Types of muscle
- Skeletal - Attached to skeleton, brings about movement
- Cardiac - Contracts without the need of external stimulation
- Smooth - Lines gut and blood vessels. Contracts slowly
Skeletal muscle is attached to bone via tendons. Here is a breakdown of what a skeletal muscle is
Muscle --> Bundle of fibres --> fibres --> myofibrils --> filaments --> myofilaments --> Actin and Myosin
In a myofibril there a few main observable sections
The A band - The band of myosin. This is where there is a dark band because it is mostly an overlap of myosin and actin. There is a lighter band within the A band called the H zone. This is where there is only myosin and hence appears lighter when where the myosin and actin over lap.
The I band - The I band is just actin and hence appears lighter than the A band. Within the I band is the Z line. The Z line is where the actin are joined together.
The sarcomere is the measurement from one Z line to another. When the muscle is in a contracted state the sarcomere is shorter compared to when it's in its relaxed state.
The myofilaments are arranged so that 6 actin surround one actin.
Above is a picture which pretty much sums up what I just said, except it's a lot easier to understand and probably doesn't have any spelling mistakes.