1. Ch. 12 The Nervous System and Nervous Tissue

2. Objectives
Understand how the nervous system is divided and the types of cells that are found in nervous tissue
Know the anatomy of a neuron and the structural and functional types of neurons
Understand what occurs at the synapse

3. The Nervous System Maintains internal coordination
Sensory information
Processing
Response
Two major subdivisions
Central (CNS)
Brain and spinal cord
Peripheral (PNS)
Nerves and ganglia

4. Divisions of Nervous System
legacy.owensboro.kctcs.edu

5. Divisions of Nervous System
CNS
brain and spinal cord
PNS
Cranial nerves
Spinal nerves
Sensory division
Sensory information form environment to CNS
Motor division
Somatic
Impulses to skeletal muscle
Autonomic
Impulses to cardiac and smooth muscle, glands
Sympathetic
parasympathetic

6. Neurons Communication cells of the nervous system
Properties that allow communication
Excitability
Conductivity
Secretion
Three functional classes
Afferent (sensory) neurons
Interneurons (association neurons)
Efferent (motor) neurons

7. Neuron Structure Soma – control center Dendrites Axon Hillock Axon
Chromatophilic (Nissl) bodies
Neurofibrils
Dendrites
Receptive sites
Conduct towards
Axon Hillock
Axon
Impulse generators
Conduct away
mindcreators.com

8. Synapse Site of neuronal communication Two types Synaptic cleft
Axodendritic
Axosomatic
Synaptic cleft
neurotransmitters
catalog.nucleusinc.com

9. Structural Classification
science.howstuffworks.com

10. Neuroglial Cells Four types of glial cells
Astrocytes
Synapse formation
Brain derived trophic factor
Nourish
Regulation of neurotransmitters
K+ regulation
Oligodendrocytes
myelination
Microglia
Immune protection
Macrophages
Ependymal cells
Internal lining of CNS
Production of CSF
Two types of glial cells found only in PNS
Schwann cells
Myelination
Satellite cells
Provide electrical insulation around soma
Chemical regulation

11. Myelination
nature.com
faculty.stcc.edu

12. Nerves Nerve Nerve composed of multiple axons Epineurium Perineurium
Collection of nerve fibers in the PNS
Nerve composed of multiple axons
Epineurium
Perineurium
Fascicles
endoneurium
web.uaccb.edu

13. Grey and White Matter of CNS
Grey matter
cell bodies, dendrites, unmyelinated axons, neuroglia
White matter
Myelinated axons
histology.leeds.ac.uk

14. Reflex Arcs Reflex Monosynaptic Polysynaptic
Rapid, autonomic motor responses to stimuli
Somatic or visceral
Monosynaptic
Direct connection between afferent and efferent neurons
Polysynaptic
One or more interneurons involved

15. Spinal Reflexes

16. Neuronal Circuits Diverging circuits Converging circuits
Signal is passed to many pathways
Converging circuits
Various signals influence one neuron
Reverberating circuit
One neuron in a series sends feedback to a previous neuron in the circuit
Serial and Parallel processing

17. Disorders of the Nervous System
Multiple Sclerosis
Autoimmune attack of myelin on CNS axons
Neuronal Regeneration
Possible to regenerate axons of PNS
Regeneration tubes