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(10 cards)
What is the signaling mechanism that LH receptors use to induce steroidogenesis?
cAMP
What other receptors do leydig cells have and what is their effect on them?
Estrogen receptors in Leydig cells reduce the proliferation and activity of these cells.
Q: What is the role of testosterone in Sertoli cells?
A: In Sertoli cells, testosterone acts as a precursor for estradiol production, modulating responses to LH.
What is the full signaling process that occurs in leydig cells after LH binds to its receptors to induce steroidogenesis?
Luteinizing hormone (LH) stimulate cAMP-PKA which activate cholesterol release from cellular stores.
Cholesterol enters mitochondria, via the steroidogenic acute regulatory protein (StAR), to form pregnenolone.
Pregnenolone is transported to the smooth ER for steroid synthesis.
Testosterone is the end-product, which diffuses into the extracellular fluid.
How does cystic fibrosis affect spermatogenesis?
Men with cystic fibrosis have normal spermatogenesis but have azoospermia.
They have congenital bilateral absence of vas deferens.
What do the seminal vesicles release?
Produces viscous alkaline seminal fluid
Fructose [substrate for glycolysis], ascorbic acid, coagulating enzyme (vesiculase), and prostaglandins
70% of the volume of semen
What two ducts join to form the ejaculatory duct?
Duct of seminal vesicle joins the ductus deferens to form the ejaculatory duct
What does the prostate release?
Secretes milky, slightly acid fluid:
Contains citrate, enzymes, and prostate-specific antigen (PSA)
Function in activation of sperm
Fibrinolysin liquefies the coagulated semen 15 to 30 minutes after ejaculation
What do the bulbourethral glands release?
مذي
Pea-sized glands inferior to the prostate
Prior to ejaculation, produce thick, clear mucus
Lubricates the glans penis
Neutralizes acidic urine in the urethra
What is the minimum volume of semen considered normal?
Greater than 1.5 ml.
