BRAIN CELLS

Question 1

What are the three main purposes of neurons?

Answer 1

Sensation, integration, and action.

Question 2

What is the function of sensory neurons?

Answer 2

To carry information from the senses to the CNS.

Question 3

What is the function of motor neurons?

Answer 3

To carry commands from the CNS to muscles and organs.

Question 4

What is the function of interneurons?

Answer 4

To connect and integrate neurons within the CNS.

Question 5

What is the resting membrane potential?

Answer 5

The difference in electrical charge across the neuron membrane at rest (~ -70mV).

Question 6

What maintains the resting membrane potential?

Answer 6

Sodium-potassium pump and ion distribution.

Question 7

What ion is more concentrated inside the cell at rest?

Answer 7

Potassium (K+).

Question 8

What ion is more concentrated outside the cell at rest?

Answer 8

Sodium (Na+).

Question 9

What does the sodium-potassium pump do?

Answer 9

Pumps 3 Na+ out and 2 K+ into the cell.

Question 10

What is depolarisation?

Answer 10

A decrease in membrane potential (more positive).

Question 11

What is hyperpolarisation?

Answer 11

An increase in membrane potential (more negative).

Question 12

What is an action potential?

Answer 12

A brief electrical charge that travels down the axon.

Question 13

What triggers an action potential?

Answer 13

Depolarisation reaching the threshold.

Question 14

What is the threshold potential?

Answer 14

Around -55mV.

Question 15

What happens during the refractory period?

Answer 15

The neuron cannot fire another action potential.

Question 16

What is saltatory conduction?

Answer 16

The jumping of action potentials between nodes of Ranvier.

Question 17

What is the function of astrocytes?

Answer 17

Support, nourish, clean debris, and form the blood-brain barrier.

Question 18

What is the blood-brain barrier?

Answer 18

A semi-permeable membrane that protects the brain from harmful substances.

Question 19

What is the main function of microglia?

Answer 19

Immune defense in the CNS.

Question 20

What is the role of oligodendrocytes?

Answer 20

Form the myelin sheath in the CNS.

Question 21

What is the role of Schwann cells?

Answer 21

Form the myelin sheath in the PNS.

Question 22

What is the difference between CNS and PNS?

Answer 22

CNS: brain and spinal cord; PNS: all other nerves.

Question 23

What is myelin?

Answer 23

A fatty substance that insulates axons and speeds up signal transmission.

Question 24

What is synaptic pruning?

Answer 24

The removal of unnecessary synapses.

Question 25

What is phagocytosis?

Answer 25

The process by which glial cells clear debris.

Question 26

What is the role of calcium in astrocytes?

Answer 26

It facilitates chemical signalling.

Question 27

What disease is associated with glial malfunction?

Answer 27

Multiple sclerosis (MS).

Question 28

What is multiple sclerosis?

Answer 28

A disease caused by demyelination due to glial cell failure.

Question 29

What glial cells are involved in neuropathic pain?

Answer 29

Schwann cells, microglia, and astrocytes.

Question 30

What is electrostatic pressure?

Answer 30

The force between charged molecules.

Question 31

What is diffusion in neurons?

Answer 31

Movement of ions from high to low concentration.

Question 32

What are afferent neurons?

Answer 32

Sensory neurons carrying signals to the CNS.

Question 33

What are efferent neurons?

Answer 33

Motor neurons carrying signals from the CNS.

Question 34

What is a synapse?

Answer 34

The gap between neurons where communication occurs.

Question 35

What neurotransmitter is involved in muscle contraction?

Answer 35

Acetylcholine (ACh).

Question 36

What is the function of dendrites?

Answer 36

To receive signals from other neurons.

Question 37

What is the axon hillock?

Answer 37

The area where action potentials are initiated.

Question 38

What happens when a neuron is polarised?

Answer 38

It has a negative charge inside relative to the outside.

Question 39

What happens when a neuron is depolarised?

Answer 39

The inside becomes less negative.