Muscle architecture for pennate muscles. Pennate muscles can be further divided into uni-, bi- or multipennate. Unipennate muscles are those where the muscle fibers are oriented at one fiber angle to the force-generating axis and are all on the same side of a tendon. The pennation angle in unipennate muscles has been measured at a variety of resting length and typically varies from 0° to 30°. The lateral gastrocnemius of wild turkeys is an example of this muscle architecture. Muscles that have fibers on two sides of a tendon are considered bipennate. The stapedius in the middle ear of humans, as well
Composition of the human body viewed on an atomic and molecular scale as shown in this article. The estimated gross molecular contents of a typical 20-micrometre human cell is as follows: Body composition can also be expressed in terms of various types of material, such as: There are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number (much less by mass or volume). Some of these symbionts are necessary for our health. Those that neither help nor harm humans are called commensal