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A&PII - Ch 16

Endocrine System

body system that includes internal organs that secrete hormones endocrine system
endocrine system influences __ activity by means of hormones metabolic
steroidal or amino acid–based molecules released to the blood that act as chemical messengers to regulate specific body functions hormones
binding of hormones to cellular receptors initiates responses that typically occur after __ __ of seconds or even days lag period
once initiated responses to hormone receptor sites tends to be much __ __ than those induced by nervous system more prolonged
reproduction; growth & development; maintenance of electrolyte, water, & nutrient balance of blood; regulation of cellular metabolism & energy balance; & mobilization of body defenses major processes controlled & integrated by endocrine system
endocrine system orchestrates processes that go on for relatively long periods or even continuously
scientific study of hormones & endocrine organs endocrinology
compared with other organs of the body the endocrine glands are small & unimpressive
endocrine organs are not __ __ in the body grouped together
endocrine organs are __ __ throughout the body widely scattered
endocrine glands are also called ductless glands
endocrine glands released their hormones into surrounding tissue fluid
within endo-
to secrete -crine
endocrine glands have __ vascular & lymphatic drainage that receives their hormones rich
most of hormone-producing cells in endocrine glands are arranged in __ & __ networks cords; branching
cords & branching networks are a situation that __ contact between endocrine glands & capillaries surrounding them maximizes
includes pituitary, thyroid, parathyroid, adrenal, & pineal glands endocrine glands
considered a neuroendocrine organ because, along with its neural functions, it produces & releases hormones hypothalamus
pancreas, gonads, & placenta, along with performing other functions, contain endocrine tissue
endocrine function of adipose cells release leptin
endocrine function of thymus is release thymic hormones
are found in walls of small intestine, stomach, kidneys, & heart hormone-producing cells
hormones are long-distance chemical signals that travel in __ throughout the body blood/lymph
chemicals that exert their effects on same cells that secrete them autocrines
also act locally but affect cell types other than those releasing the chemicals paracrines
certain prostaglandins released by smooth muscle cells cause those smooth muscle cells to contract making it a(n) autocrine
released by one population of pancreatic cells inhibits release of insulin by a different population of pancreatic cells making it a(n) paracrine
synthesize hormones identical to those made in normal endocrine glands in excess/uncontrolled fashion leading to problems due to hormone-mediated pathology certain tumor cells, such as lung/pancreatic cancer
most hormones are __ __ based amino acid
simple amino acid derivatives amines & thyroxine
short chains of amino acids peptides
long polymers of amino acids proteins
group of chemical substances including certain hormones & cholesterol; fat soluble & contain little oxygen steroid
only gonadal & adrenocortical hormones are steroids
biologically active lipids are released by nearly all cell membranes; includes leukotrienes & prostaglandins eicosanoids
signaling chemicals that mediate inflammation & some allergic reactions leukotrienes
have multiple targets & effects, ranging from raising blood pressure & increasing expulsive uterine contraction of birth to enhancing blood clotting, pain, & inflammation prostaglandins
because effects of eicosanoids are typically highly localized, they generally act as paracrines/autocrines instead of true hormones
true hormones influence __ targets distant
all major hormones circulate to __ __ tissues virtually all
influences activity of only certain tissue cells, referred to as its target cells given hormone
hormones bring about their characteristic effects on target cells by __ cell activity, either decreasing/increasing rates of normal cellular processes altering
hormonal stimulus typically alters plasma membrane permeability/potential (or both) by opening/closing ion channels
hormonal stimulus typically __ __ of proteins or regulatory molecules (such as enzymes within cell) stimulates synthesis
hormonal stimulus typically activates or deactivates __ enzymes
hormonal stimulus typically stimulates mitosis
hormones act at receptors in the plasma membrane when they are water-soluble hormones
water-soluble hormones are all amino acid-based hormones except for thyroid hormone
water-soluble hormones are coupled via regulatory molecules called __ to one/more intracellular 2nd messengers which mediate target cell's response G proteins
act on intracellular receptors, which directly activate genes lipid-soluble hormones
lipid-soluble hormones include steroid & thyroid hormones
receptor for water-soluble hormones must be in __ __ since these hormones cannot enter cell plasma membrane
receptor for lipid-soluble steroid & thyroid hormones are __ cell inside
intracellular molecule generated by the binding of a chemical (hormone or neurotransmitter) to a plasma membrane receptor; mediates intracellular responses to the chemical messenge second messengers
with exception of thyroid hormone, all __ __ hormones exert their signaling effects through intracellular second messengers amino acid-based
intracellular second messenger that mediates the effects of the first (extracellular) messenger (hormone or neurotransmitter); formed from ATP by a plasma membrane enzyme (adenylate cyclase) cyclic AMP
cyclic AMP is used by __ & __ receptors neurotransmitters; olfactory
cyclic AMP mechanism involves interaction of __ plasma membrane components to determine intracellular levels of cyclic AMP three
cyclic AMP cAMP
three plasma membrane components to determine intracellular levels of cAMP hormone receptor, G protein, & effector enzyme
hormone bind receptor on plasma membrane 1st step of cAMP mechanism
receptor activates G protein 2nd step of cAMP mechanism
when receptor activates G protein, hormone binding causes receptor to __ __, allowing it to bind a nearby inactive G protein change shape
when receptor activates G protein, it is activates as __ bound to it is displaced by high-energy compound __ GDP (guanosine diphosphate); GTP (guanosine triphosphate)
once activated (cAMP) G protein behaves like a light switch, off when __ is bound to it and on when __ is bound GDP; GTP
G protein activate adenylate cyclase 3rd step of cAMP mechanism
during cAMP mechanism, activated G protein (moving along membrane) binds to effector enzyme adenylate cyclase
G protein that stimulates adenylate cyclase Gs
G protein that inhibits adenylate cyclase Gi
during cAMP mechanism, eventually GTP bound to G protein is __ to GDP, & G protein becomes inactive once again hydrolyzed
during cAMP mechanism, G protein cleaves terminal phosphate group off GTP in much same way that ATPase enzymes hydrolyze ATP
adenylate cyclase converts ATP to cyclic AMP 4th step of cAMP mechanism
during cAMP mechanism, for as long as activated Gs is bound to it, adenylate cyclase generates second messenger cAMP from ATP
cyclic AMP activate protein kinase 5th step of cAMP mechanism
cAMP, which is free to diffuse throughout cell, triggers __ of chemical reactions by activating protein kinase cascade
enzymes that phosphorylate various proteins, many of which are other enzymes protein kinase
because __ activates some proteins and inhibits others (during cAMP) a variety of processes may be affected in same target cell at same time phosphorylation
type of intracellular enzymatic cascade during cAMP has a huge __ effect amplification
each activated adenylate cyclase generates large numbers of cAMP molecules, and a single kinase enzyme can catalyze hundreds of reactions
as cAMP mechanism reaction cascades through 1 enzyme intermediate after another, number of product molecules __ __ at each step increases dramatically
depends on type of target cell, specific protein kinase it contain, & substrates within that cell available for phosphorylation by protein kinase sequence of reaction set into motion by cAMP
binding of thyroid-stimulating hormone promotes synthesis of thyroid hormone thyroxine
in liver, binding of glucagon activates enzymes that breakdown glycogen, releasing glucose to blood
since some G proteins inhibit rather that activate adenylate cyclase, reducing cytoplasmic concentration of cAMP, even slight changes in levels of __ __ can influence target cell's activity antagonistic hormones
epinephrine, ACTH, FSH, LH, glucagon, PTH, TSH, & calcitonin are all hormones that act via cAMP mechanisms
action of cAMP persists only briefly because molecules is rapidly degraded by intracellular enzyme phosphodiesterase
any of a class of enzymes that catalyze the cleaving of phosphodiester bonds, such as those between nucleotides in nucleic acids, to produce smaller nucleotide units phosphodiesterase
because of amplification effect of cAMP mechanisms, most hormones need to be present __ __ to cause desired results only briefly
in PIP2-calcium signaling mechanism, intracellular calcium ions act as final mediator
phosphatidyl inositol bisphosphate PIP2
enzyme called phospholipase C splits plasma membrane phospholipid called PIP2 into diacylglycerol (DAG) and inositol trisphosphate (IP3) PIP2-calcium signaling mechanism
in PIP2-calcium signaling mechanism, ___ activates protein kinase C which triggers responses within target cell diacylglycerol (DAG)
in PIP2-calcium signaling mechanism, __ __ releases Ca2+ from intracellular storage sites inositol trisphosphate (IP3)
PIP2-calcium signaling mechanism, __ __ takes on second-messenger role, either by directly altering activity of specific enzymes & channels or by binding to intracellular regulatory protein calmodulin liberated Ca2+
in PIP2-calcium signaling mechanism, once Ca2+ binds to calmodulin it activates enzymes that __ cellular response amplify
thyrotropin-releasing hormone (TRH), antidiuretic hormone (ADH), gonadotropin-releasing hormone (GnRH), oxytocin, & epinephrine are all hormones known to act on their target cells via PIP2 mechanism
insulin & other growth factors work __ second messengers without
tyrosine kinase enzyme that is activated by autophosphorylation when insulin binds insulin receptor
activated insulin receptor provides docking sites for intracellular __ proteins relay
initiate series of protein phosphorylations that triggers specific cell responses relay proteins
in certain instances, any of second messengers & hormone receptor itself can cause changes in intracellular Ca2+ levels
thyroid hormone receptors are __ bound to DNA even in absence of thyroid hormone always
for steroid & thyroid hormones, activated receptor-hormone complex makes way to nuclear chromatin and then binds to region of DNA; this interaction "turns on" a gene that prompts transcription of DNA to produce messenger RNA (mRNA)
for steroid & thyroid hormones, once mRNA produced, it is then translated on __ __, producing specific protein molecules cytoplasmic ribosomes
protein molecules produced by mRNA include enzymes that promote metabolic activities induced by that particular hormone & in some cases promote synthesis of structural proteins or proteins to be transported from target cell for steroid & thyroid hormones
for steroid & thyroid hormones, in absence of hormone receptors are bound up in receptor-chaperonin complexes
receptor-chaperonin complexes that takes place in absence of steroid & thyroid hormones, keep receptors from binding to DNA and may protect them from proteolysis
hydrolytic breakdown of proteins into simpler, soluble substances such as peptides and amino acids, as occurs during digestion proteolysis
when steroid & thyroid hormones are present receptor-chaperonin complexes __ allowing hormone-bound receptor to bind to DNA & influence transcription dissociate
in order for target cell to respond to hormone, cell must have __ __ receptors on its plasma membrane or in it interior to which that hormones can bind specific protein
receptors for ACTH are normally found on certain cell of adrenal cortex
is principal hormone stimulating cellular metabolism, and nearly all body cells have its receptors thyroxine
responds to hormone binding by prompting cell to perform, or turn on, some gene-determined preprogrammed function hormone receptor
hormones are molecular __ rather than informational molecules triggers
target cell activation by hormone-receptor interaction __ __ on blood levels of hormone, relative numbers of receptors for that hormone on target cell, & affinity of binding btwn response to various stimuli & changes within body depends equally
for a given level of hormone in the blood, a large number of __ receptors produce a pronounced hormonal effect high-affinity
for a given level of hormone in the blood, a smaller number of __ receptors results in reduced target cell response or outright endocrine dysfunction low-affinity
receptors are __ structures dynamic
phenomenon in which target cells form more receptors in response to rising blood levels of specific hormone to which they respond up-regulation
prolonged exposure to high hormone concentration desensitizes target cells, sot that they respond less vigorously to hormonal stimulation down-regulation
down-regulation involves loss of receptors & prevents target cells from overreacting to persistently high hormone levels
hormones influence number & affinity not only of their own receptors but also receptor that respond to other hormones
progesterone induces loss of estrogen receptors in uterus, this __ estrogen's actions; while estrogen causes same cells to produce more progesterone receptors, __ ability to respond to progesterone antagonizing; enhances
hormones circulate through the blood as free or bound to protein carrier
lipid-soluble hormones travel in bloodstream attached to plasma proteins
__ of a circulating hormone in blood at any time reflects it rate of release & speed at which it is inactivated & removed from body concentration
some hormones are rapidly degraded by __ in their target cells enzymes
most hormones are removed from the blood by kidneys or liver
most hormone breakdown products are excreted from body in urine or feces
length of time for a hormone's blood level to decrease by half; varies from fraction of minute to a week half-life
__ hormones exhibit shorted half-lives water-soluble
is limited, ranging from 10 seconds to several hours duration of hormone action
because of many variations, hormonal __ __ must be precisely & individually controlled to meet continuously changing needs of body blood levels
situation when 1 hormone cannot exert its full effects without another hormone being present permissiveness
permissive effect for normal timely development of reproductive structures (along with reproductive hormones) thyroid hormone
occurs in situation where more than 1 hormones produces same effects at target cell & their combined effects are amplified synergism
glucagon & epinephrine cause liver to release glucose to blood; when they act together amount of glucose released is about 150% of what is released when each hormone acts alone
when one hormone opposes action of another hormone antagonism
may compete for same receptors, act through different pathways, or even cause down-regulation of receptors for antagonistic hormone antagonistic hormone
synthesis & release of most hormones are regulated by negative feedback system
major types of stimuli trigger endocrine glands to manufacture & released their hormones humoral, neural, & hormonal
endocrine glands secrete their hormones in direct response to changing blood levels of certain critical ions & nutrients humoral stimuli
humoral stimuli are __ endocrine controls simplest
hormones released in response to humoral stimuli include PTH, insulin, & aldosterone
nerve fibers stimulate hormone release neural stimuli
sympathetic nervous system stimulation of adrenal medulla to release catecholamines during periods of stress example of neural stimuli
most anterior pituitary hormone release is regulated by releasing/inhibiting hormones by the hypothalamus
many anterior pituitary hormones stimulate other endocrine to release their hormones
hormonal stimuli promote rhythmic hormone release, with hormone blood levels rising & falling in a specific pattern hypothalamic-pituitary-target endocrine organ feedback loop
hormonal, humoral, & neural stimuli are __ factors that affect endocrine system turn-on
feedback inhibition & others are __ factors that affect endocrine system turn-off
in the body the __ system makes certain adjustment to maintain homeostasis by overriding normal endocrine controls nervous
90-110mg/100ml of blood is the __ range of glucose levels in the blood normal
neuroendocrine gland located beneath the brain that serves a variety of functions including regulation of gonads, thyroid, adrenal cortex, lactation, and water balance pituitary gland
pituitary gland is also known as hypophysis
stalk of tissue that connects the pituitary gland to the hypothalamus superiorly infundibulum
composed largely of pituicytes and nerve fibers posterior pituitary
glia-like supporting cells pituicytes
hormones secreted by neurons; released by posterior pituitary neurohormones
posterior pituitary is a(n) __ area hormone-storage
posterior pituitary plus infundibulum; portion of the pituitary gland derived from the brain neurohypophysis
anterior pituitary; the glandular part of the pituitary gland adenohypophysis
aterial blood is delivered to pituitary via __ branches of internal carotid arteries hypophyseal
veins leaving pituitary drain into dural sinuses
posterior lobe of pituitary is actually part of the brain
nerve bundles that run through the infundibulum and connect the neurohypophysis and the hypothalamus hypothalamic-hypophyseal tract
hypothalamic-hypophyseal tract arises from __ in spraoptic & paraventricular nuclei of hypothalamus neurons
made primarily by paraventricular neurons of hypothalamic-hypophyseal tract oxytocin
made primarily by supraoptic neurons of hypothalamic-hypophyseal tract antidiuretic hormone (ADH)
when hypothalamic-hypophyseal tract neurons fire they release the stored hormones into a capillary bed in __ pituitary for distribution throughout the body posterior
originates from a superior outpocketing of oral mucosa (Rathke's pouch) and is formed from epithelial tissue anterior lobe of pituitary
after touching posterior lobe, anterior lobe of pituitary loses it connection with oral mucosa & adheres to neurohypophysis
there is no __ __ connection between anterior lobe of pituitary & hypothalamus direct neural
only connection between anterior lobe of pituitary & hypothalamus is vascular
unusual arrangement of blood vessels in which a capillary bed feeds into veins, which in turn feed into another capillary bed portal system
primary capillary plexus is located in the infundibulum
located in the infundibulum, it communicates inferiorly via the small hypophyseal portal veins with a secondary capillary plexus primary capillary plexus
primary & secondary capillary plexuses & intervening hypophyseal portal veins make up the hypophyseal portal system
releasing & inhibiting hormones secreted by neurons in ventral hypothalamus circulate to __ __ via the hypophyseal portal system anterior pituitary
hypophyseal portal system is where the regulation of hormone __ takes place for the anterior pituitary secretion
all hypothalamic regulatory hormones are __ __ based amino acid
hypothalamic regulatory hormones can be a(n) single amine to peptides to proteins
controls activity of anterior pituitary hypothalamus
all anterior pituitary hormones are proteins
large molecule isolated from anterior pituitary; prohormone & source of andrenocorticotropic hormone, enkephalin & beta endorphin, & melanocyte-stimulating hormone (MSH) pro-opiomelanocortin (POMC)
CNS neurotransmitter involved in control of appetite melanocyte-stimulating hormone (MSH)
hormone that regulates the secretory action of another endocrine organ tropic hormone
thyroid-stimulating hormone, andrenocorticotropic hormone, follicle-stimulating hormone, & luteinizing hormone are all tropic
all anterior pituitary hormones except for __ hormone affect their target cells via cyclic AMP second-messenger system growth
hormone that stimulates growth in general; produced in the anterior pituitary; also called somatotropin (STH) growth hormone (GH)
GH is produced by cells called somatotrophs
GH promotes growth and __ actions metabolic
major target(s) of GH are bones & skeletal muscles
stimulation of __ __, by GH, leads to long bone growth epiphyseal plate
stimulation of skeletal muscles by GH promotes increased __ __ muscle mass
GH is a(n) __ hormone anabolic
GH promotes protein __ synthesis
GH encourages use of __ for fuel, thus conserving glucose fats
family of growth-promoting proteins produced by liver, skeletal muscles, bone, & other tissues; mediated growth promoting effects of GH insulin-like growth factors (IGFs)
IGFs produced by __ act as hormones liver
IGFs produced in tissues other than liver act as paracrines
IGFs stimulate actions required for growth by uptake of nutrients from blood & their incorporation into proteins & DNA allowing growth by cell division
IGFs stimulate actions required for growth through formation of __ & deposition of __ __ collagen; bone matrix
acting directly GH mobilizes fat for depots for transport to cells, thus increasing levels of fatty acids
acting directly GH __ rate of glucose uptake and metabolism decreases
in the liver GH encourages glycogen breakdown & release of glucose to blood
the elevation blood glucose levels that occurs when GH acts upon liver brings about the __ __ or anti-insulin effect of GH glucose sparing
hormone from hypothalamus that stimulates GH release growth hormone-releasing hormone (GHRH)
hormone from hypothalamus that inhibits GH release growth hormone-inhibiting hormone (GHIH)
GHIH releases is triggered by __ of GH & IGFs feedback
rising levels of GH feed back to also __ its own release inhibit
GH has a daily cycle with the highest levels occurring during evening sleep
GHIH __ release of thyroid-stimulating hormone blocks
GHIH is produced in the gut where its release inhibits virtually all gastrointestinal & pancreatic __ secretions
excessive growth of the body or any of its parts, especially as a result of oversecretion of the growth hormone by the pituitary gland gigantism
chronic disease of adults marked by enlargement of the bones of the extremities, face, and jaw that is caused by overactivity of the pituitary gland secretion of GH acromegaly
GH deficiency in children results in slowed long bone growth pituitary dwarfism
tropic adenohypophyseal hormone that regulates secretion of thyroid hormones thyroid-stimulating hormone (TSH)
thyroid-stimulating hormone (TSH) is also called thyrotopin
release of thyroid-stimulating hormone (TSH) follows hypothalmic-pituitary-target endocrine feedback loop
cells of anterior pituitary that release TSH thyrotrophs
triggers thyrotrophs to release TSH thyrotropin-releasing hormone (TRH)
rising blood levels of thyroid hormones act on pituitary & hypothalamus to inhibit TSH secretion
anterior pituitary hormone that stimulates adrenal cortex to release corticosteroid hormones adrenocorticotropic hormone (ACTH)
adrenocorticotropic hormone (ACTH) also called corticotropin
ACTH release is elicited by hypothalamic corticotropin-releasing hormone (CRH)
ACTH levels peak in morning shortly before awakening
rising levels of glucocorticoids feed back and __ secretion of CRH & ACTH release block
internal & external factors that alter normal ACTH rhythm by triggering CRH release include fever, hypoglycemia, & stressors of all types
hormone produced by the anterior pituitary that stimulates ovarian follicle production in females and sperm production in males follicle-stimulating hormone (FSH)
anterior pituitary hormone that aids maturation of cells in the ovary and triggers ovulation in females; in males, causes the interstitial cells of the testis to produce testosterone luteinizing hormone (LH)
luteinizing hormone (LH) & follicle-stimulating hormone (FSH), produced by anterior pituitary, are referred to collectively as gonadotropins
in both sexes FSH stimulates __ production gamete
in females, LH works with FSH to cause an __ __ __ to mature egg-containing ovarian follicle
in both sexes LH promotes production of __ hormones gonadal
in females, LH independently triggers __ ovulation
in females, LH independently promotes synthesis & release of __ hormones ovarian
in males, LH stimulates __ __ of testes to produce testosterone interstitial cells
gonadotropins are virtually __ from blood of prepuberty boys & girls absent
during puberty to gondotrophs of anterior pituitary are activated and gonadotropin levels begin to rise, causing gonads to mature
in both sexes, produced by hypothalamus, gondaotropin release by anterior pituitary is promoted by gonadotropin-releasing hormone (GnRH)
produced in response to the gonadotropins, feed back to suppress FSH & LH gonadal hormones
adenohypophyseal hormone that stimulates the breasts to produce milk; protein hormone structurally similar to GH prolactin (PRL)
prolactin release is controlled primarily by inhibitory hormone prolactin-inhibiting hormone (PIH), known as dopamine
prolactin-releasing factor TRH
in females, prolactin levels rise & fall in rhythm with __ blood levels estrogen
estrogen stimulates prolactin release directly & indirectly
most frequent abnormality of anterior pituitary tumors hyperprolactinemia
made largely of axons of hypothalamic neurons; stores antidiuretic hormone (ADH) and oxytocin posterior pituitary
composed of 9 amino acids; differ in only 2 amino acids ADH & oxytocin
influences body water balance ADH
hormone synthesized in the hypothalamus and secreted by the posterior pituitary; stimulates contraction of the uterus during childbirth and the ejection of milk during nursing oxytocin
oxytocin acts via __ second-messenger system to mobilize Ca2+ allowing stronger contractions PIP-Ca2+
childbirth & milk ejection result from positive feedback mechanisms
urine production diuresis
substance that inhibits or prevent urine formation antidiuretic
hormone produced by the hypothalamus and released by the posterior pituitary; stimulates the kidneys to reabsorb more water, reducing urine volume antidiuretic hormone (ADH)
ADH is also called vasopressin
ADH prevents wide swings in __ balance water
sensory end organ that responds to changes in osmotic pressure; continually monitors solute concentration of blood osmoreceptor
ADH targets __ __ via cAMP kidney tubules
pain, low blood pressure, & drugs such as nicotine, morphine, & barbiturates are all stimuli that trigger ADH release
drinking alcoholic beverages __ ADH secretion inhibits
diuretic drugs __ effects of ADH and cause water to be flushed from the body antagonize
at high blood concentrations ADH causes __ of the visceral blood vessels vasoconstriction
disease characterized by passage of a large quantity of dilute urine plus intense thirst and dehydration caused by inadequate release of antidiuretic hormone (ADH) diabetes insipidus
pulmonary cancers are known to secrete ADH
marked by retention of fluid, headache & disorientation due to brain edema, weight gain & decreased solute concentration in blood syndrome of inappropriate ADH secretion (SIADH)
one of the largest of the body's endocrine glands; straddles the anterior trachea thyroid gland
median tissue mass of thyroid gland isthmus
hollow, spherical, colloid-containing structure of the thyroid gland follicles
formed largely by cubiodal or squamous epithelial cells & produce glycoprotein thyrogolubulin follicle cells
central cavity of thyroid follicle lumen
lumen of thyroid follicle __ colloid stores
amber-colored, sticky substance in the thyroid gland containing thyroglobulin protein with attached iodine atoms colloid
derived from iodinated thyroglobulin thyroid hormone
population of cells in thyroid gland that produce calcitonin; lie in follicular epithelium but protrude into soft connective tissue that separates & surrounds thyroid follicles parafollicular cells
major hormone secreted by thyroid follicles; stimulates enzymes concerned with glucose oxidation thyroid hormone (TH)
thyroid hormone (TH) is often referred to as the body's major metabolic hormone
iodine-containing hormone secreted by the thyroid gland; accelerates cellular metabolic rate in most body tissues; major hormone secreted by thyroid follicles thyroxine (T4)
thyroid hormone; secretion and function similar to those of thyroxine (T_4) triiodothyronine (T3)
most T3 is formed at the target tissue by conversion of T4 to T3
TH enters a target cell and initiates transcription of mRNA for protein synthesis
by turning on transcription of genes concerned with glucose oxidation, TH has calorigenic effect
increases basal metabolic rate & body heat production calorigenic effect
TH provokes increase in number of __ receptors in blood vessels, playing important role in maintaining blood pressure adrenergic
important in regulating tissue growth & development, as well as critical for normal skeletal & nervous system development/maturation, & reproductive capabilities TH
thyroid gland has ability to store its hormone extracellulary & stored amount remains constant & sufficient to provide levels of hormone release for two to three months
when TSH from anterior pituitary binds to receptors on thyroid follicle cells, first response is to secrete stored thyroid hormone
when TSH from anterior pituitary binds to receptors on thyroid follicle cells, second response is to begin synthesizing more colloid to restock thyroid follicle lumen
TSH levels are __ during the day lower
TSH levels __ just before sleep peak
TSH levels remain __ during the night high
when thyroglobulin is synthesized and discharged into follicle lumen step 1 synthesis of TH by follicle cells
iodide is trapped by active transport by follicle cell, then moves into lumen by facilitated diffusion step 2 synthesis of TH by follicle cells
iodide is oxidized to iodine step 3 synthesis of TH by follicle cells
iodine is attached to tyrosine at junction of follicle cell apex & colloid, & is mediated by peroxidase enzymes step 4 synthesis of TH by follicle cells
attachment of 1 iodine to a tyrosine produces monoiodotyrosine (MIT or T1)
attachment of 2 iodine to a tyrosine produces diiodotyrosine (DIT or T2)
iodinated tyrosines are linked together to form T3 & T4; enzymes in colloid link MIT & DIT together; hormones are still part of thyroglobulin colloid step 5 synthesis of TH by follicle cells
2 DITs result in T4
coupling of MIT & DIT produces T3
thyroglobulin colloid is endocystosed; follicle cells must reclaim iodinated thyroglobulin by endocytosis & combine vesicles with lysosomes step 6 synthesis of TH by follicle cells
lysosomal enzymes cleave T4 & T3 from thyroglobulin & hormones diffuse from follicle cell into bloodstream step 7 synthesis of TH by follicle cells
some T4 cane be converted to T3 __ secretion before
most T3 is generated in peripheral tissues
most T3 & T4 released immediately binds to transport proteins, most importantly thyroxine-binding globulins (TBGs)
thyroxine-binding globulins (TBGs) are produced by the liver
T3 that binds to target tissue receptors does so much more avidly & is about 10x more active
most peripheral tissues have enzymes needed to convert T4 to T3 by removing one iodine
regulation of blood levels of TH is on a(n) negative feedback loop
falling TH blood levels trigger __ of TSH release
rising levels of TH feed back to __ hypothalamic-anterior pituitary axis, temporarily shutting off stimulus for TH release inhibit
condition that increase body energy requirements, such pregnancy & exposure of infants to cold, stimulate hypothalamus to secrete __ __ which triggers TSH release allowing it to overcome negative feedback controls thyrotropin-releasing horomone (TRH)
GHIH, dopamine, & rising levels of glucocorticoids are factors that inhibit TSH release
excessively high blood iodine concentrations inhibit TH release
condition resulting from underactive thyroid gland in adults myxedema
if myxedema results from lack of iodine, enlargement & protrusion of thyroid gland endemic/colloidal goiter
severe hypothyroidism in infants cretinism
disorder resulting from hyperactive thyroid gland Grave's disease
protrusion of eyeballs, if tissue behind eyes becomes edematous & then fibrous; common in Grave's disease exophthalmos
polypeptide hormone released by the thyroid; lowers blood calcium levels only when present at high (therapeutic) levels calcitonin
calcitonin is produced by parafollicular / C cells
effect of calcitonin is is to __ blood Ca2+ lower
calcitonin has an antagonizing effect on __ hormone parathyroid
targets of calcitonin include skeleton & bony matrix
targeting the skeleton, calcitonin inhibits __ activity, inhibiting bone reabsorption & release of Ca2+ from bony matrix osteoclast
targeting the bony matrix, calcitonin __ Ca2+ uptake & incorporation into bone matrix stimulates
calcitonin has a __ effect bone-sparing
excessive blood levels of Ca2+ (approx. 20% above normal) act as a __ stimulus for calcitonin release humoral
declining blood Ca2+ levels inhibit C cell __ Activity secretory
calcitonin is given therapeutically to patient's with Paget's disease
small endocrine glands located on the posterior aspect of the thyroid gland parathyroid glands
parathyroid glands are arranged in thick branching cords containing scattered __ cells and large numbers of smaller __ cells oxyphil; chief
most abundant parenchymal cells of the parathyroid, being polygonal epithelial cells rich in glycogen, having granular cytoplasm and vesicular nuclei, and arranged in plates or cords chief cells
acidophilic cells found in the parathyroid glands oxyphil cells
protein hormone released by parathyroid glands; single most important hormone regulating blood calcium level parathyroid hormone (PTH)/parathormone
Ca2+ homeostasis is essential for so many functions, including transmission of nerve impulses, muscle contraction, & blood clotting
PTH release is triggered by __ blood Ca2+ levels falling
PTH release is inhibited by __ blood Ca2+ levels rising
PTH increases Ca2+ levels in blood by stimulating targets organs of skeleton, kidneys, & intestine
skeleton contains considerable amount of __ __ in its matrix, making it an apt target organ of PTH calcium salts
bone-reabsorbing cells osteoclast
PTH release stimulates osteoclast to digest some of the bony matrix and release ionic calcium & phosphates to the blood step 1 PTH
enhances reabsorption of Ca2+, as well as excretion of phosphate (PO43-) by kidneys step 2 PTH
promotes activation of vitamin D3 thereby increasing absorption of Ca2+ by intestinal mucosal cells step 3 PTH
required for absorption of Ca2+ from food vitamin D
vitamin D ingested or produced by skin is a(n) inactive form
for vitamin D to exert its physiological effects it must be converted by kidneys to its active vitamin D3 form of calcitriol
group of active metabolites of cholecalciferol (vitamin D3);increases intestinal absorption of calcium & phosphate, enhances bone resorption, & prevents rickets dihydroxycholecalciferol/calcitriol
rare & usually results from tumor; calcium is leached from bones causing bones to soften & deform as their mineral salts are replaced by fibrous connective tissue hyperparathyroidism
bones have moth-eaten appearance on x-rays & tend to fracture spontaneously osteitis fibrosa cystica
abnormally elevated blood Ca2+ levels hypercalcemia
hypercalcemia causes __ of nervous system and formation of __ stones depression; kidney
calcium deposits that form is soft tissues throughout body & severely impair vital organ functioning metastatic calcification
PTH deficiency; often follows parathyroid gland trauma or removal during thyroid surgery hypoparathyroidism
extended deficiency of dietary magnesium, required for PTH secretion) can cause functional hypoparathyroidism
low blood Ca2+ levels hypocalcemia
hypocalcemia resulting from functional hypoparathyroidism __ excitability of neurons & accounts for classical symptoms of tetany increases
loss of sensation, muscle twitches, & convulsions tetany
untreated symptoms of functional hypoparathyroidism progress to respiratory paralysis & death
hormone-producing pyramid-shaped organs located superior to kidneys; each consists of medulla & cortex areas adrenal glands
adrenal glands are enclosed in fibrous capsule & cushion of fat
adrenal glands are often referred to as suprarenal glands
each adrenal glands is structurally & functionally two endocrine glands
inner portion; more like a knot of nervous tissue; part of sympathetic nervous system adrenal medulla
outer portion; encapsulating medulla & forming bulk of gland; glandular tissue derived from embryonic mesoderm adrenal cortex
each region of adrenal gland produces its own hormones
all adrenal hormones help up cope with stressful situations
over two dozen steroid hormones synthesized by adrenal cortex are called corticosteroids
multistep steroid synthesis pathway, of adrenal cortex, starts with cholesterol
steroid hormones are not __ in cells stored
the rate of steroid hormone release in response to stimulation depends on their rate of synthesis
large, lipid-laden cortical cells of adrenal cortex are arranged in 3 layers/zones
cell clusters forming superficial layer; produce mineralocorticoids zona glomerulosa
steroid hormone of adrenal cortex that regulates Na^+ & K^+ metabolism & fluid balance mineralocorticoids
cells forming middle layer; arranged in more/less linear cords; produce glucocorticoids zona fasciculata
steroid hormones that affect glycogenesis in the liver; anti-inflammatory, are active in protection against stress, and affect carbohydrate and protein metabolism glucocorticoids
innermost cells abutting adrenal medulla in netlike arrangement; mainly produce small amounts of gonadocorticoids zona reticularis
adrenal sex hormones gonadocorticoids
2 innermost layers of adrenal cortex __ __ of glucocorticoids & gonadocorticoids, although each layer predominately produces one type share production
single most abundant cation in extracellular fluid is Na+
amount of Na+ in body largely determines __ of extracellular fluid volume
where Na+ goes __ follows water
lead to changes in blood volume & blood pressure changes in Na+ blood concentration
coupled to Na+ is regulation of other ions, including K+, H+, HCO3 (bicarbonate), & Cl- (chloride)
sets the resting membrane potential of cells & determine how easily action potentials are generated in nerve & muscle extracellular contractions of K+
Na+ & K+ __ are crucial to overall body homeostasis regulation
hormone produced by the adrenal cortex that regulates Na+ reabsorption and K+ secretion by the kidneys aldosterone
aldosterone is the most __ mineralocorticoid potent
aldosterone accounts for __ __ 95% of the mineralocorticoids produced more than
aldosterone __ excretion of Na+ from body reduces
primary target of aldosterone is __ parts of kidney tubules, where it stimulate Na+ reabsorption & water retention accompanied by K+ elimination distal
in some instances aldosterone's effect on distal kidney tubules can alter __ balance of blood by H+ excretion acid-base
aldosterone __ Na+ reabsorption from perspiration, saliva, & gastric juice enhances
aldosterone's regulatory effects are __ lasting approx. 20 minutes, allowing plasma electrolyte balance to be precisely controlled brief
involves synthesis & activation of proteins required for Na+ transport, such as Na+-K+ ATPase, pump that exchanges Na+ for K+ mechanism of aldosterone activity
aldosterone is also secreted by __ organs cardiovascular
in cardiovascular organs aldosterone is a(n) paracrine
aldosterone secretion is __ by decreasing blood volume & pressure, as well as rising levels of K+ stimulated
renin-angiotensin, plasma concentrations of K+, ACTH, & atrial natriuretic peptide (ANP) mechanisms that regulate aldosterone secretion
hormone released by the kidneys that is involved with raising blood pressure renin
influences both blood volume & pressure by regulating release of aldosterone and therefore Na+ & water reabsorption by kidneys renin-angiotensin mechanism
in renin-angiotensin mechanism, specialized cells of __ __ in kidneys become excited when blood pressure/volume declines, and thus release renin juxtaglomerular apparatus
in renin-angiotensin mechanism, when renin is released it cleaves off part of plasma protein angiotensinogen, which triggers enzymatic cascade leading to formation of angiotensin II
potent vasoconstrictor activated by renin; also triggers release of aldosterone by glomerulosa cells angiotensin II
all of effects of renin-angiotensin mechanism are ultimately involved in raising blood pressure
fluctuating blood levels of K+ directly influence zona glomerulosa cells in adrenal cortex; increased K+ stimulates aldosterone release, whereas decreased K+ inhibits it plasma concentration of K+to regulate aldosterone secretion mechanism
under severe stress, hypothalamus secretes more corticotropin-releasing hormone (CRH), 7 resulting rise in ACTH blood levels steps up rate of aldosterone secretion to small extent; resulting in increased blood volume/pressure ACTH mechanism to regulate aldosterone secretion
hormone secreted by heart when blood pressure rises; fine-tunes blood pressure & sodium-water balance of body atrial natriuretic peptide (ANP)
one of major effects of atrial natriuretic peptide (ANP) is to inhibit renin-angiotensin mechanism
ANP blocks renin & aldosterone secretion & inhibits other __ mechanisms that enhance water & Na+ reabsorption angiotensin-induced
decrease blood pressure by allowing Na+ (and water_ to flow out of body in urine ANP mechanism's overall influence
producing salty urine natriuretic
hypersecretion of aldosterone; typically results from adrenal tumors aldosteronism
if K+ loss is __ neurons become nonresponsive & muscle weakness (eventually paralysis) occurs extreme
hyposecretory disease of adrenal cortex, generally involving a deficient output of both mineralocorticoids & glucocorticoids Addison's disease
glucocorticoids are adrenal cortex hormones that increase blood glucose levels and aid the body in resisting long-term stressors
under normal circumstances glucocorticoids help body to adapt to intermittent food intake by keeping __ __ levels fairly constant, and maintain blood pressure by increasing action of __ blood glucose; vasoconstrictors
severe stress due to hemorrhage, infection, or physical/emotional trauma evokes a dramatically __ output of glucocorticoids, which help body negotiate crisis higher
cortisol, cortisone, corticosterone glucocorticoid hormones
glucocorticoid produced by the adrenal cortex; release is promoted by ACTH; rising levels feed back to act on both hypothalamus & anterior pituitary cortisol (hydrocortisone)
basic mechanism of glucocorticoid action on target cells is to modify gene activity
glucocorticoid secretion is regulated by negative feedback
driven by patterns of eating & activity, occur in a definite pattern throughout day & night cortisol secretory bursts
cortisol blood levels peak __ __ we arise in morning shortly before
__ __ of cortisol occur in evening just before and shortly after we fall asleep lowest levels
__ __ __ can be interrupted by acute stress of any variety as higher CNS center override the usually inhibitory effects of elevated cortisol level & trigger CRH release normal cortisol rhythm
under __ __ the resulting increase in ACTH blood levels causes an outpouring of cortisol from adrenal cortex acute stress
stress results in __ __ in blood levels of glucose, fatty acids, and amino acids dramatic rise
cortisol's __ __ effects is to provoke gluconeogenesis prime metabolic
formation of glucose, especially by the liver, from noncarbohydrate sources, such as amino acids gluconeogenesis
in order to save glucose for the __, cortisol mobilizes fatty acids from adipose tissue & encourages their increased use for energy brain
under cortisol's influence, __ __ are broken down to provide building blocks for repair or for making enzymes to be used in metabolic processes stored proteins
cortisol enhances the __ nervous system's vasoconstrictive effects, and the rise in blood pressure & circulatory efficiency that results helps ensure that these nutrients are quickly distributed to cells sympathetic
cortisol __ is associated with significant inflammatory & anti-immune effects excess
depress cartilage /bone formation; inhibit inflammation by decreasing release of inflammatory chemicals; depress immune system; promote changes in cardiovascular, neural & GI function excessive levels of glucocorticoids
rheumatoid arthritis & allergic reactions use __ __ to control symptoms of chronic inflammatory disorders glucocorticoid drugs
pathology of glucocorticoid excess; may be caused by ACTH-releasing pituitary tumor, ACTH-releasing malignancy of lungs, pancreas, or kidneys, or tumor of adrenal cortex Cushing's disease
Cushing's disease is most often a result of clinical administration of __ __ of glucocorticoid drugs pharmacological doses
characterized by persistent elevated blood glucose levels, dramatic losses in muscle/bone protein, & water/salt retention leading to hypertension & edema Cushing's syndrome
persistent elevated blood glucose levels brought on by pharmacological doses of glucocorticoids steroid diabetes
include swollen "moon" face, redistribution of fat to the abdomen & posterior neck, tendency to bruise, & poor wound healing cushingoid signs
major hyposecretory disorder of adrenal cortex, usually involves deficits in both glucocorticoids & mineralcorticoids; weight loss, plasma glucose & sodium levels drop, & potassium levels rise Addison's disease
sex hormones, primarily androgens, secreted by the adrenal cortex gonadocorticoids
hormone such as testosterone that controls male secondary sex characteristics androgen
androstenedione & dehydroepiandrosterone (DHEA) are converted to __ in tissue cells in males testosterone
androstenedione & dehydroepiandrosterone (DHEA) are converted to __ in tissue cells in females estrogens
hypersecretion of gonadocorticoids causes adrenogenital syndrome
spherical cell that stains readily with chromium salts, especially a cell of the adrenal medulla chromaffin cells
chromaffin cells are modified ganglionic __ __ that synthesize catecholamines sympathetic neurons
chief hormone produced by the adrenal medulla; also called adrenaline epinephrine
catecholamine neurotransmitter and adrenal medullary hormone, associated with sympathetic nervous system activation norepinephrine (NE)
adrenal medulla synthesize catecholamines via __ __ from tyrosine to dopamine to NE to epinephrine molecular sequence
blood glucose levels rise, blood vessels constrict & heart beats faster, blood is diverted from nonessential organs to heart & skeletal muscles & preganglionic sympathetic nerve endings weaving through adrenal medulla signal for catecholamine release when sympathetic nervous system is mobilized, in flight-or-flight
release of catecholamines from adrenal medulla reinforce or prolong fight-or-flight response
more potent catecholamine stimulator of metabolic activities, bronchial dilation, & increased blood flow to skeletal muscles & heart epinephrine
catecholamine that has greater influence on peripheral vasoconstriction & blood pressure norepinephrine
epinephrine is used clinically as heart stimulant & to dilate bronchioles during acute asthmatic attack
catecholamines cause relatively __ responses to stressors brief
deficiency of hormones of adrenal medulla is not a problem because these hormones merely __ activities set into motion by sympathetic nervous system intensify
adrenal catecholamines __ __ essential for life are not
produces symptoms of uncontrolled sympathetic nervous system activity hypersecretion of catecholamines
symptoms include hyperglycemia, increased metabolic rate, rapid heartbeat & palpitations, hypertension, intense nervousness & sweating; tumor of chromaffin cells of adrenal medulla pheochromocytoma
hormone-secreting part of diencephalon of brain thought to be involved in setting biological clock & influencing reproductive function pineal gland
hormone secreted by pineal gland; secretion peaks at night and helps set sleep-wake cycles; also a powerful antioxidant melatonin
pineal gland indirectly receives input from __ pathways concerning the intensity & duration of daylight visual
area referred to as our biological clock; richly supplied with melatonin receptors suprachiasmatic nucleus
gland located behind stomach, between spleen & duodenum; produces both endocrine & exocrine secretions pancreas
zymogen-secreting cells of the pancreatic; produce enzyme-rich juice that is carried by ducts to small intestine during digestion acinar cells
tiny cell clusters (scattered among acinar cells)that produce pancreatic hormones pancreatic islets
pancreatic islets are also know as islets of Langerhans
glucagon-synthesizing cells of pancreas alpha cells
insulin-producing cells of pancreas beta cells
act as tiny fuel sensors, secreting glucagon & insulin appropriately during fasting & fed states alpha & beta cells
insulin is a(n) __ hormone hypoglycemic
glucagon is a(n) __ hormone hypoglycemic
some __ __ cells also produce peptides, such as somatostatin, pancreatic polypeptide (PP), etc. pancreatic islet
hormone formed by alpha cells of pancreatic islets; raises the glucose level of blood; 29-amino-acid polypeptide glucagon
one molecule of glucagon can release 100 million molecules of __ into the blood glucose
breakdown of glycogen to glucose glycogenolysis
glycogenolysis, gluconeogenesis, release of glucose to blood by liver cells, causing blood glucose levels to rise major targets of glucagon
fall in amino acid concentration in blood as liver cells sequester glucagon molecules to make new glucose molecules secondary effect of glucagon
humoral stimuli, falling glucose levels, prompt __ cells to secrete glucagon alpha
sympathetic nervous system stimulation & rising amino acid levels are also __ for glucagon release stimulatory
glucagon release is __ by rising blood glucose levels, insulin, & somatostatin suppressed
hormone that enhances carrier-mediated diffusion of glucose into tissue cells, thus lowering blood glucose levels; small protein consisting of 2 amino acid chains linked by disulfide bonds insulin
insulin is synthesized as part of a larger polypeptide chain called proinsulin
main effect of insulin is to __ blood glucose levels, but it also influences protein & fat metabolism lower
middle portion of proinsulin polypeptide chain is excised by enzymes releasing __ insulin functional
functional insulin "clipping" takes places in secretory vesicles just before insulin is released from the beta cells
insulin's effects are most obvious when we have just eaten
main effect of insulin is to lower blood sugar
insulin also influences protein & fat metabolism
circulating insulin lowers blood glucose levels by enhancing membrane __ of glucose into body cells, especially muscle & fat transport
circulating insulin lowers blood glucose levels by inhibiting __ of glycogen to glucose breakdown
circulating insulin lowers blood glucose levels by __ conversion of amino acids or fats to glucose inhibiting
insulin does no accelerate glucose entry into liver, kidney, & brain tissues because they have easy access to blood glucose regardless of insulin levels
insulin roles in the __ participate in neuronal development, feeding behavior, & learning/memory brain
inhibiting effects of insulin counter any metabolic activity that would increase __ __ of glucose plasma levels
at cellular level insulin activates its receptor __ __ enzyme which phosphorylates specific proteins beginning the cascade that leads to increased glucose uptake & insulin's other effects tyrosine kinase
after glucose enters target cell, insulin binding triggers enzymatic activities that catalyze __ of glucose for ATP production oxidation
after glucose enters target cell, insulin binding triggers enzymatic activities that join glucose molecules together to form glycogen
after glucose enters target cell, insulin binding triggers enzymatic activities that convert glucose to fat, particularly in adipose tissue
as a rule, energy need are met first, followed by __ __ glycogen formation
if excess glucose is available, after energy needs have been met, it is then converted to fat
insulin stimulates amino acid uptake & protein synthesis in muscle tissue
pancreatic beta cells are stimulated to secrete insulin chiefly by elevated blood glucose levels
pancreatic beta cells are stimulated to secrete insulin by rising __ __ of amino & fatty acids plasma levels
pancreatic beta cells are stimulated to secrete insulin by release of acetylcholine by __ nerve fibers parasympathetic
as body cells take up glucose & other nutrients, and plasma levels of these substances drop, insulin secretion is suppressed
glucagon, epinephrine, growth hormone, thyroxine, & glucocorticoids are all hyperglycemia hormones
any hyperglycemia hormone called into action as blood glucose levels drop __ __ insulin release by promoting glucose entry into bloodstream indirectly stimulates
somatostatin & sympathetic nervous system activation __ insulin release depress
insulin is the major __ __ that counterbalances the many hypoglycemic hormones hypoglycemic factor
disease caused by deficient insulin release or by insulin resistance, leading to inability of the body cells to use carbohydrates diabetes mellitus (DM)
excess of glucose lost from body in urine glycosuria
fatty acid metabolites; strong organic acids ketones
sugars cannot be used as cellular fuel, more fats are mobilized resulting in high fatty acids levels in blood lipidemia
when ketones accumulate in blood, the blood pH drops and ketones begin to spill into the urine ketoacidosis
ketones begin to spill into the urine ketonuria
polyuria, polydipsia, & polyphagia are the three __ __ of diabetes mellitus cardinal signs
excessive glucose in kidney filtrate act as __ __ resulting in polyuria osmotic diuretic
excessive urine output polyuria
excessive thirst polydipsia
excessive hunger & food consumption polyphagia
excessive insulin secretion hyperinsulinism
hyperinsulinism __ __ hypoglycemia results in
hyperinsulinism can result from __ __ tumor islet cell
hyperinsulinism can result from an __ of insulin overdose
male & female gonads produce steroid sex hormones __ to those produced by adrenal cortical cells identical
ovaries produce important hormones of estrogen & progesterone
temporary endocrine organ; secretes several steroid & protein hormones that influence course of pregnancy placenta
include estrogens & progesterone, as well as human chorionic gonadotropin (hCG) placental hormones
prompts kidneys to increase their production of salty urine & inhibits aldosterone release by adrenal cortex; thereby decreasing amount of sodium in extracellular fluid, reducing blood volume & pressure ANP
hormone secreting cells sprinkled in mucosa of GI tract; release several peptide hormones that help regular wide variety of digestive functions enteroendocrine cells
enteroendocrine cells release amines, like serotonin acting as paracrines, diffusing to & influencing nearby target cells without first entering bloodstream
enteroendocrine cells are sometimes referred to as __ because they are similar in certain ways to neurons & many of their hormones & paracrines are chemically identical to neurotransmitters paraneurons
hormone that stimulates production of red blood cells; protein hormones that signals bone marrow to increase RBC production erythropoietin (EPO)
erythropoietin is secreted by interstitial cells in kidneys
hormones function of kidneys is secretion of erythropoietin & renin
inactive form of vitamin D, when modified cholesterol molecules in epidermal cells are exposed to UV radiation cholecalciferol
cholecalciferol is hormone secreted from skin
cholecalciferol is modified in the __ and becomes fully activated in the __ liver; kidneys
calcitrol is __ __ of carrier system that intestinal cells use to absorb Ca2+ from ingested food essential regulator
hormone released by fat cells that signals satiety; serves to tell body how much stored energy is available leptin
leptin binds to CNS neurons concerned with __ __ appetite control
hormones released by adipose cells that affect sensitivity of cells to insulin resistin & adiponectin
insulin antagonist secreted by adipose tissue resistin
enhances sensitivity to insulin & is secreted by adipose tissue adiponectin
hormone secreted by osteoblasts that prods pancreatic beta cells to divide & secrete more insulin; restricts fat storage by adipocytes & triggers release of adiponectin osteocalcin
is that glucose handling is improved & body fat is reduced result of osteocalcin
osteocalcin levels are __ in type 2 diabetes low
lymphoid organ and endocrine gland active in immune response; site of maturation of T lymphocytes thymus
peptide hormones secreted by thymus; thought to be involved in normal development of T lymphocytes & immune response thymulin, thymopoietins, & thymosins
thymulin, thymopoietins, & thymosins are called hormones but they mainly act as paracrines
hormone-producing glands arise from all three embryonic germ layers
endocrine glands derived from __ produce steroid hormones mesoderm
endocrinology involves the study of endocrine organs and hormones
steroids are synthesized from cholesterol
any given hormone will influence the activity of its target cell
PIP2-calcium signaling mechanism is mechanisms of hormone action in which intracellular calcium ions act as a final mediator
down-regulation involves loss of receptors & prevents target cells from overreacting to persistently high hormone levels
when one hormone opposes the action of another hormone, the interaction is called antagonism
within a negative feedback system the target organ effects inhibit further hormone release
anterior pituitary has traditionally been called the "master endocrine gland" because many of the numerous hormones it produces regulate the activity of other endocrine glands
in recent years, anterior pituitary has been dethroned by the __, which is now known to control the activity of the anterior pituitary hypothalamus
growth hormone stimulates most body cells to increase in size and divide
pituitary dwarfism is homeostatic imbalance resulting from hyposecretion of growth hormone
follicle-stimulating hormone stimulates gamete (sperm or egg) production
as blood levels of __ __, the expulsive contractions of labor gain momentum and finally end in birth oxytocin rise
because TH provokes an increase in number of __ __ in blood vessels, it plays an important role in maintaining blood pressure adrenergic receptors
chief cells are found within the parathyroid gland that secrete parathyroid hormone
if left untreated hypoparathyroidism can lead to paralysis/death
Addison's disease is homeostatic imbalance that usually results from deficits in both glucocorticoids & mineralocorticoids
adenohypophysis secretes TSH
neurohypophysis secretes ADH
thyroid gland secretes calcitonin
adrenal gland secretes aldosterone
pineal gland secretes melatonin
FSH stimulates development of the follicle in the ovaries
GH mobilizes fats, spares glucose, and promotes the protein synthesis necessary for growth
ACTH stimulate adrenal cortex
TSH stimulate thyroid gland
ADH stimulates kidney tubules to reabsorb water from urine
condition that would be balanced by insulin high levels of blood sugar
condition that would be balanced by ADH loss of body fluids
condition that would be balanced by aldosterone loss of Na+ from extracellular fluids
condition that would be balanced by thyroxine decrease in body metabolism
condition that would be balanced by parathyroid hormone decrease in blood Ca+ levels
function of thyroid-stimulating hormone stimulates production of thyroxine
function of growth hormone causes cells to undergo mitosis & increase in size
function of oxytocin increases contraction of uterine smooth muscles
function of adrenocorticotropic hormone causes adrenal cortex to produce hormones
function of follicle-stimulating hormone affects functions of ovaries & testes
site of release & function of TSH anterior pituitary; causes thyroid gland to synthesize thyroxine
site of release & function of FSH anterior pituitary; causes ovarian follicles to grow & produce estrogen & spermatogenesis in testes
site of release & function of LH anterior pituitary; causes ovulation & interstitial cells to produce testosterone in testes
site of release & function of oxytocin posterior pituitary; causes uterine contractions
site of release & function of ADH posterior pituitary; causes kidneys to conserve water
function of prolactin stimulates mild production
function of oxytocin stimulates milk ejection from mammary glands
function of thyroxine increase metabolic rate
function of calcitonin lowers blood Ca2+ levels
function of parathyroid hormone raises blood Ca2+ levels
gland/organ that produces calcitonin thyroid gland
gland/organ that produces parathyroid hormone parathyroid glands
gland/organ that produces adrenocorticotropic hormones pituitary gland
gland/organ that produces glucocorticoids adrenal cortex
gland/organ that produces epinephrine adrenal medulla
pineal gland produces melatonin
testes produce testosterone
thymus produces thymosin
heart produces atrial natriuretic peptide
placenta produces human chorionic gonadotropin (HCG)
function of melatonin associated with drowsiness at night
function of testosterone associated with sexual maturity in males; needed for normal sperm production
function of thymosin essential for normal immune response
function of atrial natriuretic peptide reduces blood volume, blood pressure, and blood sodium concentration by signaling the kidneys
function of HCG helps to sustain pregnancy
hormone that adipose tissue produces leptin
hormone that skin produces cholecalciferol
hormone that kidney produces erythropoietin
hormone that duodenum of small intestine produces cholecystokinin
hormone that stomach produces gastrin
function of leptin binds to CNS neurons concerned with appetite control
function of cholecalciferol activated by the kidneys to Vitamin D; stimulates active absorption of Ca2+ by intestinal cells
function of erythropoietin stimulates the production of red blood cells
function of cholecystokinin stimulates release of bile
function of gastrin stimulates stomach to released hydrochloric acid
organ that produces glucagon pancreas
organ that produces TSH anterior pituitary (adenohypophysis)
organ that produces thyroxine thyroid gland
organ that produces renin kidneys
organ that produces ADH posterior pituitary (neurohypophysis)
function of glucagon increases blood sugar level by stimulating liver
function of TSH stimulates the thyroid gland to produce thyroxine
function of thyroxine increases the metabolic rate
function of erythropoietin increases red blood cell production
function of ADH increases water reabsorption in kidney tubules
category of hormone of FSH & LH gonadotropins
category of hormone of cortisol glucocorticoids
category of hormone of androgens gonadocorticoids
category of hormone of aldosterone mineralocorticoids
function of gonadotropins regulate functions of gonads in both sexes
function of glucocorticoids increase blood levels of glucose, fatty acids, and amino acids during stress
function of androgens produce masculinizing effects when produced in large quantities
function of mineralocorticoids regulate Na+ reabsorption by the kidneys and thereby regulates other electrolyte levels
hormone produced by posterior pituitary antidiuretic hormone
hormone produced by anterior pituitary growth hormone
hormone produced by pancreas insulin
hormone produced by adrenal cortex aldosterone
hormone produced by adrenal medulla epinephrine
function of antidiuretic hormone causes kidneys to conserve water
function of growth hormone stimulates embryonic cells (stem cells) to undergo mitosis
function of insulin facilitates glucose transport into cells
function of aldosterone increases Na+ reabsorption in the kidneys
function of epinephrine increases cell reactions during sympathetic response
hormone that would help to restore the balance for homeostatic imbalance of lowered levels of Ca2+ in the blood parathyroid hormone
hormone that would help to restore the balance for homeostatic imbalance of too much Ca2+ in blood calcitonin
hormone that would help to restore the balance for homeostatic imbalance of elevated levels of blood sugar insulin
hormone that would help to restore the balance for homeostatic imbalance of decreased levels of blood sugar glucagon
hormone that would help to restore the balance for homeostatic imbalance of excessive levels of Na+ in extracellular fluids aldosterone
gland that would produce the hormone needed to restore homeostasis for end of 9 month pregnancy posterior pituitary
gland that would produce the hormone needed to restore homeostasis for loss of Na+ from profuse sweating adrenal cortex
gland that would produce the hormone needed to restore homeostasis for high blood sugar due to eating too many sweets pancreas
gland that would produce the hormone needed to restore homeostasis for drop in blood levels of Ca2+ due to extreme inactivity parathyroid
gland that would produce the hormone needed to restore homeostasis for delayed/stunted growth anterior pituitary
homeostatic imbalance of gigantism would be due to the hormone deficiency/overproduction of overproduction of GH
homeostatic imbalance of diabetes mellitus would be due to the hormone deficiency/overproduction of insulin deficiency
homeostatic imbalance of sympathetic nervous system overactivity would be due to the hormone deficiency/overproduction of oversecretion of catecholamines
homeostatic imbalance of Grave's disease would be due to the hormone deficiency/overproduction of hypersecretion of thyroid hormone
homeostatic imbalance of diabetes insipidus would be due to the hormone deficiency/overproduction of hyposecretion of ADH
principle hormone produced by zona reticularis androgens
principle hormone produced by zona glomerulosa mineralocorticoids
principle hormone produced by zona fasciculate glucocorticoids
principle hormone produced by beta cells insulin
humoral control mechanisms monitoring blood levels of substances and correct them
neural control mechanism axons cause hormone release
hormonal control mechanism hormone release is dependent upon other hormone levels
is NOT a major endocrine organ, but produces hormones in addition to its major function kidneys
produce the hormones renin and erythropoietin kidney cells
primary function of kidney cells is excretion of body waste
steroid hormones influence cellular activities by binding to DNA and forming a gene-hormone complex
steroid hormones enter cell & form DNA/hormone complex before they change cellular function
preganglionic fibers of sympathetic neurons stimulate adrenal medulla to produce epinephrine & norepinephrine
is either amino acid-based hormones or steroids chemical classification of hormones
__ __ of most body tissues is controlled directly by TH metabolic rate
secretion of parathyroid hormone is a good example of humoral stimuli
stimulus for producing insulin is high blood glucose concentration
transcription of new messenger RNA is a function of steroid hormones
iodine is required for synthesis of thyroid hormone
hypophyseal portal system transports releasing & inhibiting hormones from hypothalamus to anterior pituitary gland (adenohypophysis)
signal that would affect local cells by releasing chemicals into extracellular fluid paracrine
permissiveness is the property in which a hormone __ __ its full effect without another hormone CANNOT exhibit
NOT a true hormone, but, rather, a trophic substance TSH
hypothalamus is considered a __ organ neuroendocrine
protein kinases affect enzymes by adding phosphate group (phosphorylation) to enzyme
"hormone response element" is located on the cell DNA
"hormone response element" represents site for a hormone to bind
water-soluble hormones exhibit shortest half-life
normal endocrine controls can be __ __ by the nervous system directly overridden
POMC is a __ for ACTH prohormone
iodination of thyroid hormones is mediated by peroxidase enzymes
congenital condition that includes mental retardation, short disproportional body size, and a thick tongue and neck is caused by deficiency of thyroxin
osteitis fibrosa cystica is caused by increase in parathyroid hormone
resistin, an insulin antagonist, is a hormone produced by adipose tissue
somatostatin is considered paracrine because it acts on cells other than those that secrete it
alcohol intake inhibits the secretion of ADH, thus the absence of ADH there is increased urine output
sympathetic nerve stimulation causes release of epinephrine and norepinephrine from adrenal medulla
adrenal medulla is a(n) __ stimulated gland neurally
autoimmune response is said to be cause for __ __ diabetes type I
hormones of the thymus gland are essential in formation of immune cells
__ __, main cells of immune system, mature in thymus gland, where they are stimulated by thymosin hormones T lymphocytes
secretion of digestive enzymes is a(n) __ function for the pancreas exocrine
for the pancreas, production of insulin and glucagon is a(n) __ function endocrine
is high at night and low during daylight hours blood level of melatonin
skin, the heart, and the kidneys contain cells or tissues that produce hormones
synthesis & release, or blood levels, of most hormones are regulated by a(n) __ __ negative-feedback system
__ __ for oxytocin are the smooth muscle cells of the uterus and the myoepithelial cells of the mammary glands target tissues
hormones are __ __ the extracellular fluids secreted into
most hormones can be __ __ as either amino-acid based/steroids classified chemically
hormones are __ __ signals that travel in blood or lymph throughout the body "long-distance" chemical
local hormones are released into the __ __ and affect only adjacent cells in the same tissue extracellular fluid
hormones that are derived from __ are called steroids cholesterol
hormones may communicate with their target cells __ __ to an extracellular receptor by binding
hormones may communicate with their target cells by direct __ __ gene activation
a given hormone influences __ __ __ referred to as "target cells" only certain cells
hypothalamus __ __ of the pituitary gland regulates activity
thymic hormones are involved in __ immunity
antagonism has a(n) __ affect opposite
Created by: lfrancois
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