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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.
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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 hard mother
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.
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 Nervous System
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
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