Homeostasis & Response

Nervous System
1. Electrical Impulses along neurones
2. Stimulus
  1. Change that causes a response
3. Sense Organs
  1. Sensetive to stimuli
  2. Cluster of receptor cells
4. Reflexes
  1. Automatic
  2. Rapid
  3. Protects body from harm
  4. Basic body functions
    1. ie. breathing
  5. Sequences
    1. Stimulus => Receptor => Coordinator => Motor neurone => Effector => Response
5. Synapses
  1. Junction between 1 neurone and another
    1. ie. Sensory => Motor
Endocrine System
1. Homeostasis
  1. Maintanence of a constant internal organism.
2. Hormones
  1. Chemical substances secreted by glands
3. Pituitary gland
  1. Master gland
  2. ADH - urine produced by kidneys
  3. FSH - Follicle Stimulating Hormone - Stimulates ovaries to make Oestrogen
    1. Egg to mature
  4. TSH - stimulates thyroid gland to make thyroxine
  5. LH - Lutenising Hormone - stimulates eggs release
4. Thyroid Gland
  1. Thyroxin
    1. Regulates metabolism
5. Adrenal gland
  1. Adrenaline - fight or flight
6. Ovaries
  1. Oestrogen - Growth + Repair of Uterus wall
  2. Progesterone - Maintains thickness of Uterus wall
7. Testes
  1. Testerone
The Brain
1. controls behaviour
2. Cerebral Cortex
  1. Consciousness
  2. Memory
  3. Balance
  4. Intelligence
3. Cerebellum
  1. Coordinating muscular activity
  2. Balance
4. Medulla
  1. Unconscious Activity
    1. Heart rate
    2. Gut movements
    3. Breathing
5. Hypothalamus
  1. Controls body temperature
6. Studying Brain Damage
  1. People suffering from damage can be used to map the brain's behavior
  2. Electrically Stimulating parts of the brain
    1. Remove top of Skulls
    2. See effect
  3. MRI scans
    1. Brain tumour will affect behaviour
      1. MRI scan shows where the affected area is
  4. Brain Tumours
    1. Conscious patients
      1. No Nerve endings
The Eye
1. Sense Organ
2. Cornea
  1. Shields the eye from bacteria & Protects front of eye
3. Iris
  1. Controls amountof light entering the eye via pupil
  2. Dilated pupil
    1. Circular muscles relaxes
    2. Radial Muscle contracts
  3. Pupils constricts
    1. Circular muscles contracts
    2. Radial Muscle contracts
4. Lens
  1. Focuses light rays
  2. Produces image on Retina
5. Retina
  1. Layer of light Sensitive Lights
  2. Converts light to neural signals
6. Optic Nerve
  1. Transfers visual info => brain
  2. Sensory Neurones
7. Sclera
  1. Tough / Fibrous
  2. Resistant to squashing
8. Ciliary Muscles + Suspensory Ligiment
  1. Controls shape of lens
9. Binocular / Monocular Vision
  1. Binocular
    1. Two eyes
      1. Overlapping fields
    2. Good depth perception
    3. Smaller field of view
  2. Monocular
    1. Two eyes used seperately
    2. Limited depth perception
    3. Large field of view
10. Accomodation
11. Vision Problems
  1. Myopia
    1. Short Sighted
    2. Distant objects = blurry
  2. Hyperopia
    1. Near objects = blurry
    2. Long Sighted
Controlling body temperature
1. Controlled by thermoregulatory centre in brain
  1. Hypothalamus
2. Hot
  1. Vasodilation
    1. Arterioles dilate so more blood enters and more heat is lost
  2. Sweat
    1. Sudorific glands remove heat when water changes state
  3. Pilorelaxation
    1. Hairs flatten
  4. Stretching out
    1. Larger SA
3. Cold
  1. Vasoconstriction
    1. Arterioles get smaller so less blood enter and less heat is lost
  2. Shivering
    1. Rapid contraction & Relaxation
      1. Heat from respiration
  3. Piloerection
    1. Hairs on skin stand up
  4. Curling up
    1. Smaller SA
Controlling Blood Glucose levels
1. Blood glucose % monitored by pancreas
2. Diabetes
  1. Cannot control levels of blood glucose
  2. Type 1
    1. Treated by daily insulin injections
      1. Can not be given in tablet form as it would be digested
      2. Live normal lives
    2. Genetic problem
  3. Type 2
    1. Links to
      1. Old age
      2. Obesity
      3. Lack of excersise
    2. Treated by
      1. Balanced diet
      2. Losing weight
      3. Regular excersise
      4. Otherwise drugs that
        Insulin work better on the body
        Pancreas make more Insulin
        Reduce amount of glucose you absorb
Maintaining water + Nitrogen Balance
1. Osmoregulation
  1. Regulating aount of water in the body
2. Nitrogen
  1. Manufacture of proteins
  2. Removed by Urea
  3. Filtered from Kidneys + expelled in urine
3. Kidneys
  1. Filter blood to clean it
  2. Blood passes once every 5 minutes
  3. Selective Reabsorption
    1. Too concentrated = ADH produced
    2. Tiny tubules
      1. More ADH = More water absorbed
    3. Receptor Cells detect concs of solutes in the blood
  4. Kidney problems
    1. Dialysis
      1. Blood leaves body and flows through machine
        Partially permeable membranes
      2. Dialysis fluid
        % of dissolved substances in a healthy person
      3. 8 hours for dialysis to be complete
      4. Disadvantages
        Controlled diet
    2. Kidney Transplants
      1. Replaced from donor kidney
      2. Joined to patient's groin
      3. Rejection due to different antigens
        Immunosuppressant drugs
        Poor immune system
      4. Lasts roughly 9 years

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Homeostasis & Response

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	Created by Megan Leek about 7 years ago