Transcript 1. Neuron - cloudfront.net

Structure and Function
Learning Targets:
• Classify the major structures of the nervous
system (R)
• List the general functions of the nervous
system (K)
Nervous System
Anatomy
Physiology
Organs are divided into two groups:
1. Central Nervous System (CNS)
a. Brain
b. Spinal Cord
2. Peripheral Nervous System (PNS)
a. Nerves
A
B
C
Nervous System
Anatomy
Physiology
Together, organs perform 3 main
functions
1. Sensory
monitor internal and external
environment
2. Integration
information from the sensory nerves
is integrated into the CNS by neurons
3. Motor Output
stimulation of muscles or glands to
move or secrete substances
Nervous Tissue
Learning Target: Identify and state the function
of the components of nervous tissue. (K)
1. Neuron (Nerve Cell)
a. specialized to react to physical and chemical changes in their
surrounding
b. Excitable- transmit information in the form of electrochemical
changes called nerve impulses along nerve fibers to other
neurons and other types of cells
c. Structures of a neuron1) Cell Body- contains the nucleus and organelles
2) Dendrites- receive info from other neurons
3) Axons- send impulses away from the cell body
2
3
1
4
Fun Fact:
A cell body diameter ranges from 5 - 135 µm
An axon diameter ranges from 1 - 20 µm
The axons length ranges from 2 mm - 1 m.
Let's scale this up!
The
classroom
will equal 1
cell body
How far would this axon travel
out of the room?
Up to 1.6 km (1 mile)- That’s all
the way to the HC library!!!!
2. Neuroglial cellsa. Specialize to support the neuron
b. Non-excitable-do not send impulses
c. Four types in the CNS
1) Astrocytes– form connections between blood
vessels and neurons
A tissue sample from the brain. The area
where the astrocyte connects to the blood
vessel is called a foot process.
2) Oligodendrocytes-insulate neurons, form the
myelin sheath
Electron micrograph showing
branched oligodendrocytes with
processes extending to several
underlying axons
3. Microglial cells- engulf microbes and remove
wastes
Activated microglial cells in a rat brain.
When activated, these cells are
phagocytic helping to removing damaged
or dying cells.
4. Ependymal cells- help circulate cerebrospinal
fluid
Ependymal cells found in the 3rd ventricle of the brain
of a 32 week old fetus.
d. 2 types in the PNS
1) Satellite cells- surround and control the
chemical environment of the neuron
2) Schwann- insulate the neuron, form the
myelin sheath
What is the name of the similar cell in the CNS?
Fun Fact: For every nerve cell in your body there
are 50 glial cells.
If a person looses brain cells every day, how does a
child's brain increase in mass from 400 g to 1400g in
adulthood?
1. The number of glia cells increases tremendously.
2. More synapses are formed.
*When glia cells reproduce uncontrollably, a person
has cancer.
Homework:
9.03 Cells of the nervous system worksheet