Flashcards in Reproductive Endocrinology Deck (54)
What is a simple neural reflex?
Nerves that release simple neurotransmitters directly onto the target tissue.
What is a neuroendocrine reflex?
Needs a neurohormone to enter blood and act at a remote location.
What is the neural control center for repro hormones?
What organ deposits neurohormones directly into circulation?
What regulates GnRH?
Male: Tonic center
Female: Tonic and Surge centers
What quantity of repro hormones do you need?
How long are repro hormone half-lives?
Where does GnRH come from?
Where do FSH, LH and prolactin come from?
Where does Oxytocin come from?
Which repro hormones are a peptide?
Which repro hormones are a glycoprotein?
Which repro hormones are steroids?
What does PGF2a do?
Lyses the corpus luteum
What does PGE2 do?
Relaxes the cervix
How do protein hormones cause their actions?
Bind to plasma membrane bound receptors
How do steroid hormones cause their actions?
Travel freely through the plasma membrane into the cytoplasm and bind to the specific nuclear receptors
What does binding of hormones result in?
New protein synthesis
What are two functions of pheromones?
Influence the onset of puberty
Lets the male know who is in heat
What 4 things affect the strength of a hormone?
Pattern and duration of secretion
Receptor density (this is really important)
NOTE: We can play with receptor-hormone affinity to make synthetic hormones that bind better than the natural hormone.
What are3 different patterns and duration of secretion?
What is Episodic secretion?
Burst or pulse
NOTE: generally associated with hormones under nervous control.
What is Basal secretion?
Secretion stays low, but fluctuates with low amplitude pulses.
What is Sustained secretion?
Hormone remains elevated, but in a steady fashion for a long period.
NOTE: Steroids tend to be secreted this way.
Where are steroids metabolized and excreted?
Excreted: Urine and feces
What organ is usually larger in high producing dairy cows?
Why can pregnancy tests be a urine test?
Because the protein hormones (eg. hCG) are metabolized in the liver and excreted by the kidneys.
What is estrus?
"Heat" or secual receptivity
What is estrous?
Length of the estrous cycle