Reading Log Procedures
Grab a text book
Reading Log- Week (i.e. 1/11-1/15)
Date
Write out essential question and
page numbers
Respond in no less than 5 complete sentences
Reading Log Grading
100 Points
80 Points
The response indicates
The response indicates
that the student has a
that the student has a
complete understanding partial understanding of
of the reading concept.
the reading concept.
The response is
Not all aspects of the
accurate, complete, and question are addressed,
is fully supported by
or response is not
information from the
rooted or derived from
text.
the text.
50 Points
The response is
inaccurate, confused,
and/or irrelevant. The
student has failed to
respond to the task.
The Nervous
System
CHAPTER 7
Objectives
To explain the main components of the nervous system.
To compare and contrast the central nervous system and the peripheral
nervous system.
To differentiate between the somatic and autonomic nervous systems.
Nervous System
Think back to when we talked about nervous tissue. What is it’s
function? How does it go about doing this?
General Functions:
◦ Sensory (detect change)
◦ Integrative (make sense of it)
◦ Motor (cause a response)
Functions of the Nervous System
gather information
response of
muscles/organ
Figure 7.1
CNS vs. PNS
CNS (Central Nervous System):
◦ Brain
◦ Spinal Cord
PNS (Peripheral Nervous System):
◦ Cranial nerves
◦ Spinal Nerves
PNS
Contains a sensory division and a motor division.
Sensory Division:
◦ Contains sensory receptors that convert info into a nerve impulse and
transmit it back to the CNS to make sense of it.
◦ Monitors environmental changes such as light and sound
◦ Detects changes in homeostasis ( ex: temperature, oxygen level)
Motor Division
Utilize peripheral neurons to carry impulses from the CNS to an effector
which will cause a response
◦ Ex: muscle contraction, gland secretion, etc.
Motor Division
Somatic Nervous System:
◦ Controls skeletal muscle and voluntary
movement.
Autonomic Nervous System:
◦ Controls effectors that are involuntary
◦ Ex: heart, smooth muscle, certain glands
Lets put that
all together…
1. Turn in Stimulus Response Lab
2. Begin working on reading log
Reading Log- Week (i.e. 1/11-1/15)
Date
Write out essential question and
page numbers
Respond in no less than 5 complete sentences
Reading Log Grading
100 Points
80 Points
The response indicates
The response indicates
that the student has a
that the student has a
complete understanding partial understanding of
of the reading concept.
the reading concept.
The response is
Not all aspects of the
accurate, complete, and question are addressed,
is fully supported by
or response is not
information from the
rooted or derived from
text.
the text.
50 Points
The response is
inaccurate, confused,
and/or irrelevant. The
student has failed to
respond to the task.
Objectives
To identify the basic structure and classification of neurons.
Nervous Tissue
Two Principal types of cells:
◦ Neurons (nerve cells)- transmit nerve impulses from one
part of the body to another
◦ Neuroglia (or simply glial cells)- supporting cells of
nervous tissue
◦ Protect, support and insulate neurons
◦ Ex: Astrocytes, Microglia, Ependymal Cells, Oligodendrocytes,
Schwann Cells
Structure of a Neuron
Reacts to physical/chemical changes in
surroundings
Transmit information through nerve impulses
to other neurons and other cells.
Structure of a Neuron
Label using the diagram on pg 233
Neuron Structures
Axon
Node of Ranvier
Axon terminals
Nucleus
Cell body
Schwann cells
Dendrites
Synaptic Cleft
Myelin sheath
Neuron Structures
Axon - the long extension of a neuron
that carries nerve impulses away from
the body of the cell.
Axon terminals - the hair-like ends of the
axon; release neurotransmitters into
synaptic cleft
Cell body - the cell body of the neuron; it
contains the nucleus (also called the
soma)
Dendrites - the branching structure of a
neuron that receives messages and send
to cell body(attached to the cell body)
Myelin sheath - the fatty substance that
surrounds and protects some nerve
fibers
Node of Ranvier - one of the many gaps
in the myelin sheath - this is where the
action potential occurs during saltatory
conduction along the axon
Nucleus - the organelle in the cell body
of the neuron that contains the genetic
material of the cell
Schwann cells - cells that produce myelin
- they are located within the myelin
sheath.
Synaptic Cleft- gap between axon
terminals of one neuron and the
dendrites of another
EQ: How does a nerve impulse
travel down a neuron? Pgs 237-239 (1 column)
st
Reading Log- Week (i.e. 1/11-1/15)
Date
Write out essential question and
page numbers
Respond in no less than 5 complete sentences
Objectives
To explain how a nerve impulse occurs.
To explain different things that inhibit an action potential.
To understand components of a neuron that contribute to impulse
velocity.
I. Stages of a Nerve Impulse
1. Resting Neuron
a.
b.
polarized = more (+) ions outside nerve cell than inside. SALTY
Resting potential = -70 mV
(potential= difference)
BANANA
Na+
K+
Na+
I. Stages of a Nerve Impulse
2. Depolarization
a. influx of sodium (Na+)
b. initiates an action potential
c. “all-or-none” response: -50 mV
3. Repolarization
a. Peaks at +30 mV
b. exit of K+ ions
+30
4. Initial Conditions Restored
a. Na+/ K+ Pump- Restores initial concentrations of Na+ and K+
3 Na+ pumped out
2 K+  Pumped in
USES ATP
Let’s Simulate it!
I need 3 volunteers!
◦Na+ Channel x 2
◦K+ Channel x 1
◦Na+/K+ Pump x 1
EQ: What are the components
of a reflex arc? Pg 240
Reading Log- Week (i.e. 1/11-1/15)
Date
Write out essential question and
page numbers
Respond in no less than 5 complete sentences
Objectives
To understand components of a neuron that contribute to impulse velocity.
To understand the synaptic communication between neurons
To examine the components of a reflex arc
Figure 7.9 The nerve impulse.
[Na+]
[K+]
Na+
+
Slide 3
(a) Resting membrane electrical conditions. The
external face of the membrane is slightly positive;
its internal face is slightly negative. The chief
extracellular ion is sodium (Na+), whereas the chief
intracellular ion is potassium (K+). The membrane is
relatively impermeable to both ions.
(b) Stimulus initiates local depolarization. A
stimulus changes the permeability of a “patch” of
the membrane, and sodium ions diffuse rapidly into
the cell. This changes the polarity of the membrane
(the inside becomes more positive; the outside
becomes more negative) at that site.
Figure 7.9 The nerve impulse.
[Na+]
[K+]
Na+
+
(a) Resting membrane electrical conditions. The
external face of the membrane is slightly positive;
its internal face is slightly negative. The chief
extracellular ion is sodium (Na+), whereas the chief
intracellular ion is potassium (K+). The membrane is
relatively impermeable to both ions.
(b) Stimulus initiates local depolarization. A
stimulus changes the permeability of a “patch” of
the membrane, and sodium ions diffuse rapidly into
the cell. This changes the polarity of the membrane
(the inside becomes more positive; the outside
becomes more negative) at that site.
Na+
+
Slide 4
(c) Depolarization and generation of an action
potential. If the stimulus is strong enough,
depolarization causes membrane polarity to be
completely reversed and an action potential is
initiated.
Figure 7.9 The nerve impulse.
Slide 6
(d) Propagation of the action potential.
Depolarization of the first membrane patch causes
permeability changes in the adjacent membrane, and
the events described in (b) are repeated. Thus, the
action potential propagates rapidly along the entire
length of the membrane.
+
K+
(e) Repolarization. Potassium ions diffuse out of the
cell as the membrane permeability changes again,
restoring the negative charge on the inside of the
membrane and the positive charge on the outside
surface. Repolarization occurs in the same direction
as depolarization.
Figure 7.9 The nerve impulse.
Slide 7
(d) Propagation of the action potential.
Depolarization of the first membrane patch causes
permeability changes in the adjacent membrane, and
the events described in (b) are repeated. Thus, the
action potential propagates rapidly along the entire
length of the membrane.
+
(e) Repolarization. Potassium ions diffuse out of the
cell as the membrane permeability changes again,
restoring the negative charge on the inside of the
membrane and the positive charge on the outside
surface. Repolarization occurs in the same direction
as depolarization.
K+
Cell
exterior
Na+
Diffusion
Na+
Na+
Na+
K+
Na+
Cell
interior
K+
K+
+
K+ K
Na+
Na+ – K+
pump
(f) Initial ionic conditions restored. The ionic
conditions of the resting state are restored later by
the activity of the sodium-potassium pump. Three
Plasma
membrane sodium ions are ejected for every two potassium
ions carried back into the cell.
Myelin Sheaths
◦ Whitish, fatty material wrapped
jelly-roll style around the axon
◦ Produced by schwann cells outside
CNS (oligodendrocytes in CNS)
Saltatory Conduction
1.
“Jumping” of nerve impulse
2.
Myelinated FASTER than unmyelinated nerves
Multiple Sclerosis (MS)
Individuals with multiple sclerosis (MS),
experience destruction of their myelin
sheath. How would this affect the
transmission of an impulse? What symptoms
would you expect to see?
II. SYNAPTIC COMMUNICATION
* Synapse = gap (space) between neurons
Sequence of Events at Synapse
1. Arrival of nerve impulse (action potential)
Axon of
transmitting
neuron
Axon
terminal
Action
potential
arrives
Vesicles
Synaptic
cleft
Receiving
neuron
Synapse
Text p. 240 Figure 7.10
2. Diffusion of Neurotransmitter (into synapse)
Examples:
a. adrenaline
b. acetylcholine
c. serotonin
3. Post-Synaptic Activation (of next neuron)
Neuromuscular
Junction
Review : Transmission of a Signal at Synapses (Fig 7.10)
Axon of
transmitting
neuron
Axon
terminal
Action
potential
arrives
Vesicles
Synaptic
cleft
Receiving
neuron
Synapse
Transmitting neuron
Vesicle
fuses with
plasma
membrane
Neurotransmitter binds
to receptor
on receiving
neuron’s
membrane
Neurotransmitter is released into
synaptic cleft
Neurotransmitter
molecules
Synaptic cleft
Ion channels
Receiving neuron
Neurotransmitter
broken down
and released
Neurotransmitter
Receptor
Na+
Na+
Ion channel opens
Ion channel closes
Figure 7.10
CLINICAL APPLICATIONS
1. PARKINSON’S DISEASE: LOW DOPAMINE in brain
2. DEPRESSION: LOW SEROTONIN LEVELS
Reflexes
Ordinarily, a receptor sends a signal to the brain where the brain
coordinates a response.
What happens when you touch something hot?
Reflex Arc
A reflex is a rapid action that happens without thought and does not
involve the brain.
Lets take a look…
◦ http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/human/t
henervoussystemrev3.shtml
Reflex Arc
1) Receptor- sense organ in skin, muscle, or other organ
2) Sensory Neuron- carries impulse towards CNS from receptor
3) Interneuron- carries impulse within CNS
4) Motor Neuron- carries impulse away from CNS to effector
5) Effector- structure by which animal responds (muscle, gland, etc).
Reflex Arc
Types of Reflexes
Babinski Reflex