Chapter 14- Peripheral Nervous System Flashcards
Sensory Receptors
Detect internal or external conditions
Motor endings
innervate effectors
Nerves
Bundles of axons travelling to similar destinations
Ganglia
Cluster of cell bodies in the PNS
Cranial nerves
Attach to brain and pass through skull foramina
I + II attach to forebrain
III - XII attach to brainstem
Sensory, motor, or mixed
Cranial Nerve Names
I- Olfactory
II- Optic
III- Oculomotor
IV- Trochlear
V- Trigeminal
VI- Abducens
VII- Facial
VIII- Vestibulocochlear (Auditory)
IX- Glossopharyngeal Nerve
X- Vagus
XI- Accessory
XII- Hypoglossal
Cranial Nerve I
Olfactory Nerve
Sensory
Responsible for sense of smell
Cranial Nerve II
Optic Nerve
Sensory
Responsible for Vision
Cranial Nerve III
Oculomotor nerve
Motor
Innervate 4 of 6 external eye muscles
Cranial Nerve IV
Trochlear Nerve
Motor
Innervates extrinsic eye muscle
Cranial Nerve V
Trigeminal Nerve
Mixed
Sensory innervation to face
Motor innervation to chewing muscles
Cranial Nerve VI
Abducens
Motor
Abducts eyeball
Cranial Nerve VII
Facial Nerve
Mixed
Muscles of facial expression
Some taste and ear sensation
Branches of Facial Nerve
Temporal
Zygomatic
Buccal
Mandibular
Cervical
Cranial Nerve VIII
Vestibulocochlear Nerve
Sensory
Responsible for hearing and balance
Cranial Nerve IX
Glossopharyngeal Nerve
Mixed
Control tongue and pharynx
Some taste
Cranial Nerve X
Vagus Nerve
Mixed
Controls parasympathetic response
Runs throughout thorax and abdomen
Cranial Nerve XI
Accessory Nerve
Motor
Innervates neck and back muscles
Sternocleidomastoid and trapezius
Cranial Nerve XII
Hypoglossal Nerve
Motor
Controls tongue muscles
Spinal Nerves
31 Nerve pairs innervating the body
8 Cervical
12 Thoracic
5 Lumbar
5 Sacral
1 Coccygeal
Spinal nerve naming patterns
Cervical- Share name with vertebrae on top of
Example- C4 (nerve) is between C3+C4 (vertebrae)
Exception- c8, under C7 vertebrae
Other- Share name with vertebrae below
Example- T2 (nerve) is between T2+T3 (vertebrae)
Parts of Spinal Nerves
Roots- Connect spinal nerve and spinal cord
Rami- Branch from spinal nerve to innervate body
Dorsal and ventral for each
Dorsal root
Sensory fibers and cell bodies for sensory neurons
Ventral root
Motor neuron fibers emerging from spinal cord
Dorsal rami
Sensory and motor fibers that innervate the posterior torso in neat, segmented patterns
Ventral rami
Sensory and motor fibers that innervate the anterolateral torso and limbs
Form plexuses
Thoracic Innervation
Dorsal and Ventral Rami (T2-T12) follow neat, segmented pattern
Ventral rami lead to intercostal nerve, lateral cutaneous, and anterior cutaneous nerves
Nerve plexuses
Branching and merging of ventral rami to form a network of new nerves
Primarily serve limbs
Cervical, Brachial, Lumbar, and Sacral
Cervical Plexus
Ventral rami of C1-C4
Deep in neck
Innervate skin and muscles in anterior neck
Phrenic nerve- Innervates Diaphragm
Brachial Plexus
Ventral rami of C5-C8 and T1
Lie in neck and axillary regions
Form musculocutaneous, median, ulnar, radial, and axillary nerves
Nerves of the Lateral cord
Musculocutaneous and Median
Nerves of the Medial Cord
Median and Ulnar
Nerves of the Posterior Cord
Radial and Axillary
Musculocutaneous Nerve
Lateral cord
Innervates anterior arm
Median Nerve
Lateral and medial cords
Innervates anterior forearm and lateral palm (thumb side)
Ulnar Nerve
Medial cord
Innervates intrinsic hand muscles and medial hand on both sides (Pinky side)
Radial nerve
Posterior cord
Largest nerve of brachial plexus
Innervates posterior upper limb
Axillary nerve
Branch of radial nerve (posterior cord)
Inntervates deltoid and teres minor
Lumbar plexus
Ventral rami of L1-L4
Form femoral and obturator nerves
Femoral Nerve
Lumbar plexus
Innervates anterior thigh
Obturator nerve
Lumbar plexus
Innervates medial thigh (adductor muscles)
Sacral plexus
Ventral rami of L4-L5 and S1-S4
Forms Sciatic nerve, gluteal nerves, and pudendal nerves
Sciatic Nerve
Largest nerve of leg
Two nerves in 1 sheath:
Tibial nerve
Fibular (peroneal) Nerve
Tibial nerve
Innervates posterior lower limb
Fibular (peroneal) nerve
Innervates anterolateral leg
Superior and inferior gluteal nerves
Innervate gluteal muscles
Pudendal nerves
Innervate muscles of the perineum
Dermatomes
Map of cutaneous innervation by spinal nerve
Upper limb- Brachial plexus
Anterior lower limb- Lumbar plexus
Posterior lower limb- Sacral plexus
Flaccid Paralysis
Damage between spinal cord and muscle
No contraction
Spastic Paralysis
Damage between brain and spinal cord
Unconscious and uncontrolled muscle contraction