What are hormones
Chemical molecules released directly into the blood, carried to different parts of the body (target organs)
What are hormones produced by
Endocrine glands
Pituitary gland / ‘master gland’
Produces many hormones that regulate body conditions
The hormones act on other glands, directing them to release hormones to bring about a change in
Thyroid
Produce thyroxine
Regulates rate of metabolism, heart rate, temperature
Adrenal gland
Produces adrenaline
Prepare body for ‘fight or flight’ response
Pancreas
Produces insulin
Regulates blood glucose level
Ovaries
Produces oestrogen
Involved in menstrual cycle
Testes
Produce testosterone
Controls puberty and sperm production
Nerves activity
Fast action
Act for short time
Act on very precise area
4 stages of menstrual cycle
- Starts - Lining of uterus breaks down for around 4 days
- Uterus lining builds up again from day 4-14 into thick spongy layer full of blood vessels, ready to receive a fertilised egg
- Ovulation - Egg develops and is released at day 14
- Wall is maintained for around 14 days until day 28
If no fertilised egg lands on uterus wall by day 28, spongy layer starts to break down and cycle starts again
Hormone activity
Slow action
Act for long time
Act in more general way
Glucose too high =
Insulin added
Glucose too low =
Glucagon added
Type 2 diabetes
what happens?
Person becomes resistant to own insulin (body’s cells don’t respond)
= blood sugar level to rise dangerously high
Type 2 diabetes control methods
- carbohydrate controlled diet
- regular exercise
4 hormones controlling menstrual cycle
- FSH (Follicle-Stimulating Hormone)
- Oestrogen
- LH (Luteinising Hormone)
- Progesterone
FSH - follicle stimulating hormone
Produced in pituitary gland
Causes egg to mature in one of ovaries in structure called follicle
Stimulates ovaries to produce oestrogen
Oestrogen
Produced in ovaries
Causes lining of uterus to grow
Stimulates release of LH* and prevent release of FSH
LH - luteinising hormone
Produced by pituitary gland
Stimulates release of egg at day 14
Progesterone
Produced in ovaries by remains of follicle after ovulation
Maintains uterus lining - when progesterone level falls, lining breaks down
Prevents release of LH and FSH
Oestrogen reducing fertility
If regularly taken, inhibits production of FSH
After a while, egg development + production stop and stay stopped
Progesterone reducing fertility
Stimulates production of thick mucus which prevents sperm reaching egg
The pill reducing fertility
Contains oestrogen and progesterone
Side effects of the pill
Does not protect against STDs
Headaches
Nausea
