bio

• The brain controls complex behaviour. It is made of billions of interconnected neurones and has different regions that carry out different functions.
• Neuroscientists have been able to map the regions of the brain to particular functions by studying patients with brain damage, electrically stimulating different parts of the brain and using MRI scanning techniques. The complexity and delicacy of the brain makes investigating and treating brain disorders very difficult.
• cerebral cortex

  • consciousness
  • memory
  • intelligence
  • language
• cerebellum

  • muscle coordination
  • movement
  • balance
• Medulla

  • unconscious activity (heart and breathing rate)
• near object

  • lens thicker
  • light rays bend stronger
  • suspensory ligaments slacken
  • clilary muscles contract
• distant object

  • lens thinner
  • light rays bend slightly
  • suspensory ligaments tighten
  • clilary muscles relax
• dim light

  • radial muscles contract
  • circular muscles relax
  • pupil dilates
• bright light

  • radial muscles relax
  • circular muscles contract
  • pupil constricts (smaller)
• short sight (myopia)

  • lens too thick and curved
  • rays focus on the front of the retina as the eyeball is too long/ too thick
  • need a concave lens (light diverges more)
• long sight (hyperopia)

  • lens not thick enough
  • rays of light from near object focus behind the retina as eyeball is to short (lens to thin)
  • need a convex lens (light refracts more)
• retina - receptors/ light sensitive send impulses to optic nerve
• optic nerve - carries impulses from the retina to the brain
• scelera - tough white outer layer
• lens - focuses light onto retina
• cornea- transparent layer of the eye that refracts light to focus it on the retina
• iris- controls the size of the pupil, which controls the amount of light entering the eye
• ciliary muscle - contracts and relaxes to change shape of lens
• suspensory ligaments - connects lens to ciliary muscle
• • New technologies now include hard and soft contact lenses, laser surgery to change the shape of the cornea and a replacement lens in the eye.
• Type 1 diabetes is a disorder in which the pancreas fails to produce sufficient insulin. It is characterised by uncontrolled high blood glucose levels and is normally treated with insulin injections.
• In Type 2 diabetes the body cells no longer respond to insulin produced by the pancreas. A carbohydrate controlled diet and an exercise regime are common treatments. Obesity is a risk factor for Type 2 diabetes.
• If the blood glucose concentration is too low, the pancreas produces the hormone glucagon that causes glycogen to be converted into glucose and released into the blood.
• If the blood glucose concentration is too high, the pancreas produces the hormone insulin that causes glucose to move from the blood into the cells. In liver and muscle cells excess glucose is converted to glycogen for storage.
• Blood glucose concentration is monitored and controlled by the pancreas.
• FSH (follicle-stimulating hormone)

  • pituitary gland
  • stimulate egg to be matured in ovary
  • stimulates oestrogen production
• oestrogen

  • ovaries
  • causes thickening of uterus lining
  • inhibits FSH stimulates LH
• LH (luteinising hormone)

  • pituitary gland
  • stimulates ovulation
  • stimulates progesterone production
• Progesterone

  • ovaries
  • maintains uterus lining
  • inhibits FSH and LH
• menstrual cycle

  • lining breaks down
  • egg matures
  • lining builds up
  • ovulation
  • uterus lining maintained
• polydactyl

  • extra fingers and toes
  • dominant allele
  • homozygous dominant /hetrozygous
  • only 1 parent has to have
• cystic fibrosis

  • disorder of cell membrane ( build up of mucus in lungs)
  • recessive allele
  • both parents have to have
• they can scan embryos alleles to see if it has inherited disorder
• reasons for screening

  • alleviate suffering
  • reduce health care cost
  • choice about termination
• reasons against screening

  • risk of miscarriage
  • expensive
  • chance of false results
  • decision to terminate
  • suggest unwanted
• Gibberellins are important in initiating seed germination.
• Ethene controls cell division and ripening of fruits.
• Plants produce hormones to coordinate and control growth and responses to light (phototropism) and gravity (gravitropism or geotropism). Unequal distributions of auxin cause unequal growth rates in plant roots and shoots.
• light

  • auxin moves to shaded side
  • auxin increases cell growth
  • shoot bends towards light
• gravity :

  shoots:

  • auxin moves to lower side
  • auxin increases cell growth on lower side
  • shoot bends up towards gravity

  roots:

  • auxin moves to lower side of tooy
  • auxins inhibit cell growth
  • bends towards gravity