Nervous System and Cranial Nerves Part 1

What is cranial nerve I?

Olfactory

Is cranial nerve I (Olfactory) sensory, motor, or mixed?

Sensory

Name one function of cranial nerve I (Olfactory).

Smell

What is cranial nerve II?

Optic

Is cranial nerve II (Optic) sensory, motor, or mixed?

Sensory

Name one function of cranial nerve II (Optic).

Vision

What is cranial nerve III?

Oculomotor

Is cranial nerve III (Oculomotor) sensory, motor, or mixed?

Motor

Name one function of cranial nerve III (Oculomotor).

Most eye movements and pupil constriction

What is cranial nerve IV?

Trochlear

Is cranial nerve IV (Trochlear) sensory, motor, or mixed?

Motor

Name one function of cranial nerve IV (Trochlear).

Controls superior oblique muscle for eye movement

What is cranial nerve V?

Trigeminal

Is cranial nerve V (Trigeminal) sensory, motor, or mixed?

Mixed

Name one function of cranial nerve V (Trigeminal).

Facial sensation and chewing

What is cranial nerve VI?

Abducens

Is cranial nerve VI (Abducens) sensory, motor, or mixed?

Motor

Name one function of cranial nerve VI (Abducens).

Moves eye laterally (abduction)

What is cranial nerve VII?

Facial

Is cranial nerve VII (Facial) sensory, motor, or mixed?

Mixed

Name one function of cranial nerve VII (Facial).

Facial expressions

What is cranial nerve VIII?

Vestibulocochlear

Is cranial nerve VIII (Vestibulocochlear) sensory, motor, or mixed?

Sensory

Name one function of cranial nerve VIII (Vestibulocochlear).

Hearing and balance

What is cranial nerve IX?

Glossopharyngeal

Is cranial nerve IX (Glossopharyngeal) sensory, motor, or mixed?

Mixed

Name one function of cranial nerve IX (Glossopharyngeal).

Swallowing and taste

What is cranial nerve X?

Vagus

Is cranial nerve X (Vagus) sensory, motor, or mixed?

Mixed

Name one function of cranial nerve X (Vagus).

Parasympathetic control of heart and digestive organs

What are the four major regions of the brain?

Cerebrum, diencephalon, brainstem, cerebellum

Which brain region controls thinking, memory, and voluntary movement?

Cerebrum

Which brain region coordinates balance and fine movements?

Cerebellum

Which brain region contains centers that regulate vital breathing and heart functions?

Brainstem

Which brain region relays sensory information and helps regulate hormones?

Diencephalon

What is a major function of the frontal lobe?

Voluntary movement, planning, decision-making, and personality

What is a major function of the parietal lobe?

General somatic sensation, including touch

What is a major function of the temporal lobe?

Hearing and smell

What is a major function of the occipital lobe?

Vision

What is a major function of the insula lobe?

Taste processing

Where is the primary motor cortex?

Precentral gyrus of the frontal lobe

What does the primary motor cortex control?

Voluntary skeletal muscle movement

Where is the primary somatosensory cortex?

Postcentral gyrus of the parietal lobe

What does the primary somatosensory cortex process?

Touch, pain, temperature, pressure, and body position

Where is the primary visual cortex?

Occipital lobe

What does the primary visual cortex process?

Incoming visual information

Where is the primary auditory cortex?

Temporal lobe

What does the primary auditory cortex process?

Hearing

Where is the primary gustatory cortex?

Insula

What sensory information does the gustatory cortex process?

Taste

Where is the primary olfactory cortex?

Temporal lobe

What does the olfactory cortex process?

Smell

What separates the precentral from the postcentral gyrus?

Central sulcus

What is a gyrus?

A raised fold of cerebral cortex

What is a sulcus?

A shallow groove between folds

What is a fissure?

A deep groove

What separates the two cerebral hemispheres?

Longitudinal fissure

What connects the right and left cerebral hemispheres?

Corpus callosum

What is the main function of the thalamus?

Relay most conscious sensory information to the cerebral cortex

Which sense is the usual exception to the initial thalamic sensory relay?

Smell (olfaction)

Spinal nerve pairs

31 pairs

Cervical nerve pairs

8 cervical

Thoracic nerve pairs

12 thoracic

Lumbar nerve pairs

5 lumbar

Sacral nerve pairs

5 sacral

Coccygeal nerve pairs

1 coccygeal

Cervical nerve count reason

C1 to C7 exit above matching vertebrae; C8 exits between C7 and T1

Thoracic nerve exit relative to vertebrae

Below the vertebra of the same number

Spinal cord gray matter location

Inside, shaped roughly like an H

Spinal cord white matter location

Outside, surrounding gray matter

Posterior root function

Carries sensory axons into the spinal cord

Anterior root function

Carries motor axons out of the spinal cord

Posterior root ganglion contents

Sensory neuron cell bodies

Posterior horn function

Receives and processes sensory input

Anterior horn contents

Somatic motor neuron cell bodies

Lateral horn contents in T1 to L2

Sympathetic autonomic motor neuron cell bodies

Spinal nerve classification

Mixed: sensory and motor axons

Spinal nerve formation

Union of a posterior root and anterior root

Reflex arc sequence

Receptor to sensory neuron to integration center to motor neuron to effector

Ascending spinal tracts carry

Sensory information toward the brain

Descending spinal tracts carry

Motor commands toward spinal motor circuits

Decussation definition

Crossing of a nerve pathway to the opposite side

Three meninges

Dura, arachnoid, pia

Subarachnoid space contains

Cerebrospinal fluid

Epidural anesthesia space

Epidural space, outside the dura mater

Spinal cord end in adults

Conus medullaris near vertebral level L1

Cauda equina definition

Bundle of spinal nerve roots below the conus medullaris

Main spinal nerve plexuses

Cervical, brachial, lumbar, sacral

Brachial plexus nerve roots

C5 to T1

Cervical plexus nerve roots

C1 to C4

Cervical nerve pairs count

8 pairs

Thoracic nerve pairs count

12 pairs

Lumbar nerve pairs count

5 pairs

Sacral nerve pairs count

5 pairs

Coccygeal nerve pairs count

1 pair

Cervical vertebrae vs nerves count

8 cervical nerves but only 7 cervical vertebrae

C1 to C7 nerve exit relative to vertebrae

Exit above matching vertebrae

C8 nerve exit location

Exits between C7 and T1

T1 and onward nerve exit relative to vertebrae

Generally exit below the vertebra of the same number

Spinal cord gray matter cross-section location

Inside, shaped roughly like an H