human reproduction Flashcards
prostate gland
produces fluid called semen
- provides sperm cells
sperm duct
- where sperm passes to be mixed with fluids produced by gland
- before urethra for ejaculation
urethra
- tube running down centre of penis
- carry out urine or semen
what prevents urethra and semen from mixing
ring of muscles inside urethra
testis
contained in a bag of skin and produces sperm and testosterone
scrotum
sac supporting tests
- outside body to keep sperm and slightly lower temp
penis
passes urine out of body from bladder
- allows semen to pass into vagina
oviduct
- connects ovary to uterus
- lined with ciliated cells to push the released ovum down it
where does fertillization occur
oviduct
ovary
- contains ova which will mature and develop when hormoes are released
cervix
ring of muscle and lower end of uterus to keep developing foetus in place
vagina
muscular tube that leaders inside a womens body
- where penis enters and sperm is deposited
adaptation of sperm cell
- has flagellum
- contains enzymes in head region known as acrosome
adaptation of egg cell
- cytoplasm containing a store of energy
- jelly like coating that changes after ferillation
when is fertillisation most likely to occur
1-2 days after ovulation
fertillization process in humans
- head of sperm releases enzymes that digest path through protective outer layer of egg
- allows sperm to pass
- egg cell releases thick layer of material that prevents any more sperm cells from entering
how does zygote dived by
mitosis
describe mitosis during fertillization
- forms 2 new cells
- continue to divide until embryo is formed
- cells further dived to become specialised
what is ovulation
when an egg is released which occurs halfway through cycle.
what does failiure to fertillize egg cause
menstruation
what is menstruation
breakingn down of thickened lining of uterus
what is the menstrual crycle controlled by
hormones
describe oestrogen levels
rises from day 1 to day 14
what does oestrogen cause
uterine walls to thicken and egg to mature
desctibe progesterone levels
stays low- day 1-14
rises once ovulation occurs
what does rise in progesterone cause
uterine lining to thicken
what does fall in progesterone cause
lining to breakdown
what is FSH
Follicle stimulating hormone
what releases FSH and LH
pitutary gland
what does FSH do
- egg to start maturing
- stimulated ovaries to release oestrogen
when is LH released
when oestrogen has reached its peak
What does LH do
causes ovulation to occur and stimulates ovary to produce progesterone
what happens in placenta
mothers blood comes into very close proximity to blood of foetus but it never mixes
what is the placenta connected by
unbilical cord
what does mothers blood absorb from foeuts
- waster products like CO2 and urea
why is CO2 and urea absorbed by mum
so they dont build up to dangerous levels
placenta adaptations
- large SA
- thin wall
for efficient diffusion
how does placenta prevent toxins
acts as a barrier
what is afterbirth
- placenta pushed out after birth due to contractions in muscular walls of uterus
how long does zygote take to travel towards uterus
3 days
- zygote dives to form embryo
what happens when zygote reaches the uterus
- embryo embed itself onto thick lining of uterus
what is a placenta
organ to ensure materials can be exchanged between the blood of the mother and blood of embryo
what is embryo surrounded by
amniotic fluid which is held in amniotic membrane
why is amniotic fluid important
- protects embryo during development by cushioning it from bumps to mothers abdomen
gestation period
embryo growing in uterus
what are secondary sexual characteristics controlled by
oestrogen and testosterone
Female Secondary Sexual Characteristics
- breasts develop
- body hair grows
- menstrual cycle begins
- hips get wider
Male Secondary Sexual Characteristics
- growth of penis and testes
- growth of facial and body hair
- muscles develop
- voice breaks
- testes produce sperm
