Sexual Reproduction in Humans Flashcards
Function of the testes
Produce gametes and testosterone
Function of the epididymis
Sperm are stored there to mature and become fully mobile
Function of the vas deferens
Carries sperm to the penis
Function of the seminal vesicle
Secretes fluid to nourish the sperm and counter the acidity of the vagina
Function of the prostate gland
Secretes fluid containing zinc and is alkaline to counter the acidity of urine and the vagina
Function of the urethra
Carries semen and urine out of the body
Function of the ovary
Produces gametes and oestrogen and progesterone
Function of the fallopian tubes
Waft the secondary oocyte towards the uterus
Function of the uterus
Site of foetal development
Function of the endometrium
site of implantation of the blastocyst and placenta formation during pregnancy.
Function of the cervix
A narrow ring of connective tissue which separates the uterus from the outside world
Function of the vagina
Sperm travel from the vagina to the uterus
Where does spermatogenesis take place
In the seminiferous tubules
List the order of the gradually more developed male gametes
Germinal epithelium Spermatogonium Primary spermatocyte Secondary spermatocyte spermatid spermatozoa
Which cells provide nourishment to the spermatids
Sertoli cells
Describe the structure of a sperm cell
Acrosome head - contains enzyme for acrosome reaction
Microtubules - responsible for movement of tail, require large numbers of mitochondria
Tail - allows the cell to propel itself forward
List the order of gradually more developed female gametes
Germinal epithelium Oogonium Primary oocyte Secondary oocyte Ovum
Describe the structure of a secondary oocyte
Central cell containing chromosomes suspended at anaphase II until fertilisation, surrounded by jelly-like zona pellucida and corona radiata
What three reactions occur in fertilisation
Capacitation
Acrosome
Cortical
Describe the capacitation reaction
increases the permeability of the cell membrane in the head of the sperm above the acrosome
Describe the acrosome reaction
releases hydrolase enzymes which digest the zona pellucida.
Describe the cortical reaction
Prevents polyspermy by fusing cortical granules with the cell membrane and modifying the zona pellucida
What happens when the sperm and secondary oocyte fuse
genetic material of sperm cell enters the secondary
oocyte triggering completion of meiosis II and formation of ovum and second polar body.
Describe implantation
Cleavage occurs and the cells multiply to form a blastocyst. The blastocyst moves to the uterus and implants in the endometrium. The cells around the blastocyst called trophoblast cells form trophoblastic villi which attach to the endometrium and form the placenta.
