Chapter 3: Resting Membrane Potential Flashcards
All neurons transmit an electrochemical signal and this signal is the same in all neurons. What changes between different neurons is the —– message being released.
Chemical message that is released
What is potential in regards to the neuron membrane and how is it measured?
Potential is a separation of charges across the membrane and is measured in voltage ( V.)
Membrane potential is measured in voltage. Can you define what voltage is?
It is the difference in electric potential between the inside and outside of a neuron. Voltage inside the cell is measured in comparison to the outside.
Greater voltage means there is more or less current movement you can observe?
The greater the voltage, the more current movement you can see.
What are the names of the three electrical potentials?
The resting membrane potential ( RMP. Graded potentials & action potentials.
What are the three things necessary to measure the membrane potential of a neuron?
Microelectrodes, ( reference & intracellular or recording,) an amplifier, and an oscilloscope on a computer.
What are microelectrodes?
A tiny metal device used to record electrical potentials.
Intracellular microelectrode is placed into intra or extracellular fluid? Reference microelectrode is placed in intracellular or extracellular fluid?
Intracellular microelectrode is place into intracellular fluid. Reference microelectrode is placed in extracellular fluid.
Imagine that the voltage of a neuron is -60mV. Does this mean that the inside of the cell is more negative than the extracellular fluid or that the outside of the cells is more negative than the intracellular fluid?
The inside of the cell is more negative than the extracellular fluid.
Where is an intracellular microelectrode placed?
This microelectrode is placed into intracellular fluid.
Where is a reference microelectrode placed?
This microelectrode is placed in extracellular fluid.
The resting membrane potential is being recorded outside of the cell. When the recording electrode is outside of the cell, the difference between the reference and recording electrode is what?
Zero.
The resting membrane potential is being recorded with the recording electrode inserted into the cell membrane. Is a negative or positive potential difference seen?
When the recording electrode is inserted into the membrane, a negative potential difference is seen. The neuron is more negative inside relative to the outside of the cell. This is referred to as the resting membrane potential.
What are ions?
An ion is any element that contains a different number of protons and electrons. They are electrically charged particles.
All elemental atoms contain the same number or protons & electrons. Does this give them a positive or neutral charge?
This gives them a neutral charge.
The environment surrounding the neuronal membrane is a watery environment that contains several electrically charged particles. What are these electrically charged particles known as?
These are known as ions.
Do cations have a negative or positive charge?
Cations are ions that have a positive charge.
Do anions have a negative or positive charge?
Anions have a negative charge.
What are the five ions that surround the membrane?
Cations: Sodium ( Na+) , Potassium ( K+) , Calcium ( Ca2+)
Anions: Chloride ( Cl-), Negatively charged proteins ( A-)
How many cations surround the neuronal membrane? What are their names?
- Sodium ( Na+)
- Potassium ( K+)
- Calcium ( Ca2+)
How many anions surround the neuronal membrane?
- Chloride ( Cl-)
- Negatively charged proteins ( A-)
Are ions stationary?
No. Ions are in constant motion and their movement is guided by diffusion & electrostatic pressure.
What two things guide ion currents?
Diffusion & electrostatic pressure
What is diffusion ( concentration gradients) and its relationship to ions?
Diffusion guides ion movement by moving ions from areas of high to low concentration. High to low concentration.
What is electrostatic pressure & its relationship to ions?
Electrostatic pressure moves ions toward oppositely charged areas. Negative to positive or positive to negative.
DIffusion refers to the tendency of molecules to move from an area of (lower/higher) concentration to an area of ( higher/lower) concentration.
Diffusion refers to the tendency of molecules to move from an area of higher concentration to an area of lower concentration.
When there is a difference in concentration, what does it produce?
A concentration gradient.
What is a concentration gradient?
It is what happens when there is a difference in concentration.
Does diffusion produce an uneven or even distribution of molecules?
Diffusion produces an even distribution of molecules.
If a semipermeable membrane restricts the flow of substances, those substances that can pass will diffuse across until unequally or equally concentrated on both sides?
Passage of substances in a semipermeable membrane will diffuse across until equally concentrated on both sides.