Reproduction - Male Flashcards
What is it called when the testes are undescended?
Cryptorchisism
What are the mechanisms for temperature regulation of the testes?
- sweat glands
- cremaster muscle can adjust the position of the testes
- pampiniform plexus - network of blood vessels within the spermatic cord, responsible for blood supply of the testes. Heat exchange occurs between testicular artery and pampiniform plexus, some heat from the artery is transferred and taken away by the veins
Where does sperm finish maturing?
Epididymis
What is the function of the epididymis?
Sperm maturation (gain mobility, metabolic changes, cell membrane changes), storage and transport
What are the characteristics of the epididymis?
- single, highly coiled tube
- 2-6 day passage
What is the ejaculatory duct?
Transition between vas deferens and urethra
Bulbourethral gland
- paired glands
- less than 5% seminal fluid
- alkaline (neutralises environment in urethra)
- pre-ejaculatory fluid
Seminal vesicles
- paired glands
- 65% of seminal fluid
- alkaline (neutralises environment in vagina)
- contains prostaglandin clotting proteins - prevent sperm from falling out of female, protections against acidic environment and fructose (fuel source for flagellum)
Prostate
- single Gland
- 30% of seminal fluid
- liquefying protein - counteract prostaglandins
What are the three bodies of erectile tissue?
Two larger: Corpus cavemosum
One smaller: Corpus spongiosum
What happens in an erection?
More blood entering than leaving
What does the Corpus spongiosum do?
Maintains urethra so that is doesn’t close enabling sperm and ejaculate to exit
What is capacitation?
- sperm attain their fertilising capacity
- occurs in the uterus or uterine tube due to estrogen
What is capacitation characterised by?
- change in motility (hyperactive tail, more vigorous movement)
- change in cell surface membrane (activation of enzymes which are designed to burrow into and digest the binding matrix of cumulus cells)
What is the acrosome reaction?
- sperm encounters the egg
- exocytosis of the acrosome, releasing the enzymes needed to penetrate the egg
What happens after the acrosome reaction?
Chain of events that prohibits polysoermy
Why is the first sperm to reach the egg not the one to fertilise it?
- sperm must first penetrate the cumulus cells and zona pellucida that surround it
- it may require hundreds of sperm to clear a path for the on sperm that penetrates the egg
What occurs in spermiogenesis?
- Golgi forms acrosomal vesicle and then acrosome which covers the head of the sperm
- nucleus condenses
- distal centriole migrates out to membrane and forms the flagellum, mitochondria migrate to proximal part of flagellum
- cytoplasm ejected as a residual body
