Topic 7: Nervous System Part 2: Peripheral Nervous System

• How many pairs of cranial nerves are there?

  12 pairs
• Where are cranial nerves attached?

  To the undersurface of the brain
• How many pairs of spinal nerves are there?

  31 pairs
• What does the somatic nervous system relay information from?

  Skin, sense organs, and skeletal muscles
• What does the autonomic nervous system regulate?

  Involuntary responses of the body
• What is the function of the sympathetic nervous system?

  Emergency response during stress
• What is the function of the parasympathetic nervous system?

  Normal everyday conditions
• How do spinal nerves connect to the body?

  To sensory receptors, muscles, and glands
• What are the protective coverings of spinal nerves called?

  Endoneurium, perineurium, and epineurium
• What type of neurons do cranial nerves I, II, and VIII contain?

  Only sensory neurons
• What is the function of cranial nerve I?

  Smell
• What is the function of cranial nerve II?

  Visual fields and ability to see
• What is the function of cranial nerve III?

  Eye movements and eyelid opening
• What is the function of cranial nerve V?

  Facial sensation
• What is the function of cranial nerve VII?

  Eyelid closing and facial expression
• What is the function of cranial nerve VIII?

  Hearing and sense of balance
• What is the function of cranial nerve IX?

  Taste sensation and swallowing
• What is the function of cranial nerve X?

  Swallowing and taste sensation
• What is the function of cranial nerve XI?

  Control of neck and shoulder muscles
• What is the function of cranial nerve XII?

  Tongue movement
• What are the main differences between the somatic and autonomic nervous systems?

  • Somatic Nervous System (SNS):
  • Voluntary control
  • Relays information from skin and muscles
  • Autonomic Nervous System (ANS):
  • Involuntary control
  • Regulates smooth and cardiac muscles
• What regulates the autonomic nervous system?

  Mainly the hypothalamus and brain stem
• What do autonomic motor neurons regulate?

  Activities of cardiac and smooth muscle
• What are the two divisions of the autonomic nervous system?

  • Sympathetic Nervous System
  • Parasympathetic Nervous System
• What is dual innervation in the autonomic nervous system?

  Most organs receive impulses from both divisions
• What is the sympathetic division also called?

  Thoracolumbar division
• Where do sympathetic preganglionic neurons originate?

  Thoracic and lumbar segments of spinal cord
• How many postganglionic neurons can a sympathetic preganglionic axon synapse with?

  20 or more
• What happens once a sympathetic preganglionic neuron enters a sympathetic trunk ganglion?

  It may follow one of four paths
• What are the functions of the sympathetic nervous system?

  • Maintains homeostasis
  • Increases heart rate
  • Bronchial dilation
  • Increases cardiac output
  • Dilation of pupils
• What does the sympathetic nervous system target during extreme conditions?

  The adrenal medulla to secrete epinephrine
• What is the parasympathetic division also called?

  Craniosacral division
• Where are parasympathetic ganglia located?

  Near or within autonomic effectors
• What is the primary function of the parasympathetic nervous system?

  Conserves body’s natural activity
• What are the neurotransmitters of the autonomic nervous system?

  • Acetylcholine
  • Norepinephrine
• What is a sensation?

  Conscious or subconscious awareness of changes
• What are the two types of senses?

  • General senses (somatic and visceral)
  • Special senses (smell, taste, vision, hearing, balance)
• What conditions must be satisfied for a sensation to occur?

  A stimulus, sensory receptor, nerve impulses
• What is the role of sensory receptors in sensation?

  Convert stimulus to an electrical signal
• What must happen to nerve impulses for a sensation to occur?

  They must be conducted along a neural pathway