Download Nerve activates contraction

Warm-Up
• Name as many structures of the nervous system as you
can
• What do you think the major functions of the nervous
system are?
• Name one other body system and how you think it
works with the nervous system
The Nervous System: An Overview
Ch. 7a
Functions of the Nervous System
 Sensory input
 gathering information to monitor changes
occurring inside & outside the body
 changes = stimuli
 Integration
 process & interpret sensory input & decide if
action is needed
 Motor output
 response to integrated stimuli
 response activates muscles or glands
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.1a
Quick Quiz 1 of 5
1. What are the 3 major functions of the
Nervous System?
2. Give an example of the nervous system
performing these functions
Structural Classification of the
Nervous System
 Central nervous system (CNS)
 brain
 spinal cord
 Peripheral nervous system (PNS)
 nerves outside the brain & spinal cord
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.2
Quick Quiz 2 of 5
1. What organs make up the Central Nervous
System?
2. Which do you think would have a greater
negative effect on the body and WHY?:
•
Damaging the CNS, or
•
Damaging the PNS
Some important terms…
• Afferent
• toward the body (spinal cord & brain)
• often called “sensory”
• Efferent
• away from the body (spinal cord & brain)
• often called “motor”
Functional Classification of the
Peripheral Nervous System
 Sensory (afferent) division
 nerve fibers that carry information to the
central nervous system
Figure 7.1
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.3a
Functional Classification of the
Peripheral Nervous System
 Motor (efferent) division
 nerve fibers that carry impulses away from
the central nervous system
 two subdivisions
 somatic nervous system = voluntary
 autonomic nervous system = involuntary
Figure 7.1
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.3b
Functional Classification of the
Peripheral Nervous System
Figure 7.1
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.3c
Quick Quiz 3 of 5
1. What is the function of the Afferent Nervous
System?
•
Give an example
2. What is the function of the Efferent Nervous
system?
•
Give an example
Organization of the Nervous System
Figure 7.2
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.4
What makes up the nervous system?
• Nervous tissue made of:
• neurons
• cells of the nervous system that transmit
messages throughout the body
• neuroglia
• non-neural tissue of the nervous system
• provides support
Nervous Tissue: Support Cells
(Neuroglia)
 Astrocytes
 abundant, star-shaped cells
 brace neurons
 form barrier
between capillaries
and neurons
 control the chemical
environment of
the brain
Figure 7.3a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.5
Nervous Tissue: Support Cells
 Microglia
 spider-like phagocytes
 dispose of debris
 Ependymal cells
 line cavities of the
brain and spinal cord
 circulate
cerebrospinal
fluid
Figure 7.3b, c
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.6
Nervous Tissue: Support Cells
 Oligodendrocytes
 produce myelin
sheath around
nerve fibers in the
central nervous
system
Figure 7.3d
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.7a
Nervous Tissue: Support Cells
 Satellite cells
 protect neuron cell bodies
 Schwann cells
 form myelin sheath in the peripheral
nervous system
Figure 7.3e
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.7b
Quick Quiz 4 of 5
1. What is the difference between Schwann
Cells and oligodendrocytes?
Nervous Tissue: Neurons
 Neurons = nerve cells
 cells specialized to transmit messages
 major regions of neurons
 cell body – nucleus and metabolic center
of the cell
 processes – fibers that extend from the
cell body
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.8
Neuron Anatomy
 Cell body
 Nissl substance –
specialized rough
endoplasmic
reticulum
 Neurofibrils –
intermediate
cytoskeleton that
maintains cell shape
Figure 7.4a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.9a
Neuron Anatomy
 Cell body
 nucleus
 large nucleolus
Figure 7.4a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.9b
Neuron Anatomy
 Extensions outside the
cell body
 Dendrites
 conduct impulses
toward the cell body
 receivers
 Axons
 conduct impulses away
from the cell body
 senders
Figure 7.4a
Slide 7.10
Nerve Fiber Coverings
 Schwann cells
produce myelin
sheaths in jelly-roll
like fashion
 Nodes of Ranvier
gaps in myelin
sheath along the
axon
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 7.5
Slide 7.12
Axons and Nerve Impulses
 Axons end in axonal terminals
• Axonal terminals release vesicles
with neurotransmitters
 Axonal terminals are separated from the
next neuron by a gap
 Synaptic cleft
 gap between adjacent neurons
 Synapse
 junction between nerves
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.11
Quick Quiz 5 of 5
1. What is the function of the dendrites?
2. How does a nerve impulse travel from one
neuron to the next?