BIO 1306 Lecture Notes - Lecture 9: Heart Valve, Pulmonary Artery, Gas Exchange
Document Summary
Every organism must exchange materials with its environment. Exchanges ultimately occur at the cellular level by crossing the plasma membrane. In ___________________ organisms, these exchanges occur directly with the environment. For most cells of multicellular organisms, direct exchange with the environment is not possible. Gills are an example of a specialized exchange system in animals diffuses from the ___________________ vessels. Internal transport and gas exchange are functionally related in most animals. Concept 42. 1: circulatory systems link exchange surfaces with cells throughout the body. Small molecules can move between cells and their surroundings by ___________________ Diffusion is only efficient over small distances because the time it takes to diffuse is proportional to the square of the distance. In small or thin animals, cells can exchange materials directly with the surrounding medium. In most animals, cells exchange materials with the environment via a fluid-filled circulatory system.
