Nervous System (Overview/General) Flashcards
Most common neuron that makes up skeletal muscle and Autonomic Nervous System
Multipolar Motor Neuron
Neuron that conducts sensory information from periphery to Central Nervous System.
Pseudo-unipolar Sensory Neuron
Neuroglia
Non-excitable and non-neuronal cells; support, insulate and nourish neurons; in both CNS and PNS
CNS is composed of ___ and ___.
Brain; Spinal Cord
Gray Matter
Composed of neuron cell bodies.
White Matter
Composed of interconnecting fiber tracts.
Meninges
Protect CNS; 3 layers
Dura Mater
Outer most layer; thick/tough
Arachnoid Mater
Intermediate layer; delicate, and avasular
Pia Mater
Innermost layer; delicate and transparent; covers outer surface of brain and spinal cord
PNS has two types of nerve fiber, what are they?
Myelinated and non-myelinated
How many pairs of cranial nerves are there?
12; 11 from brain; 1 from superior spinal cord
How many pairs of spinal nerves are there?
31; 8 cervical; 12 thoracic; 5 lumbar; 5 sacral; 1 coccygeal
A _____ is when nerve fibers mingle and a new set of multi segmental peripheral nerves emerge.
Nerve Plexuses
Most muscles are innervated by how many peripheral nerves?
One
Most muscles are innervated by how many spinal nerves?
One
Dermatome
Unilateral area of skin, innervated by sensory fibers of a single spinal nerve.
Screen for nervous system function by clinically examining dermatomes:
C5, C6, C7, C8, T1, L1, L2, L3, L4, L5, S1, S2
C5: Mid deltoid C6: Dorsal aspect of thumb web space C7: Dorsal aspect of mid-finger C8: Medial border of 5th metacarpal T1: Medial forearm L1: Inguinal area L2: Anterior Mid-thigh L3: Medial knee L4: Medial malleolous L5: Distal medial dorsum of foot S1: Lateral border of foot S2: Medial/Posterior calcaneous
Myotome
Unilateral mass of muscle innervated by motor fibers of a single spinal nerve.
Screen nervous system function by clinically examining myotomes (using manually resisted, isometric strength tests):
C1-2, C3, C4, C5, C6, C7, C8, T1, L2-3, L3-4, L4-5, L5, L5-S1 (2), S1-2
C1-2: Cervical flexion C3: Cervical side bend C4: Scapular elevation C5: Shoulder abduction C6: Elbow flexion C7: Elbow extension C8: Thumb abduction T1: Funger abduction L2-3: Hip flexion L3-4: Knee extension L4-5: Ankle DF L5: Great toe extension L5-S1: knee flexion, ankle eversion S1-2: Ankle PF
Hyporeflexia is seen with injury to what nervous system?
PNS
Hypereflexia is seen with injury to what nervous system?
CNS
Muscle stretch reflexes
assessed in conjunction with dermatomes and myotomes; tap tendon = small but rapid stretch
In assessing muscle stretch reflexes, the reflex is ____ with in the spinal cord.
Mediated
In assessing muscle stretch reflexes, the reflex is ____ through descending inhibition from the brain.
Modulated
Screen nervous system function by clinically examining muscle stretch reflexes:
C5, C6, C7, L2-4, L5, S1-2
C5: Biceps brachii C6: Brachioradialis C7: Triceps L2-4: Quadriceps L5: Medial hamstring S1-2: Gastroc-soleous
Somatic Nervous System
Component of CNS and PNS; general sensory and voluntary motor innervation to parts of the body; only innervates skeletal muscle
Autonomic Nervous System
Regulates involuntary functions; composed of visceral sensory, and visceral motor fibers; transmit to from CNS/PNS
Visceral Sensory
Transmit afferent signals from viscera to CNS
Visceral Motor
Transmit efferent signals from CNS to smooth muscle, cardiac muscle, and glands
What are the two divisions of the ANS?
Sympathetic and Parasympathetic
Sympathetic
Fight or flight; between 1st thoracic and 2nd or 3rd lumbar regions
Parasympathetic
Promotes normal function and conserves energy; thoracic and abdominal viscera receive outflow through vagus nerve (Cranial Nerve 10)
Somatic Nervous Systems conveys what senses?
Touch, pain, temperature, and proprioception.
______ are linked to form right and left sympathetic trunks on each side of the vertebral column and extend essentially the length of the column.
Paravertebral ganglia
______ are in the plexuses that surround the origins of the main branches of the abdominal aorta.
Prevertebral ganglia
Splanchnic nerves
Convey visceral efferent and afferent fibers to and from the viscera of the body cavities.
In the gray matter of the brainstem, the fibers exit the CNS within cranial nerves 3, 7, 9, and 10, these fibers constitute the ______.
Cranial parasympathetic outflow
In the gray matter of the sacral segments of the spinal cord, the fibers exit the CNS through the anterior roots of sacral spinal nerves S2-4, and the pelvic splanchnic nerves that arise from their anterior rami, these fibers constitute the ____.
Sacral parasympathetic outflow
The Enteric Nervous System consists of what two interconnected plexuses?
Myenteric plexus of the wall of the musculature; and submucosal plexus serving the gut lining/mucosa.
