Review: The Nervous System
Mr. Yassin
07-08-14
Lesson Intention:
• Introduction
• The nervous system:
– Structural component
– Physiological functions
• Reflex Arcs:
- Knee Jerk Reflex
•
Activity: Simulating a reflex arc
• Review Test/Answers
• Homeowork
Components:
• The nervous system is composed of 2 parts:
1. Central Nervous System:
- Consists of the brain and spinal cord. Its function is to
interpret external environments and internal organ
systems through complex neuronal connections that elicit
reactions.
2. Peripheral Nervous System:
- This consists of nerves and ganglia (cluster of nerve cells)
that lie outside of the brain and spinal cord. Effectively, it
functions as a messenger between organ systems and the
central nervous system.
Neuron:
• The main unit in the nervous system.
1. Dendrites: receive nerve transmission from
other neurons via the action of
neurotransmitters.
2. Cell Body (soma): This is where that message
is transmitted to.
3. Nucleus: contains all the genetic material
(DNA)
4. Axon: transmits information to other neurons
3 Different Types of Neurons:
1. Sensory Neuron (unipolar):
Transmit nerve impulses from receptor sites to
the CNS.
2. Interneuron (bipolar):
Function as go-between neurons that facilitate the
transmission of impulses.
3. Motor Neuron (multipolar):
They transmit impulses from the central nervous
system to muscles and glands that elicit a
reaction.
Reflex Arc:
• The 3 neuron examples exist
within an interconnected
network of neurons that transmit
information to and from each
other.
• A reflex arc is a simple example
of how these cells work together
to elicit a reaction – autonomic
(involuntary control)
Knee Jerk Reflex
INPUTS
Stimulus
Receptor
Sensory
Neuron
Brain and
Spinal Cord
CNS
The nervous system in action
OUTPUT
Response
Effector
Muscle
or gland
Motor
Neuron
Action Potentials:
Release of a neurotransmitter
usually follows arrival of an
action potential at the
synapse.
How an action potential
works:
http://www.youtube.com/w
atch?v=ifD1YG07fB8
Activity:
• We’re going to simulate a reflex arc.
• Line up at the back of the room.
• ROLES:
–
–
–
–
–
–
3 people to be receptors
4 people to be sensory neurons
2 people to be interneurons
1 person as the brain
2 Motor Neurons
3 Effectors
Review Test:
- Have 15 minutes to complete it.
- Formal
- Attempt it individually
What you should know:
• The 3 main types of neurons and their
structure.
• The process of a reflex arc and examples.
• The nature of action potentials and the role of
neurotransmitters in that process.
HOMEWORK:
- Complete questions from the Biozone
Student workbook.
1. Neuron Structure and Function (p.
282)
2. Reflexes (p. 285)