Chapter 2. PART B. Communication within- and between-neurons (membrane
potentials)
Highlighted sections
Communication within a neuron
Communication between neurons
Activation of receptors, postsynaptic
potentials, termination of postsynaptic
potentials; Neural integration
1. Is the inside of the membrane positively or negatively charged with respect to the
outside?
2. Define resting potential in your own words, making sure to use the words (a)
dynamic equilibrium, (b) electrostatic force, (c) diffusion force, (d) selective membrane,
(e) sodium, (f) potassium, (g) ATP sodium/potassium pump, (h) ion channels.
3. If a positive electrical stimulus is applied to the inside of the membrane, what will be
the effect on the membrane potential? What term is used to describe this change?
4. What happens to the membrane potential when the membrane receives a very weak
depolarizing stimulus?
5. Describe what happens to the electrical charge across the membrane after it receives a
sufficiently large stimulus
6. Copy from memory the graph of an action potential sure to label x-axis, y-axis,
threshold, action potential, hyperpolarization, and depolarization.
7. About how long does the entire process –from the electrical stimulus to the return to
normal resting potential- take? ___________
8. A spoonful of sugar has been poured into a container of water. What eventually
happens to the sugar? What process does this describe? ____________
9. ______________ are substances that split into two parts when dissolved in water. The
charged particles into which they decompose are called _______________.
______________ have a positive charge and _____________ have a negative charge.
The force of attraction or repulsion between these particles is called _______________.
10 . describe the step-by-step conduction of the action potential along the myelinated
axon using these terms in this order.
a. Schawnn cells
b. Nodes of Ranvier
c. inward flow of sodium
d. extracellular sodium
e. cable properties
f. decremental conduction
g. renewed signal strength
h. saltatory conduction
24. Identify an advantage of saltatory conduction.
Communication between neurons
1. Define postsynaptic potential in your own words, noting its two possible effects
on an axon.
2. A synapse is a(n) ________________ between the _______________
________________ at the ends of axons of one neuron with the ______________
of another neuron. The membrane of the transmitting neuron is called the
___________________ membrane, and the message is received by the
___________________ membrane.
3. When molecules of the neurotransmitter diffuse across the synaptic cleft to the
postsynaptic membrane, what structures do they bind with? Once binding occurs,
what happens next?
4. a) Describe the movements of sodium and potassium ions during an EPSP and an
IPSP. b) Now describe the movement of chloride.
Key terms
Membrane potential
Oscilloscope
Resting potential
Depolarization
Hyperpolarization
Action potential
Threshold of excitation
Diffusion
Ion
Sodium-potassium transporter
Voltage-dependent ion channel
Cable properties
Salutatory conduction
Postsynaptic potential
Neuromodulator
Endocrine gland
Target cell
Binding site
Ligand
Presynaptic membrane
Postsynaptic membrane
Synaptc cleft
Postsynaptic receptor
Neurotransmitter-dependant ion channel
Second messenger
Excitatory postsynaptic potential (EPSP)
Inhibitory postsynaptic potential (IPSP)
Reuptake
Enzymatic deactivation
Acetylcholinesterase (AChE)
Neural integration
Neuronal firing