Level 3 Sport and Outdoor Activities BTEC

Skeletal system

I. Understanding the Skeletal System

• The skeletal system is a rigid framework of bones providing structure to the body, supporting soft tissues, and facilitating movement through interaction with the muscular system.

• Main components: bones, joints, cartilage, ligaments.

• The human body consists of 206 bones – this number might vary slightly depending on factors such as the presence or absence of certain tiny bones.

II. Function of the Skeletal System

• Support: Provides structural support for the body, facilitating upright posture and maintaining body shape.

• Protection: Shields vital organs like the brain, heart, and lungs from harm.

• Movement: Works with the muscular system through various types of joints (like hinge and ball-and-socket joints) to facilitate motion.

• Mineral Storage: Significant reservoir for crucial minerals like calcium and phosphate, supplying crucial minerals to the body when needed.

• Blood Cell Production: Bone marrow within certain bones is a crucial site for the creation of blood cells – a process known as haematopoiesis.

III. Types of Bones

• Long Bones: These include the femur, tibia, fibula, humerus, ulna, and radius. Primarily involved in aiding movement.

• Short Bones: Primarily found in the wrist and ankle. These bones are almost as wide as they are long and provide stability.

• Flat Bones: These include skull bones, scapula, sternum, pelvis, and ribs. They provide protection for vital organs and also large surfaces for muscle attachment.

• Irregular Bones: These include the vertebrae and facial bones. They protect nervous tissue

• Sesamoid Bones: These are small, round bones embedded in tendons. The kneecap (patella) is a sesamoid bone.

IV. Anatomy of a Bone

• Periosteum: The outer layer of the bone providing nourishment and serving as a site for attachment of tendons and ligaments.

• Compact Bone: The hard, dense layer under the periosteum. It is white, smooth, and solid.

• Spongy Bone: Found at the end of long bones and the core of others. It is light but strong.

• Marrow Cavity: Located in the centre of the bone, it contains red or yellow bone marrow.

• Cartilage: Provides a cushioning effect to prevent bones from rubbing together within joints.