Saltatory Conduction/Synapse

What is saltatory conduction ?i i

Saltatory conduction is the process where impulses travel more quickly due to the Nodes of Ranvier in myelinated axons .i i

What is a synapse ?i i

A synapse is a special location where an impulse is transmitted from one neuron to another .i i

What is a neuromuscular junction ?i i

A neuromuscular junction is a type of synapse between a neuron and a muscle .i i

Do neurons physically connect? Why ?i i

Neurons do not physically connect because they have tiny gaps between them .i i

What are the gaps between neurons called ?i i

The gaps are called synaptic cleft or a synaptic gap .i i

Describe the process of synaptic transmission .i i

1. In the presynaptic axon, the impulse reaches the synaptic knob and calcum ions enter the synaptic knob

2. Vesicles containing neurotransmitters (like Acetylcholine) move towards the presynaptic membrane

3. The vesicles attach to the presynaptic membrane and release ACH into the synaptic cleft by exocytosis

4. ACH attached to protein receptors on the postsynaptic membrane and causes it to become permeable to sodium ions

5. After all that, acetylcholinesterase breaks down acetylcholine into the synaptic cleft and fragments are taken back to the presynaptic membrane by endocytosis

6. ACH fragments are remade into ACH within the vesicle

Why do impulses travel in one direction across the synapse ?i i

To control the flow through nerve pathways .i i

What causes the impulse to be continued in adjacent neurons ?i i

Excitatory neurotransmitters .i i

What to excitatory neurotransmitters do ?i i

They cause the impulse to be continued in adjacent neurons .i i

List 3 excitatory neurotransmitters .i i

1. Acetylcholine

2. Histamine

3. Norepinephrine

What stops the impulse from being continued ?i i

Inhibitory neurotransmitters .i i

What do inhibitory neurotransmitters do ?i i

They stop the impulse from being continued .i i

List 3 examples of inhibitory neurotransmitters .i i

1. Serotonin

2. Epinephrine

3. Glycine

What happens if the body's average impulse is excitatory ?i i

An impulse will be transmitted .i i

What happens when the body's average is inhibitory ?i i

An impulse will not be transmitted .i i