Homeostasis and response

• The nervous system is made up of: the central nervous system and a network of nerves
• The CNS is made up of: the brain and the spinal cord
• Nervous system response pathway + description

  Stimulus: change is detected by receptors

  Receptors: info from receptors is passes along neurons to the CNS as electrical impulses

  Coordinator: the CNS coordinates the bodies response

  Effector: bring about a response
• Homeostasis


  Regulation of internal conditions
• What does the human body regulate (3)

  Blood glucose levels

  Body temp

  Water levels
• 3 control systems


  Receptor cells

  Coordination center

  Effectors
• Factors effecting reaction times

  Tiredness

  Distractions

  Caffeine

  Alcohol
• Reflex actions: unconscious actionS
• Why are reflex actions important?

  They prevent damage to the body
• 2 types of effectors

  Muscles and glands
• What do the coordination centers

  receptor cells: detect stimuli

  Coordination centers: receive and process information

  Effectors: produce responses
• What is the endocrine system composed of

  Glands that secrete hormones
• How do the effects of the nervous system compare to those of the endocrine system

  Endocrine system effects last longer
• What is the role of the hormone secreted by the pituitary gland

  Controls growth in children

  Men= Stimulates testes to make sperm and testosterone

  Women= Stimulates ovaries to produce eggs and make oestrogen
• What is the role of the hormone secreted by the thyroid

  Controls rate of metabolism
• What is the role of the hormone secreted by the pancreas

  Controls blood glucose levels
• What is the role of the hormone secreted by the adrenal gland

  prepares for stress

  involved in fight or flight
• What is the role of the hormone secreted by the ovaries

  controls menstrual cycle
• What is the role of the hormone secreted by the testes

  involved in the production of sperm
• What do negative feedback systems do+ what hormones are controlled

  Work to maintain a steady state

  Blood glucose, water, thyroxine
• Adrenaline

  Produced by adrenal gland

  Increases heart rate + oxygen + glucose to brain
• Thyroxine

  Produced by the thyroid gland

  Regulates metabolic rate
• Diabetes

  Non-communicable disease

  Body cant produce/respond to insulin
• Type 1 diabetes

  Early onset

  Pancreas stops producing sufficient insulin

  Treated through insulin injections
• Type 2 diabetes

  Later onset

  Body doesn't respond to insulin provided

  Treated through diet and exercise
• Follicle stimulating hormone (fsh)released by, function

  Released by pituitary gland

  Causes eggs to mature in ovaries

  Stimulates ovaries to produce oestrogen
• Luteinising hormone (lh)released by, function

  Released by pituitary gland

  Stimulates the release of mature eggs from the ovaries
• Oestrogen released by, function

  Released by the ovaries

  Causes lining of uterus wall to thicken

  Inhibits release of fsh

  Stimulates release of lh
• Progesterone released by, function

  Released by ovaries

  Maintains thick uterus lining

  Inhibits release of fsh and lh
• IVF treatment

  1. Mother given fsh and lh
  2. Eggs collected
  3. Fertilised eggs develop into embryos
  4. One or two eggs inserted into mothers uterus
• Hormonal contraception

  Oral - contain hormones to inhibit fsh so no eggs mature

  Injection, implant, patch, iud - slowly release progesterone to inhibit maturation and release of eggs
• Non-hormonal contraception

  Barriers - prevent sperm from reaching the egg

  Copper iud - prevents implantation

  Sterilisation