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Physiology Essentials

Illustration comparing external environment with internal environment showing body systems within the integumentary boundary

Body Envrionments

Diagram of fluid compartments showing intracellular, interstitial, and plasma (extracellular) fluid separated by endothelium

Fluid Compartments

Diagram of simple diffusion showing particles moving from high to low concentration until evenly distributed

Simple Diffusion

Diagram of simple diffusion across a cell membrane with particles moving through the bilayer from high to low concentration

Simple Diffusion (Membrane)

Diagram of facilitated diffusion through a membrane channel showing ions moving from extracellular to intracellular fluid

Diffusion Through a Channel

Diagram of membrane transport via channel-mediated diffusion and facilitated transport from extracellular to intracellular

Membrane Transport

Diagram of the sodium-potassium ATPase cycle showing ATP-driven transport of Na⁺ out and K⁺ into the cell

Sodium-Potassium ATPase

Diagram of fenestrated capillaries showing pores (fenestrations) and intercellular clefts for fluid and solute exchange

Fenestrated Capillaries

© EveryBody Physiology 2026. All rights reserved. This work is licensed under CC BY-NC-ND 4.0.

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