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Nervous System
Nervous System
Nervous System
CNS-Central Nervous System Control stimulates and coordinates all other
body systems Command center
Nervous System
PNS-Peripheral nervous system Nerves outside the spinal cord
Nervous System
ANS-Autonomic nervous system
Nervous System
Fundamental unit of nervous tissue is the neuron Neuron is a nerve cell that includes the
dendrites and axons.
Nervous System
Dendrite- fiber branches that receive impulses from other parts of the nervous system and bring it to the cell.
Axons- transmit the impulses away from the cell body.
Nervous System
Myelin- fatty sheath surrounding the axon. Speeds up impulse conduction. Grey Matter is unmyelinated fiber, in the
cerebral cortex and central spinal cord White matter is myelinated fiber within spinal
cord and fiber systems.
Nervous System
Synapse- transmission of impulses from one neuron to another occurs at here.
Nervous System
Afferent neuron- sensory neuron takes the message from the skin to the brain. Or periphery to the CNS.
Nervous System
Efferent Neuron- motor neuron that takes the message from the brain to the muscle. Or CNS to the periphery.
Nervous System-CNS
Central Nervous System is made up of the Brain and spinal cord.
Brain is made up of the cerebrum, brainstem and cerebellum.
Nervous System
Cerebrum is the largest and main portion of the brain, it is responsible for the highest level of function. It has four lobes.
Nervous System
The four lobes each have different functions.
Nervous System
Thalamus is inside the cerebrum, this is where the nerve cells relay body sensations, where pain is perceived.
Nervous System
Cerebellum means “little brain.” The main function is to control muscle coordination, tone and posture.
Nervous System
Brainstem has three parts, the midbrain, pons, and medulla. Midbrain is center for visual reflexes Medulla is the center for automatic control of
respiration and heart rate.
Nervous System
Brain Protection Skull- bones with fused joints for greater
strength of protection.
Nervous System Brain Protection-three membranes-meninges
Dura mater-outer thickest layer that means in latin
Nervous System-Injuries
Nervous System
Brain Protection-three membranes-meninges Arachnoid mater- middle layer Subarachnoid space- where the shock
absorbing cerebrospinal fluid is located. Pia mater- carries blood
vessels to the brain.
Nervous System
Spinal Cord is 17 inches long (approximate) Has the same 3 protective layers as the brain
Outer dura mater Arachnoid memebrane Inner pia mater Cerebrospinal fluid flows
between arachnoid layer and pia mater
Spinal cord and spinal nerves
Vertebrae
Vertebral Foramen-passageway for the spinal cord.
Intervertebral foramen- sides of the vertebral column, where the spinal nerve roots exit the vertebral canal
Peripheral Nervous System
The part of the nervous system outside of the vertebral column: Cranial Nerves Spinal Nerves
Peripheral Nervous System
Cranial Nerves have origin in the brain. They are sensory nerves, motor nerves or
mixed. Sensory- I, II, VIII, Motor- III, IV, VI, XI, XII Mixed V, VII, IX, X
Peripheral Nervous System
Spinal Nerves
There are 31 pairs of spinal nerves. 8 cervical-exit above their vertebrae 12 thoracic-exit below their vertebrae 5 lumbar 5 sacral 1 coccygeal
Spinal Nerves
Dermatomes- Area of skin supplied with the sensory fiber of
a spinal nerve. Most area have overlap, so total anesthesia
will not occur unless 2 nerves lose function.
Spinal Nerves
Most muscles are inervated by at least 2 spinal nerves so loss of function will not occur, likely the muscle will weaken
Spinal Nerves
Significant levels C3- damage here or above would affect
function of the diaphragm. Need assistance with breathing.
C5- damage from her down would result in loss of upper extremity function.
Spinal Nerves
Plexuses- network of nerves Root/Trunk/Cord/Peripheral nerves
Spinal Nerves
There are 3 plexuses Cervical Plexus- make up C1-C4 Brachial Plexus- make up C5-T1 Lumbosacral Plexus- make up L1-S5
Spinal Nerves
