endocrine system

what do glands in the endocrine system work to maintain?

homeostasis

what does the endocrine system use to release hormones and activity?

chemical communication

what are the three parts in the theory of communication?

the sender, the message, and the reciever

hormones are _____ released by _____ that control the function/_____ of cells generally ___ from the source of production

chemicals, glands, activity, far

autocrine

cells produce hormones that effect themselves

paracrine

cells produce hormones that effect other nearby cells

what are the five things hormones can do ?

-alter cell membrane permeability
-stimulate protein/enzyme synthesis
-activate/deactivate enzymes
-induce exocytosis
-stimulate mitosis

what are the three chemical classes of hormone?

• amino acid based

• steroid based (sterol)

• eicosanoid (lipid-based)

what is the most important functional difference between the 3 categories of hormone?

solubility

amino-acid hormone solubility

soluble in water, insoluble in fat

what benefits come from AA based hormones being able to move through water easily?

can easily move through bodily fluids and blood

target cells have ____ for each hormone

receptors

does every cell have all hormone receptors?

no

what is this process?

amino acid hormones in the cell membrane

step 1 of amino acids hormones in the cell membrane

the hormone binds to the receptor

step 2 of amino acids ihormones n the cell membrane

the receptor activates g proteins

step 3 of amino acid in the cell

g protein activates adenylate cyclase

step 4 of amino acids hormones in the cell

adenylate cyclase converts ATP to cAMP

step 5 of amino acids hormones in the cell

cAMP activates protein kinases

how do fat soluble hormones act in the cell membrane?

they can go right through the membrane

where do fat-soluble hormones bind to receptors?

in the cytoplasm

where do amino acid hormones bind to receptors?

the cell membrane

receptor-hormone complex with fat-soluble hormones can bond to ___ to initiate _____

DNA, gene expression

what are the three controllers of release/retention of hormones

• humoral stimulus

• neural stimulus

• hormonal stimuli

what is humoral stimulus?

blood levels of certain ions/nutrients

what is neural stimulus?

nerve fibers stimulate hormone release

what are hormonal stimuli?

hormones telling glands to release hormones

____ regulates most hormonal release in the body

hypothalamus

the hypothalamus has a direct link to what gland?

the pituitary

what two hormones does the hypothalamus produce?

ADH, oxytocin

where does the hypothalamus store its hormones?

the posterior pituitary

what do hormones travel through from the hypothalamus to the posterior pituitary?

the infundibulum

what does antidiuretic hormone do?

stop pee!

what kind of tissue is the posterior pituitary derived from?

nervous

what kind of tissue is the anterior pituitary derived from?

epithelial

what is the posterior pituitary perfused with?

one major artery and vein

what does the primary plexus in the anterior pituitary do?

pick up hormones from the hypothalamus

what does the secondary plexus do in the anterior pituitary

drop off hormones into the bloodstream

what hormone does the thyroid gland create?

thyroxin

what does the thyroid gland surround?

the trachea

why is the thyroid not an exocrine gland?

it secretes directly to the blood as opposed to ducts

what are the three different kinds of cells in the thyroid?

principal (follicle), colloid, parafollicular cells

what do principal cells of the thyroid create?

thyroglobulin

what do colloid cells of the thyroid do?

store thyroglobulin and iodine

what do parafollicular cells of the thyroid do?

produce calcitonin

the first step of thyroid synthesis

thyroglobulin made by follicular cells, go into follicle

the second step of thyroid synthesis

iodide is trapped from the blood

the third step of thyroid synthesis

iodide converted to iodine

the fourth step of thyroid synthesis

iodine attaches to tyrosine

the fifth step of thyroid synthesis

iodinated tyrosines are linked

the sixth step of thyroid synthesis

thyroglobulin is endocytosed

the seventh step of thyroid synthesis

thyroid hormone is processed by enzymes, diffuse from the cell into blood

what produces calcitonin?

parafollicular cells in the thyroid

release of calcitonin results in lowered blood ____

calcium

how does calcitonin work?

inhibits osteoclasts, enhances bone Ca absorption

what do the parathyroid glands create?

parathyroid hormone

what does the parathyroid hormone do?

control calcium levels

parathyroid hormone is the antagonist of

calcitonin

what are the two sections of the adrenal gland?

the adrenal medulla, the adrenal cortex

what are the three sections of the adrenal cortex?

zona glomerulosa, zone fasciculate, zona reticularis

what does the adrenal cortex generally create

corticosteroids

what does the zona glomerulosa create?

mineralocorticoids, e.g. aldosterone

what do mineralocorticoids do?

regulate ion concentration in blood

what does aldosterone do?

reduce excretion of Na from the body

where are glucocorticoids synthesized?

zona fasciculata

what does cortisol (glucocorticoid) do?

depress inflammation, increase blood sugar

where are gonadocorticoids created?

zona fascicularis/reticularis

most gonadocorticoids are weak _____

androgens

in a positive feedback loop, the product ____ its own production

enhances

in a negative feedback loop, the product _____ its own production

reduces or stops

where are chromaffin cells located?

the adrenal medulla

what do chromaffin cells in the adrenal medulla produce?

catecholamines - epinephrine and norepinephrine

where is the pineal gland located?

diencephalon

what does the pineal gland mainly produce

melatonin

what stimulates melatonin production?

limited light to eyes

what is the organ most directly related in regulating blood sugar?

pancreas

what two hormones are produced in the pancreas?

glucagon, insulin

what does glucagon do??

raise blood sugar

what does insulin do??

lower blood sugar

step one of how glucagon raises blood sugar

breakdown of glycogen into sugar

step 2 of glucagon raising blood sugar

gluconeogenesis

step 3 of glucagon raising blood sugar

release of glucose from liver into blood

step 1 of insulin lowering blood sugar

enhances cellular uptake of glucose

step 2 of insulin lowering blood sugar

inhibit gluconeogenesis

step 3 of insulin lowering blood sugar

inhibits breakdown of glycogen to glucose

diabetes mellitus is due to ____

low or non-functional insulin

since sugar cannot be absorbed into body cells in diabetes mellitus…..

• blood sugar rises

• stress makes body release more glucose

the waste products of gluconeogenesis cause what?

ketoacidosis (nail polish breath)

3 diabetes symptoms

• polyuria

• polydipsia

• polyphagia

what do the ovaries produce?

estrogen and progesterone

what does estrogen do?

regulate monthly menstrual cycle

what does progesterone do?

support pregnancy and menstruation

what do the testes create?

testosterone

what defines an endocrine gland?

a gland that releases directly into the blood

what is hormone half-life?

the time it takes for 50% of the present hormone to dissapate

define catecholamines

hormones released in fight-or-flight to constrict blood vessels and increase blood flow