Chapter 21 - AP

Cranial Nerves: Functional Classification

• The vestibulocochlear nerve does not have a functional classification of motor, unlike the oculomotor, trochlear, and accessory nerves.

Tic Douloureux

• Tic douloureux involves painful neuralgia of the trigeminal nerve.

Vagus Nerve

• The tenth cranial nerve is commonly called the vagus nerve.

Cranial Nerves and Tongue Movement

• The hypoglossal cranial nerve is responsible for movements of the tongue.

Proprioception and Cranial Nerves

• The vagus nerve isn't involved in proprioception; the hypoglossal, accessory, and abducens nerves are.

Spinal Nerve Plexuses

• The thoracic region is not a plexus of the spinal nerves.

Cervical Plexus

• The cervical plexus is located deep in the neck.
• It's formed by the ventral rami of the first four cervical nerves and part of C5.
• The phrenic nerve is part of the cervical plexus.

Brachial Plexus

• The brachial plexus contains nerves that innervate the lower shoulder and entire arm.

Sensory Cranial Nerves

• The sensory cranial nerves include the olfactory, optic, and vestibulocochlear nerves.

Cranial Nerve Originating from the Spinal Cord

• The accessory cranial nerve originates from the spinal cord.

Vagus Nerve Impulses

• Functionally, the vagus nerve increases peristalsis and decreases the heart rate.

Spinal Nerves

• Spinal nerves connect to the spinal cord and exist in 31 pairs.
• Spinal nerves contain both motor and sensory fibers.

Mixed Nerves

• A mixed nerve carries both sensory and motor fibers.

Phrenic Nerve Damage

• Phrenic nerve damage results in the inability to function

Phrenic Nerve Location

• The phrenic nerve is located in the cervical plexus.

Somatic Motor Pathway Neurotransmitter

• Acetylcholine is the neurotransmitter in a somatic motor pathway.

Nerves Innervating the Pelvic Cavity Floor

• Nerves that innervate the floor of the pelvic cavity and some surrounding areas are located in the coccygeal plexus.

Knee Jerk Reflex

• The knee jerk is a segmental reflex because the impulses that mediate it enter and leave the same segment of the spinal cord.
• The knee jerk reflex does not involve the brain.
• The knee jerk is not a flexor reflex; it's an ipsilateral reflex and a spinal cord reflex.

Babinski Reflex

• Normal infants show the Babinski reflex up to 1 year old.

Spinal Nerve Pairs

• There are 5 lumbar nerve pairs.

Lumbar Plexus

• The femoral nerve arises from the lumbar plexus.

Peripheral Nervous System Composition

• The peripheral nervous system includes cranial nerves, spinal nerves, and their branches.
• The vertebral column contains more cervical nerve pairs than vertebrae.

Ventral Nerve Root

• The ventral nerve root is also called the anterior root and contains motor neurons; it does not contain the spinal ganglion.

Dorsal Nerve Root

• The dorsal nerve root is also called the posterior root and includes sensory fibers and the spinal ganglion.

Thoracic Region Plexus

• The brachial plexus contains fibers from the thoracic region of the spinal cord.

Oculomotor Nerve Association

• Closing and opening of the eye(blink reflex) is not associated with the oculomotor nerve; movement of external eye muscles, movement of intrinsic eye muscles, and proprioception of eye muscles are.

Trigeminal Nerve Branches

• The zygomatic nerve is not a branch of the trigeminal nerve; the ophthalmic, maxillary, and mandibular nerves are.

Eye Movement and Cranial Nerves

• The trigeminal nerve is not associated with eye movement; the oculomotor, trochlear, and abducens nerves are.
• Afferent nerves or fibers are only found in sensory.

Peripheral Nervous System

• The peripheral nervous system includes autonomic, sensory, and somatic components.
• Efferent nerves or fibers are found in the autonomic and somatic systems.

Cauda Equina

• The cauda equina refers to the nerves below the ending of the spinal cord.

Spinal Nerve Pairs and Vertebral Column Segments

• The thoracic segment of the vertebral column generates more spinal nerve pairs than any other segment.

Spinal Ganglion Location

• The spinal ganglion is located on the dorsal nerve root.

Cervical Plexus and Cranial Nerves

• Small branches from the cervical plexus join the hypoglossal and accessory cranial nerves.

Babinski Reflex in Infants

• By age 2, the stimulus that once caused the Babinski reflex now causes the plantar reflex in a normal infant.

Vestibulocochlear Nerve

• The vestibulocochlear nerve is likely causing problems with balance and equilibrium.

Cranial Nerve Damage and Tongue Movement

• Hypoglossal nerve damage and a decrease in proprioception correlate with problems in tongue movement.

Motor Pathway Injury

• An injury affecting motor pathways outside the central nervous system reduces the ability to complete simple tasks.

Knee Jerk Reflex Mechanism

• A well-placed tap on the knee in a healthy adult results in the stretch of the tendon, the quadriceps femoris, and stimulation of the muscle spindles.

Somatic vs Automatic Reflexes

• A somatic reflex involves contraction of skeletal muscles, while an autonomic reflex involves contraction of smooth or cardiac muscle or secretions of glands.

Phrenic Nerve Impulse Result

• If the phrenic nerve receives an impulse from the cervical plexus, the diaphragm would stop contracting.

Herpes Zoster (Shingles)

• Herpes zoster is the result of the reactivation of the varicella zoster virus; The cutaneous nerve is affected by the virus causing shingles, which remains dormant in the dorsal root ganglion for years,

Dermatome Symptoms Post-Radiation

• Burning and itching in the affected dermatome post-radiation treatment are most likely a result of herpes zoster

Plantar Reflex in Infants

• A 1-year-old infant extends her great toe without fanning the other toes when responding to stimulation of the outer margin of the sole of the foot because the corticospinal fibers have not yet become fully myelinated, and the Babinski reflex is activated.

Vestibulocochlear Nerve Injury

• An injury that has damaged the vestibulocochlear nerve will have an effect on the ability to hear.

Nerve Plexuses and Numbness

• Numbness in the skin of the buttocks and the posterior surface of the thigh and leg likely involve a condition of the coccygeal plexus.