Spermiogenesis Flashcards
Which component of the spermatozoa forms the acrosome?
Golgi apparatus
5 stages of spermatocytogenesis
- Spermatogonia
- Primary spermatocyte
- Secondary spermatocyte
- Spermatid
- Spermatazoa
Describe 4 ways spermatogonia become differentiated
- Nucleus condense
- Mitochondria are spread out in spermatid but lined up along the (forming) tail.
- Tail starts to form with centriole and mitochondria lining up in the first part of the tail (become the mid-piece)
- Residual cells are removed by phagocytosis
Describe the time periods of spermiogenesis
- Spermatogonium to primary spermatocyte (16 days)
- Primary to secondary spermatocyte (24 days)
- Secondary spermatocyte to spermatid (hours)
- Spermatid to spermatozoa (24 days)
- Total 64 days
Which hormones activates Sertoli cells
FSH! and testosterone
5 functions of sertoli cells
- Acts as a blood testes barrier
- Secretes fluid
- Transfers nutrients to keep sperm alive
- Has a role in phagocytosis
- Produces ABP, Inhibin, AMH and oestrogens
What is the importance of the Sertoli cells as a blood-testes barrier?
Provides an immunologically safe microenvironment form sperm using tight junction
What is the importance of the fluid secreted by Sertoli cells?
Moves immobile sperm to epididymus.
What are Sertoli cells roles in phagocytosis?
To remove residual cytoplasm and dead sperm
Which receptors do Sertoli cells express
FSH and androgen receptors
What is the importance of ABP, Inhibin, AMH and oestrogens produced by Sertoli cells?
Androgen-binding protein (ABP) - maintains a high concentration of testosterone in the seminiferous tubules)
Inhibin - inhibits FSH production
Anti-mullerian hormone (AMH) - causes mullein ducts not to develop
Oestrogen - Important for spermatocytogenesis
How long do sperm take to mature and where does this occur?
Approx 1 month in epididymis (here sperm gain ability to be mobile)
Where are mature sperm stored?
Ductus deferens
What is the anatomy of the seminal vesicles?
Posterior to the bladder and drains into the ampulla of the ductus deferent and denotes the beginning of the ejaculatory duct
Function of the seminal vesicle?
Secretes thick, alkaline fluid (which protects sperm from acidic uterine tract) containing fructose, prostaglandins and coagulation factors
How does sperm move along ductus deferens?
Peristalsis
Where is the prostate located?
Inferior to the bladder
What is the function of the prostate?
To secrete a thin, milky fluid with citrate and zinc etc. including prostate specific antigen that liquefies ejaculate to allow sperm to be motile (timed to liquefy semen around 20mins after ejaculation
What percentage of the final volume of semen is produced by the prostate?
20%
Where does the ejaculatroy duct join the urethra?
Within the prostate
Where are the bulbourethral glands located?
Within the external urethral sphincter. Sitting in the deep pouch between the pelvic floor and urogenital triangle and drains into the membranous urethra.
What is the function of the bulbourethral glands?
To secrete mucus (about 10% of final semen volume)
What is the composition of ejaculate?
90% semen and 10% sperm
Where are Sertoli cells located?
Sertoli cells are the epithelial supporting cells of the seminiferous tubules.
What hormone do Sertoli cells respond to?
FSH
Which hormone do leydig cells respond to?
LH
What do leydig cells produce?
Testosterone
Where are leydig cells located?
In the interstitium
