The Brain/The Eyes / Scans

• Medulla oblongata


  Part of the brain that controls heart rate
• Cerebral cortex


  Part of the brain that controls memory
• Cerebellum


  Part of the brain that controls fine movements/coordination
• Parts of the brain

  • Cerebral cortex (or better answer is left cerebral hemisphere)
  • Cerebellum
  • Spinal cord
  • Medulla oblongata
  • Pituitary gland
  • Hypothalamus
• CT scanner


  • Shows the shape of structures (including surgical instruments) where the problem is/where to guide their instruments
• Information from the eyes is processed at the back of the brain (vision area); these areas are the most active when looking at something
• Breathing is controlled by the medulla oblongata; damage in the spinal cord in the neck prevents impulses from the medulla oblongata reaching the lungs
• Brain tumour cells are dividing rapidly and so are very active; chemotherapy drugs kill very active cells (e.g. cells that produce hair); chemotherapy drugs may be prevented from reaching the brain by the blood-brain barrier
• There are no adult stem cells in the spinal cord; so neurones cannot be produced to repair the damage; in spinal cord injury treatments, electrical wires used to stimulate nerves and muscles do not allow full movement or feeling
• CT scanning allows shapes to be seen; PET scanning allows areas of greatest activity to be seen; the combination will allow scientists to work out the particular parts that are most active during a certain activity
• The removal of the tumour also removed part of the brain or the tumour destroyed part of the brain (at the back of the head). This is the part of the brain that processes information from the eyes.
• Cerebral cortex


  • It is very dense compared to the other parts of the brain
• More active cells take in more glucose
• More gamma rays come from the strip of tissue in the cerebral cortex
• Radioactive glucose injection


  1. Radioactive atoms on the glucose cause gamma rays to be produced

  2. When the man wiggles his toes, the cells that control this become more active

  3. Greater concentration of gamma rays causes brighter areas on the screen
• An area of damage is looked for during a CT scan of the woman's brain/head
• Cerebral cortex


  Part of the brain used for vision
• Removing healthy brain tissue could cause the patient to lose body functions
• Suggestions could include headaches and problems with vision (in the left eye, since the tumour is in the part of the cerebral cortex used for vision and is in the right cerebral hemisphere)
• The spinal cord contains bundles of neurones/nerves; which transmit impulses/signals between the brain and the main part of the body; if the neurones/nerves are severed/broken then this stops the flow of information
• The spinal cord does not have (adult) stem cells
• CT scanning shows structures in the brain, PET scanning shows activity in parts of the brain, both use radioactivity
• Chemotherapy kills cells directly, radiotherapy uses high energy X-rays, brain surgery involves opening up the skull
• The blood-brain barrier stops chemotherapy drugs getting into the brain
• Chemotherapy and radiotherapy are used to try to kill any cancer cells that have been left behind
• Pupil


  Stops too much light entering the eye; which could damage the retina
• Lens


  Light rays from nearby objects need to be bent more (to focus an image on the retina); a fatter lens bends the light rays more
• Distant objects


  Appear blurry/out of focus
• Diverging lenses


  Used to spread out the light rays a little before reaching the eye; so that the light rays are focused on the retina and not in front of it
• Cataracts


  The lens; which will stop some light rays/interfere with the passage of light rays into the eye
• Lens properties


  • Flexible (so it can be squashed and stretched)
  • Clear/transparent (so that light rays easily pass through)
• Short-sightedness


  Image is focused in front of the retina, so the image on the retina is not in focus; caused by an eyeball that is too long or a cornea that is too curved and bends the light rays more than it should
• Long-sightedness


  Image is focused behind the retina, so the image on the retina is not in focus; caused by an eyeball that is too short or a cornea that is not curved enough and does not bend the light rays as much as it should
• Cataracts


  Cloudy lens caused by the build-up of a protein
• Corrections


  • Diverging lenses
  • Laser treatment to reshape the cornea
  • Converging lenses
  • Laser treatment to reshape the cornea
  • Lens is replaced by an artificial one
• Sensory Neurons


  Transmit information from sensory receptors to the CNS, allowing us to perceive and respond to the world around us.
• Motor Neurons


  Transmit signals from the CNS to muscles and glands, allowing us to move, respond, and regulate our bodily functions.
• Neurons


  The basic functional units of the nervous system, responsible for transmitting and processing information. There are three main types: sensory neurons, motor neurons, and interneurons.