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  • 1. The Brain The human brain is the site of the major coordination in the nervous system.
  • 2. The Brain Cerebrum Cerebellum Medulla Pituitary gland Hypothalamus
  • 3. Areas of the brain
    • The brain is composed of Cerebral Hemispheres, Cerebellum and Medulla
    Medulla Cerebral Hemispheres Cerebellum
  • 4. medulla
    • Controls autonomic activities including heart rate, and ventilation rate
    • Impulse transmitted from medulla via sympathetic or parasympathetic branch of automatic nervous system
    Medulla Cerebral Hemispheres Cerebellum
  • 5. cerebellum
    • Co-ordination of body movement, balance and posture
    Cerebral Hemispheres Cerebellum
  • 6.
    • Highly Folded and so has a large SA.
    • Patients with injuries to specific parts of the brain can be studied to see how their functions are altered.
    cerebrum/cerebral hemispheres Medulla Cerebral Hemispheres Cerebellum
  • 7.
    • Different parts of the brain can be stimulated electrically to see which muscles in the body respond
    • Conversely different parts of the body can be stimulated to see which parts of the brain show electrical activity.
    • More recently MRI (magnetic resonance imaging) has been used in brain study
    cerebrum/cerebral hemispheres
  • 8.  
  • 9. Areas of the cerebrum
  • 10. The Areas can be split into 3 groups
    • Sensory Areas
    • Motor Areas
    • Association Areas
  • 11. Association Motor Sensory Sensory area for impulses from eyes
  • 12. cerebrum/cerebral hemispheres
    • Sensory areas of the cerebral hemispheres receive impulses from sense organs and transmit them to the association areas
    • The association areas of the cerebral hemispheres receive impulses - interpret them in the light of similar past experiences and transmit impulses to motor areas
    • The motor areas transmit impulses to the effectors
    • The size of the sensory and motor areas is related to the number of receptors in that area
    • The left and right cerebral hemispheres control the opposite sides of the body
  • 13. Mapping of the sensory & motor areas to the body
  • 14. Sensory & Motor Maps
    • The maps show that regions of the body with many sensory (or motor) neurones have corresponding large areas of the cerebrum linked to them.
    • So for example the lips occupy a larger region of the sensory cortex than the shoulder, because there are more sensory neurones in the lips.
  • 15. Association Areas
    • Are used to compare sensory input with previous experiences, and make decisions
    • These areas are involved in speech, understanding and memory retrieval
    • The frontal lobes are large in humans and it is thought that they responsible for higher functions like abstract thought, personality & emotion.
  • 16. Speech
    • The left side of the brain
    • Patients with speech problems gave 1 st clues about how the brain controls language
    • 1981 Dr Paul Broca described a patient who could only say the word “tan”.
    • When the patient died Broca examined the brain and found damage to the left cerebral hemisphere
    • This part of the brain is now know as Broca’s area
  • 17. Broca’s Area Broca’s area
  • 18. Wernicke’s Area
    • In 1967 Karl Wernicke noticed damage to another region of the cortex.
    • Werniche’s area is connected to Broca’s area by a bundle of nerve fibres.
    • If this was damaged the patient can understand language but cannot repeat words.
    • So Werniche’s area is concerned with understanding language. Broca’s area is concerned with controlling the muscles that produce speech
  • 19. Wernicke’s Area Wernicke’s area
  • 20. Visual Processing
    • The visual sensory area is at the back of the brain & receives sensory input from the optic nerves
    • The 2 hemispheres see slightly different images from the opposite of the visual field, and differences can be used to judge distance
  • 21. Optic Chiasma
  • 22. Summary
    • Sensory areas – receive input from receptors
    • Motor areas – Origin of impulses which bring about voluntary movements
    • These receive/transmit impulses from the opposite side of the body
    • Association areas – interpret sensory information in the light of experience
  • 23. A close shave
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