Endocrinology Flashcards
what are the 2 ways that the endocrine system function
nervous system
endocrine system
what is a hormone
substance produced by a specific organ or gland that is transported to a distant site where it influences the activity of another organ or gland
(travels from the endocrine organ to the target organ via the blood stream)
what are parahormones
not produced by true endocrine glands
doesn’t fit the classic hormone definition
what are pheromones
chemical factor that will trigger a social response in members of the same species
ex: male knows that female is in estrous via pheromones
why is knowledge of hormone chemistry important (2 factors)
1) cost
2) administration
what are the 5 endocrine organs
pituitary
hypothalamus
gonads
uterus
placenta
where is the pituitary gland located
where does it rest
located at the base of the brain
rests in a cavity of the sphenoid bone called the sella turcica
what is pituitary gland composed of
2 lobes
anterior pituitary gland
posterior pituitary gland
what is the purpose of the anterior pituitary gland
responsible for the synthesis, storage and release of 6 hormones
what is somatotropin
what releases it
anterior pituitary gland
growth hormone
191 amino acid
what is thyroid stimulating hormone
what releases it
anterior pituitary gland
stimulates thyroid gland which causes the realse of thyroxine
thyroxine controls metabolic rate
what is adrenocorticotropic hormone
what releases it
anterior pituitary gland
stimulating effect on the adrenal cortex
this causes release of glucocorticoids- cortisol and used during parturition and corticosterone and used for metabolism of carbs (during times of stress)
what is follicle stimulating hormone
what releases it
anterior pituitary gland
releases gonadotropin which stimulates male and female gonads
female- development of ovarian follicles which will result in the estrogen production
male- development of the seminiferous tubules which stimulates spermatogenesis
what is luteinizing hormone
what releases it
anterior pituitary gland
releases gonadotropin which stimulates male and female gonads
female- final growth and ovulation of the follicle and maintains the corpus luteum
male- stimulates the leydig cells to produce testosterone
what are the 2 non-pituitary gonadotropins
Equine Chorionic Gonadotropin (eCG)
Human Chorionic Gonadotropin (hCG)
what is equine chorionic gonadotropin (eCG)
stimulates development of the fetal gonads in pregnant mares
mainly FSH like activity with slight LH activity
causes follicular development in mares, resulting in accessory corpus luteum
can cause superovulation in other species and synchronization
what is human chorionic gonadotropin (hCG)
produces by the early placenta of pregnant women
mainly LH like activity with slight FSH activity
basis for early preg testing
can be used in farm animals to induce ovulation and increases production of testosterone
what is prolactin
what releases it
anterior pituitary gland
favors lactation
function include: mammary development, maintain corpus luteum, maternal behavior
what is the purpose of posterior pituitary
responsible for the storage and release of 2 hormones
what are the 2 hormones that posterior pituitary gland
Antidiuretic Hormone
Oxytocin
what is antidiuretic hormone
what realeses it
posterior pituitary gland
ADH regulates amount of water absorbed by kidneys
dehydration- ADH is released and water absorption is increased by the kidneys
what is oxytocin
what releases it
posterior pituitary gland
smooth muscle stimulator: increase myometrium contraction for expulsion of fetus, aids in uterine sperm transport, aids in semen expulsion, aids in milk release
what does the hypothalamus do and where is it located
regulates hormone release by the pituitary gland
located just above the pituitary gland
what are the 3 segments of the hypothalamus
1- surge center
2- tonic center
3- paraventricular nucleus (PVN)
hypothalamus
what are the functions of the surge and tonic centers
responsible for the synthesis of hormones that regulate the release of anterior pituitary hormones
regulation occurs via hypothalamic adenohypophysis portal system which is the capillary network that connects the hypothalamus and anterior pituitary
What is the anterior pituitary aka
adenohypophysis
what is the posterior pituitary aka
neurohypophysis
what is the anterior pituitary hormone somatotropin (STH) and what is the hypothalamus releaser/inhibiter response
somatotropin releasing factor
somatotropin inhibiting factor
what is the anterior pituitary hormone (TSH) and what is the hypothalamus releaser/inhibitor response
thyroxine releasing factor (TRF)
what is the anterior pituitary hormone Adrenocorticotropic hormone (ACTH) and what is the hypothalamus releaser/inhibitor response
Corticotropin Releasing Factor (CRF)
what is the anterior pituitary hormone prolactin and what is the hypothalamus releaser/inhibitor response
prolactin releasing factor (PRF)
prolactin inhibiting factor (PIF)
what is the anterior pituitary hormone Follicle Stimulating Hormone (FSH) and Luteninzing Hormone (LH) and what is the hypothalamus releaser/inhibitor response
gonadotropin releasing hormone (GnRH)
explain this
BMR- basal metabolic rate
what are the functions of PVN (paraventricular nucleus of the hypothalamus)
responsible for synthesis and release of posterior pituitary hormone
oxytocin and antidiuretic hormone
in regard to PVN what are the functions of Oxytocin and Antidiuretic Hormone
1- travel down nerve fibers
2- stored at nerve endings
3- released into blood circulation
what is the relationship between PVN and OC (endocrine hormone that regulates glucose metabolism) in regard to nerves
nerves are stimulated by
1-optic stimuli
2-audio stimuli
3-tactile stimuli
4-olfactory
what are examples of optic stimuli
mother sees offspring
male sees female in estrus
what are examples of audio stimuli
mother hears offspring
cow hears milk pump
what are examples of tactile stimuli
physical contact between male and female in estrus
intromission
massaging the udder
induced ovulatory
what are the olfactory stimuli
male senses pheromones
female smells intact male
mother smells offspring
what are the 3 hormones produced by the gonads and placenta
estrogen
progesterone
testosterone
in regard to estrogen what are the hormones produced by the gonads and placenta where is the sources
granulosa cells of the ovarian follicles
placenta, especially during later stages of pregnancy
Sertoli cells of the testes
cortex of adrenal gland
in regard to estrogen what are the hormones produced by the gonads and placenta what is the functions
anabolic-stimulates the transfer of amino acids across cell membrane
stimulates hyperplasia and hypertrophy in variety of tissues
most growth promoting implants contain estrogen
uterine growth, mammary gland development, stimulate proliferation and dilation of blood vessels, induces estrus, recruits smooth muscle oxytocin receptors
in regard to progesterone what are the hormones produced by the gonads and placenta where is the sources
corpus luteum or luteal tissue
placenta- primary source of progesterone during late pregnancy
cortex of the adrenal gland
leydig cells of the testes
in regard to progesterone what are the hormones produced by the gonads and placenta what are the functions
keeps farm animal females out of estrous or heat
termed the “governor” of the estrous cycle
all other hormones involved in the estrous cycle are suppressed when levels of progesterone are high
relaxing effect of uterine smooth muscle, stimulates uterine gland secretions, suppresses the GnRH release
in regard to testosterone what are the hormones produced by the gonads and placenta where is the sources
leydig cells of the testes
cortex of the adrenal gland
theca cells of the follicle
steroidogenesis
the synthesis of all steroid hormones starts with _________
cholesterol
in regard to testosterone what are the hormones produced by the gonads and placenta what are the functions
spermatogenesis, supports function of the tunica dartos and cremaster muscles, development of secondary sex characteristics in the male, anabolic- stimulates transfer of amino acids across cell membranes
closure of epiphyseal lines in bones or calcification of bones, castrates will be larger frames
what is prostaglandins
where is it secreted
parahormones
every organ in the body produces prostaglandins
influence the glands that produce them
what is the function of prostaglandins
smooth muscle stimulator
receptor in vascular smooth muscle
prostaglandins play a role in blood pressure regulation
explain the luteolysis of a cow
what is the mechanisms of luteolysis of a cow
PGF causes a reduction in blood flow to the CL
PGF directly inhibits steroid production by the luteal cells
