Endocrine System (LAB)

hypothalamus

link between N.S and Endo system, via pituitary gland

secrete substances through ducts to the surface of the skin

Exocrine Gland

Endocrine Gland

Secrete hormones directly into the bloodstream

Posterior Pituitary

stores and releases hormones = oxytocin and vasopressin. produced in the hypothalamic neurons. hypo tract system.

Oxytocin

function = labor, milk production

ADH (vasopressin)

function = water reabsorption to increase BV

Anterior Pituitary

produces and secretes hormones

ATCH (adrenal glands)

FSH (affects ovaries)

GH (affects growth)

LSH (affects ovaries and testes)

Prolactin (affects milk production)

Thyroid Stim. (Affects thyroid gland)

Pineal Gland

behind 3rd ventricle

Pineal Histology

Pinealocytes = dark staining cells w/nucleolus

Glial cells (support cells)= small dark spots

pink stuff = C.T

Pineal Hormone

secretes Melatonin (affects sleep + circadian rhythm)

Thyroid Gland

lies inferior to larynx, bi-lobed, composed of thyroid follicles

Follicular Cells

TSH → secrete thyroid hormone (T3+4)

T4 + T3 function = regulates metabolism

cells are cuboidal epi cells that line the thyroid follicles

Parafollicular cells (in between)

between follicles, secrete calcitonin function=decrease blood calcium levels

inhibits osteoclast activity

Parathyroid gland

four glands embedded in posterior of thyroid gland

Chief cells

dark-staining cells with central nucleus

function=increase blood calcium

Oxyphil cells

light staining cells with visible purple nucleolus, no function

Thymus

hormone = thymosin

function = maturation of T cells

Heart

cardiac muscle

mononucleated cells, intercalated dics, striations

Heart Hormone

Atrial Natriuretic Peptide

Atrial Natriuretic Peptide function

lowers blood pressure by promoting kidney to remove salt from blood

Adrenal Glands

Adrenal cortex

Zona Glomerulosa (dark arches)

release mineralocorticoids (Aldosterone)

function = increases blood pressure by retaining water, via sodium retention

Zona Fasciculata

Glucocorticoids (Cortisol)

function = regulate glucose metabolism during stress

Zona Reticularis

synthesis of weak Androgens (DHEA)

function = production of androgens (male horm.) +estrogens

Adrenal Medulla

contains chromaffin cells

class: catecholamines

• epinephrine and norepinephrine (adrenaline)

fight or flight response

Medulla / darker spot = reticularis

Kidneys