Cranial & Peripheral Nerves – Review Flashcards

Question-and-answer style flashcards summarizing cranial-nerve identification and function, peripheral nerve structure, spinal nerves, dermatomes, and nerve plexuses for exam review.

How many pairs of cranial nerves are there and to which nervous system division do they belong?

Twelve pairs; they are part of the Peripheral Nervous System (PNS).

Which cranial nerve is the only one that extends beyond the head and neck to innervate thoracic and abdominal viscera?

CN X – the Vagus nerve.

What are the three categories of cranial-nerve function used in the mnemonic "Some Say Marry Money, But My Brother Says Big Brains Matter Most"?

Sensory, Motor, or Both (mixed).

Which cranial nerves are purely sensory?

CN I (Olfactory), CN II (Optic), CN VIII (Vestibulocochlear).

Which cranial nerves are purely motor?

CN III (Oculomotor), CN IV (Trochlear), CN VI (Abducens), CN XI (Accessory), CN XII (Hypoglossal).

Which cranial nerves carry both sensory and motor fibers?

CN V (Trigeminal), CN VII (Facial), CN IX (Glossopharyngeal), CN X (Vagus).

What is the primary function of CN I?

Olfaction (sense of smell).

Loss of smell due to damage of a cranial nerve is called what, and which nerve is involved?

Anosmia; damage to CN I (Olfactory).

Which cranial nerve carries visual impulses from the retina to the optic cortex?

CN II – the Optic nerve.

Damage to which cranial nerve can lead to blindness?

CN II (Optic).

Which midbrain nuclei-based nerve controls most extra-ocular muscles as well as pupil size and lens shape?

CN III – Oculomotor nerve.

Which single extra-ocular muscle is supplied by the Trochlear nerve, and what is the nerve’s Roman numeral?

The superior oblique muscle; CN IV.

Which cranial nerve has three major branches (ophthalmic, maxillary, mandibular) and supplies facial sensation and muscles of mastication?

CN V – Trigeminal nerve.

Name the extra-ocular muscle controlled by CN VI(Abducens)

The lateral rectus muscle (abducts the eye).

Which cranial nerve controls muscles of facial expression and carries taste from the anterior two-thirds of the tongue?

CN VII – Facial nerve.

What two special senses are carried by the Vestibulocochlear nerve, and what numeral is it?

Hearing and equilibrium; CN VIII.

Which cranial nerve provides taste to the posterior one-third of the tongue and motor supply to some pharyngeal muscles?

CN IX – Glossopharyngeal nerve.

What major somatic motor functions are mediated by the Accessory nerve (CN XI)?

Motor supply to the sternocleidomastoid and trapezius muscles.

Which cranial nerve controls tongue movements?

CN XII – Hypoglossal nerve.

Complete the mnemonic for cranial-nerve names beginning with “Oh Once One Takes …”.

Oh Once One Takes The Anatomy Final, Very Good Vacations Are Heavenly.

How many pairs of spinal nerves exist, and which body region do they generally not supply?

31 pairs; they do not supply the head (that’s the cranial nerves’ job).

Break down the 31 pairs of spinal nerves by region.

8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal.

What type of fibers are found in ventral spinal roots, and from which horn do they originate?

Efferent (motor) fibers; they originate from neurons in the ventral horn.

What type of fibers are found in dorsal spinal roots, and where are their cell bodies located?

Afferent (sensory) fibers; cell bodies are in dorsal root (spinal) ganglia.

Define a dermatome.

A skin segment innervated by a single spinal nerve.

Name the three connective-tissue coverings of a peripheral nerve from outermost to innermost.

Epineurium, perineurium, endoneurium.

Differentiate between dorsal and ventral rami of spinal nerves in terms of innervation.

Dorsal ramus supplies the back (narrow strip of skin and intrinsic muscles); ventral ramus supplies the rest of trunk and limbs, typically via plexuses.

What is a nerve plexus and which spinal nerve region (thoracic or others) does NOT form plexuses?

An interlacing network of ventral rami; thoracic T2-T12 ventral rami do not form plexuses but become intercostal nerves.

Which spinal nerve contributions form the cervical plexus, and what is its most important nerve?

Ventral rami C1-C4; the phrenic nerve (innervates the diaphragm).

List the major terminal nerves of the brachial plexus.

Axillary, musculocutaneous, median, ulnar, radial.

Which spinal roots form the brachial plexus?

Ventral rami C5-T1.

Which nerve of the lumbar plexus supplies the anterior thigh muscles?

Femoral nerve.

Which nerve of the lumbar plexus passes through the obturator foramen to the medial thigh?

Obturator nerve.

What is the largest nerve in the body, arising from the sacral plexus?

The sciatic nerve.

Which spinal roots contribute to the sacral plexus?

Ventral rami L4-S4.

Define a mixed nerve in functional classification.

A peripheral nerve containing both sensory (afferent) and motor (efferent) fibers, often with somatic and autonomic components.

What type of ganglia contain cell bodies of sympathetic and parasympathetic motor neurons?

Autonomic ganglia (motor, visceral).

Which connective-tissue layer bundles groups of axons into fascicles within a nerve?

Perineurium.

Which cranial nerve test is commonly performed by dentists when numbing the mandibular branch?

Testing the Trigeminal nerve (CN V) for facial sensation and motor to mastication.