AP 2 Endocrine

exocrine

glands that secrete products into ducts that carry secretions into body cavities, into the lumen of organs or the outer surface of the body; ex. sudoriferous (sweat) glands, sebaceous (oil) glands, mucous glands, digestive glands etc

endocrine

gland that secretes hormones into interstitial fluid & then into blood, ductless gland; ex. pituitary, thyroid, parathyroid, adrenal and pineal glands

spleen

what is the only organ that does not produce any hormones?

target cells

cells that possess specfic protein receptors for the hormone (lock & key method); their amoutn and utilization varies

down-regulation

a process receptors use when there is too much hormone and the # of receptors is consequently decreased

up-regulation

a process receptors use when there is not enough of a hormone and therefore the number of receptors is increased

paracrines (local hormones)

hormones that do not circulate, they are secreted into the immediate spaces around them

autocrines

hormones that act on the same cell that secretes them; they release hormones and attach them to self (ex. overreactive inflammatory immune response)

lipid-soluble

type of hormones that circulate bound to transport proteins; includes steroid hormones, thyroid hormones, nitric oxide; easily diffuse through cell membrane; bind to receptors WITHIN target cells

water-soluble

type of hormones that circulate freely in the plasma; have difficulty at the cell membrane; amine hormones, peptide, and protein hormones, eicosanoid hormones; bind to receptors on the EXTERIOR of the target cell

steroid hormones

aldosterone, cortisol, androgens; calcitriol; testosterone; estrogens, progesterone; lipid-soluble

thyroid hormones

T3 (triiodothyronine) and T4 (thyroxine); lipid soluble

Gas hormones

Nitric oxide; lipid-soluble

eicosanoids

prostaglandins and leukotrienes; lipid-soluble

peptides and proteins

water-soluble hormones like all hypothalamic releasing and inhibiting hormones; oxytocin, ADH; growth hormone, TSH, adrenocorticotropic hormone, FSH, LH, prolactin, MSH; insulin, glucagon, somatostatin, pancreatic polypeptide; parathyroid hormone; calcitonin; gastrin, secretin, cholecystokinin, GIP; erythropoietin; leptin

synergistic effect

when a hormones work more effectively when a second hormone is present to assist them

antagonistic effect

when hormones oppose the action of one another

negative feedback

the feedback loop in which the effects of a reaction are slowed or stopped; control the secretions of thyrotrophs, gonadotrophs, and corticotrophins;

function of hormones

help with regulation (chemical composition & volume of internal environment, metabolism and energy balance, contraction of smooth and cardiac muscle fibers, etc etc); control growth and development, regulate the operation of genital systems, help establish circadian rhythms

transport proteins

proteins synthesized by cells in the liver; make lipid-soluble hormones temporarily water-soluble (increasing solubility in the blood); passage of small molecules through the filtering mechanism in the kidneys; provide a ready reserve, already present in the bloodstream

factors that affect the responsiveness of a target cell

1) the hormones concentration in the blood; 2) the abundance of the target cell’s hormone receptors; 3) influences exerted by other hormones

anterior pituitary

aka adenohypophysis; secretes growth hormone (somatotropin), thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), adrenocorticotropic (ACTH), melanocyte stimulating (MSH)

posterior pituitary

aka neurohypophysis; stores and releases oxytocin (OT) and antidiuretic hormone (ADH); blood supplied by the inferior hypophyseal arteries

hypothalamus

secretes releasing and inhibiting hormones, controlling release of hormones by pituitary gland; releasing hormones (GHRH, TRH, PRH, GnRH) and inhibiting hormones (GHIH & PIH)

hypophyseal portal system

how hormones from the hypothalamus that reach the pituitary gland

somatotrophs

hormones that go to systemic body cells

hypoglycemia

low blood sugar; decreased blood levels of fatty acids, increased blood levels of amino acids; deep sleep; testosterone, estrogens, thyroid hormones, and ghrelin'; sympathetic activity

hyperglycemia

high blood sugar; increased blood levels of fatty acids, decreased blood levels of amino acids; obesity; aging; high blood levels of GH and IGFs

oxytocin

hormone that is released in response to stretch placed on the cervix during childbirth; affects mothers uterus and breasts

ADH

hormone whose amount varies with the blood osmotic pressure; decreases urine output; an increase in blood volume decreases this secretion while a decrease in blood volume increases this secretion

parafollicular cells

cells in the thyroid produce the hormone calcitonin to help regulate calcium homeostasis

follicular cells

cells in thyroid that are stimulated by TSH to produce thyroxine (T4, tetraiodothyronine) and triiodothyronine (T3)

calcitonin

hormone that monitors upper limits of calcium; high blood Ca2+ levels stimulate secretion; lowers blood levels of Ca2+ by inhibiting bone resorption by osteoclasts and by accelerating uptake of calcium and phosphates into bone extracellular matrix

functions of thyroid hormones

increase basal metabolic rate (BMR), help maintain normal body temperature, stimulate protein synthesis, increase the use of glucose and fatty acids for ATP production, up-regulate beta receptors that attach to catecholamines (NE/E, adrenaline), work with hGH and insulin to accelerate body growth

chief cells

cells in parathyroid gland that produce parathyroid hormone (PTH); monitor the lower limits of calcium;

oxyphil cells

type of cell in parathyroid whose function is unknown but secrete excess PTH in cases of parathyroid cancer

parathyroid hormone (PTH)

secreted by chief cells in the parathyroid gland; monitors lower limits of calcium; low blood Ca2+ levels stimulate secretion; increases osteoclast activity, encouraging bone resorption and therefore increasing blood Ca2+

adrenal cortex

aka suprarenal cortex; divided into 3 regions

adrenal medulla

aka suprarenal medulla; contains chromaffin cells that make catecholamines (NE/E - adrenaline) in the sympathetic division of ANS (fight or flight response);

zona glomerulosa

region of adrenal cortex that secretes mineralocorticoids to regulate mineral homeostasis; ex. Aldosterone (controlled by RAA pathway and helps regulate sodium & potassium)

zona fasciculata

region of the adrenal cortex that secretes glucocorticoids affecting glucose homeostasis (ex. cortisol); helps control protein breakdown, glucose formation, lipolysis, resistance to stress, inflammation and immune response

zona reticularis

region of the adrenal cortex that secretes weak androgens (ex. dehydroepiandrosterone (DHEA));

for males - no effect after puberty

for females - promote libido, converted to estrogens; menopausal - all estrogens come from adrenal

aldosterone

major mineralocorticoid secreted by adrenal gland; helps regulate sodium and potassium homeostasis; RAA pathway controls secretion of aldosterone

pancreas

organ that is both an endocrine and exocrine gland

acini

clusters of exocrine cells in the pancreas; produce digestive enzymes that are delivered to the gastro tract through ducts

islets of langherhans

clusters of endocrine tissue in the pancreas; contain secreting cells (alpha (A) cells, beta (B) cells, Delta (D) cells and F cells)

alpha (A) cells

cells in pancreatic islets that monitor lower limits of sugar & release glucose into the blood; secrete glucagon; second most predominant in islet; negative feedback loop

beta (B) cells

cells in pancreatic islets that secrete insulin; monitor upper limits of sugar in blood by reducing glucose in blood; most predominant cell in islet; negative feedback loop

delta (D) cells

cells in pancreatic islets that secrete somatostatin; paracrine secretion mechanism where this shuts down beta cells

F cells

cells in pancreatic islets that secretes pancreatic polypeptide; tells body to digest; tells beta to make insulin to prepare for digestion

gonads

name for ovaries and testes

ovaries

organ produce two estrogens (estradiol and estrone), progesterone (communicates to uterus about fertilization), relaxin (relaxes cervix & pubic symphysis), and inhibin (inhibits estrogen & progesterone)

testes

organ that produces testosterone

pineal gland

structure that secretes melatonin (helps body’s biological clock)

thymus

organ that is a nursery for T cells; produces thymosin, thymic humoral factor (THF), thymic factor (TF), and thymopoietin to make them immunocompetent

gastrin

hormone that promotes secretion of gastric juice, increases movements of the stomach

secretin

hormone that stimulates secretion of pancreatic juice and bile

cholecystokinin (CCK)

stimulates secretion of pancreatic juice; regulates release of bile from gallbladder; causes feeling of fullness after eating

hCG (human chorionic gonadtropin)

hormone that stimulates corpus luteum in ovary to continue production of estrogens and progesterone to maintain pregnancy, usually the hormone used for detection ina. pregnancy test

renin

hormone secreted by the kidneys that is part of reaction sequence that raises blood pressure by bringing about vasoconstriction and secretion of aldosterone

erythropoietin (EPO)

hormone secreted by kidneys that increases the rate of red blood cell formation

calcitriol

hormone in kidney that aids in absorption of dietary calcium and phosphorus; also the active form of vitamin D

atrial natriuretic peptide (ANP)

hormone produced by the heart to DECREASE blood pressure

leptin

hormone produced by adipose (fat) tissue that suppresses appetite, may increase FSH and LH activity

eustress

helpful everyday stress that prepares us to meet challenges

distress

any type of harmful stress that may be damaging

fight or flight response

first stage of stress response; stimulates body’s resources to prepare for immediate activity; steps: increased HR and force of heartbeat, constriction of blood vessels in skin and most visceral organs, dilation of BV in heart, brain, lungs, and skeletal muscle, contraction of spleen, conversion of glycogen into glucose in liver, sweating, dilation of airways, decrease digestive activities, water retention and elevated BP

resistance reaction

second stage of stress response; longer that fight or flight; if this is too long, exhaustion will occur

pituitary gigantism

pre-pubety hypersecretion of growth hormone (GH); usually tall and bigger

acromegaly

post-puberty hypersecretion of growth hormone (GH); usually signified by larger facial features, etc

goiter

reduction in production of thyroid hormone; not enough iodine; can fix with high salt diet

Graves disease (exophthalmos)

hyperthyroidism; swollen in places of fat storage (bulging eyes); excess thyroid hormone

Cushing’s syndrome

hypersecretion of cortisol (glucocorticoids)

Addison’s disease

hyposecretion of glucocorticoids and aldosterone

Pheochromocytomas

benign tumors causing hypersecretion of epinephrine and norepinephrine; Michael Jackson had this

Type 1 Diabetes

autoimmune disease where beta cells are destroyed; unable to make insulin; life expectancy around 20 but more now (technology)

Type 2 Diabetes

more common type of diabtetes; often linked to lifestyle factors such as obesity and inactivity; cells become master ignorer

Gestational diabetes

diabetes that happens when pregnant; get insulin during pregnancy