Action Potential Flashcards
What is the function of dendrites?
They receive information from other neurons or from the environment.
What are the functions of the cell body?
It controls the cell’s metabolic activities and it integrates input from other neurons.
What is the function of an axon?
It conducts the nerve impulse away from the cell body.
What is the function of axon endings?
They release chemicals called neurotransmitters that affect the activity of nearby neurons or an effector (muscle or gland).
What is used to transmit a message from neutron to neuron?
Action potential
What are the three types of neurons?
Sensory neurons, interneurons, motor neurons
What are the three basic mechanisms of membrane transport?
Simple diffusion, facilitated diffusion, active transport
What is an ion channel?
It is a cell membrane transport protein that allows a specific ion to cross the membrane.
What is an action potential?
It is the movement of ions through the membrane, changing the voltage across the membrane.
What is the voltage?
It is a difference in charge between the inside and outside of the membrane.
Are the ion channels involved in an action potential always open?
No, they are gated
How can a gated channel be opened?
A gated channel is closed until a signal opens it. Some gated channels are opened by changes in voltage while others are opened in the presence of a specific chemical such as a neurotransmitter.
What are the three membrane proteins that can be find along the axon of a neuron?
- Voltage-gated sodium (Na+) channels
- Voltage-gated-Potassium (K+) channels
- Sodium-Potassium pumps
What does the sodium-potassium pump do?
It actively moves Na+ out of the cell and K+ in the cell (the neuron), creating a resting membrane potential. For very three sodium ions out, two potassiums are let in. When the pump is active, the gated channels are closed, preventing the diffusion of the ions.
What is the consequence of using the sodium-potassium pump?
It creates a concentration gradient between the inside and the outside of the neuron.
What do the voltage-gated channels do?
They allow Na+ and K+ to move through facilitated diffusion across the membrane.
What is a resting neuron?
It is when the plasma membrane is charged, with the inside negative relative to the outside.
Why do neurons have a more negative charge inside compared to outside when they are at rest?
Because of the sodium-potassium pump.
When a neuron is at rest where are the potassium and the sodium?
The sodium is outside the cell and the potassium is inside.
How can a neuron be described when it is at rest?
We say that the neuron is polarized.
What kind of stimulus is needed to open the gated channels?
An “electrical” stimulus is needed.
What is the other name for action potentials?
Nerve impulses
When does an action potential occur?
When a neuron sends information down an axon.
What is the detailed definition of action potential?
An action potential is an electrochemical signal involving the flow of sodium ions (Na+) and potassium ions (K+) across the cell membrane through ion channels in a precise sequence.
