reproduction in humans

what is puberty

- when a child's body begins to develop
- and change as they become an adult

where is testosterone produced

from the testes

where is oestrogen made

in the ovaries

what is the female sex hormone

oestrogen

what is the male sex hormone

testosterone

what does testosterone in men and oestrogen in women trigger

the secondary sexual characteristics

what secondary sexual characteristics does oestrogen in women cause (4)

- extra hair on underarms and pubic area
- hips to widen
- development of breasts
- ovum release and start of periods

what secondary sexual characteristics does testosterone in men cause (5)

- extra hair on face and body
- muscles to develop
- penis and testicles to enlarge
- sperm production
- deepening of voice

what type of fertilisation do humans have - internal or external?

internal fertilisation

what is the male gamete and where is it produced

sperm produced in the testes

what is semen a mix of

sperm and liquid

what happens to semen during sexual intercourse

- it's ejaculated from the penis
- into the vagina of the female

male sex organ diagram (book)

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male sex organ diagram (rev guide)

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role of urethra

- takes sperm thru penis during ejaculation
- takes urine out the penis

role of erectile tissue

- swells when filled with blood
- to make penis erect

role of testis

where sperm + testosterone are made

role of glands

produce the liquid that is added to sperm to make semen

what are the 2 main glands that add liquid to sperm to make semen

- seminal vesicles
- prostate gland

role of sperm duct (vas deferens)

- muscular tube that carries sperm
- from testis towards the urethra

role of scrotal sac (scrotum)

- hangs behind the penis
- and contains the testes

role of epididymis

stores sperm

what fluid does the seminal vesicles produce

alkaline and fructose fluid

what fluid does the prostate gland produce

alkaline fluid

role of ureter

tube taking urine from the bladder

why is fructose fluid (seminal vesicles) added to the sperm

to provide energy for sperm

why is alkaline fluid added to sperm (both seminal vesicles + prostate gland)

to neutralise the vagina's natural acidic environment

what are the different parts of the male sex organ

- urethra
- erectile tissue
- testis
- vas deferens (sperm duct)
- head of penis
- foreskin
- scrotal sac
- prostate gland
- epididymis
- penis
- seminal vesicle
- ureter
- bladder ( not always on diagram)

female sex organ diagram (rev guide)

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female sex organ diagram (book)

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role of ovary

stores + produces ova (eggs) and sex hormones

endometrium (lining of uterus) - what does it have a good supply of and why?

- has a good blood supply
- for implantation of an embryo

What is the cervix of the uterus?

neck of the uterus

role of vagina

- muscular tube
- leads towards cervix
- where the sperm are deposited

role of uterus (womb)

- the organ where
- fertilised egg implants
- the embryo grows

fallopian tube (oviduct)

- muscular tube
- carries ovum
- from the ovary to the uterus

what are the female gametes

ova (eggs)

where is an egg produced from every 28 days

from either one of the 2 ovaries

fertilisation steps - successfully meets sperm

- ovum produced
- passes into fallopian tube - where meets sperm
- ovum starts to divide
- new cells travel down Fallopian tube to uterus
- and attach to the endometrium
- fertilised ovum develops into an embryo

what happens to an ovum if it isnt fertilised by sperm

- ovum will break up
- and pass out of the vagina

what 4 main hormones control the menstrual cycle

- oestrogen
- progesterone
- FSH (follicle stimulating hormone)
- LH (luteinising hormone)

what is a period

the loss of old womb lining

menstrual cycle - day 1

- menstruation starts
- uterus lining breaks down and is released

menstrual cycle - day 4-14

- uterus lining builds up again
- into a thick spongy layer full of blood vessels
- in preparation for a fertilised egg

menstrual cycle - day 14

egg develops and is released from ovary at day 14

ovulation

the egg being released from the ovary

menstrual cycle - day 14-28

- wall maintained
- if no fertilised egg has landed on uterus wall
- cycle restarts

FSH - where is it produced, what does it do, what does it stimulate

- made in pituitary gland
- causes egg to mature in one of the ovaries, in a structure called a follicle
- stimulates ovaries to produce oestrogen (oestrogen then inhibits (stops) release of LH)

oestrogen - where is it produced, what does it do, what does it stimulate, what does it inhibit

- produced in the ovaries
- causes lining of uterus to grow +thicken
- stimulates release of LH
- inhibits release of FSH being made

what are the ovaries

they are a gland

LH (luteinising hormone) - where is it produced, what does it do

- produced by pituitary gland
- stimulates release of egg at day 14 (ovulation)

progesterone - where is it produced, what does it do, what does it inhibit

- made by the remains of follicle after ovulation
- produced in the ovaries
- maintains the lining of the uterus during 2nd half of cycle
- inhibits release of LH and FSH

what happens when the level of progesterone falls

the lining breaks down

what is the purpose of the menstrual cycle

to prepare a womb for a fertilised egg

when is a baby an embryo

fertilization - 8 weeks

when is a baby a fetus

8 weeks - birth

what happens once an ovum has been fertilised and where does it implant

- it develops into an embryo
- it implants in the uterus

what develops once the embryo has implanted

placenta

what is the role of the placenta in nutrition of the embryo

- allows the blood of the embryo and the mother to get very close
- to allow the exchange of food, oxygen and waste

what happens to the zygote (diploid cell) after fertilisation and what does it develop into

- zygote divides by mitosis
- it develops first into an embryo then a fetus

what is the placenta, where does it grow and how is it joined to the fetus

- an organ
- that grows into the wall of the uterus
- and is joined to the fetus by the umbilical cord

does the maternal and fetal blood mix in the placenta

no

what process allows the exchange of materials between the fetus and the mother across the placenta

diffusion

what are 2 examples of things that diffuse across the placenta from the mother to the fetus

- oxygen
- nutrients

what are 3 examples of things that diffuse across the placenta from the fetus to the mother

- carbon dioxide
- urea
- other waste substances

placenta diagram

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what is the embryo protected by

- an amnion membrane
- full of amniotic fluid

where does the amnion membrane form

it surround the fetus

how does amniotic fluid protect the embryo

it protects the embryo against knocks and bumps

what happens to the hormone levels during the whole menstrual cycle

they go up and down

what 2 things does the umbilical cord contain

- umbilical artery
- umbilical vein

how is carbon dioxide and urea transported from the foetus to the mother's blood

- the umbilical artery carries urea and carbon dioxide
- from the foetus to the mother's blood

how is oxygen and nutrients transported from the mother's blood to the foetus

- the umbilical vein carries oxygen and nutrients
- from the mother's blood to the foetus

what separates the mother and the foetus' blood and allows diffusion to occur

thin membranes