Basic Physiology of the Reproductive System Flashcards
What is the male reproductive system responsible for?
Production (by testes) and transport of sperm
Production of androgens to support secondary sexual characteristics
What is the transport channel for sperm?
Ductus/vas deferens
What is the function of semen?
Provides nutrients/transportation fluid
Where does semen come from?
60% seminal glands
30% prostate
5% bulbourethral glands
What structures are the testes made up from?
Lobules containing seminiferous tubules
V. convoluted
Where is the site of spermatogenesis?
Seminiferous tubules
The seminiferous tubules merge to form which structure?
Epididymis
What does a cross section of a ST look like?
Spermatogonium right at basement membrane and divide and move forward until they are mature sperm in the lumen
Why is it important that blood doesn’t come into contact with STs?
Sperm haploid and looks different so don’t want immune cells interpreting as non-self and destroying them
How many sperm would you get from each spermatogonium?
512
How much sperm does the epididymis store?
5ml
What are some functions of Sertoli cells?
Form blood-testis barrier
Isolate haploid secondary spermatocytes, spermatids, spermatozoa from the immune system
Physically move sperm towards the lumen (spermiation)
Provide nutrients for sperm
Remove waste from sperm
Remove excess cytoplasm following cell divisions
Define spermatogenesis
How long does it take?
Where does it occur?
Process of forming mature sperm
75 days
STs
Define spermatocytogenesis
Mitotic divisions of spermatogonia (undifferentiated male germ cells) to produce primary spermatocytes
What occurs after spermatocytogenesis?
Two meiotic divisions
Meiosis I - primary spermatocytes double up DNA and there is separation of homologous chromosomes that go to make secondary spermatocytes
Meiosis II - secondary spermatocytes half again (separation of chromatids) to make spermatids
Define spermiogenesis?
Maturation of spermatids into mature, motile sperm
Occurs in epididymis
How long is the sperm stored in the epididymis until it becomes motile?
15 days
Where is the final maturation of the sperm?
In the female genital tract that allows it to penetrate the egg and have increased motility
What is the blood supply to the testis like?
Arterial blood enters dense network of capillaries coming from testis/epididymis before reaching spermatic cord - this cools it and helps to maintain a constant testicular temperature