Topic 7 - Animal Coordination, Control and Homeostasis Flashcards
What is a hormone?
A chemical messenger sent in the blood
What is an endocrine gland?
A gland that produces a hormone
Name 6 endocrine glands and the hormones they produce:
- Pituitary Gland: Many hormones
- Thyroid Gland: Thyroxine
- Pancreas: Insulin
- Adrenal Glands: Adrenalin
- Ovaries: Oestrogen
- Testes: Testosterone
What are the three differences between neurones and hormones?
- Neurones are very fast, hormones are slower
- Neurones last a short time, hormones last a long time
- Neurones are very specific to an area, hormones are more general
What does adrenalin prepare you for?
‘Fight or Flight’
How does adrenalin work?
- Binds to receptors on heart, causing more constrictions, so heart rate and blood pressure increase
- Binds to receptors on liver, causing glycogen to break down into glucose, increasing blood sugar levels
What is the purpose of a negative feedback system?
To keep the amount of a hormone in the blood at the correct/safe level
What does thyroxine regulate?
Metabolism
How does thyroxine work?
- When it is at a low level, the hypothalamus is stimulated to produce TRH
- TRH stimulates the pituitary to release TSH
- TSH stimulates the thyroid to release thyroxine
- When the level of thyroxine is too high, the hypothalamus’ production of TRH is inhibited
How long is the menstrual cycle?
28 days
How many stages are in the menstrual cycle?
4
How long does each stage of the menstrual cycle last?
- Stage 1: Day 1 - Day 4
- Stage 2: Day 4 - Day 14
- Stage 3: Day 14
- Stage 4: Day 14 - Day 28
What 4 hormones control the menstrual cycle?
- FSH
- LH
- Oestrogen
- Progesterone
How can infertility be controlled?
- Clomifene therapy: Causing more FSH and LH to be produced, causing ovulation
- IVF: Collecting eggs and fertilising them in the lab, before putting them back into the woman
What are the hormonal methods of contraception?
- Taking oestrogen every day to prevent egg maturation
- Taking progesterone stops sperm reaching the egg
- Contraceptive pill (oestrogen and progesterone)
- Contraceptive injection (progesterone)
What are the physical barrier methods of contraception?
- Male Condom
- Female Condom
- Diaphragm
What is homeostasis?
Maintaining a constant internal environment
Give 3 examples of homeostasis:
- Osmoregulation
- Thermoregulation
- Blood glucose regulation
What 2 hormones control blood glucose levels?
- Insulin
- Glucagon
How are blood glucose levels controlled?
- If it is too high, insulin is added, which makes the liver turn glucose into glycogen
- If it is too low, glucagon is added, which makes the liver turn glycogen into glucose
What is the main difference between type 1 and type 2 diabetes?
- Type 1 is caused by a lack of insulin
- Type 2 is caused by a resistance to insulin
How can type 1 diabetes be treated?
- Insulin therapy
- Taking regular exercise
What is the correlation between obesity and type 2 diabetes?
People who are obese (BMI > 30) are at higher risk of type 2 diabetes
How can type 2 diabetes be treated?
- Healthy diet
- Regular exercise
- Losing weight
What controls body temperature?
The Hypothalamus
What does homeostasis maintain our body temperature at?
37°C
What happens when we are too hot?
- We sweat to remove heat
- Hairs lie flat
- Blood vessels vasodilate to get rid of heat
What happens when we are too cold?
- We don’t sweat
- Hairs stand up to trap heat
- Blood vessels vasoconstrict to stop heat being lost
- We shiver to increase respiration rate, which transfers more energy to heat the body
What is the technical term for regulation of water?
Osmoregulation
Why is water important?
Because it keeps cells functioning
What system are the kidneys part of?
The urinary system
What are the 3 main functions of the kidneys?
- Removing urea from the blood
- Adjustment of ion levels in the blood
- Adjustment of water levels in the blood
What are nephrons?
Filtration units in the kidneys
By what hormone is water reabsorption controlled?
ADH - Anti-Diuretic Hormone
What happens if water is lost?
- Pituitary gland releases more ADH
- ADH makes the kidneys reabsorb more water
What happens if water is gained?
- Pituitary gland releases less ADH
- Less ADH makes the kidneys reabsorb less water
What does dialysis do?
Filters blood mechanically
What is the problem with kidney transplants?
Kidney may be rejected by the perosn’s immune system and thus attacked by antibodies
