Anatomy and Physiology - Peripheral Nervous System

Vocabulary flashcards for reviewing the peripheral nervous system based on lecture notes.

What is the Peripheral Nervous System (PNS)?

Nervous tissue outside the brain and spinal cord, including nerves and ganglia.

What are Nerves?

Bundles of axons outside the CNS, along with associated connective tissues and blood vessels.

Where do Cranial Nerves arise from?

Arise from the brain.

Where do Spinal Nerves arise from?

Arise from the spinal cord.

What is the Endoneurium?

Protective tissue covering around each axon.

What is the Perineurium?

Protective tissue covering around fascicle of axons.

What is the Epineurium?

Protective tissue covering around several fascicles, continuous from dura mater of CNS.

What do Sensory Nerves do?

Carry axons of sensory neurons; cell bodies in ganglia.

What do Motor Nerves do?

Predominantly axons of motor neurons. Somatic innervate skeletal muscle; Autonomic innervate smooth muscle, cardiac muscle, and glands; cell bodies in nuclei within brain.

What are Mixed Nerves?

Contain axons of both sensory and motor neurons.

What is the function of the Olfactory Nerve (I)?

Functions in sense of smell, carrying impulses from odor receptors within olfactory epithelium.

What is the function of the Optic Nerve (II)?

Functions in the sense of vision, carrying impulses from rods and cones in the retina of the eye.

What is the function of the Oculomotor Nerve (III)?

Functions in movement of eye; Carries somatic motor impulses to 4 muscles of eyeball and of the upper eyelid; autonomic motor axons adjust shape of lens and size of pupil.

What is the function of the Trochlear Nerve (IV)?

Functions in movement of eye; Carries somatic motor impulses to superior oblique muscle to move eyeball.

What is the function of the Trigeminal Nerve (V)?

Sensory impulses from scalp, face and mouth for touch, pain, temperature, and proprioception; somatic motor impulses to muscles of chewing and middle ear muscles.

What is the function of the Abducens Nerve (VI)?

Functions in movement of eye; Carries somatic motor impulses to lateral rectus muscle to move eyeball laterally (“Abducting” the eye).

What is the function of the Facial Nerve (VII)?

Sensory impulses for taste from taste buds of anterior tongue; somatic motor impulses to muscles of facial expression and middle ear muscles; autonomic motor impulses to lacrimal glands and salivary glands.

What is the function of the Vestibulocochlear Nerve (VIII)?

Functions in sense of hearing and equilibrium.

What is the function of the Glossopharyngeal Nerve (IX)?

Sensory impulses for taste from posterior tongue; somatic motor impulses to muscles of pharynx for swallowing; autonomic motor impulses to parotid gland.

What is the function of the Vagus Nerve (X)?

Sensory impulses for taste from epiglottis and pharynx; somatic motor impulses to muscles of pharynx and larynx for speech, swallowing, and coughing; autonomic motor impulses to lungs, heart, and smooth muscles and glands of respiratory passageways and GI tract

What is the function of the Accessory Nerve (XI)?

Functions in movement of head; Carries somatic motor impulses to sternocleidomastoid and trapezius muscles.

What is the function of the Hypoglossal Nerve (XII)?

Functions in movement of tongue; Carries somatic motor impulses to tongue muscles for speech, manipulation of food, and swallowing.

What are Spinal Nerves?

Union of posterior (sensory) and anterior (motor) roots of the spinal cord; connect CNS to sensory receptors, muscles, and glands.

What does the Posterior Ramus serve?

Serves posterior trunk.

What does the Anterior Ramus serve?

Serves limbs, lateral and anterior trunk.

What does the Meningeal Branch serve?

Serves vertebrae, spinal cord, and meninges.

What are the Rami Communicantes associated with?

Associated with autonomic nervous system.

What is a Plexus?

Network of various numbers of axons from adjacent nerves.

What spinal levels does the Cervical Plexus come from?

C1-C5

What spinal levels does the Brachial Plexus come from?

C5-T1

What spinal levels does the Lumbar Plexus come from?

L1-L4

What spinal levels does the Sacral Plexus come from?

L4-L5 and S1-S4

What is a Reflex?

A fast, involuntary, unplanned sequence of actions that occur in response to a particular stimulus.

Where is the Integrative center for a Cranial Reflex?

Integrative center in gray matter of brain stem.

Where is the Integrative center for a Spinal Reflex?

Integrative center in gray horns of spinal cord.

What does a Somatic Reflex involve?

Involves contraction of skeletal muscles.

What does an Autonomic Reflex involve?

Involves contraction of smooth or cardiac muscle or stimulation of gland; often not perceived consciously.

What is a Reflex Arc?

Specific pathway and sequence of a reflex.

What does a Monosynaptic Reflex Arc synapse with?

Synapse with motor neuron.

What does a Polysynaptic Reflex Arc synapse with?

Synapse with one or more interneurons as well as motor neuron.

What does Ipsilateral mean?

Sensory and motor neurons same side of body.

What is Reciprocal Innervation?

Simultaneous stimulation of one muscle and relaxation of antagonistic muscle.

What is Intersegmental?

Impulses from one sensory neuron ascend and descend to activate interneurons in other segments of spinal cord.

What is the function of Somatic Neurons?

Sensory – input from receptors, conscious; Motor – one; to skeletal muscle; voluntary; excite with acetylcholine.

What is the function of Autonomic Neurons?

Sensory – input from autonomic interoceptors in viscera and blood vessels, subconscious; Motor – two synapse; to cardiac muscle, smooth muscle, and glands; involuntary; excite or inhibit with acetylcholine or norepinephrine.

What part of the nervous system controls the Autonomic Nervous System?

Involuntary regulation by hypothalamus, brain stem, and some spinal cord segments.

What is Biofeedback?

Can learn some conscious control.

What is the Sympathetic Branch responsible for?

Fight or flight.

What is the Parasympathetic Branch responsible for?

Rest and relax or feed and breed.

What is a Preganglionic Neuron?

First in impulse series – myelinated axon in cranial or spinal nerve to ganglion; cell body in brain or spinal cord gray matter.

What is an Autonomic Ganglion?

Synapse between pre/postganglionic neurons; satellite cells protect.

What is a Postganglionic Neuron?

Second in series – unmyelinated axon to effector; Cell body in autonomic ganglion.

What do Sympathetic Trunk Ganglia innervate?

Extend on each side of the vertebral column, innervating organs above the diaphragm

What do Prevertebral Ganglia innervate?

Anterior to vertebral column in abdomen, innervating organs below the diaphragm.

Where are Terminal Ganglia located?

Located close to the effector visceral organ.

What are Autonomic Plexuses?

Network of axons from both sympathetic and parasympathetic neurons, and including some sympathetic ganglia; adjacent to major arteries in thorax, abdomen, and pelvis.

Where is the Myenteric Plexus located?

Between outer longitudinal and inner circular muscle layers.

Where is the Submucous Plexus located?

Between inner circular muscle and mucosa layers.

What do Cholinergic Neurons release?

Release acetylcholine (ACh).

What do Adrenergic Neurons release?

Release norepinephrine (NE).

What do Cholinergic Receptors bind?

Bind acetylcholine (ACh).

What do Adrenergic Receptors bind?

Bind norepinephrine (NE).

What is the function of Nicotinic Receptor?

Depolarizes to excite postsynaptic cell; On dendrites and cell bodies of postganglionic neurons; Neuromuscular junction and in medulla of adrenal gland.

What is the function of Muscarinic Receptors?

Sometimes depolarizes and sometimes hyperpolarizes different cells; On all parasympathetic effect