Physio: male repro Flashcards
2 functions in the male reproductive system controlled by the hypothalamic pituitary gonadal axis.
- Spermatogenesis in the seminiferous tubules
2. Testosterone Synthesis in the Leydig Cells
Function of FSH in the male reproductive system.
Binds sertoli cells:
-induces production of Androgen Binding Protein
Function of Androgen Binding protein
Binds testosterone to maintain elevated hormone levels locally in the seminiferous tubules to induce the maturation of sperm cells.
Function of LH in the male reproductive system.
Binds Leydig cells and induces the production of testosterone.
Function of inhibin.
Made by sertoli cells, acts as negative feedback for FSH release from the anterior pituitary
Functions of testosterone at puberty.
Spermatogenesis Hair growth deepening of the voice increased libido growth of internal and external genitalia
Functions of testosterone in postpubertal males.
- Maintains everything that occurred during puberty
- increased bone and muscle mass
Why do exogenous androgenic steroids cause sterility?
The high serum testosterone (or DHT) levels inhibit the release of FSH and LH from the anterior pituitary.
The decrease in LH decreases Leydig cell testosterone production and decreased testosterone levels locally in the seminiferous tubules.
The decreased FSH prevents Androgen Binding Hormone production in the Sertoli cells. This prevents “trapping” the locally produced testosterone from remaining in the seminiferous tubules.
Name the 5 stages of spermatogenesis.
- Spermatogonia
- Primary Spermatocytes
- Secondary Spermatocytes
- Spermatids
- Spermatozoa
What is spermiogenesis?
Maturation of Spermatids into Spermatozoa
- loss of cytoplasm
- addition of tail
What part of the spermatozoa contains the mitochondria for energy production?
Midpiece
What forms the blood testis barrier to prevent toxic substances from reaching the developing spermatogonia?
Sertoli cells form tight junctions with one another creating the barrier. The sperm cells mature between the sertoli cells
What allows nutrients thru the blood testis barrier?
Gap junctions between the sertoli cells
Which 3 glands contribute to semen production?
Seminal Vesicles (fructose, PGs, fibrinogen) Prostate (alkaline, clotting enzymes) Bulbourethral Glands (lubrication)
Components of the male reproductive tract innervated by the sympathetic nervous system.
Epididymis Vas Deferens Seminal Vesicles Prostate Internal Urethral Sphincter
Components of the male reproductive tract innervated by the parasympathetic nervous system.
Cavernous blood vessels in the penis, causes vasodilation in arteries and venoconstriction in veins.
What is the Erection Reflex?
Stimulation of the Mechanoreceptors in the glans penis activates the parasympathetic nervous system to effect blood vessels in the penis. The parasympathetics also stimulate mucus secretion from the bulbourethral glands.
Also activates sympathetics in peripheral blood vessels to move blood into penile vessels.
What are the two phases of Ejaculation?
Emission Phase
Expulsion Phase
What occurs during the emission phase of ejaculation?
Sympathetic Nervous system moves ejaculate into the prostatic urethra using peristaltic contractions of the vas deferens, seminal vesicles, and prostate.
It also causes contraction of the internal urethral sphincter.
What occurs during the expulsion phase of ejaculation?
Once the ejaculate moves into the membranous urethra, the Spinal Reflex is triggered.
The somatic nervous system causes contraction of the ishiocarvernosus and bulbospongiosus muscles forcing expulsion of the ejaculate.
