Anatomy_Key Terms_Ch17 Flashcards
endocrine system
internal regulatory system, helps to maintain the internal environment of the body within normal ranges, organs are a dispersed group of ductless glands that secrete messenger molecules called hormones into the circulation
endocrinology
scientific study of hormones and the endocrine glands
amino acid-based hormones
include modified amino acids (or amines), peptides (short chanis of amino acids), and proteins (long chains of amino acids). the cells that produce amino acid-based homones have an elaborate rough endoplasmic reticulum (ER) to produce these protein-based molecules and abundant secretory granules that secrete these hormones via exocytosis.
steroid hormones
lipid molecules derived from cholesterol. steroid-secreting cells have an extensive smooth ER, which produces the steroid molecules, and abundant lipid droplets, which contain the raw material from which steroids are made. these cells lack secretory granules; steroid hormones are secreted by diffusion across the plama membrane.
target cells
specific tissue cells influenced by a given hormone, once binding has occurred the target cell reacts in a preprogrammed way
atrial natriuretic peptide (ANP)
”"”producing salty urine””, a hormane that decreases blood volume, lowers blood pressure, and decreases blood sodium concentration, primarily by stimulating the kidney to increase its secretion of salt and its production of salty urine”
diffuse neuroendocrine system (DNES)
enteroendocrine cells are homone-secretenig cells scattered within the epithelial lining of the digestive tract. related endocrine cells occur within organs that derive from the embryonic gut, such as the respiratory tubes, pancrease, prostate, and thyroid gland. collectively, all these scattered epithelial cells make up the _
gigantism
hypersecretion of GH in which the child grows exceptionally fast and becomes extremely tall often reaching 2.4m
acromegaly
“excessive amounts of GH are secreted after the bones’ epiphyseal plates have closed; characterized by enlargement of bondy areas that are still responsive to GH—the hands, feet, and face”
pituitary dawrfs
hyposecretion of GH in children, bodies of normal proportions but rarely reach 1.2m
diabetes insipidus
”"”passing of dilute [urine]””, caused by insufficient production or secretion of antidiuretic horm (ADH) or more lrarely by the kidney’s lack of response to this hormone”
dibetes mellitus
“caused either by insufficient secretion of insulin or by resistance of body cells to the effects of insulin; as a result, glucose cannot enter most cells, so blood surgar remains high and large volumes of urine containing glucose are excreted; because glucose in unavailable as fuel, the body’s cells metabolize fats, whose acid breakdown products, ketones, accumulate in the blood; left untreated, the increased urination depletes the body of water and electrolytes, and the ketone acidosis depresses almost all physiological punctions and leads to coma”
type 1 diabetes
(formerly called insulin-dependent diabetes), autoimmune response destroys the insulin-secreting beta cells in the pancreas, insulin must be administered to type 1 diabetics several times daily to control blood glucose levels
type 2 diabetes
(non-insulin-dependent diabetes), most produce some insulin, but their cells have a reduced sensitivity to the effects of insulin, can usually be controlled by dietary modification and regular exercise
“Graves’ disease”
most common form of hyperthyroidism, an autoimmune disease in which the immune system makes abnormal antibodies that mimic TSH and stimulate the oversecretion of TH by follicular cells of the thyroid; elevated metabolic rate, rapid heart rate, sweating, nervousness, weight loss despite normal food intake
adult hypothyroidism
“or myxedema ““mucous swelling””, typically an autoimmune disease in which antibodies attack and destroy thyroid tissue (hyposecretion of TH); low metabolic rate, weight gain, lethary, constant cihllienss, puffy eyes, edema, and mental sluggishnes”
endemic goiter
the thyroid gland enlarges due to insufficient iodine in the diet
“Cushing’s disease/Cushing’s syndrome”
hypersecretion of glucocorticoid hormones caused either by an ACTH-secreting pituitary tomor or (rarly) by a tumor of the adrenal cortex or clinical administation of glucocorticoids to suppress inflammation; high levels of glucose in the blood, loss of protein from muscles, lethargy and can lead to water and salt retention resulting in hypertension and edema
“Addison’s disease”
major hyposecretory disorder of the adrenal cortex, usually involves dificiencies of both glcocorticoids and mineralcorticoids; blood levels of glucose and sodium drop and sever dehydration and low blood pressure are common, fatiguge, loss of appetite, and abdominal pain
hypophyseal pouch
“or Rathke’s pouch, pouch of ectoderm that arises from the roof of the mouth and turns into the anterior lobe of the pituitary gland”
neurohypophyseal bud
future posterior lobe of the pituitary gland grows inferiorly from the floor of the brain
pituitary gland
aka hypophysis (undergrowth [from the brain]), important endocrine organe that secretes at least nine major hormones; sits just inferior to the brain in the hypophyseal fossa, a depression in the sella turcica of tehe sphenoid bone
infundibulum
”"”funnel””, stalk of the pituitary”
anterior lobe
aka adenohypophysis (glandular hypophysis), composed of glandular tissue; has three subdivisions, the anteriormost pars distalis, just posterior lies the pars intermedia, and ust suprerior to it lies the pars tuberalis which wraps around the infundibulum like a tube
posterior lobe
aka neurohypophysis, composed of neural tissue and a part of the brain; has two subdivisions, the pars nervosa inferiorly, and the infundibulum
superior hypophyseal artery
supplies the entire anterior lobe and the infundibulum
inferior hypophyseal artery
supplies the pars nervosa
pars distalis
contains five different types of endocrine cells that make and secrete at least seven different hormones. four are tropic hormones and the remaining three adenohypophysis hormones act directly on nonendocrine target tissues (growth hormone, prolactin, and melanocyte-stimulating hormone)
tropic hormones
hormones secreted by the anterior lobe that regulate the secretion of hormones by other endocrine glands (thyroid-stimulating hormone, adrenocortico-tropic hormone, follicle-stimulating hormone, and luteinizing hormone)
thyroid-stimulating hormone (TSH)
produced by thyrotropic cells; TSH signals the thyroid gland to secrete its own hornmone, thyroid hormone, and thus ultimately controls metabolic rate
adrenocorticotropic hormone (ACTH)
”"”adrenal cortex changing””, and melanocyte-stimulating horone are splite from a common parent molecule produced by corticotropic cells in the anterior lobe; ACTH stimulates the adrenal cortex to secrete hormones that help the body cope with stress”
follicle-stimulating horome (FSH) and lueinizing hormone (LH)
produced by gonadotropic cells in the anteriol lobe and together are referred to as gonadotropins; stimulate maturation of the sex cells and induce the secretion of sex hormones
prolactin (PRL)
produced by prolactin cells in the anterior lobe; targets the milk-producing glands in the breast, the lactiferous glands, and stimulates the manufacture of milk
melanocyte-stimulating hormone (MSH)
formed from the precursor molecule produced by corticotropic cells; functions in the CNS in appetite suppression, its actions outside the CNS are not well understood
growth hormone (GH)
aka somatotropic hormone (body changing), produced in the somatotropic cells, the most abundant cell type in the anterior lobe; stimulates growth of the entire body by stimulate body cells to increase their production of proteins and by stimulating growth of the epiphyseal plates of the skeleton
acidophils
stain with acidic stains and include the somatotropic and prolactin cells
basophils
stain with basic stains and include the thyrotropic, corticotropic, and gonadotropic cells<br></br>nucleus usually has two lobes and may be bent into the shape of a U or an S, granules contain histamine and other molecules that are secreted to mediate inflammation uring allergic respnoses and parasitic infections (direct later stages)
chromophobes
”"”color avoiders””, stain poorly, either immature cells or cels whose supply of hormone has been depleted”
pars intermedia
contains corticotropic cells that secrete more MSH than ACTH
pars tuberalis
contains gonadotropic cells, thyrotropic cells, and unique, pars-tuberalis-specific endocrine cells that have receptors for melatonin, a hormone that is secreted by the pineal gland and regulates daily (circadion) rhythms according to light/dark cycles (photoperiod)
releasing hormones/releasing factors
secreted by the hypothalamus, prompt cells in the anterior lobe to release their hormones
inhibiting hormones
secreted by the hypothalamus, turn off the secretion of hormones by the anterior lobe when necessary
primary capillary plexus
secreted releasing hormones enter a _ in the median eminence of the hypothalamus and then travel inferiorly in hypophyseal portal veins to a secondary capillary plexus in the anterior lobe
hypophyseal portal system
the primary and secondary capillary plexuses in the pituitary gland, plus the intervening hypophyseal portal veins
pituicytes
neuroglial cells found in the posterior lobe of the pituitary gland
hypothalamohypophyseal tract
formed by axons of the posterior lobe of the pituitary gland, the _ arises from neuron cell bodies in the supraoptic and paraventricular nuclei in the hypothalamus and end in axon terminals in the pars nervosa
antidiuretic hormone (ADH)
aka vasopressin, targets the kidneys, which respond by resorbing more water and returning it to the bloodstream
oxytocin
produced in the paraventricular nucleus of the hypothalamus, induces scontraction of the smooth musculature of reproductive organs in both males and females, including the wall of the uterus
thyroid gland
located in the anterior neck, on the trachea just inferior to the larynx, largest purely endocrine gland in the body and has a copious blood supply from the superior and inferior thyroid arteries
lobes (thyroid)
“the buttterfly’s ““wings”” of the butterfly-shaped thyroid gland (two lateral _)”
isthmus
median bridge that connect the two thyroid lobes
follicles
thyroid gland is composed of hollow, approximately spherical _ separated by an arealar connective tissue rich in capillaries
follicular cells
layer of cuboidal or squamous epithelial cells that form the walls of each follicle
colloid
”"”gluelike””, jellylike substance that fills the central lumen of the thyroid gland”
thyroglobulin
a protein from which thyroid hormone is ultimately derived, colloid consists of it
parafollicular (C) cells
lying within the follicular epithelium, appear to porject into the surrounding connective tissue
thyroid hormone (TH)
actually two similar molecules called thyroxine (T4) and triiodothyronine (T3), secreted by the folicular cells of the thyroid gland, each is constructed from a pair of amino acids and contains the element iodine, main function is to increase the metabolic rate
calcitonin
lowers blood levels of Ca2+ by slowing the calcium-releasing activity of osteoclasts in bone and increasing calcium secretion by the kidney
parathyroid glands
lie on the posterior surface of the thyroid gland
parathyroid cells
one type of endocrine cells contained in the parathyroid gland are small, abundant _
oxyphil cells
”"”acid loving”” (stains with acidic dyes), rare, larger parathyroid _ contained in the gland, function unknown”
parathyroid hormone (PTH)
aka parathormone, increases the blood concentration of Ca2+ whenever it falls below some threshold value, by:<br></br>stimulating osteoclasts to release more Ca2+ from bone<br></br>dercreasing the excretion of Ca2+ by the kidney<br></br>activating vitamin D, which stimulates the uptake of Ca2+ by the intestine
adrenal (suprarenal) glands
pyramidal or crescent-shaped paired organs perched on the superior surface of the kidneys, each supplied by up to 60 small suprarenal arteries, each is two endocrine glands in one–the internal adrenal medulla is more like a cluster of neurons than a gland and is derived from the neural crest, and the external adrenal cortex surrounding the medulla and forming the bulk of the gland is derived from somatic mesoderm
medullary chromaffin cells
spherical modified postganglionic sympathetic neurons that secrete the amine hormones epinephrine and norepineprine into the blood to enhance the fight-or-flight response
adrenal cortex
secretes a variety of hormones, all of which are lipid-based steroid hormones; microscopically, exhibts three distinct layers/zones, from external to internal: zona glomerulosa, zona fasciculata, zona reticularis
zona glomerulosa
(ball of yarn), contains cells arranged in spherical clusters
zona fasciculata
(bundle of parallel sticks), cells are arranged in parallel cords and contain an abundance of lipid droplets
zona reticularis
cells are arranged in a branching network and stain intensely with the pink dye eosin
corticosteroids
“along with the sex hormones are the body’s major steroid hormones, secreted by the adrenal cortex, two main classes (mineralocorticoids and glucocorticoids)”
