Formation of Action Potentials -

Describe what a membrane potential is

• Do all cells have a membrane potential?

• What are excitable vs. non-excitable cells

What types of cells are excitable?

What are the different types of channels found in a cell membrane?

• What is the stimulus for each type?

How are leaky channels different from gated channels?

How are transporter proteins different from carrier proteins?

For an excitable cell, describe:

a. What ions are involved in generating the membrane potential?

b. Describe the concentrations of those ions both intracellularly and extracellularly.

c. What direction do these ions move and why in that direction? (Be specific)

d. What protein structure plays a role in maintaining the value of a resting membrane potential?

How is diffusion different from active transport – think of a few different things.

What is osmosis?

• Define the terms, hypotonic, hypertonic and isotonic

• If I place a cell that has a 0.85% NaCl solution inside of the cell into a solution of 0.05% NaCl,

what will happen to the cell?

• Which way will water move and why?

What is the physiological importance of active transport? What would happen if we did not have it?

What does a stimulus cause to happen to a cell’s membrane?

Define what an action potential is.

Why is reaching “threshold” important in terms of an action potential?

What are the different stages that are seen in an action potential?

Be able to graph an action potential (AP) and indicate the following (know the values in the brackets):

• The value of a resting membrane potential and of threshold in millivolts (mV)

• The ions involved in each stage of an action potential

• Direction of ion flux (which way are the ions moving – in or out?)

• Which gates are open/closed? and where in the graph that is taking place?

• Different stages of the action potential

• The maximal “+” (positive) charge in the membrane potential in millivolts (mV)

• The maximal “-“ (negative) charge in the membrane potential in millivolts (mV)

Why does the neuron’s cell membrane only reach a + 30mv value … why not say, +70mv?

What is used to restore the concentration of ions that are involved in an action potential?

Explain the different components (parts) of the refractory period seen with an action potential?

How does the refractory period influence the formation of an action potential?

• What is the absolute refractory period?

• What is the relative refractory period?

• Why does the intensity of a stimulus need to change during a the relative refractory period in order to initiate a second AP?

Describe the 3 classifications of axons based on size and velocity of propagation.

The release of a neurotransmitter is dependent on what ion entering the axon terminal?

• What type of a channel does that ion flow through?

• What caused that ion’s channel to increases its permeability (to open) to allow the influx of that ion?

• Why did that ion flow into the cell (what was the ion following)?

Starting with the arrival of an action potential at the telodendria, describe the sequence of events needed for the release of a neurotransmitter into the synaptic cleft.

Describe how an EPSP and an IPSP are formed – be specific

• What neurotransmitters are involved?

• Identify/describe the ions involved and direction of ion flow across the cell membrane that leads to an

EPSP and IPSP

• During a EPSP or a IPSP how does the resting membrane potential change?

• What physiological terms are used to describe the change in the membrane potential?

(There are two you want to be thinking of)

What are the terms “EPSP” and “IPSP” referring to specifically – what are they talking about?

Do excitatory and inhibitory postsynaptic membrane regions generate action potential or graded potential?

In terms of an EPSP and IPSP, what do the terms hyperpolarize and hypopolarize refer to?

How are temporal and spatial summations different?

Explain presynaptic inhibition and facilitation?

• What chemical signals are involved with each type?

• What type of gated-channels are involved with each type?

Based on the type of neurotransmitter released what are the different groups of nerve fibers (neurons)?

What are the different general categories of receptors for acetylcholine and norepinephrine?

• What are the specific receptors that acetylcholine and norepinephrine could bind with?

What are the two divisions of the autonomic nervous system?

How can you end the effects of a neurotransmitter?

How can you extend, or prolong the effects of a neurotransmitter?

What are the different classifications of neurons based on axon diameter?

• How are they different from each other?