Fertilization Flashcards
How far must spermatozoa travel through the reproductive tracts to reach the oviduct?
30-40cm
How far must spermatozoa travel to reach the oviduct in relation to their length?
> 100 000x their length
What changes must happen to sperm, following spermatogenesis, for them to gain full fertilising capacity?
- Maturation
- Capacitation
- Acrosome reaction
Where does maturation take place?
In the male reproductive tract, in the epididymis
Where does capacitation take place?
The female reproductive tract
Where does the acrosome reaction take place?
The female reproductive tract
What changes to the spermatozoa take place during maturation?
- Acquisition of mobility
- Chromatin modification
- Acrosome size alteration
- Migration of the cytoplasmic droplet from the neck to near the annulus
- Acquisition of the ability to recognise, bind and fuse with eggs
- Modification to the surface plasma membrane
What secretory products are added in the epididymis?
- Carnitine
- Fructose
- Glycoproteins
- Glycerophosphorylcholine
How long does it take the spermatozoa to move through the epididymis?
5-11 days
How long is the process of maturation?
The length of time needed to pass through the epididymis - 5-11 days
The maturation process in the epididymis is dependant on what?
Stimulation of the epididymis by androgens
Where are mature spermatozoa stored?
For a few days int he caudal epididymis, and then in the vas deferens
How are non-ejaculated sperm lost in a normal, non-ligated vas deferens?
Dribble through the terminal ampulla and into the urethra where they are then washed away in urine
How are non-ejaculated sperm lost in a ligated, e.g. post-vasectomy, vas deferens?
Build up behind the ligature - removed by intra-epididymal phagocytosis, or by leakage through the epididymal wall
What is the collective name for the glands that contribute to semen production?
Accessory glands
What are the male accessory glands?
- Seminal vesicles
- Prostate
- Bulbourethral glands
What else make a contribution to semen, aside from the accessory glands?
Testes + epididymis
What proportion volume is made by each structure to the semen?
Seminal vesicles - 60% Prostate - 20% Testes - 15% Bulbourethral glands - <5% Epididymis - <5%
What do the seminal vesicles contribute to the semen?
Fructose; ascorbic acid; prostaglandins; phosphorycholine; flavins
What does the prostate contribute to the semen?
Zinc; citric acid; phospholipids; acid phosphates; profibrolysin
What do the testes contribute to the semen?
Sperm
What do the bulbourethral glands contribute to semen?
Alkaline mucus
What does the epididymis contribute to the semen?
Carnitine; acetyl carnitine
From what is the alkaline mucus secreted?
Bulbourethral glands
