The muscular system – Level 2 Sport and Physical Activity Cambridge Technical Revision

The Muscular System: An Overview

The muscular system in humans is composed of over 600 muscles, which can be grouped into three types: skeletal, cardiac, and smooth muscles.
Skeletal muscles, also known as voluntary muscles, are responsible for all the movements of the body that we can control.
Cardiac muscle is found only in the heart, and its contractions constitute our heartbeat.
Smooth muscles, also known as involuntary muscles, control actions in the body we can’t control consciously such as digestion and the dilation or constriction of blood vessels.

Skeletal muscles are attached to bones by tendons.
Tasks like locomotion, maintaining posture, supporting soft tissues, and regulation of body temperature are all performed by the skeletal muscles.
They work in pairs of flexors and extensors: when one muscle group is contracting, the other is relaxing, creating a coordinated system for movement.

Muscle contraction is a complex process that involves several steps, it is mainly controlled by nervous system.
A stimulus from the nervous system triggers a reaction in the muscle fibres causing a release of calcium ions, these ions trigger a sliding filament model of contraction.
During contraction, thick and thin filaments within the muscle fibre slide past each other, this results in the shortening of muscle fibres and thus muscle contraction.

Strains and sprains are common types of muscle injury often caused by overuse, overstretching, or high impact.
Muscular dystrophy is a group of diseases that cause progressive weakness and loss of muscle mass.
Tendinopathy is a condition that causes pain, swelling, and reduced function in tendons; common in athletes.
Proper rest, nutrition, maintaining good form during physical activity, and warming up before exercise can help prevent muscle injuries and conditions.