Lecture 2: Action Potentials And Electrophysiology Flashcards
Name the main structures involved in an action potential
- axon
- axon hillock
- dendrites
- synapses
What is an action potential?
- a rapid and all-or-nothing self propagating change in membrane potential
What is depolarization?
- influx of sodium ions into cell
- triggers sodium channels to open
- concentration gradient forces sodium ions to enter
- channels will close when interior reaches 20mV
What is repolarization?
- an efflux of potassium ions
- when interior becomes 20mV ion channels open and force potassium ions out
- makes interior more and more negative
Explain conduction
- Involves successful initiation of an action potential (signal is successfully passed on)
- action potential in one area causes chain reaction that causes more voltage-gated channels to open further along axon
What is an axon?
- Part of neuron that conducts an action potential
- extends along long distances in the body (such as the sciatic nerve)
What is the axon hillock?
- the place just under the soma where the action potential starts
What are dendrites?
- small fibres that extend out from soma
- receive signals but aren’t as complex or long as axons
What are synapses?
- point of connection between neurons
- where transfer of neurotransmitters occur
What is resting membrane potential?
The difference in charge between the negative inside and positive outside of a neuron
What are the four ions involved in action potential and what are their charges?
- Sodium, Na+
- Potassium, K+
- Chloride, Cl-
- Proteins, -ve
What are the determining factors for resting membrane potential?
- membrane permeability
- Voltage-gated Ion channels
- Na+/K+ pumps
What are the factors that affect ion flow?
- concentration gradient
- electrical gradient
- membrane permeability
What is the concentration gradient?
The movement of an ion from an area of high concentration to an area of low concentration
What is the electrical gradient?
The natural attraction of positive and negative forces
What does membrane permeability refer to?
For large and charged particle to pass through the membrane, they must use channels inside the membrane, thee channels are made of protein
What is the resting membrane potential in my
-70mV
