Introduction to the Musculoskeletal System

The musculoskeletal system
enables human movement, comprising bones, muscles, and connective tissue.
While it’s common to separate bones and connective tissue for educational
purposes, it’s important to note that bones are a specialized type of
connective tissue. This system not only facilitates movement but also
provides structural support, stability, and protection for vital organs,
while storing minerals like calcium and generating body heat.

The human skeleton is made up of 206 individual bones, which are living
tissues and crucial to the body’s structure. These bones are primarily
composed of calcium salts, cells, blood vessels, and connective tissues. The
axial skeleton consists of the spine, skull, and rib cage, whereas the appendicular
skeleton includes the upper and lower limbs, along with the shoulder and
pelvic girdles. Notably, the shoulder girdle includes the scapula and
humerus, while the pelvic girdle is made up of the iliac bones and femur,
including the sacroiliac and hip joints.

Bones serve multiple functions: they provide muscle attachment points,
protect internal organs, facilitate movement, store essential minerals, and
house red blood cell production in the marrow. The varying shapes of bones,
from long to flat to short, reflect their specific functions. Weight-bearing
activities help strengthen bones through the stimulation of bone health, as
seen in the negative effects of prolonged weightlessness in space on bone
density.

Joints serve as connections between bones, such as the knee joint
connecting the thigh and shin bones. They are crucial for movement and
stability, composed of various fibrous connective tissues. Ligaments connect
bones, tendons attach muscles to bones, and cartilage cushions bone ends.
Joints are categorized based on their range of motion; synovial joints, for
instance, are the most common and allow for free movement.

Within synovial joints, movement is supported by a joint capsule filled
with synovial fluid that nourishes and lubricates the joint surfaces,
ensuring smooth motion. Among the different types of synovial joints are ball
and socket joints, allowing for a wide range of movement, and hinge joints,
which provide stability. Understanding joint mechanics is vital for safe
practices in activities like yoga, where the roles of different joints must
be coordinated to prevent injury.

Muscles are integral to movement, comprising bundles of fibrous tissue
capable of contraction. Skeletal muscles, responsible for moving bones,
consist of muscle cells, connective tissue, nerves, and blood vessels. They
are categorized into three types: smooth muscle (found in organs and blood
vessels), cardiac muscle (in the heart), and skeletal muscle. Importantly,
skeletal and cardiac muscles feature striations due to their organized
structures of myofilaments.

The muscular system’s primary function is to generate movement and maintain
posture. Muscles also serve essential roles in breathing, blood circulation,
and transporting substances within the body while generating heat as a
byproduct of their metabolic activity. This generated heat helps regulate
body temperature, especially during exertion, where increased muscle contractions
lead to a rise in temperature.

For further details on the musculoskeletal system, visit
https://ashtanga.tech/study-guide/anatomy-physiology/anatomy-biomechanics/musculoskeletal-system/musculoskeletal-system-introduction/.