Biology Journal 3/11/2014
What do “excitatory” and “inhibitory” mean? Which of
these drugs are excitatory, and which are inhibitory?
Drug
Cocaine
Alcohol (ethanol)
Nicotine
Amphetamines (such as “meth”)
THC (tetrahydrocannabinol)
Benzodiazepines (such as valium,
xanax, diazepam, and other
antidepressants)
Excitatory or Inhibitory effects
on nervous system?
Biology Journal 3/11/2014
Excitatory = increase neurotransmitters and thus signals
Inhibitory = decrease neurotransmitters and thus signals
Drug
Excitatory or Inhibitory effects
on nervous system?
Cocaine
Excitatory
Alcohol (ethanol)
Inhibitory
Nicotine
Excitatory
Amphetamines (such as “meth”)
Excitatory
THC (tetrahydrocannabinol)
Inhibitory
Benzodiazepines (such as valium,
xanax, diazepam, and other
antidepressants)
Excitatory
What organs make up the central nervous
system?
What organs make up the peripheral nervous
system?
1. What kind
of neuron
is A?
2. What kind
of neuron
is B?
3. What kind
of neuron
is C?
A
B
C
A is a motor neuron
because it attaches
to a muscle.
B is a sensory
neuron because it
has sensory
receptors for
dendrites.
C is a relay neuron
because it connects
neurons to other
neurons.
A
B
C
Label this diagram
4
5
1
6
7
2
8
3
Label this diagram
Mitochondrion
Neurotransmitters
Axon
terminal
Vesicle
Transport
protein
(for reuptake of
neurotransmitters)
Receptor
(for neurotransmitters)
Synapse
Dendrite
What are the effects of cocaine on the synapse?
Cocaine blocks dopamine transporter proteins (also
known as re-uptake proteins), thus dopamine stays
in the synapse, overstimulating the dopamine
receptors in the receiving neuron.
What are the effects of THC on the synapse?
THC reduces the release of dopamine-inhibitors.
Thus, lots of dopamine is freely released, causing
overstimulation of dopamine receptors.
(remember, THC “inhibits the inhibitor of dopamine,” “blocks
the blocker,” “shuts down the shutdowner,” etc.)
What could be some reasons that drugs like
cocaine and methamphetamine are so addictive?
These drugs influence dopamine and other
neurotransmitters that are involved in feelings of
pleasure, calm, and the reward mechanism of the brain.
1. What is the charge inside of an axon when it is
polarized?
2. What is the charge inside of an axon when it is
depolarized?
3. What is the charge inside of an axon when it is
repolarized?
Polarized: (-) inside axon, (+) outside axon. This is the
starting, or “resting” potential.
Depolarized: (+) inside axon, (-) outside axon. This
occurs when the Na+1 diffuses into the axon.
Repolarized: (-) inside axon, (+) outside axon. This
happens when the K+1 diffuses out of the axon.
Label this neuron cell
8
1
7
2
4
3
6
5
Label this neuron cell
Axon terminals
Dendrites
Node of Ranvier
Cell body (soma)
Myelin sheath
Nucleus
Schwann cell
Axon
When does the inside of an axon have a negative
charge? (write all correct letters)
A. When it is polarized
B. When it is depolarized
C. When it is repolarized
D. Resting potential
E. After sodium diffuses in
F. After potassium diffuses out
G. After the Na/K pump has
reset the ions following an
action potential
A C D F G
Which parts of an action potential involve passive transport?
A. When Na enters the
D. Depolarization
neuron
F. The reuptake of
B. When K leaves the
neurotransmitters by transport
neuron
proteins
C. When the Na/K pump G. The exocytosis of neurois moving ions
transmitters into the synapse
A B D
What step on the graph…
A. is the resting potential?
B. does Na diffuse into the neuron?
C. is repolarization?
D. does the Na/K pump re-position the ions?
E. is the inside of the axon positive?
0
1
4
5
2 and/or 3
What does the myelin sheath do for a neuron?
The myelin sheath speeds up and protects
the electrical signal (action potential)
6.5 Nerves
6.5.1
State that the nervous system consists of the central nervous system (CNS) and peripheral
nerves, and is composed of cells called neurons that can carry rapid electrical impulses.
6.5.2
Draw and label a diagram of the structure of a motor neuron.
 Dendrites and cell body with nucleus
 Axon and myelin sheath
 nodes of Ranvier
 motor end plates
6.5.3
State that nerve impulses are conducted from receptors to the CNS by sensory neurons, within
the CNS by relay neurons, and from the CNS to effectors by motor neurons.
6.5.4
Define resting potential and action potential (depolarization and repolarization).
6.5.5
Explain how a nerve impulse passes along a non-myelinated neuron. Include the movement of
Na+ and K+ ions to create a resting potential and an action potential.
6.5.6
Explain the principles of synaptic transmission.
 the release, diffusion and binding of the neurotransmitter
 initiation of an action potential in the post-synaptic membrane
 subsequent removal of the neurotransmitter
6.5.1
State that the nervous system consists of the central nervous system (CNS) and peripheral
nerves, and is composed of cells called neurons that can carry rapid electrical impulses.