E5 Ch. 17 Flashcards
define endocrinology
study of hormones and endocrine glands
list the various pure endocrine organs
pituitary, pineal gland, thyroid and parathyroid glands, adrenal glands
list the organs containing large portion of endocrine cells
pancreas, thymus, gonads, and hypothalamus
list the various organs that contain some endocrine cells
heart, digestive tract, kidneys, and skin
what type of molecules are secreted by the endocrine system
hormones
what are the two classes of hormones
amino acid-based and steroids (derived from cholesterol)
what is the basic action of hormones
circulate throughout body in blood vessels influencing only target cells (different effects on different target cells)
list the different types of stimuli that trigger secretion of hormones
humoral, neural, and hormonal
describe humoral hormone secretions
secretion in direct response to changing ion or nutrient levels in blood
describe neural hormone secrtion
sympathetic nerve fibers stimulate cells in adrenal medulla, induces release of epinephrine and norepinephrine
describe hormonal hormone secretion
stimuli received from other glands, certain hormones signal secretion of other hormones
what controls hormone secretion
feedback loops
how many hormones does the pituitary gland secrete
9 major hormones
where is the pituitary gland located
attached to hypothalamus by infundibulum
what are the 2 basic divisions of the pituitary gland
anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis)
what are the 3 major division of the anterior lobe of the pituitary gland
pars distalis, pars intermedia, and pars tuberalis
what are the 2 major divisions of the posterior lobe of the pituitary gland
pars nervosa and infundibulum
describe the pars distalis
largest of anterior lobe, contain 5 different endocrine cells, makes/secretes 7 different hormones, tropic hormones regulate hormone secretion by other glands (TSH, ACTH, FSH, LH)
what hormones are secreted by the anterior lobe
MSH, FSH, LH, ACTH, TSH, PRL, GH
what produces the thyroid-stimulating hormone (TSH) and what does it signal
produced by thyrotropic cells; signals thyroid gland to secrete thyroid hormone
what does the adrenocorticotropic hormone stimulate
adrenal cortex to secrete hormones that help cope w/ stress
what produces gonadotropins
gonadotropic cells; FSH and LH
what produces growth hormones (GH) and what does it stimulate
produced by somatotropic cells, stimulates body growth by stimulating increased protein production and growth of epiphyseal plates, directly/indirectly by liver’s secretion of insulin-like growth factor-1
function of melanocyte-stimulating hormone (MSH)
in humans, functions in appetite suppression
what produces prolactin, and its function
produced by prolactin cells, targets milk-producing glands in breast- stimulates milk production
what are the 5 cell types of the anterior lobe classified as
acidophils, basophils, and chromophobes
how does the hypothalamus control anterior lobe hormones
exerts control by secreting releasing hormones (prompt anterior lobe to release hormones), and inhibiting hormones (turn off secretion of anterior lobe hormones)
describe how releasing hormones are secreted
like neurotransmitters; enter primary capillary plexus to hypophyseal portal veins to secondary capillary plexus, hormones secreted y anterior lobe enter general circulation and travel to target organs
what makes up the hypothalamohypophyseal tract
axons of the posterior lobe, arise from neuronal cell bodies in the hypothalamus
what hormones does the posterior lobe make an release
doesn’t make hormones just stores and releases hormones made in hypothalamus; antidiuretic hormone (ADH) and oxytocin
where is ADH made and its target
made in supraoptic nucleus, targets kidneys to resorb water
where is oxytocin produced and function
produced in paraventricular nucleus; induces smooth muscle contraction of reproductive organs, ejects milk during breast-feeding, and signals contraction of uterus during birth
where is the thyroid gland located and what is it composed of
located in anterior neck (largest purely endocrine gland), composed of follicles and areolar CT
what hormones does the thyroid gland produce
thyroid hormone (TH) and calcitonin
where are the parathyroid glands located
on posterior surface of thyroid gland
list the types of endocrine cells the parathyroid glands contain
chief cells, and oxyphil cells
function of chief cells
produce parathyroid hormone (PTH), increase blood concentration of Ca2+ (calcium)
function of oxyphil cells
function unknown
describe the adrenal (suprarenal) glands
pyramid-shaped, located on superior surface of each kidney, supplies ~ 60 suprarenal arteries, nerve supply almost exclusively sympathetic fibers
describe the function of the adrenal medulla
cluster of neurons, derived from neural crest, part of the sympathetic NS
describe the adrenal cortex
forms bulk of gland, derived from somatic mesoderm
what do all adrenal hormones do
help body cope w/ danger, terror, or stress
what are medullary chromaffin cells
modified postganglionic sympathetic neurons that secrete amine hormones epinephrine and norepinephrine
function of epinephrine, norepinephrine and where are they stored
enhance “flight or fight” response, hormones stored in secretory vesicles
what does the adrenal cortex secrete
lipid-based steroid hormones
list the layers that comprise the adrenal cortex
zona glomerulosa, zona fasciculata, and zona reticularis
how are the cells of the zona glomerulosa arranged
in spherical clusters
how are the cells of the zona fasciculata arranged
parallel cords; contains lipid droplets
how are the cells of the zona reticularis arranged
branching network
what class of hormones does the adrenal cortex secrete list them
hormones are corticosteriods; mineralocorticoids and glucocorticoids
describe aldosterone, where are they secreted and why
mineralocorticoid; secreted by zona glomerulos, secreted in response to decline in blood volume/ BP, is the terminal hormone of the renin-angiotensin mechanism
what is the main type of glucocorticoids, where are they secreted and what do they do
cortisol main type; secreted by zona fasciculata and zona reticularis, helps body deal w/ stressful situations
where is the pineal gland located
located on roof of diencephaon
how are pinealocytes arranged
in spherical clusters and branching cords
“pineal sand”
radiopaque; used as landmark to identify other brain structures in X-ray films
what do pinealocytes secrete
melatonin; a hormone that regulates circadian rhythms
where is the pancreas located
posterior abdominal call
name the exocrine and endocrine cells of the pancreas
exocrine- acinar cells
endocrine- pancreatic islets
what do acinar cells secrete
digestive enzymes
list the main endocrine cells types of the pancreas
alpha and beta
what do alpha cells secrete and function
secrete glucagon; signal liver to release glucose from glycogen, raise blood sugar
what do beta cells secrete and function
secrete insulin; signal most body cells to take up glucose from blood, promote storage of glucose as glycogen in liver, lower blood sugar
list the 2 cell types that are found in pancreatic islets
delta and F (PP) cells
what do delta cells secrete and function
secrete somatostatin; inhibit secretion of insulin and glucagon
what do F (PP) cells secrete and function
secrete pancreatic polypeptide; may inhibit exocrine activity of the pancreas
where is the thymus located
lower neck and anterior thorax
function of thymus
site where T lymphocytes arise from precursor cells (transformation of lymphocytes stimulated by thymic hormones
what are the 2 types of thymic hormones
peptide molecules; thymopoietin and thymosin
where are the main sources of sex hormones
testes and ovaries
what do interstitial cells of males secrete
androgens primarily testosterone
function of testosterone
promote sperm formation, and maintains secondary sex characteristics
female androgens are secreted by
theca folliculi
what converts androgens to estrogen
by follicular granulosa cells
function of estorgen
maintains secondary sex characteristics
function of progesterone
preps uterus for pregnancy
describe the endocrine cells found in the heart
atria contain atrial natriuretic peptide (ANP)
what endocrine cells occur w/in the GI tract
enteroendocrine cells
describe the endocrine cells found in the placenta
sustains fetus and secretes several steroid protein hormones
describe the endocrine function of the kidneys
cells of juxtaglomerular complex (JGA) secrete renin
endothelia cells/interstitial CT secrete erythropoietin
describe the endocrine function of the skin
modified cholesterol molecules convert to a precursor of vitamin D
type of disorder is gigantism
pituitary disorder; hyper-secretion of GH in children
pituitary dwarfism
hypo-secretion of GH
what type of disorder is diabetes insipidus
pituitary disorder; pars nervosa doesn’t make enough ADH
diabetes mellitus is what type of disorder
disorder of the pancreas
what is the cause of diabetes mellitus
insufficient secretion of insulin, and resistance of body cells to the effects of insulin
describe type 1 diabetes
sudden development usually before age 15
T cell-meidated autoimmune response destroys beta cells
describe type 2 diabetes
adult onset (40 yrs), cells have lowered sensitivity to insulin, controlled by dietary changes and regular exercise
what is Graves disease
most common type of hyperthyroidism; immune system makes abnormal antibodies (over secretion of TH by follicle cells), leads to nervousness, weight loss, seating, and rapid HR
what is myxedema
adult hypothyroidism; antibodies attack/destroy thyroid tissue, low metabolic rate/weight gain common symptoms
cause of endemic goiter
lack of iodine in diet
what is cretinism
hypothyroidism in children, results in short, disproportionate body; thick tongue; and mental retardation
cause of Cushing’s syndrome
caused by hyper-secretion of glucocorticoid hormones-usually a pituitary tumor
addison’s disease
hypo-secretory disorder of the adrenal cortex, deficiencies of both mineralocorticoids and glucocorticoids
where does the thyroid gland form from
a chickening of endoderm on the floor of the pharynx
where do the parathyroids and thymus gland form from
endoderm lining the pharyngeal pouches
where does the pineal gland originate from
ependymal cells
where does the pituitary gland originate from
adenohypophysis originates from roof of mouth
neurophypophysis grows inferiorly from the floor of the brain
where do the adrenal glans from from
adrenal medulla- neural crest cells of nearby sympathetic trunk ganglia
adrenal cortex- mesoderm lining the coelom
what happens to the anterior pituitary as we age
increase in CT and lipofuscin, decrease in vascularization and # of hormone-secreting cells
what happens to the adrenal cortex as we age
normal rates of glucocorticoid secretion continue
what happens to the adrenal medulla as we age
no age-relatd changes in catecholamines
what happens to thyroid hormones as we age
decrease slightly w/ age
what happens to parathyroid glands as we age
little change w/ aging
what happens to GH, DHEA, and sex hormones as we age
marked drops in secretion w/ age
