Homeostasis and response

• Homeostasis is the maintenance of internal conditions within an organism, despite changes in external conditions.
• Homeostasis maintains - blood glucose concentration, body temperature, water levels, and pH
• The nervous system enables humans to respond to their surroundings and to coordinate their behaviour
• cns stimulus - receptor - coordinatior - effector - response
• receptors detect the change

  coordinator interpret that change

  effectors carry out the change
• receptors - skin

  coordination - brain & spinal cord

  effectors - muscles & glands
• sensory neurones carry info from receptors

  motor neurons carry to effectors
• synapses a small gap at the end of a neuron that allows the neuron to communicate with another neuron
• Reflex actions are automatic and rapid ; and dont involve the conscious part of the brain
• Endocrine system is a system of glands that secrete hormones into the bloodstream. The endocrine system regulates how much of each hormone is released
• Insulin a hormone of pancreas that lowers blood glucose levels when it gets to high
• Type 1 diabetes- pancreas fails to produce sufficient insulin and is normally treated with insulin injections
• Type 2 diabetes is when the body can't produce enough insulin or the body cells don't respond to insulin and main treatment is excersice and healthy low sugar diet
• Insulin controls blood glucose levels by signaling the liver and muscle and fat cells to take in glucose from the blood
• Glucagon ( opposite of insulin ) is released when blood glucose levels are too high
• Glucagon and insulin have a negative feedback loop in which glucagon increases blood glucose levels and insulin decreases blood glucose levels
• Follicle stimulating hormone (FSH) causes maturation of an egg in the ovary
• Luteinising hormone (LH) stimulates the release of an egg from the ovaries
• Oestrogen and progesterone are involved in maintaing the uterus lining , incase the egg is fertilised and implants
• contraception - different ways to prevent fertilisation
• Types of contraceptives

  • pill
  • implant , skin patch or injection
  • condom or diaphragm
  • intrauterine devices or IVD
  • sterilisation
• To treat infertility

  • Fertility drug in which includes FSH & LH
  • IVF treatment
• IVF

  • pros - gives a women a chance of having a baby
  • cons - the succes rate is not high , IVF is expensive , could lead to the destroying of embroys & very stressful for parents also lead to multiple babies
• Adrenaline - is a hormone that is released by the adrenal glands in times of fear and stress . It increases the heart rate and boosts the delivery of oxygen and glucose to the brain & muscles preparing for ‘flight or figh’
• Thyroxine from the thyroid gland stimulates the basal metabolic rate. It plays an important role in growth and development
• thyroxine levels are controlled by negative feedback