Lecture 18

Question 1

What is the chemical synapse

Answer 1

The junction between nerve cells were an action potential is transferred from on neuron to another or to a muscle.

Question 2

What can acetyl choline do to affect membrane potential?

Answer 2

Can open the gate/ ion channel, by binding to the protein causes the channel to open. Basically turning on the membrane potential.

Question 3

What can a presynaptic neuron attach to?

Answer 3

A postsynaptic neuron or a muscle fibre.

Question 4

What do synaptic vesicles carry?

Answer 4

The neurotransmitter

Question 5

What is in the cleft?

Answer 5

Enzymes

Question 6

What type of enzyme is in the cleft?

Answer 6

AChE so acetyl choline esterase

Question 7

What is AChE important for?

Answer 7

Useful for terminating chemical synaptic transmissions.

Question 8

Why are mitochondria important?

Answer 8

Because they give energy to the synapse.

Question 9

What is the first step to chemical synaptic transmission?

Answer 9

Action potential triggers the opening of voltage-gated calcium channels.

Question 10

What is the second step to chemical synaptic transmission?

Answer 10

Calcium ions diffuse into the axon terminal and trigger synaptic vesicles to release ACh by exocytosis.

Question 11

What is the third step to chemical synaptic transmission?

Answer 11

ACh diffuses across synaptic cleft, binds to ACh-gated sodium ion channels and produces a graded depolarisation, also called EPSP or Excitatory post synaptic potential.

Question 12

What is the fourth step to chemical synaptic transmission?

Answer 12

Depolarisation ends as ACh is broken down into acetate and choline by AChE.

Question 13

What is the fifth step to chemical synaptic transmission?

Answer 13

The axon terminal reabsorbs choline from the synaptic cleft and uses it to synthesise new molecules of ACh

Question 14

What does EPSP stand for?

Answer 14

Excitatory post synaptic potential.

Question 15

What does IPSP stand for?

Answer 15

Inhibitory post synaptic potential.

Question 16

How fast are EPSP and IPSP

Answer 16

They are in the order of milliseconds, not as fast as action potentials, usually 5-10 milliseconds for these to appear.

Question 17

Is there an axon hillock/ decision point in a neural muscular junction?

Answer 17

No otherwise you wouldn’t be able to move your muscles.

Question 18

What does temporal mean?

Answer 18

In time

Question 19

Can you add up action potentials?

Answer 19

Yes it helps to get over the axon hillock by adding more EPSP to get over the threshold and cause an action potential to occur!!

Question 20

What happens when there is enough action potential?

Answer 20

Its called action potential propagation, and it has been allowed to travel down the axon hillock.

Question 21

Temporal summation is…?

Answer 21

Summating those EPSP in time!!

Question 22

What does spatial summation mean?

Answer 22

In space or adding up graded potentials in space.

Question 23

What happens with there is two simultaneous action potentials occurring?

Answer 23

It leads to a large depolarisation as there is twice as much that can get a large action potential to overcome the axon hillock.