Para/Thyroid and Adrenal gland Flashcards
Overview of Adrenal gland
AKA suprarenal gland
Anatomical on superior poriton of kidney
Surrounded by adipose tissue
Layers of Adrenal gland
Capsule
Cortex=mesodermal tissue
Medulla=N. creast
-post gang. N.
Adrenal gland-capsule
Dense CT
Where are the endocrine gland located in the adrenal gland
Cortex
Adrenal gland hormones
All are relased in blood
Cortex=steroid hormones
Peptide hormrone/catecholamines=medulla
-released by N. sig. (sympathetic presynpatic N. endings)
How many layers in the Adrenal gland cortex
3 Zone w/ cells secreted steroid hormones=incre. lippid droplet in cytop.
- Zona glomerulosa
- zona fasiculata
- Zona retiuclaris
Zona glomerulosa
Produce mineral corticoid=Main aldosterone
Cells are arranged in circle (ie glomerulose)
REg. by angio. II
Aldosterone
Bind to highly expressed mineralcorticoid recep. in cytop.
-w/in distal nephron, colon, hippocampus
Act through aldosteron reg. kinase
-affect Na. channels
Function
-Reg. ECF vol. =incre. Na transporter to reduce H2O excretion
-Control K+ homeostasis=decre. Na excretion while incre. K+ excretion
Zona fasciculata
Cells=lighter stain in ribbon formation
-spongiocytes=spongy app b/c incre. lipid content and incre. SER (steriod horm.)
Produce gludocorticoid=cortisol (stress horm.)
Reg. by ACTH
Cortisol
Activates multiple metabolic -Gluconeogensis -Glycogen formation in liver -fat metabilization in adipose -prot. degradation in muscle -suppress immune syst. :decre. cytokine product/lymphpoiesis (immune cells) :incre. stress=incre. chances of sick
Zona reticularis
Not well arranged cells=reticulated fashion
Produce cortisol but mainly wk androgren DHEA
Reg. by ACTH
What can wk androgen DHEA cn be converted into
testosterone
What type of cells are found in the medulla of the Adrenal gland
Chromaffin cells and ganglion/nerve
Chromaffin cells
Secretory cells Modified N. Secrete peptide/catacholamines -stored in granules -detected by using potassium dicrhomates :help create a dark brown color
Catacholamine
N. epi(less potent) and Epi.(adrenalin)
Adrenaline
Fight/flight=incre. activity/E to muscle and incre. O2 in BV/sk. muscel
Function
-Vasoconstriction
:incre. activation of sm. muscle
:incre. BP(also renin)
:incre. HR=cardiac muscle and incre. F/rate
-Blood gluc.=glucagon (pancreas) and incre. insulin(incre muscle gluc.)
-other metabolic (thyroid horm.)
Pheochromocytoma
Rare chromaffin cell tumor
Incre. adrenalin
Cn be malig/begnin
Cn kill by heart attack
blood vessel in the medulla
Adrenomedullary vn,
-longitudinal sm. muscle in tunica media
:no circle sm. muscle
-drain directlh into inf. vena cava(rit side) or left renal van (left side)
-cn contract w/ organ to incre. the relase of the horm
-supplied by cortex/medulla sinusoid venules
:sm. BV near cell b/c endocrine organ=no secreting duct but CT=blood
cortical vasculature
Horm.ā>BVā>tissue
Caspuslor plexus=fensustrated
-@ capsule
Medullary arter goes throught cortex into medulla
-dup in medullary vn
Fenestrated cortical capillaies in cortex
Why arnt all horm. created throughout the cortex
b/c of type of enzyme needed
CYP17 is only in zona fasculata dn retiularis NOT GLOMERULOS
-17alpha-hydroxylase/17,20 lyase
-produce cortisol and sex horm.
Thyroid does what type of regulation
metabolic reg.
Thyroid anatomicly
2 lobes connected by the isthmus
Neart the arch of cirocid
develop downward
Thyroid gland organization
Outer capsule
Lobules
Thyroid gland-out capsule
Dense CT
Parathyroid glands
Thyroid gland-lobules
Separated by CT septa Follicles w/in lobule -Parenchyma -Lined w/ simple epithelium :cuboidal=active :sq.=inact. Filled w/ colloid Parafolicular cells b/w lobules in BsM
Thyroid gland-colloid
Thyroglobulin -Stores Thyroid horm. -lrg. glycoprot. w/ no horm. activie -140 tyr. need to make thyroid Thyroid stim. horm(TSH) -produced by pit. -+ all phases of thyroid horm.
Thyroid horm. prod.
Thyroglobulin -produced RER -glycosylated -exocytosed into follicular lumen Iodid form blood -Na/iodid symp. @ basal memb.(NIS) -Iodide/chlorid symp. (pendrin) :iodide-->lumen oxidized @ apical surface by thyroid persxidase :then iodided-->iodine Follicle lumen -Tyr of thyroglobulin r iodinated by covalent biding of 1-2 iodine molec. -Iodinated Tyr r cong. to produced horm. Release horm. of T3/4 -iodinated thyroglobulin is absorbed into follicular cell through endocytosis -vessicle fuse w/ lysosomes :transported to basal region -T3/4 freed from thryoglobulin :transported from thyroglobulin
Thyroid horm. actions
T3/4=growth, cell dif., basal metabolic rate, O2/heat consumption cross BBB
T4=liver and kid.
T3=TRH/TSH and prolactin
Other metabolic=carb, lipid, prot.
Parafollicular cells
Surrounded by follice b/w follicle cells and BsM
AKA C cell
contain calcitonin
-recep. on osteoclast for inhibition
:when blood Ca2+ is high
lighter stain than other follicular cells
Parathyroid overview
located on post capsule of thyroid
Location varies b/c embryonic migration
Parathyroid-organization
2 types of cells
-cheif cells and oxyphils
Stroma=reticular fibers to support cheif cells
Parathyroid-cheif cells
hormone producing PTH(parathryorid horm.)
Parathyroid-oxyphil cells
MC in older ppl -appear in puberty and incre. in older age lrg/incre eosin cytop. -b/c incre. mitoch. DNT secrete PTH/inactive cells
PTH
Polypeptide
Released by cheif cells
Decre. blood Ca2+ levels=+GCPR and PTH released
-incre. blood Ca+=Ca2+ bind to recep. and inhibit PTH released
Released PTH
-bind to osteoblast
:osteoblast release osteoclast stim. factor
-Osteoclast absrob bone tissue
:release Ca2+ and Phosphate
Function
-phosphate goes to renal tubuels=incre. phosphate excretion ans incre. Ca2+ reabsorp.
-inhibit osteoblast too
-stim. Vit. D synth.=incre. Ca2+ absorpt. in GIT
