5.3 Neuronal Communication Flashcards

1
Q

Why are neurones very long?

A

So that they can transmit an action potential over a large distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why does a neurone plasma membrane have many gated ion channels?

A

To control the entry or exit of Na+ , K+ and Ca2+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Sodium/Potassium pumps use _____ to actively transport Na+ ____ and K+ ____ the cell.

A

ATP, Na+ out, K+ in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the function of a dendrite?

A

To carry nerve impulses towards the cell body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the function of the axon?

A

To carry nerve impulses away from the cell body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the purpose of Shwann cells?

A

To insulate electrical activity from affecting nearby cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where do motor neurones have their cell body?

A

In the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a myelinated neurone?

A

A neurone insulated by an individual mylein sheath.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why do motor neurones have an extra long axon?

A

To carry the action potential from the CNS to an effector.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where is the cell body of a sensory neurone?

A

Just outside the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Sensory neurones have a long ______ that carries an action potential from a sensory _______ to the cell body (just outside CNS) then a short _____ carrying the impulse into the CNS.

A

Long dendrite, sensory receptor, short axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are gaps in the myelin sheath called?

A

Nodes of Ranvier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is an action potential?

A

A brief reversal of the potential difference across the membrane at a peak of +40mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is resting potential?

A

When the nerve cell is at rest with a potential difference across the membrane of -60mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the all or nothing principle?

A

All nerve impulses are identical, independent of the strength of a stimulus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What value (mV) must be reached before an action potential can be transmitted?

17
Q

What is a Pacinian corpuscle?

A

A pressure sensory receptor that detects pressure changes on the skin

18
Q

Sensory receptors are energy _________ that convert energy from one form to the other.

A

Transducers

19
Q

What is a corpuscle?

A

An oval shaped structure that consists of rings of connective tissue wrapped around a nerve cell ending

20
Q

What is generator potential (receptor potential)?

A

The change in potential across a receptor membrane

21
Q

How does a Pacinian corpuscle generate a nerve impulse?

A

When pressure is applied to the corpuscle it becomes deformed and pushes against the nerve ending, opening Na+ channels

22
Q

When a neurone is at rest, the inside of the cell is ___________ charged.

A

Negatively

23
Q

Why do larger diameter axons send faster impulses?

A

Have low SA:V so less ions leak out the axon making action potentials easier

24
Q

What is a local current?

A

The movement of Na+ along the axon, away from where they came in

25
What is summation?
When the effect of neurotransmitters can be combined to make the membrane depolarisation reach a threshold allowing an action potential to be generated
26
What is spacial summation?
When neurones converge each neurone releases a small amount of neurotransmitter and together will be enough to generate an action potential
27
What is temporal summation?
When nerve impulses arrive in quick succession making action potential more likely because more neurotransmitter is in the synaptic cleft
28
What is synaptic divergence?
When one neurone connects to many, allowing information to be dispersed to different areas of the body
29
What is synaptic convergence?
When many neurones connect to one allowing information to be amplified
30
Why can nerve impulses only be transmitted in one direction?
Because receptors for neurotransmitters are only on the postsynaptic membrane