Peripheral nervous system

What does the peripheral nervous system consist of

All nervous tissue outside the central nervous system (cranial nerves, spinal nerves, sensory receptors, ganglia, etc)

What are the two of the six types of neuroglia found in the PNS and their function

Schwann cells-forms myelin sheath around axons

Satellite cells-provides structural support and regulate the exchange of material

What is a nerve and describe the organization of the nerve

a nerve is a bundle of axons and their neuroglia wrapped in connective tissue

Endoneurium- surrounds each axon

Perineurium- surrounds each bundle of axons

Epineurium- external layer of a nerve

Describe the three functional types of nerves 

Sensory (afferent) nerves- transmit information towards the CNS

Motor (efferent) nerves- transmit information away from the CNS

Mixed nerves- composed of sensory and motor neuron (transmit information in both directions)

Out of the twelve cranial nerves, what are cranial nerves 1-4, is it sensory, motor or mixed and their function

Cranial nerve 1- Olfactory nerve sensory. Its function is smell

Cranial nerve 2- Optic nerve (sensory) its function is vision

Cranial nerve 3- Oculomotor (motor) and its function is eye movement and open eyes

Cranial nerve 4- Trochlear (motor) and its function is eye movement

Out of the twelve cranial nerves, what are cranial nerves 5-8, is it sensory, motor or mixed and their function

Cranial nerve 5-Trigeminal (motor and sensory) and its function is mastication, touch, and pain

Cranial nerve 6- Abducens (motor) and its function is lateral eye movement

Cranial nerve 7- facial (motor and sensory) and its function is muscles of the face and scalp and taste buds

Cranial nerve 8- vestibulocochlear (sensory) and its function is hearing and equilibrium

Out of the twelve cranial nerves, what are cranial nerves 9-12, is it sensory, motor or mixed and their function

Cranial nerve 9- glossopharyngeal nerve (motor and sensory) and its function is taste buds and salivation and swallowing 

Cranial nerve 10- Vagus nerve (motor and sensory) and its function is swallowing, sensation of hunger, gastrointestinal discomfort, gastrointestinal secretion and motility

Cranial nerve 11- Accessory neve (motor) and its function is swallowing head neck and shoulder movement

Cranial nerve 12- Hypoglossal (motor) and its function is tongue movement 

Are all spinal nerves considered mixed nerves? What is the dorsal root and the ventral root?

yes, the dorsal root is sensory and the ventral root is motor

What is a plexus? what are the names of the different plexus

spinal nerves cluster together to form networks known as plexuses

cervical- c1-c4

Bracchial- C5-C8

Lumbar- L1-L4

Sacral- L4-L5 and S1-S4

Coccygeal- S4-S5

Identify the plexus, nerve and their respective distribution

Cervical plexus; phrenic nerve: diaphragm

Brachial: axillary nerve: muscle of the shoulder. Radial nerve:extensor muscle of the arm and forearm (thumb). Median nerve: flexor muscle of the forearm. (in between ulnar and radius) Ulnar: flexor carpi ulanaris (pinky)

Thoracic: intercostal nerve:control the intercostal spaces

Lumbar: femoral nerve: anterior thigh muscles

Sacral plexus: sciatic nerve: flexor muscles of the thigh. Fibular nerve: Muscles of the lower leg (runs along fibula.) Tibial nerve: posterior muscles of the leg (runs along tibia)

What is the function of each element of the reflex arc

sensory receptor- responds to stimulus by producing a generator or receptor potential

sensory neuron- axon conducts impulses from receptor to integrating centor

Integrating center- one or more regions within the CNS that relay impulses from sensory to motor neurons

Motor neuron- axon conducts impulses from integrating center to effector

Effector- muscle or gland that responds to motor impulses

What are the functions of the four somatic spinal reflexes that aid in homeostasis

stretch reflex- prevents excessive stretching of the muscle. maintenance of upright posture

Deep tendon reflex-prevents over contraction of muscles. Protects tendon from injury

Withdrawal reflex-results in movement away from a negative stimulus. Flexion of a body part

Crossed extensor reflex-occurs simultaneously with withdrawal reflex. Promotes extension of the corresponding body part