Muscular System

How do muscles repair?

After you workout, your body repairs or replaces damaged muscle fibers through a cellular process where it fuses muscle fibers together to form new muscle protein strands or myofibrils. These repaired myofibrils increase in thickness and number to create muscle hypertrophy (growth)

Contractility

Contractility refers to the capacity of muscle to contract or shorten forcefully.

How are muscles structured?

Each skeletal muscle fiber is a single cylindrical muscle cell. An individual skeletal muscle may be made up of hundreds, or even thousands, of muscle fibers bundled together and wrapped in a connective tissue covering.

Elasticity

Elasticity means that if muscles are stretched, they recoil to their original resting length.

Excitability

Excitability means that muscle responds to stimulation by nerves and hormones, making it possible for the nervous system and, in some muscle types, the endocrine system, to regulate muscle activity.

Extensibility

Extensibility means that muscles can be stretched to their normal resting length and beyond to a limited degree.

Four characteristics common to all muscles

Muscle has four major functional characteristics: contractility, excitability, extensibility, and elasticity.

Satellite Cell

Satellite cells are precursors to skeletal muscle cells, able to give rise to satellite cells or differentiated skeletal muscle cells. They have the potential to provide additional myonuclei to their parent muscle fiber, or return to a quiescent state.

Muscle Stem Cell

Skeletal muscle is capable of complete regeneration due to stem cells that reside in skeletal muscle and nonmuscle stem cell populations.

Striated

Striated muscle tissue is muscle tissue that features repeating functional units called sarcomeres, in contrast with smooth muscle tissue which does not.

What are the functions of the muscular system?

The main function of the muscular system is movement. Muscles are the only tissue in the body that has the ability to contract and therefore move the other parts of the body

Tendon

a flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone.

Facicle

a separately published installment of a book or other printed work.

Cytokine

any of a number of substances, such as interferon, interleukin, and growth factors, that are secreted by certain cells of the immune system and have an effect on other cells.

Myofibril

any of the elongated contractile threads found in striated muscle cells.