Alveoli in the lungs and nephrons in the kidneys both facilitate exchange across a barrier but serve different purposes. Alveoli facilitate gas exchange (oxygen and carbon dioxide) between the lungs and the blood. Nephrons filter blood and produce urine, removing waste products and excess substances.
Alveoli:
Structure:
Tiny, sac-like structures within the lungs, one cell thick, with a rich network of capillaries surrounding them.
Function:
Facilitate gas exchange. Oxygen from inhaled air diffuses into the blood through the thin alveolar walls and into the surrounding capillaries, while carbon dioxide from the blood diffuses out into the alveoli to be exhaled.
Key Features:
High surface area for efficient gas exchange, thin walls for easy diffusion.
Nephrons:
Structure:
Tubular structures within the kidneys, consisting of a glomerulus (a network of capillaries), Bowman’s capsule, and various tubules (proximal and distal convoluted tubules, loop of Henle, and collecting duct).
Function:
Filter blood to remove waste products (like urea, uric acid, and excess water), reabsorb essential substances (like glucose, amino acids, and water) back into the bloodstream, and produce urine.
Key Features:
Complex structure allowing for filtration, reabsorption, and secretion of substances.