( series of mechanical body, part 3 )
Your body can moving cause by the function of muscles. There are hundreds muscles support your activity, from biggest ones in your arms and legs until smallest in your face muscles. To form smile, a couple of different muscles are working together to make your lips break into a beautiful smile. One muscle group is the ‘zygomaticus major’, and the other is the ‘Levator anguli oris’. These muscles contract, and they pull up the corners of your mouth into a smile.
Why the muscles can contract it self ? These ones involve the amazing chemical engine system in your body. The muscles will contract or not cause by work of chemical reaction between calcium in one direction and something called ATP what cause muscles move in other direction. A muscles is fiber contains many myofibrils, which are cylinders of muscle proteins. These proteins allow a muscle cell to contract. Myofibrils contain two types of filaments -- thick filaments made of a protein called myosin and thin filaments made of a protein called actin. Each myosin filament surrounded by six filament of actin.
To make the muscle fiber contract, the myosin filament reaches out, grabs the actin filaments and pulls on them like six pieces of rope. As this happens, the myosin filament changes shape to pull the actin filaments along .
Why the muscles start contracting ? it’s cause by the signal have sent from your brain order cell to release calcium. This one cause myosin start binding to actin fiber. When the brain stop send the signal, muscles cell will soak up and store the calcium inside for next time.
When contracting have stop and muscles back into normal condition, in cell something called ATP convert into ADP and phosphate. it’s cause many energy will be released. The cell make ATP from sugar and oxygen, then ADP will be converted back again into ATP use glukosa and oxygen. This mechanism explain where the muscles energy come from.
Rigor Mortis
What “rigor mortis” is ? When the body become stiff after it was died. Like a mummy, all of the body muscles will contracting . Why ? When the body was died the muscles cell will released all calcium out. It’s cause all of the muscles contracting. The muscles can’t change back because cell have stop working it’s ATP production, myosin will binds to actin and all muscles will contracted and stiffing the body.
( next article about Heart and Blood… )
ref : www.howstuffworks.com
