09 Anatomy and Physiology 121 The Nervous System.pdf -...

Anatomy and Physiology 121: The Nervous System
 General Functions of the Nervous System
 Terms and Topics
 Neural tissue (neurons and neuroglial cells)
 Nerves!
 Nerve impulses (bio-electrochemical)
 Synapses and neurotransmitters
 Sensory neurons and motor neurons
 Receive and respond to stimuli
General Divisions of the Nervous System
 Central Nervous System (brain and spinal cord)
 Peripheral Nervous System (cranial and spinal nerves)
 Sensory Division (sensory receptors)
 Motor Division (effectors)
 Somatic Nervous System (voluntary)
 Autonomic Nervous System (involuntary)
Structure of a Neuron
 Cell Body
 Dendrites (cellular processes)
 Axon (cellular processes)
 Neurilemma
 Nodes of Ranvier
 Schwann Cells (peripheral nervous system)
 Myelin and the Myelin Sheath
 Synaptic cleft (synapses)
 Neurofibrils
 Nissl Bodies (chromatophilic substance)
Classification of Neurons
 Structural
 Bipolar neurons
 Unipolar neurons
 Multipolar neurons

 Functional
 Sensory neurons
 Interneurons
 Motor neurons
Classification of Neuroglial Cells
 Astrocytes
 Oligodendrocytes (central nervous system) & Schwann Cells (peripheral
nervous system)
 Microglia
 Ependyma
Regeneration of a Nerve Fiber
 If a cell body is injured, the neuron is likely to die
 If a peripheral nerve is severed, its distal portion may regenerate and
reestablish its former connections
 Significant regeneration is unlikely in the CNS
Cell Membrane Potential
 Distribution of Ions
 Membrane Potential
 Resting Potential
 Local Changes and the Threshold Potential
 Summation and Action Potentials
 Refractory Period
 All or None Response
 Impulse Conduction
Synapses
 Synapse
 Synaptic cleft
 Presynaptic neuron
 Postsynaptic neuron
 Neurotransmitters