Principle of Neurobiology - Neuronal Excitability

Water

Ion

Cations are positively charged, such as sodium ion (Na+). Anions are negatively charged, such as chloride ion (Cl-).

<p>Phospholipid bilayer</p> Signup and view all the answers

<p>Channel proteins facilitate selective movement of ions across the membrane by forming pathways that allow specific ions to pass through.</p> Signup and view all the answers

<p>Diffusion is the tendency for ions to distribute themselves evenly across a space. When a concentration gradient exists, ions flow from an area of higher concentration to an area of lower concentration.</p> Signup and view all the answers

<p>Ohm's Law states that V = IR, where V represents voltage (electrical potential difference), I represents current (flow of charge), and R represents resistance (opposition to current flow).</p> Signup and view all the answers

<p>Conductance (g) is the inverse of resistance (R). Therefore, g = 1/R.</p> Signup and view all the answers

<p>K+ is more concentrated inside the neuron, while Na+ and Ca2+ are more concentrated outside the neuron.</p> Signup and view all the answers

<p>The Nernst Equation is a mathematical formula that calculates the equilibrium potential (Eion) for a specific ion across a membrane. It takes into account the charge of the ion, temperature, and the ratio of external and internal ion concentrations.</p> Signup and view all the answers

<p>The sodium-potassium pump actively transports sodium ions (Na+) out of the neuron and potassium ions (K+) into the neuron, maintaining the concentration gradients necessary for the resting potential.</p> Signup and view all the answers

<p>The calcium pump actively transports calcium ions (Ca2+) out of the cytosol, reducing intracellular calcium levels and helping to maintain the resting membrane potential.</p> Signup and view all the answers

<p>The equilibrium potential (Eion) is a theoretical membrane potential for a specific ion where there would be no net movement of that ion across the membrane because the electrical gradient exactly counterbalances the concentration gradient.</p> Signup and view all the answers

<ol> <li>Large changes in Vm (membrane potential) result in very small changes in ionic concentrations across the membrane. 2) The net electrical charge difference is mainly across the membrane surface, not within the bulk of the intracellular or extracellular fluid. 3) The rate of movement of ions across the membrane is proportional to the difference between Vm and Eion. 4) When we know the concentration difference, we can calculate the equilibrium potential (Eion).</li> </ol> Signup and view all the answers

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

<p>The blood-brain barrier is a specialized structure formed by tight junctions between endothelial cells in the brain's capillaries. It restricts the passage of many substances from the blood into the brain, including potassium ions.</p> Signup and view all the answers

<p>The activity of the sodium-potassium pump, the large potassium concentration gradient across the membrane, and the electrical potential difference across the membrane are all major contributors to the resting membrane potential.</p> Signup and view all the answers

The ability of neurons to respond to stimuli and convert them into electrical signals.

Movement of ions across neural membranes, vital for signal transmission.

The voltage difference across the neuronal membrane at rest, typically around -70 mV.

An ion with a positive charge, such as Na⁺ or Ca²⁺.

An ion with a negative charge, such as Cl⁻ or K⁺.

Mathematical formula to calculate the equilibrium potential for an ion based on its concentration gradient.

An enzyme that pumps Na⁺ out and K⁺ into the cell, vital for maintaining resting potential.

The membrane potential at which there is no net movement of a specific ion across the membrane.

The process where dissolved ions spread evenly across a medium, moving from high to low concentration.

The ability of ion channels to allow only specific ions to pass through.

A double layer of phospholipids forming the cell membrane, crucial for channel function.

A measure of how easily ions can flow through a membrane; inversely related to resistance (R).

A rapid rise and fall in membrane potential that transmits signals along neurons.

The difference in concentration of ions across a membrane, driving ion movement.

Specialized membrane proteins that allow K⁺ ions to pass, critical for setting resting potential.