Human Reproduction Flashcards
What happens days 1-5 of the menstrual cycle?
First day the lining of the uterus is shed and then FHS is released from the pituitary gland stimulating the growth of a new egg cell surrounded by a cluster of cells called a follicle
What happens days 5-14
The follicle cells produce oestrogen which causes the lining of the uterus to build up again. Around day 14 ovulation happens (where a mature egg is released) and LH is released.
Where is FSH released from and what is its role?
FSH is released from the pituitary gland and causes an egg to mature in an ovary and stimulates the ovaries to release oestrogen
Where is oestrogen released from and what is its role?
Released from the ovaries and it stops FSH being produced (so that only one egg matures in a cycle). Repairs and thickens the uterus lining. Stimulates the pituitary gland to release LH.
Where is LH released from and what is its role?
It is released from the pituitary gland and triggers ovulation (the release of a mature egg)
Where is progesterone released from and what is its role?
It is released from the ovaries and it maintains the lining of the uterus during the middle part of the menstrual cycle and during pregnancy.
What happens if fertilisation does not occur in the oviduct/fallopian tube?
The egg travels down the oviduct and is shed with the uterus. (The egg travels down the oviduct for 14 days and the oestrogen and progesterone levels fall in the last 2 days)
What is implantation?
When the embryo embeds itself into the uterus lining
What does the zygote undergo to become the embryo?
Mitosis
How long is the average menstrual cycle
28 days
How does the amniotic fluid protect a developing embryo and foetus?
It acts as a ‘shock absorber’ to protect it from bumps to the mothers body and provides a stable environment by regulating temperature
Where do substances diffuse across from the mothers blood and the baby’s blood?
Th intervillous space
How does the intervillous space protect the baby?
It can help stop harmful pathogens and some viruses from getting into the babies blood stream
What is transferred through the umbilical cord?
To the baby: small soluble nutrients (glucose, other sugars, amino acids, fatty acids and glycerol) and oxygen (as it can not do gas exchange by itself) antibodies are also transferred across (as they are very small) to provide immunity
To the mother: carbon dioxide and urea
How is the placenta adapted for exchange?
The lining is folded and has villi to increase surface area. It also has a big blood supply.
