Cells of nervous system and neuromuscular junction

Question 1

4 types of neurones

Answer 1

Unipolar, pseudounipolar, bipolar and multipolar.

Question 2

Examples of multipolar neurones?

Answer 2

Pyramidal cell, purkinje cell and golgi cell.

Question 3

Where are purkinje and golgi cells found?

Answer 3

Cerebellum.

Question 4

What neurotransmitter do purkinje and golgi cells release?

Answer 4

GABA

Question 5

What part of the neurone can be covered with myelin?

Answer 5

Axon.

Question 6

Function of dendrites?

Answer 6

Receive signals from other neurones.

Question 7

Oligodendrocyte function?

Answer 7

Myelinate neurones.

Question 8

Most abundant cell type in CNS?

Answer 8

Astrocyte.

Question 9

Astrocyte function?

Answer 9

Homeostasis of neuronal external environment.

Question 10

What are microglia?

Answer 10

Neuronal macrophages.

Question 11

What are ependyma?

Answer 11

CNS epithelial cells.

Question 12

What are the ion concentrations under resting potential?

Answer 12

High potassium inside, high sodium outside.

Question 13

What causes membrane depolarisation to happen?

Answer 13

Opening of voltage gated sodium ion channels. This results in NA+ influx. This leads to further depolarisation.

Question 14

What causes membrane repolarisation.

Answer 14

Opening of voltage gated potassium ion channels. Efflux of K+ (potassium ions move out).

Question 15

Membrane potential reseting potential difference?

Answer 15

-70mV.

Question 16

What restores the membrane potential?

Answer 16

Na+K- ATPase restores the ion gradients.

Question 17

What are the small gaps in myelin called?

Answer 17

Nodes of ranvier.

Question 18

How does myelin prevent action potential from spreading?

Answer 18

High resistance and low capacitance.

Question 19

What is saltatory conduction?

Answer 19

Action potential jumps between nodes.

Question 20

Na+ K+ ion ratio for Na+K+ ATPase?

Answer 20

3 sodium ions out and 2 potassium ions in.

Question 21

How does Na+K+ATPase work?

Answer 21

Three sodium ions and ATP bind to pump. Upon phosphorylation of pump sodium ions are transported through protein. Two potassium ions bind to pump, release of phosphate reverts channel to original form and potassium is released on the inside on the membrane.

Question 22

What happens when an action potential reaches presynaptic terminal?

Answer 22

Voltage gated Ca2+ ion channels open. Ca2+ influx leads to vesicle exocytosis.

Question 23

How does neurotransmitter re uptake take place?

Answer 23

Metabolised by enzymes in synaptic cleft. Recycled by transporter proteins.

Question 24

Neurotransmitter release is an example of what type of communication?

Answer 24

Paracrine. Can also act on same neurone in this case would be autocrine.

Question 25

Synapses are organised into 4 types. What are the 4 types?

Answer 25

Axodendritic, axosomatic, axoaxonic and dendrodentritic.

Question 26

What receptor do acetylcholine bind to on skeletal muscle?

Answer 26

Nicotinic acetylcholine receptors.

Question 27

What occurs when acetylcholine binds to receptors on skeletal muscle?

Answer 27

Change in end plate potential.

Question 28

What is the release mechanism of neurotransmitter called?

Answer 28

Quantal release.

Question 29

How does muscle contraction happen?

Answer 29

Action potential travels along t tubule. Calcium ions are released from sarcoplasmic reticulum. Muscle contraction.

Question 30

How does botulism disrupt neuromuscular junction?

Answer 30

Stops release of acetylcholine from presynaptic terminal.

Question 31

How does myasthenia gravis disrupt neuromuscular junction?

Answer 31

Antibodies disrupt acetyl choline receptor on post synaptic terminal.

Question 32

How does lambert eaton myasthenic syndrome disrupt neuromuscular junction?

Answer 32

Antibodies directed at voltage gated calcium ion channels.