Human Reproduction

Spermatogenesis + where

Sperm production + seminiferous tubules in testes

Label A-H

Vas deferens

Bladder

Penis

Urethra

Foreskin

Epididymis

Prostate gland

Seminal vesicle

Label A-F

Fallopian tube

Ovary

Endometrium

Uterus

Cervix

Vagina

Urethra

Where sperm and urine leave penis

Why are testes kept outside the body

Require slightly cooler temperature than the body

Epididymis

Store sperm

What do tested produce

Adrenaline

Vas deferens

Transports mature sperm to penis

Seminal vesicles

Produce ejaculate fluid

prostate gland

Produces additional fluid to ejaculate to increase sperm mobility when in vagina

Uterus

Site of implantation and development of foetus

Ovaries

Produce female eggs as well as oestrogen and progesterone

Fallopian tubes

Attaches ovaries to uterus - where fertilisation occurs

What happens during fertilisation (simple)

Secondary oocyte fuses with sperm cell to form a zygote

Label A-F

Spermatogonium (mitosis)

Primary spermatocyte (meiosis 1)

Secondary spermatocyte (meiosis 2)

Spermatid

Spermatozoa

Meiosis 1

Meiosis 2

3 parts of sperm cell + functions

Head - contains nucleus + acrosome (hydrolytic enzymes)

Midpiece - contains mitochondria

Tail - flagellum

Describe oogenesis

(foetal)

Oogonium - primary oocyte

Begins meiosis - halts at prophase 1

(post puberty)

Primary oocyte - secondary oocyte

Each month follicle develops and completes meiosis 1

(ovulation)

Secondary oocyte is released

Starts meiosis 2 and is released from ovary into fallopian tube

(If fertilisation occurs)

Quickly completed meiosis 2 to form ovum

Describe fertilisation

Sperm travels to fallopian tube

Sperm burrows through corona radiata and binds to zone pellucida

Acrosome reaction creates a path for sperm to bind to secondary oocyte

Cortical reaction - Releases enzymes which harden the zona pellucida preventing polyspermy

Zygote then formed

What happens after the zygote is formed in fertilisation (implantation)

Mitosis occurs to increase cell devisions

Cells divide unevenly and eventually form the blastocyst

This then embeds in the endometrium

What happens after implantation of the blastocyst

(outer layer)

Outer layer is called trophoblast

Trophoblast develops into chorion

Placneta function (3)

Secrete hormones

Exchange of gas / waste

Allows maternal antibodies to protect foetus

Adaptation of placenta

Counter current

Bloods do not mix to prevent mother developing an immune response and killing it

Pressure in capillaries is much higher - this forces substances into the intervillous space

Describe 1-7

FSH + LH produced by anterior pituitary and induces the cycle

FSH stimulates follicle development

Building follicle produced oestrogen + Ve- effect on FSH + LH

LH induces ovulation - Graafian follicule releases secondary oocyte

GF retained as corpus luteum + produce progesterone

Progesterone stimulates growth of endometrium

If no fertilisation progesterone drops and endometrium sheds

Oestrogen dropping causes FSH + LH increase so cycle restarts

Label A-D

Acrosome

Nucelus

Mitochondria

Flagellum

Amnion + later function (4)

Membrane derived from inner blastocyst

Amniotic fluid then accumulates

Maintaining temperature

Provide lubrication (between foetus and tissue)

Allowing movement

Shock absorber

What produces hormones during pregnancy + function of hormones

Placenta

Progesterone inhibits uterine walls ability to contract

Oestrogen stimulates growth of uterus

What happens to the hormones just before birth

Progesterone decreases allowing uterine wall to contract

Decrease in progesterone allows secretion of oxytocin and prolactin

Oxytocin contracts myometrium

Prolactin stimulates mammary glands to synthesise milk

Most common cause of female infertility + treatment

Blocked fallopian tubes

IVF