Explain how skeletal muscle contracts, including the release of calcium ions from the sarcoplasmic reticulum, the formation of cross-bridges, the sliding of actin and myosin filaments and the use of ATP.
The myosin filaments have heads which form cross-bridges when they are attached to binding sites on acting filaments. ATP binds to the myosin heads and causes them to break the cross bridges by detaching from the binding sites. ATP is hydrolyzed to ADP and phosphate, causing the myosin heads to change their angle. The heads attach to binding sites on actin that are further from the center of the sarcomere than the previous sites.
Muscular dystrophy is a group of diseases that cause progressive weakness and loss of muscle mass. Some who have muscular dystrophy can lose their ability to walk. Some may have trouble breathing or swallowing. There is no cure for muscular dystrophy but medications and therapy can help maintain symptoms and slow down the disease.
You have flatfeet when the arch on the inside of your feet is flattened, allowing the entire sole of your foot to touch the floor when you stand up. A common and painless condition, flatfeet occur when the arches don't develop during childhood. Most people have little to no signs or symptoms associated with flatfeet. Your family doctor may refer you to a doctor specializing in foot disorders or sports medicine.
Cardiac muscle is an involuntary muscle responsible for pumping blood throughout the body.
Skeletal muscles are the only voluntary muscle tissue in the human body and control every action that a person consciously performs.
Smooth muscle is found inside the stomach, intestines, and blood vessels. These muscles contract to move substances through the organs.