Neurophysiology 1

Question 1

What is synapse and synaptic transmission?

Answer 1

Synapse - connection and communication between pre and post synpatic cells

Synaptic transmission - presynaptic neuron releases neurotransmitter which diffuses across cleft, binds to receptors.

Question 2

Every neuron to neuron synapse has:

Answer 2

Presynaptic - releases neurotrnasmitter
Postsynaptic - neuron that has receptive ion channels transmitter bind

Question 3

How does a chemical signal get converted into an electrical signal?

Answer 3

1. A chemical signal (neurotransmitter) binds to and opens chemically gated ion channels.
2. Ions flow in or out, changing the voltage in a area of the membrane.
3. if the membrane voltage reaches -60mv at the axon hillick
4. an action potential begins.

Question 4

Chemically gated ion channel

Answer 4

1. Chemical neurotransmitter binds to ion channel
2. Channel opens
3. Ions cross the membrane driven by their electrochemical gradient
4. neurotransmitter unbinds causing channel to close.

Question 5

Voltage gated ion channels

Answer 5

1. membrane depolarizes
2. channel changes shape (opens)
3. ions cross membrane driven by electrochemical gradient.
4. membrane threshold changes causing channel to close

Question 6

Mechanically gated ion channels.

Answer 6

deformation of membrane
channel opens
ions driven by electrochemical gradient
when membrane returns to original shape the channel does.

Question 7

Where are gated ion channels on a neuron?

Answer 7

CB and Dendrites - chemically gated
AH and Axon - voltage channel
Axon Terminals - Ca voltage gated channels