Human Skeletal System Functions and Structure

The Human Skeletal System: Framework and Functions

The skeleton is the framework of the body, made of bones. It serves five major functions:

• Provides shape and support.
• Enables movement.
• Protects internal organs.
• Produces blood cells.
• Stores certain materials until the body needs them.

The Backbone (Vertebral Column)

The vertebral column is the center of the skeleton; almost all bones are connected to it in some way. It has 26 vertebrae and is flexible, allowing the body to bend. Most bones are associated with muscles, which pull the bones to enable movement.

Bone Strength and Composition

Bones are stronger than concrete or granite rock, yet they are lighter. They are primarily made up of phosphorus and calcium.

Bone Growth and Vitality

Bones are alive; they continue growing bone tissue throughout your life. They contain cells, tissue, blood, and nerves. When you break a bone, new bone tissue forms, and this new bone is often stronger than the original bone.

Structure of Bones

Bones have several distinct parts:

1. Outer Membrane: Thin and tough.
2. Compact Bone: Hard and dense but not solid; it contains blood vessels and nerves.
3. Spongy Bone: Contains many small spaces within.
4. Bone Marrow: The spaces in the spongy bone contain tissue called marrow: red (contains blood vessels) and yellow (stores fat).

How Bones Form

Cartilage is a connective tissue that is more flexible than bone. As a baby, you have more cartilage, which is later replaced by bone in adulthood.

Joints of the Skeleton

A joint is the place in the body where two bones come together. Joints allow bones to move in different ways. There are two main kinds of joints:

• Immovable: Allow little or no movement.
• Movable: Allow a range of movements.

Types of Movable Joints

Ball and Socket Joint

Allows circular movement (e.g., shoulder).

Hinge Joint

Allows forward and backward movement (e.g., knee).

Pivot Joint

Allows side-to-side movement (e.g., neck).

Gliding Joint

Allows flexion, bending, and side-to-side movement (e.g., wrist).

A ligament is strong connective tissue that holds together the bones in a movable joint.

Taking Care of Your Bones

To maintain bone health:

• Eat a balanced diet that includes enough calcium and phosphorus.
• Do regular exercise.

Osteoporosis

This is a condition in which the bones become weak and brittle. It can be prevented with regular exercise and a healthy diet throughout life.