Cranial nerves

• Cranial nerves

  • Olfactory (S): sense of smell
  • Optic (S): vision
  • Oculomotor (M): extrinsic muscle to control movement of the eyeball and upper eyelid
  • Trochlear (M): control movement of the eyeball
  • Trigeminal (B): deals with sensation of touch, pain, and temperature & muscles of mastication
  • Abducens (M): abduction of the eyeball (lateral rotation)
  • Facial (B): sensory- taste buds of the tongue; motor- facial expression
  • Vestibulocochlear (S): equilibrium and hearing
  • Glossopharyngeal (B): taste buds of the tongue; release of saliva
  • Vagus (B): sensory- proprioception and stretching, motor-muscles of swallowing and vocalization ("carries 90% of parasympathetic output), extends outside of head
  • Accessory (M): muscles that coordinate head movement (sternocleidomastoid, trapezius)
  • Hypoglossal (M): speech and swallowing
• Contralateral


  A reflex observed on one side of the body when the other side has been stimulated
• Optic nerve


  Cranial nerve
• Cochlea


  Structure in the ear
• Motor and efferent


  Nerves that carry information out of or away from the CNS
• Neurons are classified by


  The number of processes coming off the cell body
• Perikaryon


  The cell body of a neuron
• Autonomic division


  Regulates blood pressure and sweating
• Reflex arc


  Pulling your hand away after you touch a hot stove is an example of this
• How you hear sound

  1. Sound waves are collected by the outer ear

  2. The waves travel along the ear canal

  3. The waves reach the eardrum and make it vibrate

  4. The three bones amplify the vibrations and transmit them to the inner ear

  5. The cochlear turns these into nerve impulses

  6. The auditory nerve takes these signals to the brain for interpretation as hearing
• Vestibular structures


  Area of the ear that responds to gravitational pull
• Mechanoreceptor


  Category that hearing receptors belong to
• Sympathetic


  Division of the nervous system that activates the ciliospinal reflex
• Parasympathetic


  Division of the nervous system that activates the pupillary light reflex
• Trochlear nerves


  Function: Eye movement/Motor
• Blind spot


  The point on the retinal where the optic never is attached. Thus, there are no photo sensors here and no image.
• Hypoglossal nerve


  Function: Tongue movement- Motor
• Pupillary light reflex


  Function: Prevents bright light from damaging the retina
• Pupillary light reflex


  Reaction: Pupils constrict
• Schwann cell


  Neuroglial cell that forms the blood-brain barrier
• All sensory information is sent through the dorsal horns.
• Bipolar


  Type of neuron
• Multipolar


  Type of neuron
• Correct sequence of a reflex arc

  1. Receptors- sense organ in skin/muscle/organ

  2. Sensory neuron- carries impulse towards CNS

  3. Interneuron- carries impulse w/in CNS

  4. Motor neuron- carries impulse away from CNS

  5. Effector- response
• When your head moves, these move in your ear in response to gravity.
• Parasympathetic


  Division of the nervous system that activates the pupillary light reflex
• Trochlear nerves


  Function: Eye movement/Motor
• Blind spot


  The point on the retinal where the optic never is attached. Thus, there are no photo sensors here and no image.
• Hypoglossal nerve


  Function: Tongue movement- Motor
• Pupillary light reflex


  Function: Prevents bright light from damaging the retina
• Pupillary light reflex


  Reaction: Pupils constrict
• Schwann cell


  Neuroglial cell that forms the blood-brain barrier
• All sensory information is sent through the dorsal horns.
• Bipolar


  Type of neuron
• Multipolar


  most common In body
• Correct sequence of a reflex arc

  1. Receptors- sense organ in skin/muscle/organ

  2. Sensory neuron- carries impulse towards CNS

  3. Interneuron- carries impulse w/in CNS

  4. Motor neuron- carries impulse away from CNS

  5. Effector- response
• When your head moves, these move in your ear in response to gravity.