Download Chapter 7 - Rogue Community College

Chapter 7
Nervous System- master controlling and communicating system of the body.
Organization of the NS
Structural
Classification
Central
Nervous System (CNS)-
Peripheral
Functional
Nervous System (PNS)-
Classification (PNS only)
Afferent
(sensory) division-
Efferent
(motor) division-
Two subdivisions:
-Somatic nervous system-Autonomic nervous system-Sympathetic and parasympathetic.
Nervous Tissue: Structure and Function- made of two main types of cells,
supporting cells and neurons.
Neuroglia-
Astrocytes-
1
Microglia-
Ependymal
cells-
Oligodendrocytes-
neuroglia
cannot transmit nerve impulses, and they have the ability to
divide
Schwann
Satellite
Neuron
Cells-
Cells
Anatomy- Use the text and figure 7.4 to identify the following
structures:
Cell
Body
Nissl
Substance
Dendrites
Axons
Axon
Terminals
Myelin
sheath
Nodes
of Ranvier
2
Neuron
Classification
Functional
Classification
-Afferent (sensory) neurons-Efferent (motor) neurons-Interneurons (association)Structural
Classification
-Multipolar-Bipolar-UnipolarNerve
Impulses
neurons
have two major functional properties, irritability and
conductivity.
-Irritability-Polarized neuron-Depolarization-Action Potential-Repolarization-
3
-Conductivity-action potential signals the release of neurotransmitters in
axon terminals.
-neurotransmitters are picked up by receptors on receiving
neuron.
-If enough neurotransmitters are picked up, the action
potential will begin again on the new neuron. (fig. 7.10)
Reflexes-
rapid, predictable, and involuntary responses to stimuli.
Reflex
Arc-
Reflexes
can be somatic; involving skeletal muscles, or autonomic;
involving smooth muscle, cardiac muscle, and glands.
Central Nervous System- Made up of the Brain and Spinal Cord
Brain-
Cerebral
Hemispheres-
-Gyri-
4
-Sulci-Fissures-Longitudinal Fissure-Lobes-Parietal Lobe-Occipital Lobe-Temporal Lobe-Frontal Lobe-Gray matter-Cerebral white matter-Corpus callosum-Basal NucleiDiencephalon-
-Thalamus-Hypothalamus-Limbic system
5
-Pituitary gland-Mammillary bodies-Epithalamus-Choroid plexus-Pineal gland
Brain
Stem-Midbrain-Cerebral peduncles-Corpora quadrigemina-Pons-Medulla oblongata-Important fiber tract area
-Contains centers that control heart rate, blood pressure,
breathing, swallowing, and vomiting.
-Reticular Formation-Neurons of the RS involved in motor control of the visceral
organs. RAS, reticular activating system plays a role in
consciousness and the awake/sleep cycles.
6
Cerebellum-.
Protection
of the CNSMeninges-
-Dura mater-Arachnoid mater-Pia materCerebrospinal
Blood-Brain
Spinal
Fluid-
Barrier-.
Cord- continuation of the brain stem, about 17 inches long.
Two
way conduction pathway to and from the brain
Major
reflex center.
Extends
Has
from foramen magnum down to L1 or L2.
31 pairs of spinal nerves arise and exit through the intervertebral
foramen.
Cauda
equina-
7
Gray
Matter
-Posterior/Dorsal horns-Anterior/Ventral horns-Central Canal-Dorsal Root-Dorsal Root Ganglion-Ventral Root-
White
Matter
-Posterior column-Lateral and anterior columnsPeripheral Nervous SystemNerve
Structure
Nerve-
bundle of neuron fibers found outside the CNS
-Epineurium
-Fascicle
-Perineurium
-Endoneurium
8
Mixed
nerves-
Afferent
nerves-
Efferent
nerves-
Cranial
Nerves-
Named
Most
with a number and major structure they control
are mixed nerves, 3 pairs are sensory only:
-Optic, olfactory, and vestibulocochlear
Use
Spinal
Table 7.1 and figure 7.24 to identify the cranial nerves
Nerves- 31 pairs, formed by the combination of ventral and dorsal roots
of spinal cord. Named with numbers from the region they arise from
Rami-
Plexus-
Autonomic
Nervous System (ANS)-
Neurons
ANS
regulate cardiac muscle, smooth muscle, and glands.
has a 2 motor neuron pathway.
-1st motor neuron is in the brain or spinal cord, its axon,
preganglionic axon, leaves CNS to synapse with the second motor
neuron.
-2nd motor neuron is in a ganglion outside the CNS. Its axon,
postganglionic axon, extends to the organ it serves.
9
ANS
has two “arms” that serve the same organs, parasympathetic and
sympathetic.
Anatomy
of the Parasympathetic Division
Anatomy
of the Sympathetic Division
Functions
of the ANS
-Most organs receive both sympathetic and parasympathetic
impulses
-Most blood vessels, most structures of the skin, some
glands, and the adrenal medulla, all receive only sympathetic
impulses.
-When both divisions are present, they cause antagonistic effects,
due to the differences in neurotransmitters and receptors:
-All preganglionic neurons release ACh
-Sympathetic postganglionic neurons release
norepinepherine and/or epinephrine
-Parasympathetic postganglionic neurons release ACh
10
Sympathetic
Division- “Fight or Flight” system
Parasympathetic
Division- “Resting and Digesting” system
11