Neuron Physiology

Question 1

Define neuroscience.

Answer 1

study of the nervous system; including cellular and molecular processes, behavioural, affective and cognitive abilities, systems or circuitry, and disease.

Question 2

What are the components of a neuron?

Answer 2

• Dendrites
• Cell bodies
• Axon.

Question 3

Define neural unit.

Answer 3

brain is made up of individual neurons that contain specialized features (dendrites, cell body, axon).

Question 4

Define neuron specialisation.

Answer 4

units may differ size, shape, and structure according to their location or functional specialization.

Question 5

Define neuronal fibres.

Answer 5

Outgrowths of neurons.

Question 6

Define neuronal contacts.

Answer 6

Neurons are connected by sites of contact and not cytoplasmic continuity.

Question 7

Define resting potential.

Answer 7

A product of the electrical difference between extracellular and intracellular solutions.

Question 8

Define oligodendrocytes,

Answer 8

Cells that that send out projections that wrap around axons.

Question 9

Name the golgi stains used for identifying neurons and it’s colour.

Answer 9

Silver nitrate and potassium dichromate. Labels neurons dark brown/black.

Question 10

What is the Nissl stain used for and what colour is it.

Answer 10

Identifies all cells in the brain. Turns the RNA within the endoplasmic reticulum blue.

Question 11

Define dendrites.

Answer 11

Part of neuron that transmits information from sensory receptors, other neurons.

Question 12

Define cell bodies.

Answer 12

Part of neuron that integrates information; also has a nucleus).

Question 13

Define the axon of a neuron.

Answer 13

Signal output, passes information to subsequent neuron.

Question 14

Define neural unit.

Answer 14

The brain is made up of individual neurons that contain specialized features (dendrites, cell body, axon).

Question 15

Define neuronal fibres.

Answer 15

Outgrowths of neurons.

Question 16

Describe neuronal contacts.

Answer 16

Neurons are connected by sites of contact and not cytoplasmic continuity.

Question 17

Define Dale’s Law.

Answer 17

Each neuron has a specialised chemical. However recent research has found this is NOT TRUE for all neurons.

Question 18

How does the voltage within a neuron compare to the voltage of the surrounding solution.

Answer 18

Significantly lower.

Question 19

Define resting potential.

Answer 19

a product of the electrical difference between extracellular and intracellular solutions.

Question 20

Whereabouts does the resting potential usually sit?

Answer 20

between -60 and -70mV.

Question 21

What is the minimum voltage required to achieve an action potential?

Answer 21

-40mV.

Question 22

What causes the initial rising and falling voltage of an action potential?

Answer 22

Rising - inward flux of sodium.

Falling - outward movement of both sodium and potassium.

Question 23

What is the absolute refractory period?

Answer 23

The period when an action potential cannot be stimulated.

Question 24

What is the relative refractory period?

Answer 24

The period when a small voltage change can be stimulated.

Question 25

Define the excitatory presynaptic potential.

Answer 25

Presynaptic neuron stimulates a mild depolarization in neuron; leading to a graded increase in voltage.

Question 26

Define inhibitory presynaptic potential.

Answer 26

Presynaptic neuron stimulates a mild hyperpolarization in neuron; leading to a graded decrease in voltage.

Question 27

Define oligodendocytes.

Answer 27

Cells that send out projections that wrap around axons.

Question 28

What happens when myelin is degraded.

Answer 28

Multiple sclerosis - disrupts transmission of nerve signals.

Question 29

What is myelin?

Answer 29

Myelin sheaths coat Nodes of Ranvier.