Peripheral Nervous System Flashcards

Flashcards about the Peripheral Nervous System (PNS)

What is the Peripheral Nervous System (PNS)?

All neural structures outside the CNS, divided into Somatic and Autonomic systems.

What is the role of the Somatic Nervous System?

Connects CNS to skeletal muscles and skin; oversees conscious activities.

What is the role of the Autonomic Nervous System?

Fibers that connect viscera to CNS.

How many pairs of cranial nerves are there?

12 pairs.

How many pairs of spinal nerves are there?

31 pairs.

What is a nerve?

Bundle of nerve fibers.

What is a ganglia?

Cluster of neuron cell bodies.

What do mechanoreceptors sense?

Sense changes that deform receptors.

What do thermoreceptors sense?

Temperature changes.

What do photoreceptors respond to?

Light energy.

What do chemoreceptors sense?

Changes in concentration of chemicals.

What do pain receptors respond to?

Tissue damage.

Where are general sensory receptors located?

Widely spread, associated with muscles, joints, skin, and viscera.

What do exteroreceptors detect?

Body surface changes.

What do visceroreceptors detect?

Changes in viscera.

What do proprioceptors detect?

Changes in muscles and tendons.

What do Meissner's corpuscles detect?

Skin - touch.

What do Ruffini endings detect?

Skin - deep pressure.

What are nerves?

Cordlike organs consisting of a bundle of peripheral nerve fibers enclosed by connective tissue.

What is the function of endoneurium?

Encloses axons and their myelin sheaths.

What is the function of perineurium?

Bundles fibers into fascicles.

What is the function of epineurium?

Tough fibrous sheath around a nerve.

How are nerves classified?

Sensory, motor, and mixed nerves.

List the cranial nerves.

Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal.

How do spinal nerves connect to the spinal cord?

Connect to the spinal cord via ventral (motor) and dorsal (sensory) roots.

What is a nerve plexus?

A nerve network originating from different levels of the spinal cords that serve the same part of the body.

What are the five spinal nerve plexuses?

Cervical, brachial, lumbar, sacral, and coccygeal plexuses.

What does the cervical plexus serve?

Serves the head, neck, and shoulders; gives rise to the phrenic nerves.

What does the brachial plexus serve?

Serves the chest, shoulder, and upper limb.

What does the lumbar plexus serve?

Serves the back, abdomen, groin, and lower limb; gives rise to the femoral nerves.

What does the sacral plexus serve?

Serves the buttock, pelvis, perineum, and lower limb; gives rise to the sciatic nerve.

What does the coccygeal plexus serve?

Serves the skin over the coccyx.

What is a dermatome?

the area of skin innervated by the cutaneous branches of a single spinal nerve

Describe the Somatic Nervous System.

Innervates skeletal muscle, one neuron, releases Acetylcholine (Ach), stimulatory.

Describe the Autonomic Nervous System.

Reflexes, two efferent neurons, releases Ach, epinephrine, norepinephrine, cardiac, smooth muscle, glands, effectors contract, secrete or inhibit.

Describe the Parasympathetic Nervous System.

Originates from the brain stem and S1-S4 (craniosacral), uses acetylcholine, maintains daily body functions, "REST AND DIGEST".

Describe the Sympathetic Nervous System.

Originates from T1-L2 (thoracolumbar), neurotransmitter is acetylcholine, epinephrine, norepinephrine, response to stress, "FLIGHT or FIGHT".