Human Reproduction Flashcards
Asexual reproduction produces
Genetically identical offspring to parents
He number of chromosomes in the cell stay the same
Reproduction guaranteed
Asexual reproduction (Martin smart)
One parent organism
No special sex cells
Involves mitosis
Problems of asexual reproduction
Lack of genetic material means weakness to changing environments
Sexual reproduction involves
The joining of two gametes produced by meiosis
Chromosome number halved when gametes produced
Two gametes from different parents
Gametes
Specialised sex cells
Produced by meiosis
Sexual reproduction produces
Genetic variety
Ovules - ova
Pollen -sperm
Fertilisation
Sex cells fuse to form a zygote
Zygote undergoes cell division and develops into an embryo
Pituitary hormones
Follicle stimulating hormone (FSH) Lutcinising hormone (LH)
Follicle stimulating hormone (FSH)
Stimulates ova in the follicles of the ovary to develop
Stimulates the ovary to make oestrogen
Lutcinising hormone (LH)
Stimulates the release of a mature egg from the ovary
Stimulates the ovary to make progesterone
Hormones from the ovaries
Oestrogen
Progesterone
Oestrogen
Stimulates the lining of the uterus to build up
Reduces the levels of FSH produced by the pituitary
Pin creases the levels of LH
Progesterone
Stimulates the growth of blood vessels in the uterus for pregnancy
Helps to keep pregnancy going
FSH peak
Slight peak at 14/28
LH peak
Massive peak at 14/28
Oestrogen peak
Gradual built up massive peak 7-10
Progesterone peak
Slight mound from 16-26
Growth of follicle
0-14
Ovulation
14
Corpus luteum grows and breaks down
28/28
Menstruation
5/28
Growth of lining
17
Menstruated cycle starts
Following puberty
Menstrual cycle occurs
Once a month
Because of hormones
Me struck cycle stops
When pregnant (starts again after birth of baby) After menopause
Fertilisation
Sperm fertilises an ovum
A zygote is formed in the Fallopian tube
Uterus
The developing uterus moves into here to develop
Implants itself into the uterus lining
Placenta
Develops as the embryo does Gives food+oxygen to the foetus Takes urea+carbon dioxide Secretes progesterone Connected to foetus by umbilical chord
Uterus contains
Amniotic fluid
Membranes
Sustains and protects the baby
Pregnancy duration
40 weeks
Week 12 of pregnancy
Some organs start to function
Bones start to harden
Week 20 of pregnancy
Muscles are more developed
Foetus is more active
Week 24 of pregnancy
Air sacs form in the lungs
Eyes are developed
Week 36 of pregnancy
Nervous system developing rapidly
Lungs are nearly mature
