Chapter 9 Human Reproduction, Growth and Development Flashcards
the structure and function of.. ovary oviduct uterus cervix vagina
ovary - produces eggs and hormones
oviduct - cilia in the lining of the tube waft the egg from the ovary to the uterus
uterus - muscular wall protect the foetus, lining enables the exchange of materials
cervix - the neck of the uterus which dilates during labour
vagina - receives sperm and baby leaves the body here
the structure and function of... penis urethra testis scrotal sac sperm duct prostate gland
penis - transfers semen (sperm plus seminal fluid) from male to female
urethra - tube in penis which carries the semen
testis - produces sperm and hormones
scrotal sac - holds testes outside the body to keep sperm 2 degrees below body temperature
sperm duct - carries sperm from testes to urethra
prostate gland - produces seminal fluid
what is the structure and function of egg and sperm
egg - bigger, contains a nucleus, big as it has stored food
sperm - nucleus, small, tail to swim to the egg
what is the number of chromosomes in the human body cells
46 chromosomes
what does meiosis do
it halves the number of chromosomes during the formation of gametes
describe the mechanism of transferring sperin in intercourse
the penis becomes erect due to blood entering the large blood spaces in the tissue this allows the male to place the penis into the vagina, semen travels through the urethra and is deposited close to the cervix
where is the site of fertilisation
the upper part of the oviduct
how does the zygote form a embryo
the zygote divides by mitosis to from ball of cells that is moved to the uterus where implantation occurs in the lining
the ball then divides to form the foetus, the amnion and the placenta
what does the amniotic fluid do
it acts as a shock absorber to protect the foetus
what is the placenta
the placenta is an exchange surface to allow materials to diffuse to and from the foetus
what are the three stages of labour
the muscular walls of the uterus contract in order to dilate the cervix
the uterus walls squeeze to force the baby through the birth canal
following the birth the uterus contracts to push out the placenta
why does the mother require a healthy diet, moderate exercise and sufficient rest
so the baby grows healthily and has lots of energy for growth
what are the dangers of consuming alcohol or other drugs while being pregnant
alcohol - can cause learning difficulties by damaging the developing brain, this is because it can cross the placenta to harm the development of the brain
what are the dangers of carbon monoxide to a baby
this reduces the amount of oxygen available for aerobic respiration therefore there is less energy for growth resulting in low birth weight
nicotine causes the blood vessels to go into spasm so the placenta receives less oxygen and nutrients
what do gynaecologists and midwives do
they are involved in the care of the woman during pregnancy and birth
why are viruses such as rubella and HIV are able to cross the placenta and infect the foetus
they are very small molecules that get across the placenta and can cause damage to the foetus
how are identical twins and fraternal twins produced
if two eggs are released from the ovary and both are fertilised by separate sperm then twins are developed these are fraternal twins
the embryo splits into two groups of cells and these develop into separate foetus resulting in identical twins
what are the benefits of breast feeding
this helps the delivery of the placenta and starts the suckling reflex in the baby - the milk contains a lot of antibodies which help protect the baby from infections, but after a few days the milk will provide protein, fat and sugar in correct proportions
the need for parental care
human babies are completely dependent on parents to care for them
what is the growth rate
the growth rate of the whole body changes during development this is called growth spurts and are in young children and adolescents
when do many changes occur in people and what are they controlled by
adolescents and they are controlled by the sex hormones oestrogen and testosterone
when does the menstrual cycle start and how long is it
in early adolescence and 28 days
when is ovulation
mid way through 28 days
what is the menstrual cycle controlled by
hormones
what are hormones used for
as methods of contraception
how does the menstruation cycle happen
FSH - causes the egg to mature, released by the piturity gland
oestrogen and progesterone - produced by the ovaries, cause the lining of the womb to thicken for implantation, inhibit FSH
LH - produced by the pituitary gland, causes the remains of the follicle to develop unto corpus luteum and produce progesterone, stimulates ovulation
if implantation does not occur the ovaries stop producing oestrogen and progesterone and the lining of the uterus breaks down leaving the body as menstrual flow
if the woman in pregnant the fertilized egg implants and the ovaries continue to produce oestrogen and progesterone to maintain the lining of the uterus
after 12 weeks the placenta produces hormones that maintain the lining of the uterus
if a fertilised egg is not implanted the corpus luteum breaks down
what does the placenta do during pregnancy
the placenta secretes hormones some of which inhibit FSH preventing more eggs from maturing
