Cell Biology Exam Two - Membrane Potential and Neurons

Electrochemical gradients have ___ parts

Two

What are counter ions inside the cell?

K+, Ca2+, H+

What are the counter ions outside of the cell?

Na+, Cl-

Exact balance of charges on each side of the membrane. Membrane Potential =

0

Potassium leak channels are important in establishing

membrane potential

What equation is this?

Nernst Equation

What is the Nernst Equation used for?

understanding the relationship between membrane potential and ion concentration

What is the Goldman Equation used for?

understanding the combined effect of ions on membrane potential

What equation is this?

Goldman Equation

The membrane potential of a nerve or muscle cell at rest is

negative

What are the major contributors of membrane potential

Outside Na+ and Cl-

What are the key ideas of membrane potential

Inside K+ and macromolecular anions

Na+ / K+ pump and K+ leak channels are needed to

establish membrane potential

Potential differences exist when charges are

separated

membrane potentials present in all cell types, but neurons are

specialized

What are the type of specialized neurons?

dendrites

cell body

axon

myelin-sheath

Voltage Gated Na+ Channels can be

open, closed, or inactivated

When cells are adequately stimulated:

voltage-gated Na+ channels open

depolarization occurs

triggering the AP

Na+ channels are inactivated immediately following an

AP

What action potential is this?

Resting State

What action potential is this?

When the Threshold is REached

What action potential is this?

Depolarization to Repolarization

What action potential is this?

Hyperpolarization

What is this?

Influx or Efflux during an Action Potential

What is this?

Propagation of An Impulse Down an Axon

Neurotransmission: Jumping the Synaptic Cell

Presynaptic neurons communicate with postsynaptic neurons

Neurotransmitters allow an electrical signal to become a chemical signal

Presynaptic neurons communicate with postsynaptic neurons

synapse

across a gap (synaptic cleft)

Neurotransmitters allow an electrical signal to become a chemical signal

different from neuron to neuron

made in the cell body and packaged into vesicles that travel to the axon

What are the two types of neurotransmitter receptors?

Metabotropic

Ionotropic

Ionotropic

ligated gated ion channels

Some neurotransmitter receptors lead to ___ while others inhibit _____

depolarization

Bound transmitter can

depolarize (excite) or

hyper polarize (inhibit) the postsynaptic cell

Transmitter action is terminated by

reuptake or

enzymatic breakdown

What is the sequence events during synaptic transmission with acetylcholine as the neurotransmitter

1. Nerve impulse

2. Calcium ion gates open

3. Release of AcCh

4. Binding of AcCH by receptor

5A. Sodium ion gates open

5B. Chlorine ion gates open

6. nerve impulse

neural signaling is a balance between

stimulation and inhibition

Where are the voltage gated sodium ion channels on a neuron?

Axon

If Na+ channels are opened in a cell that was previously at rest, how will the resting membrane potential be affected?

It becomes more positive

The name for the phase at the end of an action potential when the membrane potential becomes more negative than it is at rest is the ____ phase.

hyperpolarizing

Hyperpolarization of the postsynaptic nerve terminal.

decreases the the chance of action potential will be initiated.