Download Neurotransmitter proteins

The Nervous System
Nervous System
• Network of connected
cells, tissue, and organs
• Controls thoughts,
movement, life
processes
• Quick responses
– Ex: Sunny day  pupils
shrinking
CNS and PNS
Neurons
• AKA: Nerve Cells
• Transfer electrical impulses to/from the brain
• 3 Main Parts
1) Cell body: contains nucleus and organelles
2) Dendrites: branches that receive messages from neighboring
cells
3) Axon: extension that carries messages away from the cell body
Resting Potential
K+
K+
K+
K+
K+
K+
K+
Interior
K+
K+
• Defined: Neuron at rest
• Neuron Interior is negative
due to abundance of
• Neuron Exterior is positive in
proteins, but…
charge due to abundance of
Na+ outside
– Some K+ inside the cell
Action Potential
• Defined: Electrical impulse
is triggered
• Front end of impulse
– Channels open and allow
Na+ to enter the cell
– Negative impulse
attracted towards
positive Na+
• Back end of impulse
– Channels open to allow
K+ to exit the cell
– Interior returns to
normal
• Impulse pulled along by the
changing of electrical
charges
imp
ulse
Na+
Na+
+
+
+
Na
Na
Na
+
+
+
+
+
+ K+
Na
Na
Na
Na
+
Na
Na
Na
+
K
+
Na
Na
+
+
+
+
+ Na+
K
Na
Na
+
+
Na
Na
Na
Na
Na+Na+
Na+
+
+
+
+
+
Na
Na
+
+
+
Na
Na
Na
+
K
Na
Na
+
+
Na
+
Na
Na
Na
Na+
Na+ Na+ Na+
Na+
Na+
K+
K+
Na
K+
K+
Na+
K+
Na+
Na+
Na+
Na+
+
+
K
K
K+
negative
+
impulse
+
Na
+
K+
Na+
Na+
K+ K+
K+
K+
K+
Na+
Na+
Na+
K+ K+
K+
K+
K++
Na
K+
K+
K+
K+
K+
Na+
K+
K+
Na+
K+
K+
K+
K+
Na+
Na+
Na+Na+ Na+
+
Na+
Na+ Na
+
Na
+
+
Na+ Na Na+ Na+ Na Na+
K+
K+
Na+
K+
K+ K+ K+
Na+
Na+
K+
+Na
Na
K+
+
Na+
Na+
Na
+
Na
Na+
K+ Na+ Na+
Na+ Na+
+
Na+
Na+
Synapse
• Defined: Gap between
neurons
• Problem: Impulse cannot
cross the gap
• Solution: Neurotransmitter
proteins sent from one cell
to another
• Steps:
– Impulse reaches
neuron’s terminal (end)
– Vesicle releases
neurotransmitters, which
attach to receptors on
neighbor
– New impulse created
Vesicle exits the
cell and dissolves
Impulse reaches the
axon terminal
Terminal end
of one cell
Dendrite of
another cell
Neurotransmitters
cross the synapse
and attach to
receptors of a
neighboring neuron
impul
se
Terminal end
of one cell
Neurotransmitters
stimulate a new
impulse
imp
ulse
Dendrite of
another cell
Brain
Feet
Impulses eventually reach the muscles…
and causes MOVEMENT!
Kobe Kuiz
1) What is the function of the nervous system?
2) List the 3 main parts and describe the purpose of the 3
main parts of a neuron.
3) Describe the internal and external environment of a
neuron in resting potential.
4) What is a synapse and why is it a problem for neurons?
5) What are the roles of the following during an action
potential?
1) NA+
2) K+
3) Neurotransmitters