quiz 4 Flashcards
define nervous system
translate external stimulus into neural signals that act on reproductive tissues
define endocrine system
relies on hormones
describe the portions of the endocrine system
hormonal, large
targets distant locations
acts as a catalyst
circulatory transport
slow transport
long duration
stimulates other hormones, nerves, or tissue
binds with receptors to activate response
describe the portions of the neural system
neurotransmitter, small
nerve/effector site
short distance
fast moving
short duration
stimulates other nerves
travels nerve to nerve or nerve to organ
define simple neural pathways
secretes neurotransmitter to target tissue
define neuroendocrine reflex
secretion of neurohormones into blood to remote target tissue
define neurotransmitter
substance releases at synapses for neuronal propagation of the electrical impulse
produced by neurons
define neurohormone
substance released by neurons directly into the blood
what are the 3 types of stimuli
thermal
tactile
visual
what sends signals to the spinal cord
afferent neurons
what sends signals to the target tissue
efferent neurons
what does the hypothalamus aid in
homeostasis
define the hypothalamic-pituitary-gonadal axis
what does it do for the female
male
both
attacks all parts of the body
estrous cycle, parturition, location
testosterone, sperm production
sexual behavior
define center
collection of neurons doing the same job
define surge center
specific hypothalamic nuclei in females that responds to high estradiol
define tonic center
controls release of GnRH
slow, regular release
define paraventricular nucleus
discrete bond of nerve cells that innervate those posterior pituitary
what is the master gland
anterior pituitary
what does the releases of GnRH stimulate
FSH and LH
how do hypothalamic hormones reach the pituitary
hypothalamo-hypophyseal portal system
why doesn’t GnRH not stay in the body long
it is small and broken down easily
describe the hypothalamus and posterior pituitary
no portal system
neurons from certain hypothalamic nuclei extend directly into the posterior lobe
neurohormones produced in the PVN are transported down axons to the terminal released into the blood
define positive feedback loop
hormone brings about a biological response that increases the release of the hormones
define negative feedback loop
rising levels of the hormones bring about the biological response that stops the release of hormones
what is produced the the negative feedback loop
gonadal steroids: testosterone, progesterone, estradiol
protein hormone: inhibin
what is produced in the positive feedback
estradiol
oxytocin during parturition
define endocrine system
relies on hormones to cause a response
what are the influential factors of the endocrine system
presence of receptors on a hormonal cell
half life of the hormone in circulation
what are the four facts of reproductive hormones
exert biological response at the nanogram level in blood
short half life
exert cell response by binding to specific receptors in cells
stimulates phenotypic response in cell through biochemical, metabolic, or genomic response
what are the 3 classifications
- the source- where it comes from
- biochemical classification
- mode of action- what target tissue/communication
what are the 4 biochemical classifications
peptide- small molecules of animo acids
glycoprotein- carbohydrate attachment
steroid- fat soluble
prostaglandin- fatty acid
what does 5a-reductase do
converts testosterone to dihydrotestosterone
what are the functions of steroids
cellular effects, feedback, behavior, secondary sex characteristics, ossification and pregnancy
what are the functions of prostaglandins
luteolysis, ovulation, inflammation, and blood pressure
defne phosphorylation
Addison of a phosphate to a protein/small molecule
define phosphatase
removes a phosphate from a protein
what are protein hormones
LH
G-Cell (membrane bound protein)
adenylate cyclase
protein kinase A
regulatory subunit
catalytic subunit
define cAMP
cyclic acetyline monophosphate
what are the 4 steps of cAMP
- hormone receptor binds on cell membrane
- g-protein transforms and AC activates; converts ATP to cAMP
- cAMP activates PKA; activated enzymes convert substrates into products
- PKA phosphorylates proteins that induce cellular change
what are examples of cAMP
LH
FSH
prolactin
eCG
hCG
what are the calcium second messengers
GnRH
g-protein
phospholipase C
phosphoinositiol phosphate (PIP2)
PKC
what are the 6 steps of the calcium second messenger
- GnRH binds to receptor
- GP, PIC, and PIP2 associate
- PLC creates DAG and IP3
- IP3 binds to receptors to release calcium
- Ca2+ activates PKA and opens Ca2+ channel
- high Ca2+ activates secretory granules to fuse with the cell membrane to release product
describe steroid hormone receptors
fat soluble, so diffuse directly through the membrane into the cytoplasm
travel though blood by binding to water soluble proteins
transcription convert DNA to RNA and RNA to mRNA
what are the 4 steps of the steroid hormone receptor
- steroids are transported into blood by carrier protiens
- diffuse through cell membrane of target cell and then through the nuclear membrane
- steroids bind to receptors in nucleus and initiates mRNA synthesis
- newly synthesized mRNA go to the ribosome for protein production
describe GnRH
classification
source
target
action
peptide
hypothalamus- tonic and surge centers
anterior pituitary
releases FSH and LH
describe relaxin
classification
source
target
action
polypeptide
placenta, corpus leteum; prostate
cervix, pelvic ligament; spermatozoa
soften ligaments, widen birth canal; enhance sperm motility
describe oxytocin
classification
source
target
action
peptide
produced by neurons in hypothalamus; stored/released by hypothalamus; synthesized by corpus luteum
uterus, mammary gland; epididymis tail, ductus deferens
uterine motility, milk letdown, uterine PGF2a synthesis; emission, PGF2a synthesis
describe prolactin
classification
source
target
action
protein
anterior pituitary
mammary gland, corpus luteum; testes
growth during pregnancy, milk production; testosterone, spermatogenesis; parental bonding
describe luteinizing hormone
classification
source
target
action
glycoprotein
anterior pituitary
theca, granulosa, and luteal cells; leydig cells
testosterone secretion, induces ovulation, supports corpus luteum; testosterone production
describe FSH
classification
source
target
action
glycoprotein
anterior pituitary
granulosa cell; Sertoli cell
follicular development, estradiol synthesis; support Sertoli cells and spermatogenesis
describe inhibin
classification
source
target
action
glycoprotein
granulosa cells; Sertoli cells
anterior pituitary
inhibits FSH secretion
describe activin
classification
source
target
action
glycoprotein
anterior pituitary, gonads, and placenta
follicle; testis
increases FSH binding, estradiol production; enhance spermatogenesis, testosterone produciton
describe equine chorionic gondotropin
classification
source
target
action
glycoprotein
endometrial cups
ovary
induces accessory CL formation to support pregnancy; LH-like activity in mares; other species have FSH-like activity
describe human chorionic gonadotropin
classification
source
target
action
glycoprotien
embryo and placenta
CL prevents luteolysis, can induce ovulation in mares
describe estrogen
classification
source
target
action
steroids
granulosa cells, placenta; Sertoli cells
hypothalamus, entire tract; hypothalamus
sexual behavoir, GnRH regulation, secretion, contractions; sexual behavior, negative feedback
describe progesterone
classification
source
target
action
steroid
CL, placenta
uterus, mammary gland, hypothalamus
secretion, myometrial contractions, increased mammary tissue, inhibit GnRH secretion and reproductive behavior
describe testosterone
classification
source
target
action
steroid
theca interna; leydig cells
granulosa cells are substrate for estradiol; accessory sex glands for secretion, seminiferous tubule promotes spermatogenesis
define prostaglandin F2a
classification
source
target
action
fatty acid
uterine endometrium; prostate or vesicular gland
corpus leuteum myometrium, follicles; epididymis
luteolysis, uterine tone, ovulation; induces contractions
