Nervous System

Question 1

What is the basic structure of a neurone?

Answer 1

Cell body, dendrites, axon, axon terminal.

Question 2

What are the three main types of neurones?

Answer 2

Sensory, motor, and interneurons

Question 3

What cells are associated with neurones?

Answer 3

Schwann cells, oligodendrocytes, astrocytes, and microglia.

Question 4

What is the difference between myelinated and non-myelinated neurones?

Answer 4

Myelinated neurones have an insulating layer of myelin, allowing faster impulse conduction, while non-myelinated neurones lack this layer and conduct impulses more slowly

Question 5

What is the resting potential of a neurone?

Answer 5

-70mV

Question 6

What causes the resting potential?

Answer 6

Selective permeability and active transport of ions (Na+/K+ pump).

Question 7

What ions are more concentrated outside the neurone at rest?

Answer 7

Sodium (Na+) and chloride (Cl-)

Question 8

What ions are more concentrated inside the neurone at rest?

Answer 8

Potassium (K+) and negatively charged proteins

Question 9

What is the sodium-potassium pump?

Answer 9

A protein that actively transports 3 Na+ ions out and 2 K+ ions into the neurone

Question 10

What is an action potential?

Answer 10

A rapid electrical signal caused by changes in membrane potential, propagating along the axon

Question 11

What is depolarisation?

Answer 11

When Na+ ions enter the neurone, reversing the membrane potential to +40mV

Question 12

What is the all-or-nothing principle?

Answer 12

An action potential either occurs fully if the threshold is reached or not at all

Question 13

What happens during repolarisation?

Answer 13

K+ ions leave the neurone, restoring the resting potential

Question 14

What is the refractory period?

Answer 14

A period after an action potential during which a neurone cannot immediately fire again

Question 15

What is saltatory conduction?

Answer 15

The “jumping” of action potentials between the nodes of Ranvier in myelinated neurones

Question 16

Why is saltatory conduction efficient?

Answer 16

It speeds up impulse conduction and conserves energy

Question 17

What factors affect conduction velocity?

Answer 17

Axon diameter, myelination, and number of synapses

Question 18

What is a synapse?

Answer 18

A junction between two neurones or a neurone and an effector cell

Question 19

What is the synaptic cleft?

Answer 19

The gap between the presynaptic and postsynaptic membranes

Question 20

What happens at the presynaptic neurone?

Answer 20

Neurotransmitters are released from synaptic vesicles into the synaptic cleft

Question 21

What happens at the postsynaptic neurone?

Answer 21

Neurotransmitters bind to receptors, causing EPSPs or IPSPs

Question 22

What is an EPSP?

Answer 22

Excitatory postsynaptic potential that depolarises the membrane

Question 23

What is an IPSP?

Answer 23

Inhibitory postsynaptic potential that hyperpolarises the membrane

Question 24

What are the main types of neurotransmitters?

Answer 24

Acetylcholine, amino acids, monoamines, and neuropeptides.

Question 25

What is acetylcholinesterase?

Answer 25

The enzyme that breaks down acetylcholine

Question 26

What is an electrical synapse?

Answer 26

A synapse where signals pass directly through gap junctions

Question 27

What is facilitation in the nervous system?

Answer 27

Increased neurotransmitter release due to residual calcium from repeated stimulation

Question 28

What is temporal summation?

Answer 28

Multiple signals from one synapse in quick succession

Question 29

What is spatial summation?

Answer 29

Signals from multiple synapses at the same time

Question 30

What determines if a postsynaptic neurone fires?

Answer 30

The sum of EPSPs and IPSPs and their proximity to the axon hillock

Question 31

What are sensory nerves (afferent)?

Answer 31

Neurones that carry signals toward the CNS

Question 32

What are motor nerves (efferent)?

Answer 32

Neurones that carry signals away from the CNS to effectors

Question 33

What are interneurons?

Answer 33

Neurones that relay signals within the CNS

Question 34

What are relay neurones?

Answer 34

Interneurons with long axons for transmitting signals over long distances

Question 35

What are local circuit neurones?

Answer 35

Interneurons with short axons for nearby communication.

Question 36

What is a reflex arc?

Answer 36

A direct pathway involving sensory input, CNS processing, and motor output

Question 37

What is the knee-jerk reflex?

Answer 37

A monosynaptic spinal reflex triggered by tapping the patellar tendon

Question 38

What is the CNS composed of?

Answer 38

The brain and spinal cord

Question 39

What is the difference between white and grey matter?

Answer 39

White matter contains myelinated axons; grey matter contains cell bodies and dendrites

Question 40

What is the PNS?

Answer 40

The peripheral nervous system includes all nerves outside the CNS

Question 41

What is the somatic nervous system?

Answer 41

A system controlling voluntary movements and sensory input

Question 42

What is the autonomic nervous system?

Answer 42

A system regulating involuntary processes like heartbeat and digestion

Question 43

What are the two divisions of the autonomic nervous system?

Answer 43

Sympathetic (fight or flight) and parasympathetic (rest and digest)

Question 44

What is the function of sensory receptors in the PNS?

Answer 44

To detect stimuli and send information to the CNS

Question 45

What is the role of the motor division of the PNS?

Answer 45

To send signals from the CNS to muscles and glands

Question 46

What is the role of Schwann cells?

Answer 46

To form myelin sheaths in the PNS

Question 47

What is the role of oligodendrocytes?

Answer 47

To form myelin sheaths in the CNS

Question 48

What are astrocytes?

Answer 48

Glial cells that provide support and regulate the extracellular environment of neurones

Question 49

What is the role of microglia?

Answer 49

To act as immune cells in the CNS

Question 50

What is the significance of the nodes of Ranvier?

Answer 50

They allow for saltatory conduction by providing points for ion exchange