Section 7- Animal Coordination, Control And Homoestasis Flashcards
What are hormones
Hormones are chemical messengers released directly into the blood and carried by the blood to other parts of the body, but only affects the target organs
What is the function of hormones
They control things in organs and cells that need constant adjustment
Where are hormones produced in
Hormones are produced and secreted by endocrine glands which makes up your endocrine system.
What makes the endocrine system
- pituitary gland
- ovaries
- testes
- thyroid gland
- adrenal gland
- the pancreas
What is the pituitary gland
Produces many hormones and regulates body conditions. These hormones act on other glands directing them to release other hormones for change
What do ovaries do
They are a female organ which produces oestrogen that is involved in the menstrual cycle
What do testes do
They are a male organ which produces testosterone which controls puberty and perm production
What do thyroid glands do
Produces thyroxine which regulates rate of metabolism, heart rate and temperature
Adrenal gland
Produces adrenaline which is used to prepare the fight or flight response
The pancreas
Produces insulin which is used to regulate blood glucose levels
Difference between hormones and neurones
NEURONES:
- very fast
- act for a short time
- act on a precise area
HORMONES:
- slower action
- act for a long time
- act in a more general way
How does your body prepare you for your fight or flight response
Adrenaline
The brain detects a stressful situation which sends a nervous impulse to the adrenal gland which secretes adrenaline.
1. Adrenaline binds into specific receptors in the heart which makes the heart muscle contract with more force so the heart rate and blood pressure increases
2. This increases blood flow to the muscles meaning cells will receive a lot of oxygen and glucose for respiration
3. Adrenaline also binds to the receptors in the liver to break down glycogen releasing glucose.
4. This increases the blood glucose level so there is more glucose in the blood to be transported into the cells.
What can hormone release be affected by
Negative feedback
When the body detects the hormone levels being too high or too low from the normal level, it triggers a release in order to bring it back to the normal level.
Where is thyroxine released
By the thyroid gland
What does thyroxine do
Regulates the metabolic rate.
What happens if your thyroid gland is under active
You gain weight as less thyroxine is being produced making your metabolic rate drop. This means that less of the glucose you take in is being broken down for respiration so more is stored as fat
What is metabolic rate
The speed at which chemical reactions in the body occur.
What happens if the blood thyroxine level is too low
- The hypothalamus is stimulated which releases TRH.
- TRH stimulates the pituitary gland which releases TSH.
- TSH stimulates the thyroid gland making thyroxine so the blood thyroxine levels rise up to normal
What happens if the blood thyroxine level is too high
- The hypothalamus is inhibited meaning the release of TRH is inhibited
- This reduces the production of TSH as TRH cannot stimulate the pituitary gland
- So TSH cannot produce thyroxine
- Blood thyroxine levels fall
What is the menstrual cycle
Monthly sequence of events where the female body releases an egg and prepares the uterus in case the egg gets fertilised.