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
The Life You Can Save book comes from the fact that Singer addresses readers directly, asking them what they will do about "the life "you" can save". Singer says that citizens of richer nations do not donate as much as they could. The author says the reasons are not philosophical, but due to psychological considerations including cognitive dissonance, diffusion of responsibility and the evolutionary history of human ancestors. For instance, according to Singer, cognitive dissonance theory predicts that humans are rationalizing creatures, making it difficult to change their minds on topics (e.g. charity) that cause any anxiety—unless they are highly motivated to bear it during