neuro - neural ectoderm

adeno - oral ectoderm (rathke's pouch)

in sella turcica of sphenoid bone.

attached to hypothalamus by infundibulum.

adeno - pars distalis (anterior pituitary), pars tuberalis, pars intermedia

neuro - pars nervosa (post pit), infundibular stem, median eminence

hypothalamus -> primary capillary plexus (PCP) at median eminence. 

(int. carotid a.) -> superior hypophysial a. -> PCP    -> hypophyseal portal veins -> secondary CP in pars distalis

hormones secreted leave via anterior hypophyseal veins.

cells of pars distalis (ant pit)

chromophils 1st type: acidophils

name two and secretions

somatotrophs -> GH (somatotropin)

mammotrophs -> prolactin

thyrotrophs -> TSH

corticothrophs -> ACTH

gonadotrophs -> LH & FSH

function of folliculostellate cells?

shape?

support parenchyma

or provide network of intercommunication w/ each other

stellate with long processes 

tuberalis contains a lil FSH & LH but doesn't excrete specific hormones

pars intermedia is rudimentary in us

contains colloid-filled follicles (rathke's cysts)

POMC

where produced? what cells? 

produced in pars distalis 

by corticotropin cells

GNRH (somatotropin releasing hormone)

what nucleus source and what function?

Arcuate Nucleus

Stimulate GH synthesis & secretion

Somatostatin

what nucleus source and what function?

Arcuate Nucleus, Para/Periventricular Nuclei

Inhibit GH synthesis & secretion

DA (dopamine)

what nucleus source and what function?

Arcuate Nucleus

Inhibit prolactin synth/secrete

CRH (corticotropin releasing hormone)

what nucleus source and what function?

Arcuate Nucleus

Stimulate POMC synth

Stim release of ACTH

GnRH (gonadotropin releasing hormone)

what nucleus source and what function?

Arcuate Nucleus

stim FSH & LH synth/release

TRH (thrytropin releasing hormone)

what nucleus source and what function?

Arcuate Nucleus

Stim TSH & prolactin synth/secrete

Hypothalamus regulating Pituitary examples.

1. TRH

2. CRH

3. GnRH

1. Hypothalamus (release TRH) -> pituitary (release TSH) -> thyroid (release T4 & T3).

2. CRH -> pituitary (ACTH) -> adrenal glands (glucocorticoids)

3. GnRH -> pituitary (release FSH & LH) -> affect target organs

LH - maturation, ovulation, corpus luteum form, testis (leyding cells) release testosterone

FSH - estrogens (overy)

Hypothalamus regulating Pituitary examples

1. GHRH

2. Somatostatin

3. PRH

4. PIH (dopamine)

hypothalamus -> pituitary -> target organ

1. GHRH -> release GH -> somatomedin C

2. Somatostatin -> inhib GH release

3. PRH -> prolactin -> milk secretion

4. dopamine -> inhibit prolactin release

Neurohypophysis

secretory cells?

what runs thru here?

Herring bodies?

what 2 hormones are found here?

no secretory cells.

100K unmyelinated axons of secretory neurons that terminate near capillaries.

Herring bodies are distentions of axons that store hormones.

1. Oxytocin fr. paraventricular nucleus -> release milk fr mammary glands

2. ADH (anti-diuretic hormone) fr supraoptic nucleus -> increase water permeability in kidney ducts

pituicytes

where found?

what marker do they contain?

function?

in pars nervosa (post pit)

glial cells containing GFAP (glial fibrillary acidic protein) - in astrocytes

surround axons where synapse onto blood capillaries

when hormones released, pituicyte pull open fenestrae to allow entry into capillary

only cells w/ nuclei in pituitary

GH tumor in children -> excessive GH secretion -> epiphysial plate continue growth

if excessive GH release in adult get Acromegaly (enlarged jaw, hands, feet) cuz epiphysial plate has ceased growth