Lecture 9 - Endocrine System Flashcards
Endocrine system
regulates metabolic activities in certain organs and tissues of the body
-produces slow and diffused effect via chemical substances called hormones
Endocrine composition
endocrine cells
- clusters of cells within certain organs of the body
- ductless, richly vascular glands
Endocrine cells
isolated in the epithelial lining of the difestive tract and in the respiratory system
Endocrine glands (list them 5)
pituitary pancreas suprarenal thyroid parathyroid
Pituitary gland
aka hypophysis
immediately adjacent to and partially attached to the brain
-gland that produces hormones responsible for regulating growth, reproduction and metabolism
-easily falls off when dissecting
Signals function of other endocrine
pituitary 2 subdivisions
develop from different embryologic sources
- adenohypophysis
- neurohypophysis
Adenohypophysis (development and divisions)
aka anterior pit. develops from an evagination of the oral ectoderm (Rathke’s pouch), which lines the primitive oral cavity. loses contact
AKA Pars distalis- (pars anterior) -most important part of anterior Pars interior Pars tuberalis (stalk)
neurohypophysis (development and divisons)
aka POSTERIOR pit. develops from a neural ectoderm as a down-growth of the Diecephalan.
Maintains attachment to diencephalon of brain
median eminence
infundibulum (stalk)
pars nervosa (another name for neurohypophysis)
Anterior Pituitary
produces own hormones in the pars distalis and secretes them
Posterior pituitary
does not make own hormone
Secretes hormones manufactured in the hypothalamus from pars nervosa
Pars nervosa
Posterior Pituitary
- stores hormones in Herring bodies
- secretes ADH, oxytocin - to stimulate contraction
Pars distalis cell types
Makes its own hormone (Anterior Pituitary)
H and E stain
acidophils - stain lighter
basophils
Pars nervosa PAS stain
secretory endings with PAS positive granules can be visualized
Pars distalis basophils (name the cells and what they release)
- thyrotropes - secrete thyroid-stim hormone (TSH)
- gonadotropes- secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
- corticotropes - secrete adrenocorticotropic hormone (ACTH)
Acidophils (name the cells and what they release)
lactotropes secrete prolactin
somatotropes - secrete growth hormone
Pancreas (what the endocrine part is called)
Also has exocrine function
Endocrine portion is call Islets of Langerhans
islets of langerhans
Has pale clusters on H and E stain label it in pic.
produce hormones which regulate carb metabolism
alpha cells
beta cells
delta cells
pancrease alpha cells
glucagon - glucose release
pancrease beta cells
insulin - glucose uptake
pancrease delta cells
somatostatin - inhibitory hormone of gastric secretion
Suprarenal (adrenal gland)( two layers)
on top of kidney
surrounded by a dense fibroelastic capsule of CT
- parenchyma of gland is divided into two histologgically different regions
- suprarenal (outer)cortex
-suprarenal (inner) medulla
Suprarenal cortex
produces corticosteroids which are synthesized from cholesterol
suprarenal medulla
functionally related to and regulated by sympathetic system
produces epinephrine and norepinephrine
Adrenal cortex (the three zones)
3 zones ( know how to identify them the order)
Zona glomerulosa
zona fasciculata
zona reticularis
zona glomerulosa
most peripheral region that contains cells in an ovoid configuration
Produces: aldosterone
zona fasciculata
middle zone composed of cells arranged in columns separated from each other by a continuous column of capillaries
Produces: cortisol &/or corticosterone
zona reticularis
situated between the fasciculata and medulla
cells organized in a loose meshwork configuration
produces androstenedione (male androgenic hormone)
Thyroid
typically bi-lobed
location: superior mediastinum
2 layers of fibrous CT surround gland and blend with fascia of the neck
Gets fatty with age
Thyroid secretion
T4 and T3 - under control of TSH from anterior pit.) which stimulates the rate of metabolism
calcitonin - aids in decreasing blood calcium levels and facilitates the storage of calcium in bone (decrase calcium)
thyroid follicles
secretory cells (follicular epithelial cells) arranged in hollow spheres (follicles) with loose, highly vascular CT between them
epithelial cells have short microvilli on apical surface
Epithelium surrounds colloid
they make the T3 and T4 While colloid stores it
colloid
contains thyroglobulin bound with T3, T4, rings of follicals surround it.
The colloid is a huge fat looking cell with a ring of cells of follicales around it
parafollicular cells - how to visualize
usually located in follicular walls
large cells - stain heavily with lead hematoxylin
produce calcitonin which lowers serum calcium
KNow staining and how to visualize)
they produce the calcitonin in these
Parathyroid glands
four or five glands located on the posterior surface of the thyroid
- usually lie within capsule of thyroid gland
- each gland has a thin CT capsule
- secretory cells arranged in cords and plates set in loose stroma of CT
- produce PTH
parathyroid production
PTH - elevates serum calcium while reducing serum potassium via stimulation of the osteoclasts
Cell types in parathyroid
Principal (chief) cells
Oxyphil cells
Principal (chief) cells
central, nucleus, slightly eosinophlic cytoplasm with glycogen and lipofuscin granules
Produce: PTH
oxyphil cells
larger than chief cells, very eosinophlic cytoplasm
less common than chief cells
believed to be the inactive phase of chief cells
Herring Bodies
Secretary Endings that store hormones in the posteriar pituitary
Be able to identify this. Small faint pink in PAS stain
