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NERVOUS. SYSTEM. TOPIC #5. Nervous System Notesheet Neuron Vocabulary Nervous System Web Lab Day 1 and 2 Neurons Notes (includes spinal nerve notesheet ) Nervous System Crossword Quiz 1 Central Nervous System Blood- BrainBarrier Article & Summary. Neuron Vocabulary. Cell body
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NERVOUS SYSTEM
TOPIC #5 • Nervous System Notesheet • Neuron Vocabulary • Nervous System Web Lab Day 1 and 2 • Neurons Notes (includes spinal nerve notesheet) • Nervous System Crossword • Quiz 1 • Central Nervous System • Blood-BrainBarrier Article & Summary
Neuron Vocabulary • Cell body • Nissl substance • Neurofibrils • Dendrites • Axons • Axonal terminals • Neurotransmitters • Synaptic cleft • Synapse • Myelin • Schwann cells • Myelin Sheath • Neurilemma • Nodes of Ranvier • Nuclei • Ganglia • Tracts
NEURAL IMPULSE Parts 2 and 3 • Continuous conduction • Unmyelinated neurons • Saltatory conduction • Myelinated neurons • Impulse travels faster as it jumps from/to each Node of Ranvier • Video • Neurotransmitters carry impulses across the synapse from pre-synaptic neurons to post-synaptic neurons
Part 8 • Resting Potential • Inside neuron is negative relative to outside • Extracellulary: More Na+ ions • Intracellularly: More K+ ions • Action Potential when neurons start firing messages/impulses • A strong enough stimulus causes charge reversal! • Positive Na+ ions rushing into neuron and K+ out = DEPOLARIZATION! • Repolarizationoccurs when K+ ions diffuse out of cell after impulse passes restoring overall negativity intracellularly • Neuron cannot conduct another impulse until repolarization is restored
TYPES of neurons • There are 12 pairs of cranial nerves in the PNS that serve the head and the neck. • Only one pair (the vagus nerve) extends to the thoracic and abdominal cavities. • There are 31 pairs of spinal nerves in the PNS. • Formed by ventral & dorsal roots of spinal cord. • Named by the region of cord from which they arise. • What happens after a spinal nerve is formed? • It divides into dorsal & ventral rami • Dorsal rami serve skin and muscles of posterior trunk • Ventral rami form plexuses (complex nerve networks that serve the limbs, motor and sensory) • T1 – T12 spinal nerves – ventral rami form intercostal nerves • Serve muscles between ribs & skin and also anterior/lateral trunk.
Central Nervous System • Embryonic development • Starts out as simple neural tube along length • Anterior end expands by 4th week = brain • Posterior end becomes spinal cord • Central canal enlarges into four main regions
SPINAL CORD • 17 inches long • Continuation of brain stem • 2-way communication pathway to/from the brain • Major reflex center • Protected by vertebrae and meninges • 31 pairs of spinal nerves arise from it • Caudaequina (page 227)
BRAIN • 4 main parts (page 215) • Cerebral Hemispheres • Divided into lobes each with its own function • Diencephalon (interbrain)
3. Brain Stem – size of thumb, 3 inches long • Midbrain • Pons • Medulla Oblongata • Reticular Formation 4. Cerebellum – provides precise timing of voluntary muscle activity, controls balance and equilibrium Draw sagittal suture of brain and color and label the parts we have talked about today (page 219)
Protection of CNS • Meninges– connective tissue membranes that cover/protect the brain • Dura Mater • Arachnoid Mater • Pia Mater • Cerebrospinal Fluid – continuously circulates in the brain maintaining normal pressure • What? • Formed from? • How can you test it? • Blood Brain Barrier (homework)