The Brain

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The Brain

• WALT
• That there are distinct areas of the brain
• That each area has a different function

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27.5.2 Structure of The Brain

• Longitudinal section through a human brain

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• Regions and Functions of the Brain
• - The brain is divided into 3 regions
• the forebrain, midbrain the hindbrain

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• 1. The Forebrain
• The cerebrum is divided into two cerebral
  hemispheres connected by nerve fibres
• The surface is folded to increase the surface
  area for increased co-ordination
• This is the centre for thinking, memory,
  reasoning, imagination, learning voluntary
  actions

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• Map of the major regions of the cerebral cortex
  and their functions

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Areas of the brain

• sensory areas receive impulses from the
  receptors
• removal of these areas results in loss of the
  senses
• motor areas send impulses to the effectors if
  these areas are damaged, no responses will be
  evoked
• association areas correlate impulses from
  different receptors and assist in producing the
  appropriate responses

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The Midbrain

• This includes the optic lobes for vision
• The floor is the hypothalamus essential for
  homeostasis
• main controlling region for the autonomic nervous
  system
• two centres (sympathetic parasympathetic)
• controls complex patterns of behaviour such as
  feeding, sleeping
• monitor composition of blood
• acts as an endocrine gland

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The Hindbrain

• The cerebellum a centre for muscular co
  ordination and body balance
• The medullar oblongata This is the reflex centre
  for controlling involuntary actions such as
  breathing, heartbeat, swallowing, coughing,
  sneezing, and salivation
• Any damage of the medulla oblongata may lead to
  death

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Internal Structure of the Brain

• -The grey matter This is the outer layer of the
  brain and consists of nerve cell bodies only
• -The white matter This is inside the brain and
  consists of nerve fibres only
• Remember--This is the reverse of the medulla
  oblongata spinal cord, the distribution of grey
  and white matters is the reverse with the grey
  matter inside and the whiote matter outside

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• Comparison of Endocrine and Nervous Systems

Endocrine system Nervous system
Communication chemical messengers or hormones Communication by nervous impulses
Transmission by blood stream Transmission by nerve fibres
Target organ receives message Effector receives message
Transmission relatively slow Transmission very rapid
Effect widespread Effect localized
Response slow Response rapid
Response is often long-term Response is short-lived
Effect permanent irreversible Effect temporary and reversible