Membrane Physiology and Electrochemical Gradients

<p>Equilibrium potential (C)</p> Signup and view all the answers

<p>Repolarization (D)</p> Signup and view all the answers

<p>Organization of phospholipid bilayer (C), Hydrophobic nature of the fatty acid tails (D)</p> Signup and view all the answers

<p>Voltage-gated channels (D)</p> Signup and view all the answers

<p>They can selectively allow certain ions to flow based on their charge. (A)</p> Signup and view all the answers

<p>It promotes passive movement of ions in accordance with their concentration and charge. (A)</p> Signup and view all the answers

<p>It isolates the intracellular and extracellular compartments. (A)</p> Signup and view all the answers

<p>They interact favorably with water and polar substances. (C)</p> Signup and view all the answers

<p>They open or close in response to mechanical deformation. (B)</p> Signup and view all the answers

<p>Mg2+ (B)</p> Signup and view all the answers

<p>Chemical force due to higher concentration inside (B)</p> Signup and view all the answers

<p>They maintain the resting membrane potential. (B)</p> Signup and view all the answers

<p>The movement of K+ ions into and out of the cell is equal (B)</p> Signup and view all the answers

<p>State of the extracellular matrix (D)</p> Signup and view all the answers

<p>Chemical force due to higher concentration outside (A)</p> Signup and view all the answers

<p>They generate the resting membrane potential when activated. (A)</p> Signup and view all the answers

<p>It determines the equilibrium potential for any ion (C)</p> Signup and view all the answers

<p>By pumping 3 Na+ out and 2 K+ into the cell. (D)</p> Signup and view all the answers

<p>Ca2+ (C)</p> Signup and view all the answers

<p>A small influx of Na+ ions caused by a stimulus. (A)</p> Signup and view all the answers

<p>It decreases the electrical force attracting K+ back in (C)</p> Signup and view all the answers

<p>The membrane potential becomes more positive (C)</p> Signup and view all the answers

<p>Selective leak channels (C)</p> Signup and view all the answers

<p>Cl- does not affect the resting membrane potential significantly (A)</p> Signup and view all the answers

<p>It prevents K+ ions from passing through gated channels. (C)</p> Signup and view all the answers

<p>Gravitational signals affecting ion channels (D)</p> Signup and view all the answers

<p>K+ (A)</p> Signup and view all the answers

<p>It represents the balance between the movement of Na+ and K+ ions. (D)</p> Signup and view all the answers

<p>They undergo permanent loss of resting membrane potentials. (A)</p> Signup and view all the answers

<p>-60 to -70 mV (B)</p> Signup and view all the answers

<p>Greater permeability to K+ than Na+ makes Em closer to EK+. (C)</p> Signup and view all the answers

<p>High concentration of K+ inside the cell creating an efflux. (C)</p> Signup and view all the answers

<p>It maintains the resting membrane potential by pumping Na+ out and K+ in. (D)</p> Signup and view all the answers

<p>Goldman equation (C)</p> Signup and view all the answers

<p>There are more K+ channels than Na+ channels. (B)</p> Signup and view all the answers

<p>It will become less negative, moving closer to ENa+. (C)</p> Signup and view all the answers

<p>It attracts positively charged ions toward the negatively charged interior. (A)</p> Signup and view all the answers

<p>Na+ (C)</p> Signup and view all the answers

<p>The number of ions moving across the membrane over time. (D)</p> Signup and view all the answers

The cell membrane is composed of a double layer of phospholipids with phosphate heads facing outwards and fatty acid tails inwards. This structure makes the membrane impermeable to polar molecules.

Ion channels are proteins embedded within the cell membrane that allow the passage of ions across the membrane. These channels are selective for specific ions and can be gated, meaning they can open and close in response to different stimuli.

Voltage-gated channels open or close in response to changes in the electrical potential across the membrane. This is crucial for generating action potentials.

Ligand-gated channels open or close when a specific molecule binds to them. This is how neurotransmitters signal across synapses.

Mechanically gated channels open or close in response to physical stimuli such as pressure or stretch.

The difference in the concentration of ions inside and outside the cell creates a chemical gradient. This gradient drives the movement of ions down their concentration gradient.

The difference in electrical charge inside and outside the cell creates an electrical gradient. This gradient drives the movement of ions towards the opposite charge.

The combined effect of the chemical gradient and electrical gradient across the cell membrane. It influences the movement of ions across the membrane.

The membrane potential at which there is no net movement of a specific ion into or out of the cell.

A positive feedback loop where an initial influx of sodium ions (Na+) triggers the opening of more sodium channels, further increasing sodium influx and depolarizing the membrane potential.

The state of a neuron when it is not transmitting a signal. It has a negative membrane potential, typically around -70 mV.

The minimum membrane potential that must be reached to trigger an action potential. For neurons, this is usually around -55 mV.

The principle that an action potential will always be of the same magnitude once initiated, regardless of the initial stimulus strength.

A type of biological tissue, like nerves and muscles, that can quickly change its electrical charge.

The temporary discharge of the resting membrane potential. It's a rapid, short-lived change in electrical charge.

A specialized region within an ion channel that determines which ions can pass through.

A region within an ion channel where ions are temporarily dehydrated.

A mechanism that controls the opening and closing of ion channels.

These transmembrane proteins use ATP to actively pump ions across the cell membrane against their concentration gradient.

This pump moves 3 sodium ions out for every 2 potassium ions it brings in, contributing to the electrical gradient.

The process by which cells die and their resting membrane potentials permanently discharge.

The electrical potential difference across the plasma membrane of a neuron when it is not actively transmitting a signal.

The relative ease with which ions can cross the plasma membrane. It determines the contribution of each ion to the RMP.

The force exerted on charged ions by the electrical potential difference across the membrane. Ions are attracted to opposite charges.

The electrical potential difference across the membrane at which there is no net movement of a particular ion. It is specific to each ion.

A mathematical equation that calculates the resting membrane potential based on the concentrations of ions and their relative membrane permeability.

A simplified version of the Goldman equation that calculates the equilibrium potential for a single ion.

A membrane-bound protein responsible for actively transporting sodium ions out of the cell and potassium ions into the cell. It maintains the ion concentration gradients important for RMP.

The difference in the concentration of sodium and potassium ions between the inside and outside of the cell. This gradient is essential for RMP and neuronal signalling.

The electrical potential difference across the plasma membrane of a neuron at rest. It is typically around -70 mV, which is closer to the equilibrium potential for potassium than for sodium.

The membrane potential at which there is no net movement of a particular ion into or out of a cell.

The tendency of an ion to move across a membrane due to its concentration difference inside and outside the cell.

The equilibrium potential of potassium (K+) is when the chemical force driving K+ out of the cell is balanced by the electrical force attracting it back in.

The equilibrium potential of sodium (Na+) is where the chemical force driving Na+ into the cell is balanced by the electrical force opposing it.

The difference in electrical charge across the membrane is measured in millivolts (mV).

The ion concentration inside the cell is typically different from the concentration outside.

The ability of a cell to maintain a stable resting membrane potential despite constant ion movement.