Anatomy - Skeletal System

The skeletal system of the human body is formed by many bones, which give the body a frame of support. Take this tour of the human skeleton to find out more.

This story was created for the Google Expeditions project by Vida Systems, now available on Google Arts & Culture.

Human Skeleton, Lateral View (1795 to 1806) by George Stubbs, 1724–1806, BritishYale Center for British Art

Bones

In addition to providing structure, bones serve other purposes, such as producing blood, regulating minerals in the body, and protecting soft internal organs. Bones are alive, constantly interacting with the other body systems. They change over the course of a lifetime. Bones are hard and strong, yet lightweight, allowing us to move around easily.

Overview of the Skeletal System

The skeletal system is what gives the body structure. Composed of bones, the skeletal system makes up the hardest part of our bodies. 

Through X-rays, doctors can observe the different parts of our skeletal system. Some bones are long and others are short. Some are arranged in a special way to allow for movement. 

The Skeletal System

The skeletal system extends throughout the whole human body. The skeletal system works together with muscles and ligaments in order to hold the body together as well as allow for physical movement.

Teeth

Attached to the skull, a group of many bones that form the shape of the head, are teeth, which assist in digestion. Teeth are considered part of the skeletal system although they are not made of bone, but of other substances called dentin and enamel.

Movable joints

Joints allow for movement. In movable joints, the ends of the bones are covered in softer cartilage. Ligaments, which are pieces of flexible connective tissue, hold the bones together. Some examples are elbows, shoulders, and knees.

Pelvis and Ribs

The human body’s internal organs are housed within the rib cage and pelvis. These structures protect the organs. While skeletons are mostly the same between men and women, the pelvis differs. A woman’s pelvis is larger to allow her to give birth to children. 

The Skeletal System’s Parts and Functions

The skeletal system is made up of 206 bones. In addition to providing a frame and support for the body, it also protects internal organs from being bumped or damaged. 

For example, the skull is a group of bones that protects the brain. Babies are born with around 300 bones that later fuse into 206 bones as they develop into adults. 

The Skeletal System

Each and every bone in the body has a special name. All are living tissue that are constantly changing. Minerals and materials are added to and removed from bones constantly. Childhood and adolescence are very important times for bone growth and development.

The Axial Skeleton and the Appendicular Skeleton

The skeletal system is divided into 2 parts: The axial skeleton and the appendicular skeleton. The axial skeleton is composed of the head, neck, and spine. The appendicular skeleton includes arms, legs, and their supports.

The Skull and Arms

The upper body includes important bones such as the skull, rib cage, and bones which support the arms. The largest bone in the arms is called the humerus. Two types of bones are small bones and long bones.

The skull is formed of small bones while the humerus is an example of a long bone.

The Humerus

The humerus is the bone that runs from the shoulder down to the elbow. Its shape allows two movable joints, one at each end, for creating movement at the shoulder and the elbow.

The Skull

The skull, formed from many different bones, is one of the strongest bone structures in the body. The bones, except for the jaw, are joined together by fixed joints so that no movement occurs in the places where these bones meet.

What are bones made of?

Long bones, such as the femur (which is the longest bone in the body) have a special structure. They have a hard, outer layer called compact bone. The inner layer is called cancellous bone. 

This inner area of the bone performs many important tasks such as storing mineral contents in the body. Some important minerals for bones include calcium and phosphorous. 

The Femur

Forming the upper leg, the femur is the longest bone in the human body. It is also the strongest bone in the body. The femur, or thigh bone, connects the pelvis to the knee.

A Bone's Structure

Bones have two main parts. The outer layer of bone is hard and solid, providing structure. Inside, and at the ends of long bones, cancellous bone is spongy, containing small holes. 

Bone Composition

The inside of bones contains marrow which helps produce red and white blood cells for the whole body. Bone marrow makes up about 4% of the mass of the human body.

The Spine

The spine runs from the skull to the pelvis. It has several very important functions. First of all it protects the spinal cord which is a thick collection of important nerves that connect the brain to the rest of the body. It also provides structure for the rest of the body.

Spine

The human spine is composed of 33 vertebrae. These small pieces of bone are linked together with ligaments. The spine includes some curves that allow humans to sit and stand upright. 

Vertebrae

Each vertebra has a small hole in the middle where the spinal cord runs. The pointed sides face the front of the body and the rounded portion is what you feel when you run your hand along your back.

Movement in the Skeletal System

The skeletal system is closely linked to the muscular system. Ligaments, muscles, and cartilage work with the bones in the skeletal system to allow the body to move. The bones act as levers. The nervous system is also involved in motion as it tells muscles what to do and when.

The Skeletal System

Muscle lays on top of the bones. Special muscles, called skeletal muscles, are directly attached to the bones by fibers called tendons. These skeletal muscles allow us to move our bodies in all directions.

Muscles

Muscles pull on the bones, and the bones act as levers. When muscles at one end of a long bone contract and get shorter, like at the elbow, for example, the bone is pulled up. Muscles and bones must interact constantly as we move.

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