Human Musculoskeletal Anatomy (Option B)

Musculoskeletal System Overview

The musculoskeletal system is an organ system that enables the body to move using muscles and skeletal system.
It provides form, support, stability, and movement to the body.
It’s made up of the body’s bones (skeleton), joints, ligaments, tendons, muscles and nerves.

The human skeleton is an internal framework that consists of 206 bones in adults.
Bones are rigid organs that support and protect various organs of the body.
The skull protects the brain, the ribs protect the heart and lungs, and the vertebrae protect the spinal cord.
The skeleton also provides the scaffold for muscles to attach, enabling movement.
Bones also produce blood cells in red marrow and store minerals like calcium and phosphorus.

A joint is a point where two or more bones meet. They provide mobility and flexibility to the skeleton.
Ligaments are fibrous connective tissue that link bones together at the joints to provide support and prevent damaging movements.
There are several types of joints: fixed (like in the skull), hinge (like the knee and elbow), pivot (like the neck), and ball and socket (like the hip and shoulder).

Muscles make up about half of the total body weight and are responsible for all types of body movement.
There are three types of muscle tissue: skeletal (which move the skeleton), cardiac (found in the heart), and smooth (found in organs and blood vessels).
Tendons are strong bands or cords of fibrous tissue that connect muscles to bones.
When muscles contract, they shorten and pull on the tendons, which then pull on the bones causing them to move.

Muscles are controlled by the nervous system. Motor neurons carry signals from the brain to the muscles, telling them when to contract or relax.
The point where a motor neuron meets a muscle fiber is called a neuromuscular junction. At this junction, a neurotransmitter called acetylcholine is released, triggering muscle contraction.
The central nervous system (brain and spinal cord) and the peripheral nervous system (motor and sensory neurons) work together to control muscle activity.
Fine, precise movements (like writing) involve fewer muscle fibers and are controlled by smaller motor units. Gross movements (like running) involve more muscle fibers and larger motor units.