Synapse

Question 1

How do synapses work?

Answer 1

-Action potential arrives at the pre synaptic knob,
-this depolarization causes calcium ion channels to open and calcium to diffuse into the presynaptic knob.
- The calcium which diffuses in causes the vesicles to move towards the pre synaptic membrane, when it fuses with the membrane, neurotransmitters are released to in to the cleft.
-Neurotransmitters bind with receptors on the post-synaptic neuron
-Receptors attached to sodium channels, if action potential is generated (enough sodium ions diffuse in, the post synapse is depolarized.
-Neurotransmitters are reabsorbed and broken down in pre synaptic neuron.

Question 2

What is summation?

Answer 2

The rapid build up of neurotransmitters in synapse to ensure an action potential is generated.

Question 3

Temporal summation

Answer 3

When one pre synaptic neuron constantly releases neurotransmitters over a period of time

Question 4

Spatial summation

Answer 4

When more than one pre synaptic neuron to one post synaptic neuron, more neurotransmitter released

Question 5

Inhibitory synapse

Answer 5

Instead of sodium channels opening in the post synaptic neuron, causes chlorine ions to open.
Also causes potassium ions to move out.
The result of negative chlorine and positive potassium ions moving in and out causes a negative membrane potential of -80. Action potential is unlikely to be triggered.

Question 6

What does unidirectional flow mean and how do synapses ensure that nerve impulses are unidirectional?

Answer 6

Uni directional flow means that neurotransmitters flow in one direction.
Synapses ensure that nerve impulses are unidirectional as receptors are only contained on post synapse and vesicles only in pre.

Question 7

Neuromuscular junctions

Answer 7

-Is still a synapse
-gap between neuron and the muscle
-found end of reflex arc

Question 8

Differences/similarities between Neuromuscular junction and synapse

Answer 8

-Both unidirectional flow

-Neuromuscular- only executory, whereas synapse both executory and inhibitory
-Neuromuscular, end of action potential, whereas synapse generated to next neuron
–Neuromuscular only connect to muscles, synapse, connect to motor, relay or synapse
-Acetylcholine binds to muscle fiber membrane whereas in synapse post synaptic nerve