Cellular Communication and Signaling Flashcards

Vocabulary flashcards covering cellular communication pathways, signaling molecules, local vs. long-distance signaling, and receptor characteristics.

Electrical Signals

Signals consisting of changes in a cell's membrane potential caused by the flux of ions across the cell membrane.

Chemical Signals

Molecules secreted by cells into the extracellular fluid to transmit information and modulate target cell function.

Signal Generator

A cell, such as a neuron, endocrine cell, or immune cell, that synthesizes and releases signal molecules to direct or control other cells.

Target Cell

Any cell that receives and responds to a signal molecule because it expresses specific protein receptors for that molecule.

Gap Junctions

Membrane-spanning protein structures made of connexin that create direct cytoplasmic connections between adjacent cells for rapid signal transfer.

Connexin

The membrane-spanning protein subunits that form the channel-like structures of gap junctions.

Contact-Dependent Signaling

Local cell-to-cell communication where surface molecules on one cell bind to receptor proteins on an adjacent cell through direct membrane contact.

Autocrine Signal

A chemical signal secreted into the extracellular fluid that binds to receptors on the surface of the same cell that released it.

Paracrine Signal

A chemical signal secreted by a cell that diffuses through the extracellular fluid to act on nearby adjacent target cells.

Hormone

A chemical signal produced by specialized endocrine cells or glands that travels through the bloodstream to act on distant target cells.

Cytokines

Signal molecules produced on demand by any nucleated cell in the body (not stored ahead of time in vesicles) that commonly regulate immune responses.

Neurocrine

Any chemical signaling substance that is produced and secreted by a neuron.

Neurotransmitter

A fast-acting neurocrine signal released from an axon terminal into the synaptic cleft to elicit rapid changes in a target cell.

Neuromodulator

A neurocrine signal that acts more slowly to produce longer-term changes in target cell function compared to a neurotransmitter.

Neurohormone

A neurocrine signal secreted by a neuron directly into the bloodstream to produce systemic impacts on distant target cells.

Signal Transduction

The process by which an extracellular signal molecule binds to a receptor and transmits a message into the cell, altering intracellular target proteins and cellular response.

Lipophilic Signal Molecules

Nonpolar signal molecules (such as steroids or eicosanoids) that can freely cross the lipid bilayer of cell membranes to bind intracellular or surface receptors.

Lipophobic Signal Molecules

Polar signal molecules that cannot pass through the phospholipid bilayer of the cell membrane and must bind to extracellular cell surface receptors.