ion channels overview 1 Flashcards
Describe the importance of ion distribution across biological membranes.
Ion distribution across biological membranes is crucial for membrane polarity and the proper functioning of electrically excitable cells.
What is the role of electrical excitation in cells?
Electrical excitation is essential for the physical function of cells.
What happens when an external signal alters the action potential of a cell?
It leads to a major function such as contraction in myocytes or communication with the body in neurons.
Define action potential in the context of electrically excitable cells.
Action potential refers to the change in electrical potential that occurs when a cell is stimulated.
How are most signals in electrically excitable cells generated?
Most signals are generated by ions, which are hydrophilic molecules essential for life.
Describe the responsibility of ions in electrically excitable cells.
Ions are responsible for the cell membrane potential and play a key role in cell function.
What is the significance of membrane potential in cells?
Membrane potential is crucial for various cellular functions, especially in electrically excitable cells.
What are some examples of functions influenced by external signals in electrically excitable cells?
Functions such as contraction in myocytes and communication with the body in neurons are influenced by external signals.
Do all diagrams in the content come from a specific source?
Yes, all diagrams have been personally created with Biorender by Dr. Falcon.
Describe membrane potential (MP)
Voltage difference (in mV) between the inner and outer surface of the cell membrane, necessary for cell homeostasis and function in electrically excitable cells and tissues.
What is the distribution of ions across a biological membrane based on membrane potential?
Extracellular space is positive, while intracellular space is negative.
Define resting membrane potential
The state where electrically excitable cells have a negative voltage difference between the inner and outer surface of the cell membrane when no ion channels are open.
Describe the distribution of ions across biological membranes rest.
ons have a particular distribution rest, meaning, when the cells do change their membrane potential.
Do ions permeate the cell membrane freely?
Ions cannot permeate the membrane freely.
Define membrane potential in the context of biological membranes.
Membrane potential is the difference in electric charge between the inside and outside of a cell membrane.
How do electrically excitable cells typically distribute ions across the cell membrane at rest?
Electrically excitable cells have an uneven distribution of ions across the cell membrane at rest.
Describe the membrane potential of a skeletal muscle cell at rest.
The membrane potential of a skeletal muscle cell at rest is -90mV.
Describe the impermeability of ions to the cell membrane.
Ions are impermeable to the cell membrane.
How is the uneven ion distribution across biological membranes maintained?
Through active transport mechanisms that determine the distribution of ions at rest.
What are examples of cell surface pumps or exchangers involved in maintaining ion distribution?
Examples include the Na+/K+ pump.
What is the energy source used by the Na+/K+ pump to move ions?
The Na+/K+ pump uses ATP as an energy source.
What is the specific action of the Na+/K+ pump in terms of ion movement?
It moves 3 Na+ ions out and 2 K+ ions in.
Describe the process of ion distribution across biological membranes.
Ions diffuse down their electrochemical gradient and reach equilibrium, known as equilibrium potential.
What is the electrochemical gradient in biological membranes?
It is the phenomenon where ions diffuse down their electrochemical gradient until reaching equilibrium.
Define equilibrium potential in the context of ion distribution across biological membranes.
It is the potential measured in volts at which the electrical force of the ion(s) balances the opposing force of the concentration gradient.
How do K+ ions reach equilibrium in the experiment described?
K+ ions reach equilibrium by diffusing down their electrochemical gradient, similar to what happens in the cell.
Describe the process of ion distribution across biological membranes and its impact on membrane polarity.
Ions move across biological membranes, influencing membrane polarity.
Define the Nernst equation and its role in calculating the equilibrium potential of ions.
The Nernst equation calculates the equilibrium potential of ions.
How does the opening of an ion channel affect the membrane potential (MP)?
Opening an ion channel can alter the membrane potential.
What effect does the type of ion permeated by a channel have on the membrane potential (MP)?
The type of ion passing through a channel can impact the membrane potential.
Do different ions have different effects on the membrane potential (MP) when passing through ion channels?
Yes, different ions can have varying effects on the membrane potential.
Describe the scenario where a neuron with a resting potential of -70 mV is given, what is happening in this situation?
The neuron is at its resting potential of -70 mV.
How can the Nernst equation be used to calculate the equilibrium potential of ions in biological systems?
The Nernst equation is applied to determine the equilibrium potential of ions in biological contexts.
Describe the ion distribution across biological membranes and its implication on membrane polarity.
Ions are distributed unevenly across biological membranes, creating a difference in charge between the inside and outside of the cell, which contributes to membrane polarity.
What happens when an ion channel is open?
When an ion channel is open, ions can flow across the membrane according to their electrochemical gradients.
What would be the effect on membrane (MP) when an ion channel is open?
The membrane potential (MP) may change depending on the direction and type of ions flowing through the open channel.
Define ENa, Em, EK, ECa, and ECl in the context of ion distribution.
ENa is the equilibrium potential for sodium ions, Em is the resting membrane potential, EK is the equilibrium potential for potassium ions, ECa is the equilibrium potential for calcium ions, and ECl is the equilibrium potential for chloride ions.
