- Hypothalamus (Gömöri’s chrome-haematoxylin)
frontal section third ventricle columns of fornix anterior commissure internal capsule optic tract telencephalon basolateral part large perikarya of paraventricular nucleus close to ventricular wall supraoptic nucleus baso-lateral, medial side of optic tract nucleus basalis of Meynert
Magnocellular nuclei
supraoptic nucleus and magnocellular division of paraventricular nucleus
produce oxytocin and vasopressin
Nucleus basalis of Meynert
in baso-medial telencephalon
large cholinergic neurons
sole source of cholinergic innervation of cortex
- Hypophysis (HE)
2 parts: neurohypophysis and adenohypophysis
on slide: neurohypophysis, pars distalis, pars intermedia
CT capsule
Chromophobe cells
Chromophil cells
Divisions of adenohypophysis
- pars distalis
- largest past
- higly vascular
- several secretory epithelial cells in cords + irregular follicles - pars tuberalis
- surrounds infundibulum
- contains hypthalamo-hypphyseal portal system - pars intermedia
- narrow between neurohypophysis and pars distalis
- rudimentary region
- basophilic cell cords and follicles,lined by chromophore cells that contain colloid material, alpha-beta endorphin, production of MSH-> melanocyte melanin
Chromophobe cells
little affinity for dyes
small amount of lightly stained cytoplasm
majority of adenohypophyseal cells
Neurohypohysis
lighter stained
masses of unmyelinated axons of secretory neurons- perikarya in supraoptic and paraventricular nuclei
25% of volume- highly branched glial cells “pituicytes” (astrocytes)
fenestrated capillaries
- Hypophysis (Gömöri’s chrome-haematoxylin phloxine)
neuro and adenohypophysis
basophils - dark bluish-grey
acidophils - bright pink
dilated axons in neurohypophysis - neurosecretory material accumulated
neurophysin in neurosecretory material - dark bluish-grey- “Herring bodies”
- Thyroid gland (HE)
- thin CT capsule + collagenous septa
- divided into lobules
- follicles with inactive hormone
- C cell/parafollicular cell
- fenestrated capillaries, lymph vessels, sympathetic nerve fibers
- sternothyroid muscle, muscle spindles
- solid nest cell, small cystic structures, mixed follicles
Thyroid follicles
large amount of inactive hormone
lined by squamous, cuboidal or low columnar secretory epithelium - secretes T3 and T4 hormones
surrounded by rich capillary network
colloid material (thyroglobulin) in lumen +stores hormones
active gland: small follicles
hypoactive gland: distended follicles + full of colloid
Calcitonin cell/ C cell/ parafollicular cell of thyroid gland
endocrine secretory cell
in intermolecular space, solid nest cells, CT space
form small clusters
secretes calcitonin
Solid nest cells of thyroid gland
embryonic remnant of endodermal origin Main cells: -polygonal, elongated, spindle-shaped -Stem cell nature C-cell: -clear cytoplasm + small dense nuclei
- Thyroid gland (calcitonin immunostaining -H)
calcitonin producing cells
in central part of lateral lobes
- Parathyroid gland (HE)
- CT capsule of thyroid encapsulates
- thin septa
- Chief/Principal cell: small, polygonal, prominent nuclei, little cytoplasm
- Oxyphil cells: larger polygonal, smaller densely stained nuclei. Occur in clumps
- Adipose tissue in older individuals
- fenestrated capillaries, lymph vessels
32.Adrenal gland (HE)
- dense, collagenous CT capsule
- adrenal cortex and medulla
- trabeculae
- prominent vein in center of medulla
- zona glomerulosa, fasciculate, reticularis
- secretory cells of medulla - catecholamines
- neurons in medulla
- medullary and suprarenal veins- longitudinal smooth m on wall(regulates blood flow, glucocorticoid hormone)
- autonomic ganglia
Zona glomerulosa of adrenal gland
outermost layer in cortex, 15%
irregular, packed, ovoid/rounded clusters of columnar /pyramidal cells
a lot of SER + lipid droplets
steroid synthesis - mineralocorticoids
Zona fasciculata of adrenal gland
widest zone, 80% narrow,parallel rows of cells, separated by sinusoid capillaries cells are large, polyhedral a lot of set and lipid droplets secrete glucocorticoids
Zona reticular of adrenal gland
innermost layer of cortex- thin, 5% contain less lipid droplets irregular anastomosing cords of smaller cells lipofuscin granules pyknotic nuclei - cell degeneration secrete weak androgens
Secretory cells of adrenal medulla
closely packed clumps + reticular fibers columnar cells around venous sinusoids a lot of capillaries around strong basophilic and granular nuclei chromaffin cells- high affinity for chrome salts, innervated by preganglionic sympathetic fibers, secrete epinephrine + norepinephrine ganglion cells
- Endocrine pancreas (HE)
islets of Langerhans- lightly stained
irregular cords of secretory cells + collagenous CT around + capillaries
thin capsule around islets
endocrine cells: small, polygonal (insulin, glucagon, somatostatin, gastric inhibitory peptide, CCK, ACTH secreting cells)
- Pineal gland (HE)
enclosed in pia mater
CT septa + blood vessels
irregular lobes/ follicles
Pinealocytes: basophilic cytoplasm, large infolded nuclei, prominent nucleoli, processes to capillaries, releases Ca2+, secretes melatonin
Astroglial cells: long cytoplasmic extensions
Myelinated nerve fibers- ramify into unmyelinated
Corpora arenacea/brain sand: calcium condensed in concentric layers
Pineal recess-> pineal stalk
Posterior commissure
Synthesis of Thyroid hormones
- Synthesis of thyroglobulin + thyroperoxidase in rER -> plasma membrane
- Uptake of iodide from blood -> iodide in colloid
- iodination of thyroglobulin (MIT + DIT)
- formation on T3 and T4
- respiration of colloid
- release of hormone in blood
Role of thyroxine
normal growth + development
increased metabolic rate
Role of calcitonin
decrease blood Ca2+ levels
Role of Chief cell in parathyroid gland
predominant type
secrete parathormone -> increase blood Ca2+ level
Acidophils in Adenohypophysis
secretes effector hormones:
- prolactin- milk formation, mammary gland development
- growth hormone- insulin-like factor I -> body growth
Basophil cells in Adenohypophysis
secretes tropic hormones:
- ACTH- secretion of glucocorticoids in adrenal gland
- TSH- secretion of thyroglobulin+thyroid hormones
- FSH- folliculo/ spermiogenesis
- LH- corpus luteum, testosteron production
Hypophyseal portal vein
internal carotid a. -> superior hypophyseal a. -> primary capillary plexus -> long portal vein -> secondary capillary plexus -> sinus cavernosus