The brain

• cerebrum


  largest part and organises most of our higher thought processes, such as conscious thought and memory
• cerebellum


  coordinates movement and balance
• hypothalamus and pituitary complex


  organises homeostatic responses and controls various physiological processes
• medulla oblongata


  coordinates many of the autonomic responses
• cerebrum


  • has two cerebral hemispheres which are connected via the corpus callosum
  • outer layer of cerebrum consists of thin layer of nerve cell bodies called cerebral cortex
• the cerebrum controls 'higher brain functions' such as:

  • conscious thought
  • conscious actions
  • emotional responses
  • intelligence, reasoning, judgement and decision making
  • factual memory
• cerebral cortex subdivided into areas responsible for specific activities and body regions:

  • sensory areas receive action potentials indirectly from sensory receptors. sizes of regions allocated to receive input from different receptors are related to sensitivity of area inputs are received from.
  • association areas compare sensory inputs with previous experience, interpret what the input means, and judge an appropriate response
• • motor areas send action potentials to various effectors. sizes of regions allocated to deal with different effectors are related to complexity of movements needed in parts of the body.
  • motor areas on left size of the brain control effectors on right side of the body and vice versa
• cerebellum 


  • involved with balance and fine coordination of movement. to do this it must receive information from many sensory receptors and process information accurately.
  • sensory receptors that supply information to cerebellum include the retina, balance organs in the inner ear, and spindle fibres in the muscles, which give information about muscle length and the joints
• cerebellum


  conscious decision to contract voluntary muscles is initiated in cerebral cortex. Cerebellum coordinates fine control of muscular movements such as:

  • maintaining body position and balance, such as when riding a bicycle
  • judging the position of objects and limbs while moving about or playing sport
  • tensioning muscles in order to use tools and play musical instruments effectively
  • coordinating contraction and relaxation of antagonistic skeletal muscles when walking and running
• cerebellum and cerebrum connected by the pons
• hypothalamus and pituitary complex


  hypothalamus controls homeostatic mechanisms in the body. It contains its own sensory receptors and acts by negative feedback to maintain a constant internal environment
• temperature regulation (hypothalamus and pituitary complex)


  • hypothalamus detects changes in core body temperature. however, it also receives sensory input from temperature receptors in skin.
  • it will initiate responses to temperature change that regulate body temperature within a narrow range. these responses may be mediated by nervous system or hormonal system (via pituitary gland)
• osmoregulation (hypothalamus and pituitary complex)


  • hypothalamus contains osmoreceptors that monitor water potential in the blood.
  • when water potential changes, osmoregulatory centre initiates responses that bring about a reversal of this change. Responses are mediated by hormonal system via the pituitary gland.
• pituitary gland consists of two lobes:

  • posterior lobe is linked to hypothalamus by specialised neurosecretory cells. Hormones such as ADH, which are manufactured in hypothalamus, pass down neurosecretory cells and are released into blood from pituitary gland
  • anterior lobe produces its own hormones, which are released into blood in response to releasing factors produced by hypothalamus. These releasing factors are hormones that need to be transported from hypothalamus to pituitary.
• medulla oblongata


  controls the non-skeletal muscles by sending action potentials out through the autonomic nervous system. The medulla oblongata contains centres for regulating several vital processes including:

  • cardiac centre, which regulates heart rate
  • vasomotor centre, which regulates circulation and blood pressure
  • respiratory centre, controls rate and depth of breathing
  • these centres receive sensory information and coordinate vital functions by negative feedback