Water Balance and Signaling in Multicellular Organisms

These flashcards cover key vocabulary terms and definitions related to water balance, osmoregulation, and membrane signaling in multicellular organisms.

Osmoregulation

The process of maintaining stable internal water and solute concentrations in the body.

Turgor Pressure

The pressure built up by water influx in plant cells, causing the cell to maintain its shape and structure.

Osmosis

The movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Aquaporins

Protein channels in cell membranes that facilitate the rapid transport of water across the membrane.

Water Potential (Ψ)

A measure of the potential energy of water in a system, which dictates the direction of water movement.

Solute Potential (Ψs)

The component of water potential that decreases as the concentration of solutes in the solution increases.

Pressure Potential (Ψp)

The component of water potential that increases as pressure builds up, usually found in turgid plant cells.

Hypoosmotic

A solution with a lower concentration of solutes compared to another solution, resulting in higher free water.

Hyperosmotic

A solution with a higher concentration of solutes compared to another solution, resulting in lower free water.

Cohesion

The attraction between water molecules, which helps maintain a continuous water column in plants.

Adhesion

The attraction between water molecules and other substances, such as plant cell walls, which aids in water transport.

Counter-Current Exchange

A mechanism in which fluids move in opposite directions to maximize efficiency, such as in the loops of Henle in kidneys.

Negative Feedback

A regulatory mechanism in which a change in a physiological variable triggers a response that counteracts the initial change, maintaining homeostasis.

ADH (Anti-Diuretic Hormone)

A hormone that promotes the reabsorption of water back into the bloodstream in the kidneys, reducing urine output.

Osmoconformers

Organisms whose internal osmolarity matches that of their external environment, typically found in marine invertebrates.

Osmoregulators

Organisms that maintain an internal osmolarity different from their external environment, often requiring energy for regulation.