Basic Physiology - Loons Flashcards
What volume of Seminal Fluid (semen) is produced by the male reproductive system and how many sperm does this contain?
2-5ml with 20-200million sperm/ml
Where is seminal fluid made?
5% in Bulbourethral Gland
30% in the prostate
60% in the Seminal Vesicle
Where does spermatogenesis occur?
The Seminiferous tubules within the testes
How is sperm transported from the site of production to the site of storage?
Made in seminiferous tubules
They join at the rete testes and follow efferent ductules into the epididymis for storage
What happens during ejaculation?
Sperm travels from the epidydimis to through the ductus deferens to the left and right ejaculatory ducts and out the urethra, mixing with the seminal fluid from the Seminal vesicles, prostate and bulbourethral glands
Sperm are haploid (23 chromosomes) meaning they don’t resemble normal body cells.
How are the maturing sperm in the seminiferous tubules protected from our own immune system?
By Sertoli cells that form the Blood-seminiferous tubule barrier
What are the functions of the Sertoli cells?
- Isolate developing sperm from immune cells
- Physically move sperm towards lumen as they develop
- Provide nutrients
- Remove waste
- Remove excess cytoplasm post cell division
- Support Spermiation
What are the stages of a sperms life cycle?
Production: (75 days) in STs
- Spermatocytogenesis
- Meiosis
- Spermiogenesis
Storage (15 days) in Epidydimis:
- Become Motile
- Ejaculation
In Vagina:
- Capacitation
How is testicular temperature regulated?
Arterial blood going towards the testes passes through a dense network of capillaries that runs alongisde venous capillairies. The venous blood cools the arterial blood thus maintaining an even temperature
What factors affect spermatogenesis?
- Temp
- Hormonal
- Loss of blood-testis barrier
- Immune reactions
- Environment
- Medications
What temperature should the testis be and how can that go wrong?
2C below Body temp
Mumps, viral and other infections can raise temperature
What hormonal factors can affect spermatogenesis?
Anabolic Steroids
Also reduction in sex hormones (Gonadotrophins and Androgens)
HOw can the blood-testis barrier be lost?
Physical damage, hopefully this shouldnt affect all seminiferous tubules
How can the immune system affect spermatogenesis?
Some men can suffer from auto-immune reactions to sperm
What environmental factors affect spermatogenesis?
Some occupations e.g. Car maker, welder, pesticide exposure etc.
Radiation
Smoking & Alcohol
