week 2 Flashcards
(48 cards)
What is the nature of signaling within a neuron?
Electrical signaling
Neurons can extend over relatively long distances and signals move from one part of a neuron to another.
Why is electrical signaling used instead of chemical diffusion in neurons?
Diffusion of chemicals would be too slow
Therefore, the signal is electrical in nature.
What is an action potential?
A sudden change in membrane voltage of a neuron in response to a stimulus
It depends on the resting membrane potential.
What is the resting membrane potential for a neuron?
-70 mV
This is the difference between the electrical potential inside and outside the cell.
How do neurons send information to other neurons?
By temporarily altering their overall polarity (electrical charge)
This involves changing the membrane potential.
What alters the membrane potential in a neuron?
The movement of ions in and out of the cell
This movement is influenced by diffusion and electrostatic pressure.
What are the two forces that prevent ions from moving freely in and out of the cell?
- Diffusion
- Electrostatic pressure (opposites attract)
These forces regulate ion movement across the cell membrane.
What are cations?
Positively charged ions
Examples include potassium (K+) ions.
What are anions?
Negatively charged ions
Examples include chloride (Cl-) ions.
What is the fluid inside the cell called?
Intercellular fluid
This fluid contains potassium (K+) ions.
What is the fluid outside the cell called?
Extracellular fluid
This fluid contains sodium (Na+) and chloride (Cl-) ions.
What is the primary movement of Na+ ions into the cell?
Diffusion
Na+ ions want to enter the cell due to concentration gradient.
What prevents Na+ ions from entering the cell despite diffusion?
Electrostatic pressure
Electrostatic pressure creates a barrier for Na+ ions.
What drives Na+ ions to want to leave the cell?
Diffusion
Na+ ions have a tendency to move out of the cell due to concentration gradient.
What prevents Na+ ions from leaving the cell?
Electrostatic pressure
The positive outside of the cell creates a force against Na+ leaving.
What is the electrostatic pressure’s effect on K+ ions wanting to enter the cell?
Can go in
Electrostatic pressure allows K+ ions to enter the cell.
What is the charge inside the cell compared to the outside?
Inside of cell = negative, Outside of cell = positive
This charge difference is important for ion movement.
What is the function of sodium-potassium pumps?
Pump Na+ out and K+ in
Sodium-potassium pumps help maintain the electrochemical gradient.
What happens to Na+ ions as the concentration inside the cell increases?
A lot of Na+ ions travel into the cell
This accumulation necessitates the action of sodium-potassium pumps.
Fill in the blank: Sodium-potassium pumps pump all the _______ out of the cell.
Na+
This action is crucial for maintaining the cell’s resting potential.
Fill in the blank: Sodium-potassium pumps pump the escaped _______ back into the cell.
K+
This helps regulate potassium levels inside the cell.
What does the sodium-potassium pump do?
It pumps out Na+ that entered the cell and pumps back in any K+ that managed to escape.
This pump is essential for maintaining the resting membrane potential in neurons.
What analogy is used to describe the sodium-potassium pump?
A sexist bouncer who believes that only boys cause fights.
In this analogy, Na+ represents boys that are kicked out, while K+ represents girls that are persuaded to return.
What is the charge change in a neuron called when sending information?
Action potential.
The action potential is a rapid change in electrical charge necessary for neuronal communication.
