Mammalian nervous system

• effective communication system should be able to:

  • detect changes in environment
  • cell signalling between all parts of the body
  • coordination of a range of effectors to respond to stimuli
  • suitable responses
• spinal chord

  1. cervical
  2. thoracic
  3. lumbar
  4. sacral
  5. coccygeal
• cervical (spine)

  • neck muscle
  • diaphragm
  • wrist
  • triceps
  • fingers
• thoracic (spine)

  • hand
  • intercostals
  • abdominals
• lumbar (spine)

  • hips
  • quadriceps
  • foot
  • hamstrings
• sacral (spine)

  • penile erection
  • bowel and bladder
• peripheral nervous system (PNS)

  • rapid communication between receptors, the CNS and effectors
• grey matter

  • non myelinated cells giving its grey colour
• Brain (CNS)

  • Brain has 86 billion neurons
  • most are relay neurons that have multiple connections allowing complex neural pathways
  • most are non myelinated cells - grey matter
• spinal chord (CNS)

  • spinal chord has a central section made of non myelinated relay neurons
  • most relay neurons that have multiple connections allowing complex neural pathways
• • grey matter - process
  • white matter - deliver
• somatic nervous system

  • relates to all sensory neurons and motor neurons joining skeletal muscle
• autonomic nervous system

  • relates to motor neurons involved with internal organs
• ACH = Acetylcholine

  NE = norepinephrine
• nervous system

  
• motor neuron

  
• sensory neuron

  
• relay neuron

  
• interneuron

  
• sympathetic

  • dilate pupils
  • inhibits salivation
  • increase heartbeat
  • relax bladder
  • relax airways
  • promote ejaculation and vaginal contraction
  • fight or flight
  • stimulate release of glucose
  • inhibit activity of intestines
• parasympathetic

  • constricts pupil
  • stimulate saliva
  • slow heartbeat
  • constrict airways
  • stimulate activity of stomach
  • contract bladder
  • inhibit release of glucose
  • promote erection of genitals
  • stimulate activity of intestines
• parasympathetic nervous system

  • relaxes organs - rest or digest
  • ACH used as neurotransmitter
  • most of upper body controlled through vagus nerve
• somatic

  • voluntary
  • single neuron from CNS to effector organs
  • skeletal muscle
  • heavily myelinated
  • rapid
  • ACH
• autonomic

  • not voluntary
  • two neuron chain from CNS to effector organs
  • smooth muscle, glands and cardiac muscle
  • lightly myelinated
  • not rapid
  • ACH and NE