C2.2 Neurons Test

Transmits nerve impulses from sense receptors to the CNS

Sensory neuron

Located in the CNS; transmits nerve impulses from neuron to neuron

Interneuron

Transmit nerve impulses from CNS to an effector

Motor neuron

The difference in electrical charge/voltage between the interior and exterior of a cell membrane

Membrane potential

Scientific tool used to measure changes in potential difference of axons during an action potential

Oscilloscope

The minimum potential difference required across a membrane to initiate action potential

Threshold potential

What is the typical threshold potential?

-55mV

The electrical potential difference of the cytoplasm of a neuron when it is not stimulated or involved in a passage of nerve impulse

Resting potential

What is the typical resting potential?

-70 mV

R squared; can be used to determine the strength of a relationship between two variables

Coefficient of determination

Spaces/gaps between neurons and other cells

Synapse

The neurotransmitter which exists in many types of synapsis, including neuromuscular junctionss

Acetylcholine

Transmembrane acetylcholine receptors on postsynaptic membrane

Cholinergic synapse

What is the location of sodium ions when the neuron is at rest?

Outside

What is the location of potassium ions when the neuron is at rest?

Inside

What is the charge outside of the neuron when it is at rest?

Positive

What is the charge inside of the neuron when it is at rest?

Negative

What is the location of sodium during depolarization?

Diffuses into neuron

What is the location of potassium ions during depolarization?

Inside

What is the charge inside of the cell during depolarization?

positive

What is the charge outside of the cell during depolarization?

Negative

What is the location of sodium ions during repolarization?

Inside

What is the location of potassium ions during repolarization?

They diffuse out of the neuron

What is the charge outside of the neuron during repolarization

Positive

What is the charge inside of the neuron during repolarization

Negative

What is the location of sodium ions at the end of the refractory period?

Pumped out

What is the location of potassium ions at the end of the refractory period?

Pumped in

What is the charge outside at the end of the refractory period

Positive

What is the charge inside at the end of the refractory period

Negative

What are two benefits of salutary conduction

1. Much faster than non-salutary

2. Requires less energy

What is the effect of neonicotinoid pesticides on synapses

Binds to receptors in postsynaptic membrane and blocks transmission resulting in paralysis and/or death

What is the effect of dopamine on synapses

It can be either excitatory or inhibitory:

—causes pleasure and motivation.

—dopamine transporters removes dopamine from synaptic clefts

What is the effect of cocaine on synapses

Binds to and blocks dopamine transporters and prevents the reuptake of dopamine

What are the 7 parts of a motor neuron

dendrite, cell body, nucleus, axon, node of ranvier, axon terminals, schwann cell, myelin sheath

What are the 3 steps of propagation of a nerve impulse across a nerve fiber

1. Action potential

2. Threshold potential

3. Propagation of action potentials

What two things must a neuron have in order to propagate a nerve impulse along the neuron

1. Action potential

2. Threshold potential

The change of voltage as a nerve impulse moves along the nerve fiber

Action potential

The minimum potential difference required across the membrane to initiate an action potential... opens voltage, gated, sodium channels, and at -55mv sodium enters a nerve fiber

Threshold potential

What are two key steps of the propagation of action potentials

Depolarization and repolarization

This step of the propagation of action potentials is the increase to potential difference across the membrane

Depolarization

What two things occur during depolarization

1.neuron at resting potential recieves stimulus and reaches a threshold potential and voltage gated sodium channel open 2. Sodium ions diffuse into the nerve fiber and voltage increases

This step of the propagation of action potentials is the restoration of potential difference across the membrane

Repolarization

What three things occur during repolarization

1. The neuron at resting potential reaches +30mV causing voltage gated sodium channels to close and voltage gated potassium channels to open. 2. Potassium moves out of the cell, reducing potential difference below resting potential (hyperpolarization) 3. Potassium is actively pumped in and sodium is pumped out resulting in a return to resting potential

The reduction of potential difference below resting potential

Hyperpolarization

What are the simple steps of proposition of nerve impulses across the neuron

Influx of sodium into the nerve fiber during depolarization—> sodium ions spread by diffusion and create local channels—> movement of sodium ions in channels in axon decrease the potential difference to threshold potential—> action potential propagated along the nerve fiber

How does the sodium/potassium pump return to resting potential

@ +30mV voltage gated sodium channels close and voltage gated potassium channels open —> potassium ions move out which decreases the potential difference below resting potential —> sodium is actively pumped out of the cell and potassium is pumped into the cell

What is the order of the 7 labels on an oscilloscope

1. Stimulus

2. Threshold

3. Depolarization

4. Action potential

5. Repolarization

6. Refractory period

7. Resting state