Chemical Messengers

These flashcards cover key vocabulary related to chemical messengers and their mechanisms of action in intercellular communication.

Intercellular Communication

Communication occurring between two or more cells, which can be direct or indirect.

Gap Junctions

Openings between adjacent cells that allow for direct communication through the movement of ions and small molecules.

Ligands

Molecules that bind reversibly to proteins to facilitate indirect communication between cells.

Paracrines

Chemical messengers that communicate with neighboring cells, requiring proximity to reach target cells by diffusion.

Autocrines

A specific group of paracrines released by a cell that act on the same cell, regulating its own secretions.

Neurotransmitter

A chemical released into interstitial fluid by neurons, specifically at the synapse, impacting neighboring cells.

Hormones

Chemicals released by endocrine glands that travel in the bloodstream to specific target cells, sometimes over long distances.

Lipophilic Messengers

Hydrophobic messengers that can easily pass through the plasma membrane and often bind to intracellular receptors.

Lipophobic Messengers

Hydrophilic molecules that cannot permeate the plasma membrane and have receptors typically on the extracellular side.

Receptor Agonist

Ligands that bind to receptors and induce a response, such as morphine blocking pain signals in the brain.

Receptor Antagonist

Ligands that bind to receptors and block a response, preventing activation by agonists.

Channel-Linked Receptors

Receptors that open ion channels when a chemical messenger binds, altering the cell's electrical properties and activity.

Enzyme-Linked Receptors

Receptors that act as enzymes in response to messenger binding, catalyzing reactions within the cell.

G-Linked Receptors

Receptors that activate G Proteins to trigger a series of biochemical events within the cell.

Half Life

The time it takes for half of a hormone in the blood to be degraded, varying by messenger.

Signal Transduction

The process by which chemical messengers transmit signals to target cells by binding to receptors.