Living cells constantly interact with the blood or tissue fluid around them, taking in some substances and secreting or excreting others. There are several mechanisms of transport that enable cells to move materials into or out of the cell: diffusion, osmosis, facilitated diffusion, active transport, filtration, phagocytosis, and pinocytosis. Some of these take place without […]

There are several kinds of connective tissue, some of which may at first seem more different than alike. The types of connective tissue include areolar, adipose, fibrous, and elastic tissue as well as blood, bone, and cartilage. A characteristic that all connective tissues have in common is the presence of a matrix in addition to […]

Multiple studies have now shown that people who maintain appropriate body fitness, using judicious regimens of exercise and weight control, have the additional benefit of prolonged life. Especially between the ages of 50 and 70, studies have shown mortality to be three times less in the most fit people than in the least fit. But […]

Muscle Blood Flow. A key requirement of cardiovascular function in exercise is to deliver the required oxygen and other nutrients to the exercising muscles. For this purpose, the muscle blood flow increases drastically during exercise. A recording of muscle blood flow in the calf of a person for a period of […]

Oxygen Consumption and Pulmonary Ventilation in Exercise. Although one’s respiratory ability is of relatively little concern in the performance of sprint types of athletics, it is critical for maximal performance in endurance athletics. Normal oxygen consumption for a young man at rest is about 250 ml/min. However, under maximal conditions, this can be increased to […]

In addition to the large usage of carbohydrates by the muscles during exercise, especially during the early stages of exercise, muscles use large amounts of fat for energy in the form of fatty acids and acetoacetic acid, and they use to a much less extent proteins in the form of amino acids. In fact, even […]