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Which cells cause resting membrane potentials to continually depolarize?
Cells with unstable resting membrane potentials, such as pacemaker cells in the heart or neurons in the brain, can continually depolarize due to the presence of a "funny" current (If) that slowly depolarizes the cell until it reaches the threshold for an action potential to be generated.
A small deviation from the resting membrane potential that makes the membrane more or less polarized?
This small deviation is called a graded potential. It can be either a depolarization, where the membrane becomes less polarized, or a hyperpolarization, where the membrane becomes more polarized. Graded potentials are important for transmitting signals over short distances in the nervous system.
A resting motor neuron is expected to?
exhibit a resting potential that is more negative than the "threshold" potential.
how does the concentration of sodium and potassium affect the resting hyper polarization and depolarization membrane potentials?
The concentration of sodium (Na⁺) and potassium (K⁺) ions significantly influences resting membrane potentials and their hyperpolarization/depolarization phases. An increase in extracellular Na⁺ can lead to depolarization, as more Na⁺ enters the cell when sodium channels open, making the interior more positive. Conversely, higher intracellular K⁺ concentrations promote hyperpolarization when K⁺ channels open, allowing K⁺ to exit the cell and making the interior more negative. Thus, the balance of these ion concentrations is crucial for maintaining the resting membrane potential and regulating excitability in neurons and muscle cells.
What is the chief positive intracellular ion in a resting neuron?
The chief positive intracellular ion in a resting neuron is a potassium ion. Just inside the cell of a resting neuron, the membrane is negative.
Which cells cause resting membrane potentials to continually depolarize?
Cells with unstable resting membrane potentials, such as pacemaker cells in the heart or neurons in the brain, can continually depolarize due to the presence of a "funny" current (If) that slowly depolarizes the cell until it reaches the threshold for an action potential to be generated.
If a resting potential becomes more negative what happens to the cell?
When the membrane potential becomes more negative it is being hyperpolarized. Remember the resting membrane potential is already at a negative state (~70mV). So if you are making a comparison of a membrane potential that is hyperpolarized in comparison to a resting membrane potential, the resting membrane potential is said to be more depolarized.When the membrane potential becomes more positive it is called depolarization.
A small deviation from the resting membrane potential that makes the membrane more or less polarized?
This small deviation is called a graded potential. It can be either a depolarization, where the membrane becomes less polarized, or a hyperpolarization, where the membrane becomes more polarized. Graded potentials are important for transmitting signals over short distances in the nervous system.
A resting motor neuron is expected to?
exhibit a resting potential that is more negative than the "threshold" potential.
What are pacemaker potentials and the action potential they trigger?
Pacemaker potentials are automatic potentials generated and are exclusively seen in the heart. They arise from the natural "leakiness" of the membrane that pacemaker cells have, resulting in passive movement of both Na+ and Ca2+ across the membrane, rising the membrane potential to about -40mV. This results in a spontaneous depolarization of the muscle that has a rise in the curve that is nowhere near as steep as the action potential of other cells. Upon depolarization, the cell will return back to its resting membrane voltage, and continue the potential again.
Are graded potentials the same as local potentials?
Postsynaptic potentials are changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Graded potentials are changes in membrane potential that vary in size, as opposed to being all-or-none, and are not postsynaptic potentials.
What is the chief positive intracellular ion in a resting neuron?
The chief positive intracellular ion in a resting neuron is a potassium ion. Just inside the cell of a resting neuron, the membrane is negative.
Electrical charge resulting from the difference between positive and negative ions outside and inside the brain cell membrane is called?
This electrical charge is called the resting membrane potential. It is generated by the unequal distribution of ions such as sodium, potassium, chloride, and calcium inside and outside the cell. The resting membrane potential plays a crucial role in cell communication and proper functioning of the nervous system.
Why does the number of action potentials vary with increased stimulation frequency?
Increased stimulation frequency can lead to a phenomenon called summation, where individual action potentials merge together or "sum" to produce a larger response. This allows for greater depolarization of the membrane potential, leading to more frequent firing of action potentials. As the stimulation frequency increases, the membrane may not return to its resting potential before receiving the next stimulus, resulting in a higher number of action potentials being generated.
The chief positive intracellular ion in a resting neuron?
The chief positive intracellular ion in a resting neuron is potassium (K+). At rest, the neuron has a higher concentration of K+ inside its cell membrane compared to outside. This creates a negative membrane potential, which is crucial for maintaining the resting state of the neuron.
What is an unstimulated neuron?
An unstimulated neuron is a nerve cell that is not currently transmitting signals. It is in a resting state, with a stable membrane potential, and is not actively firing action potentials or sending messages to other neurons.
If a resting neuron is stimulated and there is an inward flow of positive charges into the cell the membrane potential will?
If a resting neuron is stimulated and there is an inward flow of positive charges into the cell, the membrane potential will depolarize, meaning the inside of the cell becomes less negative. This can trigger an action potential if the depolarization reaches the threshold level.
