Nervous System Physiology Essentials 2

A type of cell communication where a cell communicates with itself without releasing signals outside the cell.

Cell communication through direct contact between cells.

A cell releasing a signal that binds to receptors on the same cell; signal goes out and back in

Cells communicating over short distances.

Nerve cells communicating across synapses using neurotransmitters.

Cells communicating using hormones carried in the blood over long distances.

Receptors located on the cell membrane, receiving signals from outside the cell.

Receptors located inside the cell, often targeting lipophilic signals like hormones.

Each receptor recognizes and binds only to a specific ligand molecule, like a lock and key.

The strength of the bond between a receptor and its ligand. High affinity means a strong bond even at low ligand concentrations.

The maximum binding capacity of a receptor when all available binding sites are filled.

Different molecules can compete for the same receptor binding site, impacting signal transmission.

The cell increases the number of receptors in response to low ligand levels or continuous stimulation.

The cell decreases the number of receptors in response to prolonged stimulation.

A molecule that binds to a receptor and activates it, triggering signal transmission.

A molecule that binds to a receptor and blocks its activation, preventing signal transmission.

The electrical charge difference across the membrane of a neuron when it is not actively transmitting a signal, typically around -70mV. It keeps the cell ready for stimulation.

A protein pump that actively transports 3 sodium ions out of the cell and 2 potassium ions into the cell, using ATP. This helps maintain the negative charge inside the cell.

Channels in the cell membrane that allow potassium ions to leak out of the cell, contributing to the negative charge inside the cell.

The minimum level of depolarization needed to trigger an action potential, typically around -55mV. It's like the tipping point.

A temporary, localized change in membrane potential that varies in strength depending on the stimulus strength. It can be either excitatory or inhibitory.

A type of graded potential generated by sensory receptors in response to stimuli, like touch, temperature, or light.

A type of graded potential in cardiac muscle cells, responsible for the heart's rhythmic beating. It allows the heart to beat autonomously.

A graded potential that develops on the postsynaptic membrane of a neuron in response to neurotransmitters released from a presynaptic neuron.

A period after an action potential where the neuron cannot produce another action potential, regardless of the stimulus strength. This ensures unidirectional signal propagation.

A period after the ARP where the neuron can generate an action potential, but only with a stronger than usual stimulus. This allows the neuron to gradually regain its resting potential.

The process of an action potential traveling along an unmyelinated nerve fiber. Depolarization spreads to neighboring areas, transmitting the signal.

The rapid transmission of an action potential along a myelinated nerve fiber, jumping from one node of Ranvier to the next.

To ensure a powerful signal amplification, each node of Ranvier contains a high concentration of Na+ channels, preventing signal loss during propagation.

A rapid, short-lasting, and large change in membrane potential that travels along the length of a neuron or muscle cell. It is an all-or-none event, meaning it either occurs fully or not at all.

These channels, specifically for sodium (Na+) and potassium (K+), open and close in response to changes in membrane potential. They are crucial for the rapid influx and efflux of ions that generate the characteristic shape of an action potential.

The minimum level of membrane depolarization required to trigger an action potential. If the stimulus is strong enough to reach the threshold, an action potential will occur.

The process where the membrane potential becomes more positive, moving towards zero. During an action potential, this is caused by the rapid influx of sodium (Na+) ions into the cell.

The return of the membrane potential back to its resting state, becoming more negative. This is caused by the outward flow of potassium (K+) ions from the cell.

A brief period after repolarization where the membrane potential dips below the resting potential. This is due to the slow closing of potassium (K+) channels.

The brief period after an action potential where the cell is less excitable. This ensures that action potentials travel in one direction and prevents them from happening too frequently.