Myosin can only bind to actin when the binding sites on actin are exposed by calcium ions. Actin molecules are bound to the Z line, which forms the borders of the sarcomere. Other bands appear when the sarcomere is relaxed. A muscle fiber from a biceps muscle may contain 100,000 sarcomeres.uscle fibers are composed of tubular myofibrils. Myofibrils are composed of repeating sections of sarcomeres, which appear under the microscope as dark and light bands. Sarcomeres are composed of long, fibrous proteins as filaments that slide past each other when a muscle contracts or relaxes.
Even people with binge-eating disorder who are overweight are acutely aware of their body shape and appearance, and berate themselves after eating binges. The constant reinforcement of thinness may worsen her self-image and actually lead to more frequent bingeing as a woman seeks relief from feelings of shame.
A. anorexia nervosa B. bulimia nervosa C. binge eating disorder D. muscle dysmorphia Answer: B Page(s): 181 Objective(s): 2 25. Rachel purges her food after meals. She can expect all of the following health effects, EXCEPT A. electrolyte imbalances leading to irregular rhythms of the heart.