Histology Of The Endocrine Organs 1

hypothalamus

Parts of the hypophysis:

anterior

hypophysis

posterior

Adenohypophysis: - Pars tuberalis - Pars intermedia

Neurohypophysis: - Median eminence - Infundibulum

- Pars distalis

- Pars nervosa

Slide 67, hypophysis Staining method: hematoxylin-eosin

Plane of cutting: horizontal

Slide 67, hypophysis, H&E, 4x Neurohypophysis: pars nervosa

Adenohypophysis: pars intermedia

Adenohypophysis: pars distalis

Slide 67, hypophysis

pars nervosa, H&E, 40x

endothelial cell

capillaries (fenestrated endothelium)

pituicytes

axons (hypothalamohypophyseal tract)

Slide 67, hypophysis

pars intermedia, H&E, 40x simple cuboidal epithelium

cyst filled with colloid

The cell types of the adenohypophysis chromophil Staining (H&E)

acidophil

Cell type

1

Hormone secreted

GH

2

LTH

chromophobe

basophil

1

2

ACTH TSH MSH

1

2

LH

FSH

IL-6

Slide 67, hypophysis

pars distalis, H&E, 40x

chromophobe cell

basophil cells

acidophil cells

To identify the parts of the hypophysis and the structures listed: Pars nervosa: capillaries, pituicytes Pars intermedia: cysts filled with colloid Pars distalis: chromophobe, acidophil, basophil cells

The hypothalamo-hypophyseal system Magnocellular nuclei: Hormone secreted: oxytocin, vasopressin Axon terminals: pars nervosa E.g.: nucl. paraventricularis nucl. supraopticus

Parvocellular nuclei: Hormone secreted: releasing / inhibiting hormones (pl. CRF, TRH) Axon terminals: infundibulum E.g.: nucl. arcuatus

Slide 85, hypothalamus: magnocellular nuclei cerebrum

Origin of the section: rat brain cerebellum

Cortex cerebri

brainstem Plane of cutting: frontal nucl. paraventricularis nucl. supraopticus

hypothalamus

Staining method: oxytocin immunocytochemistry

Slide 85, hypothalamus, oxytocin immunocytochemistry, 4x nucl. paraventricularis axons (hypothalamohypophyseal tract)

3rd ventricle

optic tract

nucl. supraopticus

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) / Parafollicular (C) cells: thyroxin (T4) - Between the follicles, capillaries bellow the follicular cells - Ectodermal origin - calcitonin

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

follicles

connective tissue septum

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

follicular epithelial cells

follicle

colloid (thyroglobulin)

capillary

The synthesis of hormones by the follicular cells The synthesis of thyroglobulin colloid

Synthesis

colloid

pinocytosis

The uptake of circulating iodide: 3040x 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

rough endoplasmic reticulum

iodide

capillary

To identify the follicles of the thyroid gland To examine the follicular epithelium