Vöðvavefnum

Vöðvavefnum, commonly referred to as muscle tissue, is a primary tissue type found in animals. It is composed of specialized cells called myocytes, which are elongated and capable of contraction. This contractile property is fundamental to movement, both voluntary and involuntary.

There are three main types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle. Skeletal muscle is attached to bones and is responsible for voluntary movements such as walking, running, and lifting. It is characterized by its striated appearance, meaning it has a striped pattern under a microscope. Cardiac muscle, found only in the heart, is responsible for pumping blood throughout the body. It is also striated but is involuntary, meaning its contractions are not under conscious control. Smooth muscle, also known as visceral muscle, is found in the walls of internal organs such as the stomach, intestines, and blood vessels. It is responsible for slow, sustained contractions that move substances through these organs.

Muscle tissue plays a vital role in maintaining body posture, generating heat, and protecting internal organs. The ability of muscle cells to contract is due to the interaction of specialized proteins, primarily actin and myosin. When a nerve impulse stimulates a muscle cell, these proteins slide past each other, causing the cell to shorten and generate force. This process is known as excitation-contraction coupling. The coordinated action of many muscle cells allows for complex movements and essential bodily functions.