Nerves and Synapses

HideShow resource information
What is the function of the myelin sheath and nodes of Ranvier?
To create Saltatory conduction (speed up transmission)
1 of 20
How are neurons separated?
a narrow fluid gap called the synaptic cleft
2 of 20
What does the depolarisation of the pre synaptic nerve cause?
Vesicles of neurotransmitter move to the pre synaptic membrane and fuse with it, releasing the neurotransmitter into the synaptic cleft by exocytosis
3 of 20
How does neurotransmitter cross the synapse?
It diffuses across the cleft, binding to receptors on the post-synaptic nerve
4 of 20
What type of receptors are on the post synaptic membrane?
Transmitter-gated sodium channels
5 of 20
What happens when transmitter binds to the receptors?
Sodium ions diffuse into the post-synaptic neuron, causing deploarisation
6 of 20
How is continuous synaptic transmission prevented?
Neurotransmitter left in the synaptic cleft is broken down and re absorbed into the pre-synaptic nerve
7 of 20
What is a cholinergic synapse?
A synapse which uses the neurotransmitter acetylcholine
8 of 20
How is acetylcholine prevented from causing continuous synaptic transmission?
broken down into acetyl groups and choline by the enzyme cholinesterase
9 of 20
How do neonicotinoid pesticides kill insects?
It binds (and cannot be broken down, so remains bound) to acetylcholine receptors, preventing acetylcholine from binding
10 of 20
What is the resting potential?
The voltage across the plasma membrane of a neuron when it is not conducting a nerve impulse
11 of 20
What mV is the resting potential, and why?
-70mV, because of unequal exchange of Na+ and K+ at sodium/potassium pumps
12 of 20
During resting potential, what is the formation of the K+ and Na+ channels?
both closed
13 of 20
What is the action potential?
brief depolarisation caused by changes in currents
14 of 20
What is the action potential threshold?
-50mV
15 of 20
What is the voltage of an action potential?
+40mV
16 of 20
During an action potential, what happens to the voltage gated Na+ and K+ channels?
They open, so Na+ enters and K+ leaves, along the electrochemical gradient created by the resting potential
17 of 20
What is repolarisation?
The restoration of the resting potential
18 of 20
What is the formation of the K+ and Na+ channels during repolarisation?
K+ channels open, Na+ channels closed
19 of 20
What is hyperpolarisation?
a brief lowering of the voltage to -75mV (below the polarised level), caused by a delay in the activation of the sodium potassium pumps and closing of Na+ and K+ channels
20 of 20

Other cards in this set

Card 2

Front

How are neurons separated?

Back

a narrow fluid gap called the synaptic cleft

Card 3

Front

What does the depolarisation of the pre synaptic nerve cause?

Back

Preview of the front of card 3

Card 4

Front

How does neurotransmitter cross the synapse?

Back

Preview of the front of card 4

Card 5

Front

What type of receptors are on the post synaptic membrane?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Human Physiology resources »