12 Cranial Nerves



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12 Cranial Nerves





  1. Olfactory – sense of smell

  2. Optic – visual information from the eye to the brain

  3. Occulomoter – external eye muscles

  4. Trochlear – superior oblique muscles of eye

  5. Trigeminal – 3 large branches a. ophthalmic b.maxillary c. mandibular *chewing

  6. Abducens – lateral rectus muscles of the eye

  7. Facial – taste and facial muscles

  8. Vestibulocochlear – a. vestibular b. cochlear * hearing

  9. Glossopharyngealtongue and throat, corotid sinus which controls blood pressure

  10. Vagus – (wonderer) has many widely distributed branches: pharynx, larynx, trachea, heart, lungs, esophagus, stomach, small intestine, and gall bladder.

  11. Accessory – “accessory” to the vagus nerve

  12. Hypoglossal – “under the tongue” – controls the tongue



Nervous System

Central Nervous System (CNS) - brain and spinal cord

Peripheral Nervous System (PNS) - Nerves connecting the brain and spinal cord to other parts of the body

CNS



PNS

  • Nerve tissue that lies on the “outer regions” or periphery

  • Nerves that originate in the brain are called cranial nerves

  • Nerves that originate in the spinal cord are called spinal nerves


Afferent (carry toward)

* all incoming sensory pathways



Efferent (carry away)

*all the outgoing motor pathways


Somatic – Carry information to skeletal muscles
Autonomic – Carry information to smooth muscle, cardiac muscles, and glands
Neuron – excitable cells that conduct the impulses that make possible all nervous system functions
* Human brain contains about 100 billion neurons 10% of the nervous system cells

Cell body contains nucleus, cytoplasm

Axon

Dendrite



Dendrite “tree” – distal ends are called receptors that receive stimuli that initiate nerve signals

- receive signal and conduct electrical signals toward the cell body


Axons – conduct impulses away from the cell body

* mylenation increases impulse speed


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