Skeletal system
I. Understanding the Skeletal System
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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.
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Main components: bones, joints, cartilage, ligaments.
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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
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Support: Provides structural support for the body, facilitating upright posture and maintaining body shape.
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Protection: Shields vital organs like the brain, heart, and lungs from harm.
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Movement: Works with the muscular system through various types of joints (like hinge and ball-and-socket joints) to facilitate motion.
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Mineral Storage: Significant reservoir for crucial minerals like calcium and phosphate, supplying crucial minerals to the body when needed.
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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
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Long Bones: These include the femur, tibia, fibula, humerus, ulna, and radius. Primarily involved in aiding movement.
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Short Bones: Primarily found in the wrist and ankle. These bones are almost as wide as they are long and provide stability.
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Flat Bones: These include skull bones, scapula, sternum, pelvis, and ribs. They provide protection for vital organs and also large surfaces for muscle attachment.
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Irregular Bones: These include the vertebrae and facial bones. They protect nervous tissue
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Sesamoid Bones: These are small, round bones embedded in tendons. The kneecap (patella) is a sesamoid bone.
IV. Anatomy of a Bone
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Periosteum: The outer layer of the bone providing nourishment and serving as a site for attachment of tendons and ligaments.
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Compact Bone: The hard, dense layer under the periosteum. It is white, smooth, and solid.
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Spongy Bone: Found at the end of long bones and the core of others. It is light but strong.
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Marrow Cavity: Located in the centre of the bone, it contains red or yellow bone marrow.
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Cartilage: Provides a cushioning effect to prevent bones from rubbing together within joints.