Neuronal structure, function and organisation Flashcards Preview

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Flashcards in Neuronal structure, function and organisation Deck (45)
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1
Q

What are excitable cells?

A

Generate an electrical current by flowing through ion channels that rapidly changes the trans-membrane potential

2
Q

What are the two types of excitable cell?

A

Nerve and muscle

3
Q

What is a neuron?

A

A single nerve cell

4
Q

What is a nerve?

A

Collection of neurone running together

5
Q

What so neurofibrils do?

A

Provide cellular stability/structure

6
Q

Function of axon hillock

A

Branches to axon itself

7
Q

Function of terminals

A

Release neurotransmitters

8
Q

Function of Schwann cells

A

Insulate neurons

9
Q

Function of node of Ranvier

A

Saltatory conduction

10
Q

What is the ‘all-or-nothing’ principle?

A

Intensity of action potential doesn’t change but firing frequency does

11
Q

What is an absolute refractory period?

A

No action potential in this time because sodium channels inactivated

12
Q

What is the relative refractory period?

A

Below -70mV, another AP can be stimulated but stimulus must be larger than normal because it is more negative

13
Q

Why does an AP only go in one direction?

A

Inactivation of sodium channels (axon body to bacon terminals)

14
Q

How is an AP propagated?

A

Sequential opening of voltage-gated ion channels

15
Q

What are neurotubules?

A

Transport system - forms chain of tubulin running between cell body and axon terminal. Moves vesicles along the outside of the tubules using foot-like processes

16
Q

What is carried from cell body to axon terminal?

A

Neurotransmitters, proteins and lipids

17
Q

Transport molecule for going from cell body to axon terminal

A

Kinesin

18
Q

Transport molecule for going from axon terminal to cell body

A

Dynein

19
Q

What is carried from axon terminal to cell body?

A

Cell debris

20
Q

Function of myelin

A

Electrical insulation to prevent current loss

21
Q

Where does depolarisation take place?

A

Nodes of Ranvier

22
Q

What is saltatory conduction?

A

Current jumps between nodes

23
Q

Which nervous system are Scheann cells in?

A

PNS

24
Q

Which nervous system are oligodendrocytes in?

A

CNS

25
Q

Characteristics of Schwann cells

A

Whole cell wraps around axon

Applied to single neuron

26
Q

Characteristics of oligodendrocytes

A

Processes from cell wrap around axon

Applied to multiple neurones

27
Q

Are there Na+ channels under myelin in Schwann cells?

A

No, no membrane depolarisation, instead the impulse travels to the Na+ channels are the next node of Ranvier

28
Q

What are satellite oligodendrocytes?

A

Unattached and regulate the environment

29
Q

Function of oligodendrocytes

A

Myelination of CNS neurons

30
Q

Function of astrocytes

A

Maintain microstructure, regulate blood-brain barrier, biochemical homeostasis, chemical communication

31
Q

Function of microglia

A

Immune cells (e.g. monocytes), produce growth factors

32
Q

Function of ependymal cells

A

Produce CSF, line CSF spaces, cilia aid CSF movement

33
Q

What are motor nerves?

A

Voluntary control of movement via skeletal muscle

34
Q

Are motor nerves afferent or efferent?

A

Efferent

35
Q

What are sensory nerves?

A

Input carrying a variety of senses triggered by many stimuli

36
Q

Are sensory nerves afferent or efferent?

A

Afferent

37
Q

What are autonomic nerves?

A

Involuntary control of organs and tissues

38
Q

Are autonomic nerves afferent or efferent?

A

Efferent

39
Q

What are afferent nerves?

A

Towards centre

40
Q

What are efferent nerves?

A

Away from centre

41
Q

How to increase speed of conduction

A

Increases with myelination - saltatory conduction

Increases with larger diameter - less current loss

42
Q

Peripheral matter in brain

A

Grey matter (cell bodies)

43
Q

Central matter in brain

A

White matter (axons)

44
Q

Peripheral matter in spinal cord

A

White matter (axons?

45
Q

Central matter in spinal cord

A

Grey matter (cell bodies)