Cranial + Spinal Nerves

Question 1

Vegas nerve (X)

Answer 1

Special mixed cranial nerve that goes to the viscera in the body and into the organs in the ventral body cavity.

Question 2

Cranial nerves definition

Answer 2

12 pairs of nerves that come out of the brain, labeled 1-12 in Roman numerals. 11 cranial nerves go to the head and the vegas nerve goes to the viseral organs. The nerves are composed of efferent, afferent, and sometimes both (mixed) neurons.

no such thing as a purely efferent neron

Question 3

Afferent Neuron

Answer 3

Neurons from special senses (eyes, ears, nose, tongue)
* Somatic senses from the skin, muscles, joints of the head
* Visceral senses from organs in the ventral cavity + some places in the head + neck

Question 4

Efferent Neuron

Answer 4

Somatic + parasympatheic multipolar neurons with their cell bodies in the grey matter of the brain stem.
No pure “efferent” neurons
- Any nerve carrying somatic motor signals out to muscles
- All carrying somatic sensory neurons back from muscle
- Almost all are efferent

Question 5

Somatic motor neurons

Answer 5

Efferent neurons that go to muscles in the face, head, and neck.

Question 6

Parasympathetic efferent neurons

Answer 6

Neurons that go to some places in the head + to organs in the ventral cavity .

Question 7

Olfactory Nerve
I

Answer 7

Composed of bipolar afferent neurons coming from the the nasal cavity through the ethmoid bone sinuses to synapse on the olfactory bulb (below the frontal cortex).
The cell bodies are in the nasal cavity

Question 8

Optic Nerve
II

Answer 8

Afferent bipolar neurons with cell bodies in the retina. It recieves signals from other neurons then passes them through the optic canal in sphenoid bone.
Some of the neurons cross to the other side of the brain through the Optic Chiasma then synaps in the thalmus and continue on to the primary visual cortex (occipital).

Question 9

Oculomotor
III

Answer 9

Efferent Parasympathetic Autonomic
motor neurons for internal eye muscles
that constricts the pupils and lens focus on distance.
Emerges from the anterior midbrain (near pons) and goes out the superior orbital fisure in the sphenoid.

Question 10

Trochlear
IV

Answer 10

Emerges from the posterior midbrain, wraps around the midbrain from behind and emerges through the superior orbital fisure in the sphenoid.