Endocrine 2- The Pituitary gland
thyroid stimulating hormone release is inhibited by feedback inhibition due to rising thyroid hormone levels in the blood and by ___
GHIH
the anterior pituitary is also called the
adenohyphysis
thyroid stimulating hormone release is simulated by _____ which is released when blood concentrations of throid hormones are low
thyrotropin releasing hormone (TRH)
anabolic
tissue building
of the six hormones released by anterior pituitary four are called ____ because they regulate the secretions of other endocrine glands: TSH, ACTH, FSH, and LH
tropic hormones
antidiuretic hormone (ADH=vasopressin) inhibits ___ to help prevent dehydration
urine formation (diuresis)
direct effects of human growth hormone ( anti-insulin actions)
- incrased blood sugar (mimics the high blood sugar levels of diaberte mellitus) -increased lip0lysis (breaskdown of fat molecules= mobilazation of fats) increased blood fatty acid levels
Human growth hormone (hGH)
-in general the effects are anabolic (tissue building) -promotes protein synthesis -promotes the sue of fats over glucose as a fuel (glucose sparing)
indirect effects of human growth hormone (somatotrophic) actions
-most are mediated by insulin-like growth factors (IGFs= somatomedins) produced by the lover, skeletal muscle and bone -stimulate uptake of amino acids from the blood and their incorporation into cellular proteins -stimulate the uptake of sulfur used by the production of chondroitin sulphate in cartilage matrix skeletal effects: increased skeletal growth and cartilage formation extraskeletal effects: increased cell growth and proliferation
in males and non-lactating females oxytocin is involved in
-sexual arousal -orgasm - and satisfaction and promotes nurturing and affectionate behavior (the "cuddle" hormone)
oxytocin
-stimulates smooth muscle contractions, especially in the uterus, this is the hormone that is released during labour and childbirth and also the drug used to induce labour, as the uterus is stretched, impulses to the hypothalamus increase, causing more of it to be released, in turn causing more forceful contractions - it also causes milk secretion in womens breasts that are producing milk in response to stimulation of the areolas and nipples
growth hormone is released in __-__ pulses through the day
8-12
about __ % of all growth hormone is released in the first sleep cycle (NREM Stage 3/4)
80
prolactin release is stimulated by ___ which is released when estrogen levels are high (puberty in females) and as a result of an infant suckling
Prolactin releasing hormone (PRH)
antidiuretic hormone is suppressed by ____ - all of which cause dehydration due to the resulting overproduction of urine
alcohol, caffeine, and diuretic drugs
hormones released by hypothalamus into posterior pituitary are _____ transported to their terminals, stored and released when impulses from the brain stimulate the axon terminals
axonally
antidiuretic hormone affect the kidney tubules, causing more water to be reabsorbed from the urine and returned to __
circulation
adrenocorticotropic hormone is stmulated by _____ which is released during stress and during normal circadean rhythms
corticotropin releasing hormone (CRH)
the anterior pituitary secretes six non-steriod hormones, all six hormones affect their target tissues via the ______
cyclic AMP second-messenger system
growth hormones affects target tissues..
directly or indirectly
follicle-stimulating hormone/luteinizing hormone release is inhibited by feedback inhibition due to rising ___ levels in females and ___ levels in males
estrogen, testosterone
the anterior pituitary is composed of ____ that produce and secrete hormones into circulation via capillaries in the anterior pituitary the release of these hormones is regulated by other hormones that are secreted from the hypothalamus into capillaries tehre
glandular tissue
adrenocorticotropic hormone release is inhibited by feedback inhibition due to rising blood concentration of ____
glucocorocoids (cortisol)
follicle-stimulating hormone/luteinizing hormone release is stimulated by ____ which is released through life after puberty in makes and females (levels cycle monthly in women)
gonadotropin releasing hormone
with the exception of ___, all the anterior pituitary secretions, in turn, promote the activities and secretions of other glands in the body
growth hormone
the human growth hormone is inhibited by _______ which is released when blood levels of hGH, IGF, blood glucose are high or low?
growth hormone inhibiting hormone (GHIH), high
the human growth hormone is stimulated by the _____ which is released when blood levels of hGH are high or low?
growth hormone releasing hormone (GHRH), low
only __ hormone and ___ have known inhibiting hormones specific to their secretions
growth, prolactin
the two capillary beds are connected by a small blood vessel called the _____
hypophyseal portal system
another name for pituitary gland (has two lobes)
hypophysis
each hormone is produced and released by a specific cell type, which is a target cell for the
hypothalamic regulatory hormones
all six anterior pituitary hormone secretions are stimulated by
hypothalamic releasing hormones
the anterior pituitary secretory cells do not store much of the hormone they produce they await stimulation from the __
hypothalamic releasing hormones
all the anterior pituitary secretions are regulated by hormones produced and released by the ______ , this is an important functional link between the CNS and the endocrine system
hypothalamus
posterior pituitary secretions are released as demanded by the CNS via stimulation of specialized regions in the ___
hypothalamus
gonadotropins: luteinizing hormone (LH)
in females: works in concert with FSH to promote the development of the egg-containing follicle in the ovaries; sure causes ovulation In males: stimulates the interstitual cells of the testes to produce testosterone
the pituitary gland is physically connected tot he hypothatlamus of the brain by a stalk of tissue called the
infundibulum
if the secretion inhibits the anterior pituitary from producing and releasing its hormone it is called an
inhibiting hormone
milk secretion
let down
prolactin affects the _____ glands which are exocrine or endocrine?
mammary glands, exocrine
there is no direct ____ connection between the hypothalamus and the anterior pituitary
neural
posterior pituitary secretions: the posteriror pituitary produces 2 non-steroid hormones: oxytocin and antidiuretic hormone (ADH) because they are produced by neurons rather than gland cells, they are sometimes reffered to as
neurohormones
the posterior pituitary and infundibulum together are called the
neurohypothysis
antidiuretic hormone is released due to inputs from ___ in the hypothalamus when the blood concentration of solutes is high and during periods of high activity (exercise)
osmoreceptors
the posterior pituitary does not produce any hormones but is the site of release of hormones produced in the hypothalamus the hormones released here are
oxytocin and antidiuretic hormone (ADH)
both oxytocin and antidiuretic hormone (secreted by posterior pituitary) are ___ composed of nine amino acids and both us the _____ system to affect their target cells
polypeptides, inositol triphosphate second-messenger system
prolactin release is inhibited by feedback inhibition from ______, dominated through life in males
prolactin inhibiting hormone (PIH=dopamine)
if the hypothalamic secretion causes the anterior pituitary to produce and release its hormone it is referred to as a
releasing hormone
prolactin (PRL)
stimulates breast development and milk production in females
gonadotropins: follicle-stimulating hormone:
stimulates gamete (egg and sperm) production
adrenocorticotropic hormone (ACTH)
stimulates the adrenal cortex to release corticosteriod hormones
thyroid stimulating hormone (TSH)
stimulates the development of the thyroid gland and causes thyroid secretions
in high concentrations ADH is also a powerful ____ (causes the blood vessles to contrict) which occurs when blood pressure drops dramatically (hemorrhage)
vasoconstrictor
