Endocrine System

oxytocin

location: posterior pituitary

function: stimulates uterine contraction during labor, stimulates the milk letdown reflex, triggers prostate gland contraction

antidiuretic hormone (ADH)

location: posterior pituitary

function: increase water re-absorption by kidneys, elevates blood pressure by increasing blood volume

gonadotropins (LH and FSH)

location:anterior pituitary

function: stimulate sperm and ova development and secretion of sex hormones

producing cells: gonadotrophs

growth hormone (GH)

location: anterior pituitary

function: stimulate bone & muscle growth, protein synthesis, and lipid degradation (glucose sparing)

producing cells: somatotrophs

prolactin (PRL)

location: anterior pituitary

function: stimulates mammary gland development and milk production

producing cells: lactotrophs

thyroid stimulating hormone (TSH)

location: anterior pituitary

function: stimulate secretion of T3 and T4 from thyroid

producing cell: thyrotrophs

adrenocorticotropic hormone (ACTH)

location: anterior pituitary

function: stimulates secretion of glucocorticoids from adrenal cortex

producing cells: corticotrophs

melanocyte-stimulating hormone (MSH)

location: anterior pituitary

function: stimulate melanocytes to darken the skin

producing cells: corticotrophs

mineralocorticoids (aldosterone; corticosteroids)

location: zona glomerulosa; adrenal cortex

function: Increase renal resorption of sodium, bicarbonate, and water. Elevation of blood pH.

glucocorticoids (cortisol; corticosteroids)

location: zona fasciculata, adrenal cortex

function: increase stress tolerance and blood glucose, decrease inflammation

gonadocorticoids (androgens and estrogens: corticosteroids)

location: zona reticularis, adrenal cortex

function: provide each sex with the benefit of the hormone of the opposite sex

catecholamines (Epinephrine and Norepinephrine)

location: medulla

function: make the effects of the sympathetic nervous system global and long-lasting for ensured survival during immediate and extreme stress.

glucagon

location: pancreas

function: increase blood glucose levels

alpha cell

insulin

location: pancreas

function: decrease blood glucose levels

beta cell

growth hormone-inhibiting hormone (GHIH)

location: pancreas

function: inhibits secretion of insulin and glucagon

delta cell

direct, paracrine, endocrine, synaptic

the four ways of cell-cell communication

G protein

the link between a first messenger and a second messenger in a cell that responds to peptide hormones

ATP is consumed and cAMP is formed.

What happens when adenyl cyclase is activated?

endocrine cells

release their secretions directly into body fluids

FSH, GH, TSH

secretory cells of the adenohypophysis release:

gene transcription is linked

what happens after a steroid hormone binds to its receptor to form an active complex?

direct communication

intercellular communication through gap junctions exchange of ions

paracrine communication

intercellular communication through extracellular fluid, paracrine factors, local action

endocrine communication

intercellular communication through circulatory systems, hormones, target cells are in other tissues

synaptic communication

intercellular communication across synaptic clefts, neurotransmitters

hypothalamus

production of ADH, oxytocin, and regulatory hormones

pineal gland

production of melatonin

triiodothyronine (T₃) and thyroxine (T₄)

location: thyroid gland

function: stimulate and maintain metabolic processes

calcitonin

location: thyroid gland

function: lowers blood calcium levels, increases calcium in bones

parathyroid hormone

location: parathyroid

function: increase blood calcium levels, decrease calcium in bones

thymosins

location: thymus gland

function: promotes maturation of T-lymphnocytes

natriuretic peptides

location: heart

function: removes sodium and water from blood