The Menstrual Cycle, Pregnancy and Birth Flashcards
What are the 4 important hormones that control the menstrual cycle in females?
- Follicle-Stimulating Hormone (FSH)
- Luteinising Hormone (LH)
- Oestrogen
- Progesterone
What does FSH cause?
Follicle-Stimulating Hormone (FSH) - causes a follicle to mature
What does LH do?
Luteinising Hormone (LH) - makes the egg burst out of the follicle, this is ovulation
What does oestrogen help do?
Oestrogen - lining of the uterus grows thicker
What does progesterone help do?
Progesterone - maintains the lining of the uterus, when it’s levels drop, the lining sheds
What happens in stage 1 of the menstrual cycle?
Day 1 - 4: period (menstruation), bleeding, breakdown of uterus lining
What happens in stage 2 of the menstrual cycle?
Day 4 - 14: pre-ovulation, lining starts to thicken from the ovaries
What happens in stage 3 of the menstrual cycle?
Day 14: egg released (ovulation)
What happens in stage 4 of the menstrual cycle?
Day 14 - 28: Maintaining of the lining of the uterus (post ovulation)
How long is a menstrual cycle typically?
28 days long
Where is oestrogen produced?
In the ovaries
Where is progesterone produced?
In the ovaries
Where is LH produced?
In the pituitary gland - centre of the brain
Where is FSH produced?
In the pituitary gland - centre of the brain
On which day does the period start in the menstrual cycle?
Day 1 - 5
What happens if an egg isn’t fertilised?
The lining of the uterus sheds
Why doesn’t a woman have a period while she’s pregnant?
A woman doesn’t have a period while she’s pregnant as the uterus lining is maintained
Which days is a woman most fertile?
Days 6 - 17
What day is a zygote classified a zygote?
Day 1
When is a blastocyst classified as a blastocyst?
7 days
When is an embryo classified as an embryo?
2 weeks
When is a fetus classified as a fetus?
9 weeks till birth
When is a baby classified as a baby?
At birth
How long does a baby take to develop?
38 weeks to develop - from fertilisation to birth
What is the baby classified as at 8 weeks?
The first 8 weeks, the baby is called an embryo - because all the specialised cells are developing (differentiation)
Why is the first 8 weeks of pregnancy critical?
It is a critical period of development and growth for the baby. The baby can be affected by smoking, drugs or alcohol
What does the developing embryo float in?
It floats in a fluid enclosed within a membrane called the amnion
How does a blastocyst form?
The zygote begins to divide and travels down the fallopian tube towards the uterus. As it travels it keeps dividing until a hollow ball of cells called a blastocyst forms
How does implantation happen?
Around 5 -7 days after the fertilisation, the blastocyst reaches the uterus and burrows into the uterus lining - this is known as implantation
Does the mother’s blood mix with the embryo’s blood?
No
How are food and oxygen given to the embryo?
Food and oxygen from the mother’s blood pass through the placenta to the embryo
What are the 3 stages of birth?
Labour – Dilation of the Cervix to
10cm – around 10 hours (there’s a
big range)
Delivery – Birth of the Baby via the
vagina (expulsion) (unless C-section,
then through the abdomen)
Placental Delivery – the afterbirth
What are the dates of the 3 trimesters in pregnancy?
1st Trimester – up to 12 weeks
2nd Trimester – 13-27 weeks
3rd Trimester – 28-40 weeks
What is the gestational period?
The period during which the baby
develops in the uterus is known as
the gestation period
Note “Weeks pregnant” refers to
the time since the first day of a
woman’s last period
What is the umbilical cord?
The umbilical cord joins the embryo in
its abdomen
What is your belly button?
Your “belly button: is where your
umbilical cord joined you to your
mother in the uterus
What is copulation?
It is a term for 2 individuals joining together for sexual reproduction (or commonly known as ‘sex’ in humans)
What happens in sexual intercourse?
The penis becomes stiff and erect and it is inserted into the vagina
What does stimulation cause?
Stimulation causes sperm to be squeezed out of the penis in a process called ejaculation
What does ejaculation deposit?
Ejaculation deposits several hundred MILLION sperm near the cervix
How can sperm swim?
Sperm can swim, propelled by their tail using the sugar in their semen as their energy source
