A&P - Chapter 19 (Part 1) Flashcards Preview

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Flashcards in A&P - Chapter 19 (Part 1) Deck (31)
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1
Q

Nerve impulse

A

A self propagating wave of electrical disturbances that travels along the surface of a neruon’s plasma membrane

2
Q

What is the direction of a neural impulse?

A

Towards the axon terminals

3
Q

What is the charge on the outside of a membrane?

A

Slightly positive

4
Q

What is the charge on the inside of a membrane?

A

Slightly negative

5
Q

Membrane potential

A

Is the result of difference in an electrical charge across the membrane

6
Q

Potential

A

Ions of opposite charges the have the potential to move toward one another if they get an opportunity to cross the membrane

7
Q

What is a membrane said to be if it exhibits a membrane potential?

A

Polarized

8
Q

Resting membrane potential

A

When a neuron isnt conducting electrical signals

9
Q

During what phase is there slightly more positive ions outside the membrane?

A

In resting position

10
Q

What do neurons of the plasma membrane contain?

A

Channels that allow efficient movement of the positive ions across it

11
Q

What are 2 examples of positive ions that can move across the membrane?

A
  1. Na+
    - sodium ions
  2. K+
    - potassium ions
12
Q

What are the channels called that move Na and K?

A

Sodium-potassium pumps

13
Q

What directions do Na and K move through the channels?

A

In opposite directions

14
Q

What does the movement of Na and K do?

A

It maintains the electrical difference across the plasma membrane
- slightly positive on the outside

15
Q

Local potentials

A

A fluctuation in the resting membrane potential in a specific part of the plasma membrane

16
Q

When do local potentials occur?

A

In response to a stimulus

- excitation

17
Q

What does excitation trigger?

A

The opening of stimulus gated channels in the plasma membrane

18
Q

What does the opening of the stimulated gates allow?

A

For more Na+ to enter the neuron

- charge is now more slightly negative on the outside

19
Q

Depolarization

A

More Na+ entering the neuron means that the size of the membrane potential is reduced

20
Q

What initiates an action potential?

A

Depolarization

21
Q

Resting potential

A

The membrane of a resting neuron has a slightly positive charge on the outside and a negative charge on the inside

22
Q

Action potential

A

A stimulus triggers the opening of the Na+ channels in the plasma membrane of the neuron (starting at the dendrites) allowing Na+ to rush into the neuron (depolarization

23
Q

When do action potentials move faster?

A

When they are myelinated

24
Q

Nerve impulse

A

An electrical disturbance of the neurons membrane stimulates Na+ channels in the adjacent section of the membrane to open

25
Q

What does the nerve impulse travel along?

A

The entire length of the neurons membrane

26
Q

Why do signals travel faster in myelinated neurons?

A

Because the impulse will jump over it making it faster

- saltatory conduction

27
Q

Do neurons normally touch each other or the effector they act on?

A

No

28
Q

What is there between neurons and the effector that prevent them from touching?

A

Synapse

29
Q

What 2 things can synapse be?

A
  1. Electrical

2. Chemical

30
Q

Where do electrical synapse occur?

A

Where cells joined by gap junctions allow an action potential to simply continue along the postsynaptic membrane

31
Q

Where do chemical synapse occur?

A

Where presynaptic cells release chemical transmitters across tiny gaps to the post synaptic cells
- possibly inducing an action potential

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