Lect 9 - Male Reproduction Flashcards
Jan 18, 2019
What type of cells, along with spermatogonia, line the lumen of the seminiferous tubules?
Sertoli cells
Where do Leydig cells lie in relation to the seminiferous tubules?
in the interstitium
Which cells are responsible for the blood-testis barrier?
Sertoli cells
Where is LH released from? FSH?
both from anterior pituitary
LH binds receptors on which cells?
Leydig cells
What happens after LH binds receptors in the testes?
increase in cAMP, increase in PKA, increased transcription and production of testosterone
What second messenger is involved in FSH receptor binding?
cAMP
What are four molecules/types of molecules that are increased with FSH receptor binding?
1) inhibin
2) aromatase
3) androgen binding protein
4) growth factors
What is the purpose of inhibin?
inhibit FSH
What is the general interaction between Leydig and Sertoli cells?
Leydig cells produce testosterone, travels to Sertoli cells which converts it to estradiol; growth factors then migrate from Sertoli cells to Leydig cells
What are some regulators of the release of GnRH?
- sleep/wake cycle
- negative feedback
- stress
- hormones
What structure does GnRH act on?
anterior pituitary
How and how often is GnRH released from the hypothalamus?
pulsatile release, every 1-3 hours
What type of cells release GnRH and where are these cells?
gonadotrophs in the hypothalamus
What is the second messenger present in gonadotroph cells which causes release of LH/FSH?
IP3 and DAG–>Ca increase
Where does testosterone exert its negative feedback on? Where does inhibin exert its negative feedback?
Testosterone inhibits the hypothalamus and the anterior pituitary. Inhibin inhibits the anterior pituitary.
How much of testosterone is bound in plasma?
97%
What are the two molecules that testosterone is bound to in the plasma?
1) sex-hormone binding globulin
2) albumin
In what state does testosterone exert a physiological action?
free testosterone unbound to plasma protein
What type of receptors does testosterone bind to?
nuclear receptors
beta-hCG is analogous to which hormone?
luteinizing hormone
There are three times that testosterone will spike in males during a lifetime, when are they?
1) in utero - sex determination
2) right after birth - ? reason
3) during puberty - secondary sex characteristics
The ejaculate volume is stored in three areas of the male reproductive system…what are these areas?
1) epididymis/vas deferens
2) seminal vesicles
3) prostate
Which part of the male reproductive system adds the most volume to the ejaculate?
seminal vesicles
What neural activity is responsible for an erection?
Increase in parasympathetic activity
What second messenger is increased which relaxes smooth muscle to allow for an erection?
cGMP
Which vasoactive substances work to vasodilate in erectile tissue?
nitric oxide and acetylcholine
What are some common causes of ED?
1) diabetes mellitus
2) drugs
3) stress
Which enzyme does Levitra, Cialis, and Viagra all inhibit?
Phosphodiesterase 5 (PDE5)
What is one complication of priapism?
necrosis of tissue
What is Fröhlich’s syndrome?
hypothalamic tumor leading to obesity and depressed release of gonadotropin
What is another name for Fröhlich’s syndrome?
adiposogenital dystrophy
