Reproduction 1 - MALE Flashcards
Pathway of sperm starting from testes
Testes (seminpherous tubules)—> efferent —> epididymis —> vas defran —> prostrate gland —> bulbo-utheral gland
—> urethra
Why are testes housed in scrotum?
Keeps temp 2 degrees lower then body temp to preserve sperm cells and their development.
Descent of testes
1) 3 months: in abdominal cavity.
- no penis, gubernaculum
2) 7 months: begin to descent towards scrotal sack
3) birth: by birth they descent
What happene if balls dont drop?
Cant produce sperm, can still produce hormones
Where is the site of gamete production for sperm?
Seminpherous tubules
Cells inside the seminiferous tubules?
Spermatogenetic cells:
- space in center / lumen
Which cells are effected by mumps?
Spermatogenic cells
What happened if you get mumps in childhood ?
- Cells that line outer periphery of each seminiferous tubule becomes smaller.
- size of cells decrease
- defects sperm production ability.
- vaccine
Cells of the testes: sites of sperm production
1) leydig cells
2) sertoli cells
3) smooth muscle muscles
4) blood test is barrier
Leydig cells
(Interstitial cells)
- secrete and produce testosterone
Sertoli cells
(Epithelial cells, make up seminiferous tubules)
- support sperm production
- linked together with tight junctions (where spermatogenesis occurs)
Smooth muscle (myloid cells)
- Contractile functions = seminiferous tubules contract to move sperm cell out via peristalsis
The important of the tight junctions is that it creates a
blood-testis barrier
blood-testis barrier:
Barrier protects junction (site of spermatogenesis) form any outside chemicals or antibodies or infections cuz of the protective barrier.
The tight junctions makes the barrier via two compartments, the
- luminal compartment
- basal compartment
Basal stretches like a ring which prevents anything coming form outside to coming inside.
Functions of Sertoli Cells
- Support sperm development: “trophic role” —> secrete factors
- Secrete luminal fluid in for sperm housing
- Secrete androgen-binding protein
• Androgen buffer (binds to androgens)
• Helps maintain steady [androgens] in lumen - Act as target cells for testosterone and FSH
• Secrete paracrine factors that stimulate spermatogenesis - Secrete inhibin
• Hormone of negative feedback loop for FSH - Secrete paracrine factors that affect Leydig cell function
- Phagocytosis of old and damaged sperm
- Site of immunosuppression
(blood testis barrier)
Testosterone and FSH use __________ as their target and help in __________
Sertoli cells
sperm development
Function of gonads
– Production of sperms
– Production of hormone
Epididymis function
– Maturation of sperm
– Storage site for sperm
Vas deferens function
– Conduit
– Storage site for sperm
Accessory sex glands function
– Production of seminal fluid
At what age do testes make testosterone?
Puberty (10-14)
How are hormones secretes regulated?
By Sertoli cells by producing androgen binding proteins
maintains testosterone
inhibin function?
Hormone of negative feedback loop for FSH = decreases FSH secretion.
Who produces inhibin
Sertoli cells.
Between the basal compartment and luminal compartment, which is bigger?
The luminal a lot bigger
Corticosteroid synthesis
Cholesterol —> progesterone —-> (aldosterone, cortisol, androgens)
Steroids are synthesized by________ and secreted by the _____
adrenal cortex
gonads
Steroids are ____ soluble hormones and gets easily
lipid
diffused through target cell membrane, often found in cytoplasm and nucleus.
Production of testosterone in leydig cell pathway
Cholesterol —> pregnenolone —> progesterone —> angdrogens (testosterone)
= leaves leydig cell and into blood
Once testosterone leaves the leydig cells in the testes and enters the blood, what does it convert to?
- testosterone
- Dihydrotestosterone (required for sex organic dev)
- estrogen
Patterns of Male Reproductive Activity Over the Human Life Span
Males never stop produce testosterone, levels changes with lifespan
Describe the peaks of testosterone secretion during male life span
1) second trimester of pregnancy: huge spike of testosterone during
2) neonatal period: (right after birth) spike before the age of 1.
3) puberty: large rise, then gradual decrease after age ~60. Never reaches 0.
What does the large spike of testosterone during neonatal period do?
final maturation of reproductive structures.
What regulates testosterone secretion of the leydig cells?
Hypothalamus (release GnRH) and ant. Pit. (Release FSH)