passive transport

passive transport,

the movement of small molecules across the membrane of a cell by diffusion. Passive transport occurs when the chemicals outside a cell become concentrated and start moving into the cell, changing the intracellular equilibrium. Passive transport is essential to various processes of metabolism, such as the intake of digestive products by the cells lining the intestines. Compare active transport, osmosis.

---

transport [trans´port]

1. movement of materials in biologic systems, particularly across the cell membrane into and out of cells or across epithelial layers.

2. in the nursing interventions classification, a nursing intervention defined as moving a patient from one location to another.

active transport see active transport.

oxygen transport the carrying of oxygen through the bloodstream bound to hemoglobin (see oxyhemoglobin).

passive transport the movement of materials, usually across cell membranes, by processes not requiring expenditure of metabolic energy. See also active transport.

---

transport,

n the movement of biochemical substances from one site to another.

transport, active,

n transport of substances through membranes or epithelium, requiring metabolic energy.

transport, passive,

n transport along a gradient without the use of metabolic energy.