Animal Coordination, Control & Homeostasis Flashcards
Where are hormones produced?
In endocrine glands
What is a hormone?
Chemical messengers that are carried in the blood to alter the activity of specific target organs
Where is adrenaline produced?
In the adrenal glands
What are the effects of adrenaline?
- Increased heart rate
- Increased blood pressure
- Increased blood flow to muscles
- Increased blood sugar levels by stimulating the liver to turn glycogen into glucose
What is negative feedback?
Mechanism that makes sure substances (eg. hormones) stay at the right level
What happens if blood glucose levels are too high?
The pancreas produces insulin which causes glucose to convert into glycogen and is stored in the liver
What happens if blood glucose levels are too low?
The pancreas produces glucagon which causes the liver to break down the glycogen stores, releasing glucose into the blood
Where is thyroxine produced?
In the thyroid gland
What does thyroxine do?
Stimulate the metabolic rate
What happens if thyroxine levels in the blood are low?
- The hypothalamus releases TRH
- This causes the pituitary gland to release TSH
- This causes the thyroid to produce more thyroxine
What does TRH stand for?
Thyroid Releasing Hormone
What does TSH stand for?
Thyroid Stimulating Hormone
What happens when thyroxine levels in the blood are normal?
Thyroxine inhibits the release of TRH and TSH
Which two hormones control the menstrual cycle?
- Oestrogen
- Progesterone
Where is oestrogen produced?
The ovaries
Where is progesterone produced?
The ovaries
What does FSH do?
Causes an egg to mature
What does LH do?
Stimulate the release of an egg
What does FSH stand for?
Follicle Stimulating Hormone
What does LH stand for?
Luteinising Hormone
What does oestrogen do?
Involved in thickening and repairing uterus lining
What does progesterone do?
Involved in maintaining the uterus lining
Describe each stage of the menstrual cycle
- Days 1-5: Uterus lining sheds
- Day 14: Ovulation
- Days 15-28: Uterus lining thickens
What is ovulation?
The release of an egg cell