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58 Cards in this Set
- Front
- Back
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Chapter 7
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The Nervous System
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• Organization
The Nervous System |
– Central Nervous System
–Peripheral Nervous System |
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-Central Nervous System
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• Brain & spinal cord
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–Peripheral Nervous System
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• Cranial & spinal nerves
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• Cells
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– Neurons
– Glial cells |
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– Neurons
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• Electrically excitable
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– Glial cells
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• Supportive
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Neurons
structure |
– Cell body
– Dendrites – Axon |
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– Cell body
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• Nucleus, Nissl bodies
• Nuclei vs. Ganglia |
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– Dendrites
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• Input region
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– Axon
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• Transmits signals
• Axon hillock • Axon collaterals • Axon terminal – Output region |
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• Axon terminal
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– Output region
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Based on function:
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• Sensory/Afferent
Motor/Efferent: |
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• Sensory/Afferent:
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to CNS
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Motor/Efferent:
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from CNS to effectors
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– Somatic:
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skeletal m.
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– Autonomic:»
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cardiac m., smooth m., glands
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Sympathetic »
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“fight or flight”
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Parasympathetic•
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“rest and digest”
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Association/Interneuron:
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within CNS
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Based on structure:
neurons |
Pseudounipolar
Bipolar Multipolar |
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• Pseudounipolar
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– Sensory neurons
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• Bipolar
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– Retina
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• Multipolar
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– Motor neurons
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Neuroglial cells
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Peripheral nervous
system Central nervous system |
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Peripheral nervous
system |
– Schwann cells:
Satellite cells: |
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– Schwann cells:
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myelination
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Satellite cells:
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protection
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Central nervous system
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Oligodendrocytes
– Microglia: Astocytes: Ependymal cells: |
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Oligodendrocytes
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myelination
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Microglia:
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fight disease
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– Astocytes:
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regulatory;
blood brain barrier |
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– Ependymal cells:
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form
CSF |
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Myelination
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Wrapping of glial cell
around axon |
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Wrapping of glial cell
around axon |
– Insulation
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Myelinated vs.
unmyelinated axons |
a
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Nodes of Ranvier
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a
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White matter vs. gray
matter |
a
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Blood Brain Barrier
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• Structure:
• Purpose |
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• Structure:
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Tight junctions between endothelial cells
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• Purpose
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Prevent unwanted substances from reaching brain
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• Allowed through:
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Gases, glucose, lipid-soluble drugs
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Not allowed through:
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– Cells, proteins, water-soluble drugs
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Blood Brain Barrier
Astrocytes’ role |
– Influence tight junction, carrier, channel and enzyme
production in endothelial cells – Secretion of chemical to affect “tightness” – Allows for glucose movement |
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Electrical Activity
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At rest:
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At rest:
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• K+ high inside; Na+ high outside
– Maintained by Na+/K+ pump |
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– At rest:
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• RMP = -70 mV
– Inside cell is negative; outside is positive |
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– Created by:
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» Concentration gradients
» Different permeabilities |
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Electrical Activity
– Excitability |
• Ability to change membrane potential
• Types of changes: |
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• Ability to change membrane potential
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– Caused by ion current
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• Types of changes:
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– Depolarization
– Repolarization – Hyperpolarization |
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– Depolarization
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» Less negative (-70 mV to +30 mV)
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– Repolarization
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» Back to rest (+30 mV to -70 mV)
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– Hyperpolarization
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» More negative (-70 mV to -90 mV)
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Electrical Activity
• Ion gating |
– Some ion channels
are always open – Some ion channels are gated |
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– Some ion channels
are always open |
• Leak channels
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Some ion channels
are gated |
• Opening of gate
increases permeability |
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• Types of gates:
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– Voltage
– Chemical |
