Histology of the Endocrine Organs 1

Neurohypophysis:Neurohypophysis:

-- MedianMedianeminenceeminence

-- InfundibulumInfundibulum

-- Pars nervosaPars nervosa

hypophysishypophysis

hypothalamushypothalamus

AdenoAdeno--hypophysis:hypophysis:

-- ParsParstuberalistuberalis

-- ParsParsintermediaintermedia

-- ParsParsdistalisdistalis

anterioranterior posteriorposterior

Parts of the hypophysis:Parts of the hypophysis:

Slide 67, hypophysis

Plane of cutting:Plane of cutting:horizontalhorizontal

Staining method: hematoxylinStaining method: hematoxylin--eosineosin

Slide 67, hypophysis, H&E, 4x

Neurohypophysis:Neurohypophysis:pars nervosapars nervosa

Adenohypophysis:Adenohypophysis:pars intermediapars intermedia

Adenohypophysis:Adenohypophysis:pars distalispars distalis

Slide 67, hypophysis pars nervosa, H&E, 40x

capillariescapillaries(fenestrated(fenestratedendothelium)endothelium)

pituicytespituicytes

endothelialendothelialcellcell

axons(hypothalamo-hypophyseal tract)

Slide 67, hypophysis pars intermedia, H&E, 40x

cyst filled with colloidcyst filled with colloid

simple cuboidal epitheliumsimple cuboidal epithelium

The cell types of the adenohypophysis

Hormonesecreted

Cell type

Staining (H&E)

IL-6FSHLHTSHACTH

MSHLTHGH

212121

basophilacidophil

chromo-phobe

chromophil

Slide 67, hypophysis pars distalis, H&E, 40x

acidophil cellsacidophil cellsbasophil cellsbasophil cells

chromophobe cellchromophobe cell

To identify the parts of the hypophysisand the structures listed:

Pars nervosa: capillaries, pituicytesPars intermedia: cysts filled with colloidPars distalis: chromophobe, acidophil, basophil cells

Magnocellular nuclei:Magnocellular nuclei:Hormone secreted:Hormone secreted:

oxytocin, vasopressinoxytocin, vasopressinAxon terminals:Axon terminals:

pars nervosapars nervosaE.g.:E.g.:nucl. paraventricularisnucl. paraventricularisnucl. supraopticusnucl. supraopticus

Parvocellular nuclei:Parvocellular nuclei:Hormone secreted:Hormone secreted:

releasing / inhibitingreleasing / inhibitinghormoneshormones(pl. CRF, TRH)(pl. CRF, TRH)

Axon terminals:Axon terminals:infundibuluminfundibulum

E.g.:E.g.:nucl. arcuatusnucl. arcuatus

The hypothalamoThe hypothalamo--hypophyseal systemhypophyseal system

Slide 85, hypothalamus:magnocellular nuclei

Staining method:oxytocin immunocyto-chemistry

cerebellum

brainstem

cerebrumOrigin of the section: rat brain

Plane ofcutting:frontal

nucl. paraventricularis

nucl. supraopticus

Cortex cerebri

hypothalamus

nucl. paraventricularis

nucl. supraopticus

axons(hypothalamo-hypophyseal tract)

optic tract

3rdventricle

Slide 85, hypothalamus, oxytocin immunocytochemistry, 4x

Slide 85, nucl. supraopticus, oxytocin immunocytochemistry, 40x

To identify the magnocellular nuclei of the hypothalamus

The histology of the thyroid gland

Follicles:Follicular epithelium:- simple cuboidal- follicular epithelial cells (thyreocytes)-Microvilli on the apical surface- endodermal origin- triiodothyronine (T3) / thyroxin (T4)Parafollicular (C) cells:

- Between the follicles,bellow the follicular cells- Ectodermal origin- calcitonin

capillaries

Slide 68, thyroid gland, H&E, 4x

connective tissue septum

follicles

Slide 68, thyroid gland, H&E, 40x

folliclefollicularepithelialcells

colloid(thyroglobulin)

capillary

The synthesis of thyroglobulincolloid

The uptake of circulating iodide: 30-40x concentration colloid

Iodination of tyrosine residues in the colloid: on the surface of the microvilli

Colloid pinocytosis

Pinocytotic vesicles fusion with lysosomes cleavage of active hormones

T3 / T4 capillaries

The synthesis of hormones by the follicular cells

Synthesis colloid pinocytosis

roughendoplasmicreticulum iodide capillary

To identify the follicles of the thyroid gland

To examine the follicular epithelium