Physiology of male reproduction Flashcards
(32 cards)
Where is sperm produced?
Seminiferous tubules of the testes
What is the volume and pH of semen?
Volume 2-6ml
pH 7.2-7.6
What is the composition of semen?
1) Spermatozoa (10%)
2) Seminal vesicle fluid (60-70%)
* Fructose and other nutrients
* Fibrinogen to clot the semen
* Prostaglandins; uterine stimulation
* Last volume to be ejaculated
3) Prostate gland secretions (20%)
* Thin, milky secretions, alkaline
* Prostate specific antigen (PSA); protease to break down clotted semen
* Acid phosphatase: activates sperm
4) Bulbourethral gland secretions (10%)
* Mucoproteins; neutralise any urine and lubricate the urethra
* Released prior to ejaculation
How long can the sperm survive in the female reproductive tract?
24-72 hours
Where is sperm produced?
Seminiferous tubules
Where is sperm matured?
Efferent ductules and rete testis
Where is sperm stored?
Ductus deferens
What are key functions of sertoli cells?
1) Essential for providing nourishment for developing spermatogonia
2) Forms adhesions and gap junctions with all stages of developing sperm; directly provides structural support
3) Produce testicular fluid; secreted into the lumen of the seminiferous tubules, including androgen binding protein
4) ABP concentrates testosterone in the lumen; essential for development of spermatogenesis
What do leydig cells do?
Testosterone synthesis
How do leydig cells help with sperm motility?
There is a layer of contractile smooth muscle around the leydig cells to force out the sperm.
What is the blood-testis barrier?
The tight junction (direct contact between corresponding proteins on adjacent cells) that separates the lumen of the seminiferous tubules from the rest of the body. Prevents sperm from being attacked by the immune system.
How does meiosis occur safe from an immune response?
Primary spermatocytes are able to move past the blood-testes barrier.
How long do sperm spend in the epididymis and why?
30 days maturing and developing motility.
What are the key structural components of sperm?
Acrosome, nucleus, midpiece, principal piece and tail
What is the acrosome of the sperm?
A membrane bound compartment containing enzymes and proteins used to penetrate with the egg
What is the nucleus of the sperm?
Contains the chromosomes and is very highly condensed.
What is the midpiece of the sperm?
Contains many mitochondria which generate the ATP required to drive the whip-like movements of the tail.
What is the principle piece of the sperm?
Contains an intricate array of contractile microtubules that make use of ATP to drive the movement of the tail.
What is the role of the tail of the sperm?
Allows it to move faster. Side by side motions to develop speed.
What is semen?
An essential supporting factor of the survival and activation of sperm.
What is semen comprised of?
Spermatozoa (<10%)
* 15-150 million per millimetre
Seminal vesicle fluid (60%)
* Fructose and other nutrients for the sperm
* Fibrinogen to clot semen (keep it lodged in the female reproductive tract)
* Prostaglandins to stimulate the uterus
Prostate gland secretions (20%)
* Thin, milky, alkaline secretions
* Prostate specific antigen (PSA) to break down clotted sperm
* Acid phosphatase to activate sperm
Bulbourethral gland secretions (10%)
* mucoproteins to neutralise any urine in the urethra and lubricate the urethra
How long can sperm survive in the female reproductive tract?
24-72 hours
Why does ejaculated semen clot?
Due to fibrinogen and lodges at the base of the cervix so it doesn’t flow out. PSA slowly breaks down the clot so that the sperm can swim into the uterus.
What is capacitation?
The process of morphological, physiological and biochemical changes the sperm must go through before the sperm is capable of penetrating and fertilizing an ovum.
