Nerve Conduction and Synapse Transmission

Question 1

What are Dendrites?

Answer 1

They receive inputs from other neurones and convey graded electrical signals passively to the soma

Question 2

What is the Soma? (Perikaryon)

Answer 2

Synthetic and metabolic centre.

Question 3

What does the Soma contain?

Answer 3

The nucleus
Ribosomes
Mitochondria
ER/RER

Question 4

What happens at the Axon hillock and initial segment?

Answer 4

All or nothing action potential

Question 5

What does the Axon do?

Answer 5

Conducts the output signals as action potentials to other neurones
mediates transport of materials between soma and presynaptic terminal

Question 6

What is the synapse?

Answer 6

Point of chemical communication between neurones

Question 7

Give an example of a unipolar neurone

Answer 7

peripheral autonomic neurone

Question 8

Give an example of a pseudounipolar neurone

Answer 8

Dorsal root ganglion (DRG)

Question 9

Give an example of a Bipolar neurone

Answer 9

Retinal Bipolar neurone

Question 10

Give an example of a Multipolar neurone

Answer 10

Lower Motor neurone (LMN)

Question 11

What causes the upstroke in an action potential?

Answer 11

Voltage-activated Na+ channel

Question 12

What causes the downstroke in an action potential?

Answer 12

Voltage gated K+ channel

Question 13

How big may an axon be?

Answer 13

Up to 1 metre

Question 14

The distance over which a current spreads depends upon what?

Answer 14

membrane resistance
Axial resisitance (axoplasm)

Question 15

True or False:

The longer the length in constant, the greater the local current spread?

Answer 15

TRUE

Question 16

What does a Schwann cell surround?

Answer 16

A single axon

Question 17

What does a Oligodendrocyte surround?

Answer 17

many axons

Question 18

What is the name of the node that the action potential jumps from one to another?

Answer 18

Ranvier

Question 19

In the CNS, what is the most common excitatory transmitter?

Answer 19

Glutamate

Question 20

What are the excitatory and inhibatory responses?

Answer 20

Excitatory = depolarizing
Inhibatory = hyperpolarizing

Question 21

In the CNS, what is the most common inhibatory transmitter?

Answer 21

Gamma-Aminobutyric acid (GABA)
or
Glycine

Question 22

What do the excitatory transmitters activate?

Answer 22

Postsynaptic cation sleective ionotrophic glutamate receptors

Question 23

What do the inhibatory transmitters activate?

Answer 23

Posysynaptic anion selective ionotrophic receptors

Question 24

What does e.p.s.p stand for?

Answer 24

Excitatory postsynaptic Potential

Question 25

WHat does i.p.s.p stand for?

Answer 25

Inhibatory postsynaptic potential

Question 26

What holds the pre and post synaptic cleft together?

Answer 26

A matrix of fibrous extracellular protein within the cleft

Question 27

What receptors are involved in the excitatory process?

Answer 27

Sodium

Question 28

What receptors are involved in the inhibatory process?

Answer 28

Chlorine

Question 29

What happens in Spatial Summation?

Answer 29

Many inputs converge upon a neurone to determine its output

Question 30

What happens in Temporal summation?

Answer 30

A single input may modulate output by variation in action potential frequency of that input

Question 31

Where are amino acids and amines released from?

Answer 31

Synaptic vesicles

Question 32

Where are peptides released from?

Answer 32

Secretory vesicles

Question 33

How are enzymes transported in the body?

Answer 33

By axoplasmic transport along microtubules to the presynaptic terminal