Download Nervous System

Nervous System
The master controlling and
communicating system of the body
2.7 Diagram the general scheme of the nervous system.
The Central Nervous System (CNS)
• The Central Nervous System (CNS) consist of
the Brain and the Spinal Cord.
• The spinal cord carries messages from the
body to the brain, where they are analyzed
and interpreted.
• Response messages are then passed from the
brain through the spinal cord and to the rest
of the body.
• Both the brain and the spinal cord are encased
in bone.
The Peripheral Nervous System (PNS)
2.6 Explain the difference between sensory and motor neurons
• The Peripheral Nervous System (PNS)
consists of the neurons NOT Included in the
brain and spinal cord.
• Somatic Nervous System (part of PNS)
– AFFERENT NEURONS - Peripheral Neurons collect
information from the body and transmit it
TOWARD the CNS (sensory)
– EFFERENT NEURONS. - Peripheral Neurons
transmit information AWAY from the CNS (motor)
2.8 Compare the parasympathetic and
sympathetic division of the autonomic system.
Parasympathetic Division
Sympathetic Division
Pupils contract
EYES
Pupils dilate
Increases
SALVATION
Decreases
Dries
SKIN
Perspires
Decreases
RESPIRATION
Increases
Slows
HEART
Accelerates
Activates
DIGESTION
Inhibits
Decrease secretion of
stress hormones
ADRENAL GLANDS
Secrete stress hormones
Anatomy of the Autonomic Nervous
System
Figure 7.25
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.73
Autonomic Functioning
 Sympathetic – “fight-or-flight”
 Response to unusual stimulus
 Takes over to increase activities
 Remember as the “E” division = exercise,
excitement, emergency, and
embarrassment
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Autonomic Functioning
 Parasympathetic – housekeeping
activites
 Conserves energy
 Maintains daily necessary body functions
 Remember as the “D” division - digestion,
defecation, and diuresis
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Comparison of Somatic and
Autonomic Nervous Systems
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 7.24
Slide 7.69
2.5 Describe the general functions of
the nervous system.
1. Nervous system and endocrine system are the chief control
centers in maintaining body homeostasis.
2. Nervous system uses electrical signals (nerve impulses)
which produce immediate (but short- lived) responses;
endocrine system uses chemical signals (hormones) that
produce slower ( but long lasting) responses.
3. Nervous system has 3 major functions:
1.
2.
3.
Sensory input – sensory or afferent neutron detect internal or
external changes ( stimuli ) and send the message to the brain or
spinal cord.
Integration – interneurons in the brain or spinal cord process and
interpret the message from the sensory neurons, and relay the
message back to body parts.
Motor output – motor or efferent neurons receive the message
from interneuron and produce a response at the effector organ
(a muscle or a gland).
Nerve Tissue
1. Nerve tissue is composed of 2 main types of cells:
– Neurons- nerve cells that are specialized to detect and
react to stimuli, by generating and conducting nerve
impulses.
– Neuroglial cells- accessory cells for filling spaces and
supporting neurons.
2. Microscopic anatomy of neurons
–
–
All neurons have a cell body called soma which contains a
nucleus, organelles, and a modified endoplasmic
reticulum called Nissl body.
Although there is DNA in the neuron, somehow DNA
replication and mitosis do not occur, resulting in the
neurons lack of ability to reproduce or regenerate.
2.3 Draw and label a diagram of the
structure of a motor neuron.
Neurons
• Extensions of the soma form nerve such as dendrites
which conduct nerve impulses toward the soma, and
axon which conducts nerve impulses away from the
soma (to another neuron, or to an effect or organ).
• The number of dendrites ranges from 1 ( in unipolar
and bipolar neurons) to thousands ( in multipolar
neurons).
• All neurons only contain 1 axon.
• Longer axons are enclosed by a lipoprotein substance
called myelin sheath produced by type of neuroglial
cells called schwann cells.
Classification of Neurons
• Classification based on structure:
– unipolar neuron - a single nerve fiber is extended from
the soma, and it divides into a dendrite and an axon
(sensory neurons that conduct reflexes or detect
various stimuli).
– bipolar neuron - a dendrite and an axon extend from
the soma independently (sensory neurons involved in
special senses such as vision, olfaction, and hearing).
– multiple neuron - one axon and many dendrites
extend from the soma (interneurons located inside
the brain and spinal cord).
2.1 Classify neurons as afferent,
efferent, or interneurons.
• classification based on function:
– sensory or afferent neuron: - conducts nerve impulses from the
body to the brain or spinal cord. - endings of its dendrite may be
modified to become nerve receptors. - usually unipolar in
structure.
– interneuron: - relays nerve impulse from sensory neuron to
motor neuron . - located totally inside the tissues of the brain or
spinal cord. - involved in the processing and integration in the
nervous system. - usually multipolar in structure.
– motor or efferent neuron: - conducts nerve impulses from the
brain or spinal cord to the effector organ (muscles or glands). usually multipolar in structure. - accelerator motor neurons
cause an increase of activity in the effector organ; while
inhibitory motor neurons cause a decrease of activity in the
effector organ.
2.9 Diagram a reflex arc using the
knee-jerk reflex as an example
• Reflex—rapid, predictable, and involuntary
response to a stimulus
– Occurs over pathways called reflex arcs
• Reflex arc—direct route from a sensory
neuron, to an interneuron, to an effector
The Reflex Arc
Skin
Stimulus at distal
end of neuron
Spinal cord
(in cross section)
Sensory neuron
Receptor
Motor neuron
(a)
Effector
Integration
center
Interneuron
Figure 7.11a
The Reflex Arc
Skin
Stimulus at distal
end of neuron
Receptor
(a)
Figure 7.11a, step 1
The Reflex Arc
Skin
Stimulus at distal
end of neuron
Sensory neuron
Receptor
(a)
Figure 7.11a, step 2
The Reflex Arc
Skin
Stimulus at distal
end of neuron
Receptor
(a)
Spinal cord
(in cross section)
Sensory neuron
Integration
center
Interneuron
Figure 7.11a, step 3
The Reflex Arc
Skin
Stimulus at distal
end of neuron
Spinal cord
(in cross section)
Sensory neuron
Receptor
Motor neuron
(a)
Integration
center
Interneuron
Figure 7.11a, step 4
The Reflex Arc
Skin
Stimulus at distal
end of neuron
Spinal cord
(in cross section)
Sensory neuron
Receptor
Motor neuron
(a)
Effector
Integration
center
Interneuron
Figure 7.11a, step 5
Simple Reflex Arc
Sensory receptors
(stretch receptors
in the quadriceps
muscle)
Sensory (afferent)
neuron
Spinal cord
Sensory receptors
(pain receptors in
the skin)
Sensory (afferent)
neuron
Synapse in
ventral horn
gray matter
Interneuron
Motor
(efferent)
neuron
Motor
(efferent)
neuron
(b)
Effector
(quadriceps
muscle of
thigh)
Effector
(biceps
brachii
muscle)
(c)
Figure 7.11b–c
Simple Reflex Arc
Sensory receptors
(stretch receptors
in the quadriceps
muscle)
Spinal cord
(b)
Figure 7.11b, step 1
Simple Reflex Arc
Sensory receptors
(stretch receptors
in the quadriceps
muscle)
Sensory (afferent)
neuron
Spinal cord
(b)
Figure 7.11b, step 2
Simple Reflex Arc
Sensory receptors
(stretch receptors
in the quadriceps
muscle)
Sensory (afferent)
neuron
Spinal cord
Synapse in
ventral horn
gray matter
(b)
Figure 7.11b, step 3
Simple Reflex Arc
Sensory receptors
(stretch receptors
in the quadriceps
muscle)
Sensory (afferent)
neuron
Spinal cord
Synapse in
ventral horn
gray matter
Motor
(efferent)
neuron
(b)
Figure 7.11b, step 4
Simple Reflex Arc
Sensory receptors
(stretch receptors
in the quadriceps
muscle)
Sensory (afferent)
neuron
Spinal cord
Synapse in
ventral horn
gray matter
(b)
Motor
(efferent)
neuron
Effector
(quadriceps
muscle of
thigh)
Figure 7.11b, step 5
Simple Reflex Arc
Sensory receptors
(pain receptors in
the skin)
Spinal cord
(c)
Figure 7.11c, step 1
Simple Reflex Arc
Sensory receptors
(pain receptors in
the skin)
Spinal cord
Sensory (afferent)
neuron
(c)
Figure 7.11c, step 2
Simple Reflex Arc
Sensory receptors
(pain receptors in
the skin)
Spinal cord
Sensory (afferent)
neuron
Interneuron
(c)
Figure 7.11c, step 3
Simple Reflex Arc
Sensory receptors
(pain receptors in
the skin)
Spinal cord
Sensory (afferent)
neuron
Interneuron
Motor
(efferent)
neuron
(c)
Figure 7.11c, step 4a
Simple Reflex Arc
Sensory receptors
(pain receptors in
the skin)
Spinal cord
Sensory (afferent)
neuron
Interneuron
Motor
(efferent)
neuron
Effector
(biceps
brachii
muscle)
(c)
Figure 7.11c, step 4b
Simple Reflex Arc
Sensory receptors
(stretch receptors
in the quadriceps
muscle)
Sensory (afferent)
neuron
Spinal cord
Sensory receptors
(pain receptors in
the skin)
Sensory (afferent)
neuron
Synapse in
ventral horn
gray matter
Interneuron
Motor
(efferent)
neuron
Motor
(efferent)
neuron
(b)
Effector
(quadriceps
muscle of
thigh)
Effector
(biceps
brachii
muscle)
(c)
Figure 7.11b–c
2.1 Compare how a nerve impulse passes along a nonmyelinated neuron and myelinated neuron.
2.12 Describe the function of a named neurotransmitter
The Architecture of the Brain
The Forebrain
• The forebrain is the largest
and most highly developed
part of the human brain: it
consists primarily of
the cerebrum and the
structures hidden beneath it
• It is the source of intellectual
activities. It holds your
memories, allows you to plan,
enables you to imagine and
think. It allows you to
recognize friends, read books,
and play games.
The Architecture of the Brain
The Midbrain
• The uppermost part of the
brainstem is the midbrain,
which controls some reflex
actions and is part of the
circuit involved in the
control of eye movements
and other voluntary
movements.
The Architecture of the Brain
The Hindbrain
• The hindbrain includes the
upper part of the spinal cord,
the brain stem, and a wrinkled
ball of tissue called
the cerebellum
• The hindbrain controls the
body’s vital functions such as
respiration and heart rate. The
cerebellum coordinates
movement and is involved in
learned rote movements
2.11 Categorize the regions of the adult
brain and general function of each.
Objective: Create matching cards with image on one card and function on the
other
Instructions:
1. Cut out pictures of brain
2. Color or highlight one of the areas of
the brain
3. Paste the picture onto one piece of
cardstock
4. Write the function of that area of the
brain onto another piece of cardstock
5. Repeat with the other areas of the
brain
Parts of the Brain:
1. Medulla
2. Pons
3. Reticular Activating System
4. Cerebellum
5. Thalamus
6. Hypothalamus
7. Pituitary Gland
8. Amygdala
9. Hippocampus
10. Occipital Lobe
11. Parietal Lobe
12. Temporal Lobe
13. Frontal Lobe