CNS & PNS ANATOMY

Afferent nerves...

(sensory) - conduct impulses to CNS

Efferent nerves...

(motor) - conduct impulses away from CNS

Somatic nervous system...

Under conscious control (reflex arcs are an exception)

Autonomic nervous system...

Controls involuntary functions. Separated further into sympathetic & parasympathetic

A nucleus is...

Collections of cell bodies in the CNS

A ganglion is...

Collections of cell bodies outside the CNS

What are cranial nerves?

12 pairs that exit the cranial cavity through foramina in the cranium

What are spinal nerves?

31 pairs arising from a specific segment of spinal cord and exiting the vertebral column through interverterbral foramina

What are nerve rootlets?

Connect the CNS with PNS and are groups of axons

At what level does the spinal cord end?

Between L1-L2

What is a dermatome?

An area of skin supplied by a single spinal nerve

What is a myotome?

A group of muscles supplied by a single nerve root

What is the dosal ramus?

Supplies nerve fibres to the back (joints of the vertebral column, muscles of the back and the overlying skin)

What is a ventral ramus?

Supply nerve fibres to skin and muscles of the anterior and lateral regions of the trunk, lower and upper limbs

What cranial nerves originate from the brainstem?

III-XII

Sensory cranial nerves?

I (Olfactory, II (optic), VIII (vestibulocochlear)

Motor cranial nerves?

III (oculomotor), IV (trochlear), VI (abducent) XI accessory) XII (hypoglossal)

Cranial nerves which are both sensory & motor?

V (trigeminal), VII (facial), IX (glossopharyngeal), X (vagus)

Sympathetic cranial nerves?

I (olfactory), II (optic), IV (trochlear), V (trigeminal), VI (abducent), VIII vestibulocochlear), XI (accessory), XII (hypoglossal)

Parasympathetic cranial nerves?

III (oculomotor), VII (facial), IX (glossopharyngeal), X (vagus)

Difference between nerve and nerve fibre

Many multiple nerve fibres per each nerve

What does a general sensory nerve fibre do?

Transmit sensations from the skin (pain, temperature, touch and pressure) or pain and proprioceptive sensations from muscles, tendons and joints

What does a somatic motor nerve fibre do?

Transmit impulses to skeletal muscles

What do visceral sensory nerve fibres do?

Transmit pain or subconscious visceral reflexs sensations (information concerning distension, blood gas, and blood pressure etc) from hollow organs and blood vessels to the CNS

What do visceral motor nerve fibres do?

Transmit impulses to smooth muscle and glandular tissues

What does a special somatic afferent do?

Transmits impulses of special senses from e.g. retina/vestibular apparatus

What does a special visceral afferent do?

Transmits impulses from the taste buds of the tongue/olfactory mucosa

What does a special visceral efferent do?

Transmit impulses to skeletal muscles derived from the branchial arches

A sensory neuron carrying information toward the spinal cord enters through which type of spinal root?

Ventral

A motor neurone exits through which type of spinal roor?

Dorsal