Male Reproductive Flashcards
What’s the function of the male reproductive tract?
Forming sperm (gametes) And depositing these to the female
What makes a male male? Pt1 (what are male and female gonads derived from?)
Male and female gonads (organ that produces gametes) are derived from the same embryological tissue
When do males become males?
Until week 6 it’s undifferentiated, on week 7 a gene on the Y chromosome (SRY) gene is expressed and testes develop. If this gene isn’t expressed, testes don’t develop and in week 11 ovaries develop
What are the male and female ducts called?
Male- wolffian ducts
Female- Müllerian ducts
What’s the functional unit of the male reproductive tract?
The testes
Explain the anatomy of the testes?
Seminiferous tubules (800 per testicle) very coiled/highly convoluted tubule
There’s 2 cell types- sertoli cells (epethelial cells)
Adjacent to Sertoli cells are sperm cells
Between the tubules are leydig cells (make testosterone)
What does simple ducting ensure ?
Delivery of sperm to a penis
What’s the function of the vas deferens?
Drains the epididymis of any sperm
During ejaculation, sperm moves from epididymis through the muscular VS
Vas deferens end/terminate in the ejactulatory duct near the PG
What is semen? (Where is it secreted from?)
Fluid which is ejaculated from the sperm + secretions
Secretions from:?
-seminal vesicles: mucus,fructose and prostaglandins contribute 60% semen volume
-prostate gland (alkaline buffer, clotting factors, PSA
-bulbourethral glands
What does the ejactulatory duct do?
Open into the urethra
What’s the role of the testes?
- produce sperm
- produce androgens (especially testosterone)
What is spermatogenesis?
- production of mature sperm (CONTINUOUS PROCESS)
- each ejaculate (2-10ml) contains 100million sperm per ml
Where does spermatogenesis occur?
In the seminiferous tubules
Some stem cells give rise to sperm, what are these called ? And where are these stem cells located ?
Spermatogonia
These stem cells are located at the periphery of the tube
Developing sperm cells move towards the lumen as they mature
What line the cells of the seminiferous tubules?
Sertoli cells:
These are a source of nutrition to the sperm
-phagocytosis of dead sperm
-formation of blood testes barrier
-production of seminiferous tubules fluid
What’s testosterone produced by?
Leydig cells under the influence of LH (from the anterior pituitary gland)
Testosterone is an example of what?
An androgen
What has a direct paracrine effect on spermatogenesis?
Testosterone (the remainder is secreted into the vascular system)
Gonadotrophin releasing hormone is produced by ?
Parvocellular neurons in the pre-optic area and elsewhere
What does GnRH do?
It binds to its receptors
Sperm cells are produced from stem cells called s?
Spermatogonia
Majority of other endocrine actions are via its metabolite?
5-a DHT (5a dihydrotestosterone)
Due to the action of 5a reductase
T= primary sexual characteristics
DHT= secondary sexual characteristic (hair growth)
How do T and 5a-DHT act via?
They act via androgen receptors. They act as nuclear transcription factors (influence transcription of a gene)
What controls male reproduction?
Gonadotrophin releasing hormone (GnRH)
GnRH binds to its receptors in the gonadotropes of the anterior pituitary gland and stimulates secretion of LH and FSH
Leydig cells respond to LH via a cAMP pathway which results in testosterone production
Sertoli cells respond to FSH:
-have growth cells to increase stem cell activity
-Androgen binding protein: transport molecule
Inhibin b- produces a negative feedback effect
