Peripheral nervous system Flashcards
How many pairs of spinal nerves are there
thirty one pairs connected to the spinal cord
How many cranial nerves are there
twelve paired
Cervical nerves
Eight pairs located C1 through C 8
Thoracic nerves
twelve pairs located at T1 through T 12
Lumbar nerves
5 Pairs located L1 through L5
Sacral nerves
Five pairs located s1 through s5
coccygeal
one pair
What are nerve plexus
Networks formed by ventral rami of most spinal nerves, just not thoracic, which subdivide and join to form to form individual nerves
What do cervical plexus nerves do
Supply sensory and motor innervation to the head, neck and trunk
What provides motor innervation to the upper limbs
brachial plexus
What provides motor innervation to the lower limbs
lumbar plexus
What do nerves of the sacral plexus do
They provide sensory and motor innervations to the posterior thighs, legs, feet and pelvis
What does the coccygeal plexus do
Provides sensory innervations to the skin over the coccyx and the perianal region
What is dermatome
a region of the skins surface supplied by afferent fibers of a specific spinal nerve
What is a myotome
skeletal muscle supplied by efferent fibers of a specific spinal nerve
What cranial nerves are only sensory
Olfactory (Conducts sensory for smell), optic nerve, vestibulocochlear deals with hearing and equilibrium
What cranial nerves are only motor
Oculomotor nerve and trochlear nerves and abducens nerve (control eye movements), spinal accessory (controls sternocleidomastoid and trapezius muscles), Hypoglossal nerve (tongue movements)
What cranial nerves are mixed nerves
Trigeminal (conducts sensory signals from the face, scalp and teeth, also control the chewing muscles), facial nerves (conduct sensory signals for taste and motor signals that control facial expressions), glossopharyngeal (control swallowing and signals for mouth throat and ear), vagus nerve (signals for head neck chest abdomen and throat, heart and digestive.
What are the two divisions of peripheral nervous systems
Afferent (sensory) divisions and the efferent (motor division)
What are efferent divisions
include the somatic motor, nervous system and automatic nervous systems
What is the difference between somatic and automatic reflexes
somatic reflexes use skeletal contractions, autonomic reflexes involve smooth muscle and cardiac muscle as well as secretion by glands.
what are withdraw reflections
when the body twitches from stimuli, muscles contract, crossed extensor reflex causes contractions of the extensor muscles on opposite sides of the stimulus
WHat does the knee jerk reflex do
causes extensions of the leg
Spinal cord reflex
located in gray spinal cord matter
segmental reflex
nerve impulses enter and leave at the same spinal cord segment
ipsilateral reflex
nerve impulse come and go to the same side of the body
stech or myotatic reflex
stimulus that causes reflexive stretching of the tendon
extensor reflex
produced by the extensor muscles of the leg
deep tendon reflex
stimulation of deep sensory receptors produces the reflex (ankle jerk reflex)
plantar reflex
stimulation of the outer sole, causes feet to point down and inward
Babinski sign
toe curling response
corneal reflex
closing of eye when touched
abdominal reflex
when the abdominal wall goes inward due to stimulation
superfical reflex
occurs when skim is stimulated
