What are hormones?
Chemicals that target certain organs which create a specific response.
What are hormones produced by?
How do hormones travel to their target organs?
They travel through the blood.
Where are TRH and CRH produced and what is its target organ?
They are both produced in the hypothalamus in the brain.
-They target the pituitary gland.
Where are TSH, ADH, FSH, and LH produced and what are their target organs?
They are all produced in the pituitary gland.
- FSH and LH targets the ovaries
- ADH targets the kidney
- TSH targets the thyroid gland
Where is adrenalin produced and what organs does it target?
It is produced in the adrenal gland.
- It targets various organs like the heart, liver, and skin etc.
Where are oestrogen and progesterone produced and which organs do they target?
They are both produced in the ovaries.
- Oestrogen targets the ovaries, uterus, and pituitary gland
- Progesterone targets the uterus
Where is testosterone produced and what organs does it target?
It is produced in the testis and it targets the male reproductive system.
Where are insulin and glucagon produced and what are their target organs?
They are both produced in the pancreas.
They both target the liver, and muscle and adipose tissue.
Where is thyroxine produced and what organs does it target?
It is produced in the thyroid gland and targets the digestive system, the heart, the brain and bones (it is important for good health).
What is negative feedback?
When a change from the normal level (higher or lower) brings about more changes to restore it to the normal level.
What response is adrenalin responsible for?
The ‘fight or flight’ response.
How does adrenalin affect your body?
- It increases heart rate
- Dilates blood vessels that take blood to the muscles
- Constrict blood vessels that aren’t going to vital organs.
- Causes the liver to convert glycogen into glucose
How does thyroxine affect your body?
- It controls your metabolic rate, which is the rate at which cells respire.
Which hormones control the menstrual cycle?
What is menstruation?
It is the break down of the uterus lining after the egg that has been released is not fertilised. This lasts from day 1 for about 5 days.
What happens during the second week of the menstrual cycle?
The uterus lining gradually builds up.
What is ovulation?
On around day 14, an egg is released from an ovary.
Between which days in the menstrual cycle is fertilisation most likely to take place?
From around day 14 to 16.
What happens during most of week 3 and week 4 of the menstrual cycle?
The uterus lining continues to build up.
What happens if fertilisation occurs?
The uterus lining is maintained and menstruation does not occur.
What happens if fertilisation does not occur?
Menstruation occurs and the menstrual cycle repeats.
What is contraception?
A way to prevent fertilisation.
How does hormonal contraception work and what are some examples?
It works by releasing hormones to prevent ovulation and thicken the mucus at the cervix to prevent sperm from passing. It includes: - hormone pills - hormone implants - hormone injections
How do barrier methods of contraception work and what are some examples?
Barrier methods prevent sperm from reaching the egg with a physical barrier. These include: - condoms (male and female) - the diaphragm - caps - sponges
What are the levels of progesterone and oestrogen during menstruation?
Progesterone = low Oestrogen = high
What do high levels of oestrogen stimulate?
The release of LH.
What do low levels of progesterone stimulate?
The release of FSH
What does FSH do?
It stimulates the growth and maturation of follicles.
What does LH do?
What do maturing follicles stimulate?
A rise in oestrogen levels.
What happens to progesterone levels when the egg is released?
Progesterone levels experience a sudden increase.
What does oestrogen do?
Builds the uterus wall.
What does progesterone do?
Maintains the uterus wall.
What do increases in oestrogen and progesterone do?
Cause thickening in the uterus wall.
What does a decrease in oestrogen and progesterone stimulate?
It triggers menstruation.
What is clomifene?
A fertility drug that causes an increase in FSH and LH.
What is IVF (In-vitro fertilisation)?
Fertilisation outside a woman’s body.
- This is offered to people who struggle conceiving.
What is the definition of Homeostasis?
Maintaining conditions inside the body at a constant level.
What is osmoregulation?
It controls how much water is lost in urine and the amount of water in the body.
What is thermoregulation?
It keeps core body temperature steady at around 37°C.
- It is controlled by the hypothalamus which triggers changes in the skin and muscles.
What changes occur in the body when it is too hot?
- Blood vessels near the skin will dilate to flow more blood near the skin.
- Sweat glands release more sweat onto the skin surface to evaporate.
- Sebaceous glands produce oil that helps sweat to spread out over the skin.
- All of this increases transfer of energy (heat) into the surroundings.
What changes occur in the body when it is too cold?
- Blood vessels near the skin will constrict to reduce the flow of blood near the skin.
- Sweat glands stop producing sweat.
- Body hairs are raised by erector muscles in skin.
- All of this reduces the transfer of energy (heat) into the surroundings.
What is vasoconstriction?
Blood vessels constrict to restrict the amount of blood flow.
- Less in surface capillaries and more in deep skin
What is vasodilation?
Blood vessels dilate to increase the amount of blood flow.
- Less in deep skin vessels and more in surface capillaries.
What happens in the pancreas when the blood glucose levels are too high?
- Pancreas detects rise in blood glucose concentration.
- Pancreas increases the amount of insulin and decreases the amount of glucagon.
- Increased insulin causes muscles and liver cells to remove glucose from blood and store it as glycogen.
- Blood glucose concentration decreases.
What happens in the pancreas when the blood glucose levels are too low?
- Pancreas detects fall in blood glucose concentration.
- Pancreas decreases the amount of insulin and increases the amount of glucagon.
- Increased glucagon causes liver cells to convert stored glycogen into glucose and release it into the blood.
- Blood glucose concentration increases.