• The brain, alongside the spinal cord, is part of the?central nervous system?(CNS)
• The brain is made of billions?of?interconnected?neurones
• Within the brain are?different regions?that carry out?different functions

Different regions of the brain carry out different functions

• You need to know the functions of the following brain regions

The cerebrum

• The cerebrum is the?largest part?of the brain in humans, accounting for about 80% of the total mass of the brain
• It carries out a large?variety of functions?involved with?conscious activities, including:
  • Vision
  • Hearing
  • Speech
  • Thinking
  • Memory
• The cerebrum is divided into?two halves?known as the?cerebral hemispheres
  • The hemispheres are joined together by a?band of nerve fibres?known as the?corpus callosum
  • The?right hemisphere?controls the?left side of the body?and the?left?one controls the?right side
• The cerebrum has a?thin outer layer?known as the?cerebral cortex?or 'grey matter'
  • The cerebral cortex consists of the?cell bodies of neurones
  • It is?highly folded, which?increases its surface area?and allows it to contain a?greater number of neurones
    • With more neurones in the brain,?more neurone connections?can be made
    • This is important, as the more connections between neurones in the brain, the?greater the ability of the brain to carry out more complex behaviours
• Beneath the cerebral cortex or grey matter layer is the 'white matter'
  • The white matter consists of the?myelinated axons of neurones

The cerebrum consists of two hemispheres joined by the corpus callosum

The hypothalamus

• The hypothalamus monitors?the blood?as it flows through the brain and, in response,?releases hormones?or?stimulates?the?neighbouring?pituitary gland?to release hormones
  • The hypothalamus plays an important role in some?homeostatic?mechanisms
• Hypothalamus functions include
  • Regulating body temperature
    • The hypothalamus?monitors blood temperature?and initiates a homeostatic response if this temperature gets too high or too low
  • Osmoregulation
    • Cells in the hypothalamus?monitor the water balance of the blood?and releases the hormone ADH if the blood becomes too concentrated
      • ADH increases absorption of water in the kidneys
  • Regulating digestive activity
    • The hypothalamus regulates the hormones that control appetite as well as the secretion of digestive enzymes
  • Controlling endocrine functions
    • The hypothalamus causes the pituitary gland to release hormones that control a variety of processes e.g. metabolism, growth and development, puberty, sexual functions, sleep, and mood

The cerebellum

• The cerebellum?coordinates movement
  • This includes?balance;?a highly complex function that requires coordination between multiple parts, including the eyes, semicircular canals in the ears, and many muscles

The medulla oblongata

• Also known as the?medulla
• The medulla contains co-ordination centres that control different functions e.g.
  • The cardiac centre?controls heart rate
  • The respiratory centre?controls breathing rate