hypothalmus that are transported to the ends of the axons in the neurohypophysis, where they accumulate
2) Peptides in the hypothalmus that are carried along axons until they end in the median eminence of the adenohypophysis where theya re stored and liberated. They enter median eminence and are transported to the adenohypohpysis thru hypophyseal portal system
3) proteins bade by cells of the pars distalis and liberated into second stretch of the portal circulatuion - neurohypophisis
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made of pars nervosa and the neural stalk
does not containsecretory cells
made mainly of unmyelinated axons
accumulations of neurosecretions (Herring bodies)
and Glial cells called pituicyte - what does vasopressin do?
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Released by neurohypophysis
Increases permeability to water in collecting tubules - Parts of the adenohypophyis
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Pars distalis
Pars intermedia
Pars tuberalis - Parts of the neurohypophysis
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Median eminence
Infundibulum
Pars nervosa - structure of pars distalis
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cords o f epitheial cells interspersed with caps
3 cell types: chromophobes, basophilic chromophils, and acidophilic chromophils - How is vasopressin secreted
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1) blood pressure acts on osmoreceptors in the anterioor hypothalmus (
2) hADH is secreted from urpaoptic neurons to the posterior pituitary/neurohypophysis - Identifying different acidophils
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stained orange/yellow
1) regular cuboidal or columnar cells arranged in rows = sommatotrophs = GH
2) scattered irregular cells with processes = lactotropes = PRL - Identifying different basophils
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In pars distalis of adenohypophyis (chromatophil)
1) Large and rectangular = gonadotrophs
2) small and irregular = thyrotrophs - Identifying the pars intermedia
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area between pars distalis and pars nervosa
contains many colloid filled cysts or follicles - What do herring bodies contain?
- Either oxytocin or vasopressin
- One more time: colors and cell types in hypophysis
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Acidophilic - orange red:
1) somatotrophs. cuboidal. arranged in rows. Secrete GH.
2) lactotrophs. secrete PRL. irregular, smaller
Basocphilic
1) gonadotrophs. PAS pruple. large and recutangulr
2) thryrotrophs; PAS red. smaller irregular
3) corticotrophs: light blue.