Lesson

The muscular system and skeletal system are often referred to as the "musculoskeletal system." The muscles, joints, and bones work together, providing a framework for support and movement. Bones are hard and dense, made of compact minerals, and help to protect delicate internal organs, such as the brain, the heart, and the spinal cord. The growth of long bones from the ends (epiphyseal plates) allows us to attain our adult height.

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Human Skeleton Anterior & posterior views of the human skeleton

Besides providing a framework for the body, the bones protect the internal organs from exposure and injury, and store calcium, a mineral that is necessary for bone density and hardness. Some related combining forms are:

• oss/e, oss/i
• oste/o, ost/o

Hematopoiesis is the term used to describe the formation of red blood cells, white blood cells, and platelets in red bone marrow. Yellow bone marrow serves as a fat storage area for fat cells. A related combining form is:

• myel/o

Joints are places where two or more bones come together, termed "articulations." Freely movable joints, such as those along the vertebral column, allow us a wide range of motion, including bending and turning at various angles. Other joints, such as the suture joints in the skull, are tightly knit and immovable, providing added protection for the underlying brain tissue.

Cartilage is connective tissue that cushions the ends of bones, acts as a shock absorber, and allows ease of movement at joints. A related combining form is:

• chondr/o

Ligaments connect one bone to another. A related combining form is:

• ligament/o

Muscles permit external movement since they are attached to bones. Internal movement of muscles allows certain organs to perform their jobs, such as the constant beating of the heart, the contractions of the diaphragm, and the rhythmic contractions of the uterus during childbirth.

The muscular system's primary function is to make body movement possible. A related combining form is:

• my/o, myos/o

The fascia primarily functions to cover, support, and separate muscles. A related combining form is:

• fasci/o

There are four muscle classifications:

• Prime movers
  
• Antagonists
  
• Synergists
  
• Fixators