Histology of endocrine system Flashcards
What type of tissue is Pituitary gland made of
epithelial tissue
neural tissue
Which lobe of the pituitary gland apprears in darker staining
anterior lobe
Hormones secreted by adenohypophysis
TSH, FSH, LH, ACTH, GH and PRL
3 parts of the adenohypophysis
Pars distalis - bulk of anterior lobe
Pars intermedia - separates PD from PN
Pars tuberalis - superior extension of PD
How are the cells in the adenohypophysis organised
Clumps and cords
Separated by fenestrated sinusoidal capillaries
What are the three different types of cells identified in the Pars Distalis according to their staining reaction
Basophils (10%)
Acidophils (40%)
Chromophobes (50%)
What are the 5 cell types identified in the pars distalis according to immunocytochemical reactions
Somatotrope Lactotrope Corticotrope Gonadotrope Thyrotrope
What cell has the darkest staining in the pars distalis
Basophils
what cells does the pars intermedia contain
contains basophils and chromophobes
What does the Neurohypophysis consist of
Pars nervosa - contain unmyelinated axons and their nerve endings
Infundibulum - connects it to the hypothalamus
What are the dilated potions of axon called
Herring bodies
What are the dilated potions of axon called
Herring bodies
What is the only specific cell in the neurohypophysis
Pituicyte
Describe pituicytes
Specialised glial cells
irregular in shape
nuclei are either round or oval
What is the structural and functional unit of thyroid gland
Thyroid follicle
A spherical cyst like compartment with a wall consisting of a simple cuboidal or low columnar epithelium
contains gell like mass called colloids
Two types of cells in follicular epithelium
Follicular cells
Parafollicular cells
What are follicular cells
Responsible for production of T3 and T4 thyroid hormones
Vary in shape and size
Exhibit lightly basophilic basal cytoplasm
What are parafollicular cells
Located in peripheral follicular epithelium within the follicle basal lamina
Larger than follicular cells
Secrete calcitonin
Pale staining
What does calcitonin do
regulates calcium metabolism
Two main cell types in parathyroid glands
Chief cells - small polygonal cells with centrally located nucleus
Oxyphils - occurs singly or in clusters, more rounded and considerably larger than chief cells
What does parathyroid hormone do
PTH raises calcium levels in response to low blood calcium
WHat is the difference in shape between he right adrenal gand and left
Right - Flattened triangular shape
Left- Semilunar shape
What are the three zones of the adrenal cortex and what is their cortical volume
Zona glomerulosa - narrow outer zone, 15% cortical volume
Zona fasciculata - thick middle zone, 80% cortical volume
Zona reticularis - inner zone that constitutes around 5-7%
Describe the zona glomerulosa
Cells arranged in clusters
relatively small columnar or pyramidal shape
Cells secrete aldosterone
Describe the zona fasciculata
cells arranged in straight bundles, one or two cells thick
cells are large and polyhedral in shape
Produce glucocorticoids
Describe zona reticularis
Cell arranged in anastomosing cords separated by capillaries
Cells are smaller than ZF, nuclei closer packed and deeply stained
Principle secretion is sex hormones
What does the adrenal medulla contain
Chromaffin cells
ganglion cells
connective tissue
sinusoidal blood capillaries and nerves
What are the chromaffin cells
Modified neurons; columnar shape, basophilic, organised in ovoid clusters
Produce and secrete catecholamines, mainly epinephrine and norepinephrine
