Neuronal structure, function and organisation

Question 1

What are excitable cells?

Answer 1

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

Question 2

What are the two types of excitable cell?

Answer 2

Nerve and muscle

Question 3

What is a neuron?

Answer 3

A single nerve cell

Question 4

What is a nerve?

Answer 4

Collection of neurone running together

Question 5

What so neurofibrils do?

Answer 5

Provide cellular stability/structure

Question 6

Function of axon hillock

Answer 6

Branches to axon itself

Question 7

Function of terminals

Answer 7

Release neurotransmitters

Question 8

Function of Schwann cells

Answer 8

Insulate neurons

Question 9

Function of node of Ranvier

Answer 9

Saltatory conduction

Question 10

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

Answer 10

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

Question 11

What is an absolute refractory period?

Answer 11

No action potential in this time because sodium channels inactivated

Question 12

What is the relative refractory period?

Answer 12

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

Question 13

Why does an AP only go in one direction?

Answer 13

Inactivation of sodium channels (axon body to bacon terminals)

Question 14

How is an AP propagated?

Answer 14

Sequential opening of voltage-gated ion channels

Question 15

What are neurotubules?

Answer 15

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

Question 16

What is carried from cell body to axon terminal?

Answer 16

Neurotransmitters, proteins and lipids

Question 17

Transport molecule for going from cell body to axon terminal

Answer 17

Kinesin

Question 18

Transport molecule for going from axon terminal to cell body

Answer 18

Dynein

Question 19

What is carried from axon terminal to cell body?

Answer 19

Cell debris

Question 20

Function of myelin

Answer 20

Electrical insulation to prevent current loss

Question 21

Where does depolarisation take place?

Answer 21

Nodes of Ranvier

Question 22

What is saltatory conduction?

Answer 22

Current jumps between nodes

Question 23

Which nervous system are Scheann cells in?

Answer 23

PNS

Question 24

Which nervous system are oligodendrocytes in?

Answer 24

CNS

Question 25

Characteristics of Schwann cells

Answer 25

Whole cell wraps around axon | Applied to single neuron

Question 26

Characteristics of oligodendrocytes

Answer 26

Processes from cell wrap around axon | Applied to multiple neurones

Question 27

Are there Na+ channels under myelin in Schwann cells?

Answer 27

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

Question 28

What are satellite oligodendrocytes?

Answer 28

Unattached and regulate the environment

Question 29

Function of oligodendrocytes

Answer 29

Myelination of CNS neurons

Question 30

Function of astrocytes

Answer 30

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

Question 31

Function of microglia

Answer 31

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

Question 32

Function of ependymal cells

Answer 32

Produce CSF, line CSF spaces, cilia aid CSF movement

Question 33

What are motor nerves?

Answer 33

Voluntary control of movement via skeletal muscle

Question 34

Are motor nerves afferent or efferent?

Answer 34

Efferent

Question 35

What are sensory nerves?

Answer 35

Input carrying a variety of senses triggered by many stimuli

Question 36

Are sensory nerves afferent or efferent?

Answer 36

Afferent

Question 37

What are autonomic nerves?

Answer 37

Involuntary control of organs and tissues

Question 38

Are autonomic nerves afferent or efferent?

Answer 38

Efferent

Question 39

What are afferent nerves?

Answer 39

Towards centre

Question 40

What are efferent nerves?

Answer 40

Away from centre

Question 41

How to increase speed of conduction

Answer 41

Increases with myelination - saltatory conduction | Increases with larger diameter - less current loss

Question 42

Peripheral matter in brain

Answer 42

Grey matter (cell bodies)

Question 43

Central matter in brain

Answer 43

White matter (axons)

Question 44

Peripheral matter in spinal cord

Answer 44

White matter (axons?

Question 45

Central matter in spinal cord

Answer 45

Grey matter (cell bodies)