PNS Flashcards
Peripheral nervous system
Serves as their interface between the CNS, the rest of the body and surrounding environment in which we live
Cranial nerves
Nerves that emerge directly from the brain
Relay information between brain and other parts of the body especially the head and neck
How many pairs of cranial nerves are there
12
CN I
Olfactory nerve
Sensory innervation: smell
CN II
Optic nerve
Sensory: sight/ vision
CN III
Oculomotor
Motor: eye movement
CN IV
Trochlear nerve
Motor: eye movement
CN V
trigeminal
Sensory: facial sensation
Motor: chewing muscles
CN VI
abducens
Motor: eye movement
CN VII
facial nerve
Sensory: taste from anterior 2/3 of tongue
Motor: muscle of facial expression
CN VIII
vestibutocohlear ( auditory nerve)
Sensory: equilibrium and hearing
CN IX
glossopharyngeal nerve
Sensory: taste of posterior from 1/3 of tongue
Motor: swallowing
CN X
vagus nerve
Only cranial nerve that travels into thoracic and abdomen
Sensory: from throat, thoracic and abdominal visceral
Motor: swallowing muscle, diaphragm and motor activity of thoracic and abdominal visceral
CN XI
accessory nerve
Motor: head rotation and shoulder movement
CN XIII
hypoglossal nerve
Motor: tongue movement for speech and swallowing
Spinal nerve
Each segment of spinal cord is connected to a pair of spinal nerves which innervate respective side of the body
How many spinal nerves are there
There are 31 nerves entering and exiting the spinal nerves at various levels
__  Pairs of cervical nerves
C1-C8
__ pairs of thoracic nerves
T1-T12
__ pairs of lumbar nerves
L1-L5
__ Pairs of sacral nerve
S1-S5
__pairs of coccygeal nerves
CO1
Why are there eight pairs of cervical nerves but seven cervical vertebrae
Spinal nerve C1 exits superior to vertebra C1 whereas spinal nerve C8 exits inferior to vertebrae C7
Dorsal root
Posterior and provide sensory input
Contains the axons of sensory neurons who sells bodies are located in dorsal root ganglia
Dorsal root ganglion
Cluster of nuclei present only on the dorsal root
Ventral root
Anterior and delivers motor input
Contains the axons of Motor neurons who Cell bodies are located in gray matter tracks of spinal cord
Roots
Medial to spinal nerves and strictly sensory or motor fibers
Rami
Lateral to spinal nerves and contain sensory and motor fibers
Nerve plexuses
Net work of parietal nerves
 The ventral rami of all spinal nerves branch and join one another lateral to The vertebral column to form a plexus which
Primarily innervate limbs
Fibers from different ventral rami redistribute so that
Each end branch Of the plexus Contains fibers from Several different spinal nerves
Fibers from each central Remus travel to the body periphery via several different branches 
Cervical plexus
Neck
Innervate skin and muscles of neck
Cervical plexus
Phrenic nerve
Most important branch of the cervical plexus
Receives fibers from C3-C5
Innervates diaphragm
Brachial plexus
Lower neck and axiliary region
Receives fibers from C5-T1
Innervates upper limb 
Brachial plexus
Musculocutaneous nerve
Innervates biceps brachii and brachialis
Distal to the elbow it provides sensation of lateral forearm 
Brachial plexus
median nerve
Innervates both vessels of the anterior forearm
Passes to get carpal tunnel and innervates the muscle of lateral palm
Brachial plexus
Ulnar nerve
Travels along the medial side of arm at the elbow it passes posterior to the medial epicondyle
Innervates most hand muscles
receives sensory input from medial hand
Brachial plexus
Radial nerve
Innervates post to your side of upper limb
receives sensory input from dorsal lateral hand
Lumbar plexus
Psoas major muscle
Receives fibers from L1- L5
Smaller branches innervate parts of abdominal wall in the Psoas but its main branch descend to innervate anterior thigh
Lumbar plexus
Femoral nerve
Runs deep to inguinal ligament
Innervates anterior thigh muscle
Lumbar plexus
Obturator nerve
Passes through obturator foramen Of the pelvis to enter medial thigh
Innervates adductor muscles
Sacral plexus
Inferior to lumbar plexus
Receives fibers from L4-S4
Innervates pelvis, buttox, lower limb
Lumbosacral plexus
Lumbar and sacral plexuses are often Combined since some fibers from the lumbar plexus contribute to the sacral plexus
Lumbosacral plexus
Sciatic nerve
Largest nerve in body
passes through greater sciatic notch innervates posterior thigh
Branches into the tibial nerve in common fibular nerve
 Lumbosacral plexus
Tibial nerve
Innervates all muscles in posterior leg as well as skin on sole of feet
Lumbosacral plexus
Common fibular nerve ( common peroneal)
Innervates antrolateral leg
Lumbosacral plexus
Pudendal nerve
Innervates muscles and skin of perineum help stimulate erection and sexual arousal
Autonomic nervous system
System of motor neurons that innervate smooth, cardiac muscles and glands
Sympathetic nervous system
Fight or flight
controlled by E and norepinephrine
Mobilize body to respond to stress when more energy is needed
Parasympathetic nervous system
Rest and digest controlled by vagus nerve routine maintenance and allows body to relax and conserve energy
