What type of material are muscles made out of?

Muscles are primarily made up of muscle tissue, which is a type of soft tissue that is composed of specialized cells called muscle fibers or myocytes. These muscle cells are responsible for the contraction and relaxation of muscles, which leads to movement.

There are three main types of muscle tissue:

1. Skeletal muscle: This type of muscle is attached to the bones and is responsible for voluntary movements, such as walking, running, and speaking. Skeletal muscles are composed of long, cylindrical muscle fibers that are arranged in parallel bundles.

2. Smooth muscle: Smooth muscle is found in the walls of internal organs, such as the stomach, intestines, and blood vessels. It is responsible for involuntary movements, such as digestion and the regulation of blood flow. Smooth muscle fibers are spindle-shaped and arranged in sheets or layers.

3. Cardiac muscle: Cardiac muscle is found only in the heart. It is responsible for the rhythmic contractions of the heart that pump blood throughout the body. Cardiac muscle fibers are branched and interconnected, forming a complex network of cells.

All types of muscle tissue are made up of myofilaments, which are thin filaments composed of the proteins actin and myosin. These filaments slide past each other during muscle contraction, causing the muscle fibers to shorten and the muscle to contract. The energy for muscle contraction is provided by ATP, a molecule that is produced in the cells' mitochondria.