The nerves system

• Nerve system


  Controls sight, hearing, taste, smell, and feeling (sensation)
• Nerve system


  • Voluntary system
  • Involuntary system
• Voluntary actions


  Require a conscious decision to be made
• Involuntary actions


  Do not involve conscious decisions, are much faster and produce the same response
• Involuntary actions


  Are due to reflexes
• Voluntary system


  • Consists of peripheral nerves which spreads out from the brain and spinal cord (central nervous system, CNS)
  • The peripheral nerves travel to and from our skin & muscles
  • Contains two types of nerve cells: sensory & motor neurons
• Neurons


  Specialised cells that are the basic building blocks of the nervous system, responsible for transmitting electrical and chemical signals throughout the body
• Neurons


  • Have three main parts: the cell body, the dendrites, and the axon
• Sensory neurons


  Carry messages from sense organs such as pain receptors in the skin to the CNS
• Motor neurons


  Carry messages from the CNS to tissues such as muscles
• Involuntary system or autonomic system

  • Made up of two networks of nerves: the sympathetic and the parasympathetic systems
  • Sympathetic prepares you for action for any possible type of emergency
  • Parasympathetic system is an antagonist, a network of nerves that relaxes your body after periods of stress or danger
• Functions of the autonomic nervous system

  • Parasympathetic nerves: rest & digest
  • Sympathetic nerves: fight or flight
• Functions of the parasympathetic nerves

  • Constrict pupils
  • Stimulate saliva
  • Slow heartbeat
  • Relax airways
  • Stimulate stomach
  • Inhibit activity of stomach
  • Stimulate release of glucose, inhibit gall bladder
  • Stimulate intestines
  • Contract bladder
  • Promote erection of genitals
• Functions of the sympathetic nerves

  • Dilate pupils
  • Inhibit salivation
  • Increase heartbeat
  • Constrict airways
  • Inhibit activity of stomach
  • Inhibit release of glucose, stimulate gallbladder
  • Inhibits intestines
  • Relax bladder
  • Promote ejaculation and vaginal contraction
• Components of the nervous system

  • Cervical nerves
  • Thoracic nerves
  • Lumbar nerves
  • Sacral nerves
  • Sciatic
  • Peripheral leg nerves
  • Brain
  • Spinal cord
  • Cerebellum
  • Coccygeal nerves
• How the nervous system works

  1. The nervous system uses nerve cells called neurons to send signals, or messages, all over the body

  2. These electrical signals travel among your brain, skin, organs, glands and muscles

  3. The messages help you move your limbs and feel sensations, like pain

  4. Your eyes, ears, tongue, nose and the nerves all over your body take in information about your environment

  5. Nerves carry that data to and from your brain
• Nervous system disorders


  • Alzheimer's disease
  • Cancer
  • Cerebral palsy
  • Epilepsy
  • Huntington's disease
  • Infection (meningitis)
  • Parkinson's disease
  • Stroke
  • Traumatic brain injury
  • Multi sclerosis
• Common signs or symptoms of nervous system disorders

  • Movement and coordination changes
  • Memory loss
  • Pain, numbness or a pins and needles feeling
  • Behavioural and mood changes
  • Difficulty with thinking and reasoning
  • Seizures
• Multiple sclerosis (MS)


  • 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 your body
  • The disease can cause permanent damage or deterioration of the nerve fibers
• Symptoms of multiple sclerosis

  • Numbness or weakness in one or more limbs that typically occurs on one side of your body at a time
  • Tingling
  • Electric-shock sensations that occur with certain neck movements, especially bending the neck forward (Lhermitte sign)
  • Lack of coordination
  • Unsteady gait or inability to walk
  • Partial or complete loss of vision, usually in one eye at a time, often with pain during eye movement
  • Prolonged double vision
  • Blurry vision
  • Vertigo
  • Problems with sexual, bowel and bladder function
  • Fatigue
  • Slurred speech
  • Cognitive problems
  • Mood disturbances
• Tests for nervous system disorders

  • Computed tomography (CT) scan
  • Electrocardiogram (ECG or EKG)
  • Electroencephalogram (EEG)
  • Lumbar puncture (spinal tap)
  • Magnetic resonance imaging (MRI) scans
• Ways to keep the nervous system healthy

  • Seeing a healthcare provider regularly
  • Maintaining good health (like eating balanced foods)
  • Avoiding harmful substances (like not smoking tobacco)
  • Wearing protective gear or equipment (a helmet) when playing sports or participating in certain activities
  • Managing any underlying health conditions
• Treatments for nervous system disorders

  • Taking medications
  • Having surgery
  • Participating in counselling for mental and emotional support
  • Receiving supportive care (to keep you comfortable)