3.5

• function of the nervous system -

  • To monitor and respond to stimuli in the internal and external environment
• stimuli - a change in the environment
• • nervous tissue
  • Nervous tissue is made up of specialized cells called neurons
  • Your brain, spinal cord, and nerves are all made of neurons
  • A neurons job is to send and receive messages
• dendrites - receive information from other neurons and carry it to the cell body
• axon - the long extension of a neuron that carries nerve impulses away from the cell body
• CNS - Central Nervous System - consists of the brain and spinal cord
• PNS - peripheral nervous system - all the nerves outside the brain and spinal cord
• sensory neurons - carry impulses from the receptors to the CNS
• motor neurons - carry impulses from the CNS to the body
• somatic nervous system - controls voluntary responses
• autonomic nervous system - controls involuntary functions of the body, such as heart rate and digestion
• brain - recives stimuli from sensing organs

  • It reacts to stimuli and sends messages to the appropriate body parts
• spinal cord

  • The spinal cord connects the brain to the peripheral nervous system
  • It acts as a highway for messages between the brain and the body
  • It contains a type of neuron called an interneuron 
• interneuron - connect one neuron to another
• reflex -

  • sensory neurons work together without involving the brain
  • autonomic response to an external stimuli
• • Cerebral Palsy: A condition marked as impaired muscle coordination and/or other disabilities caused by damage to the brain before birth
• • Multiple Sclerosis (M.S.): A potentially disabling disease of the brain and spinal cord (Central Nervous System). 
  • The Immune system attacks the protective sheath (myelin) that covers nerve fibers and causes communication problems between the brain and the rest of the body
• • Epilepsy: Central Nervous System (neurological) disorder in which brain activity becomes abnormal, causing seizures or periods of unusual behaviour, sensations and sometimes loss of awareness