2 a) Functions of: skeleton: To provide support and protection of body parts. It acts as sites for muscle attachment, blood cell production, and calcium and phosphate storage. Cartilage: Serves as structural models for bones that replace them. It maintains the shape of the nose, outer ear, and other body parts. It also serves to cushion joints between adjacent bones of the vertebral column, limbs, hands, and elsewhere.

Ligaments: These bridge the gap between bones Tendons: Cords or straps of connective tissue that attach muscle to bones 2 b) Bone development and structure development: New bone is formed by cells called osteoblasts, which secrete collagen fibres on which calcium is later deposited. Bone is laid down in thin concentric layers called lamellae, like so many layers of paint on an old pipe. The lamellae are laid down as series of tubes around narrow channels called haversian canals, which run parallel to the length of the bone. The haversian canals are interconnected and contain blood vessels and nerve cells.

The blood vessels provide a life-line to living bone-forming cells, while the nerves control the diameter of the blood vessels, and thus, the flow through them. When bone is first formed in the embryo, osteoblasts use the cartilage skeleton as a template for bone formation. Later, new bone is formed along the stress lines. Structure: bone is composed of two types of tissue; spongy bone tissue and compact bone tissue.

Spongy bone tissue forms much of the body's red blood cells, while compact bone tissue gives strength to withstand mechanical stress. 2 c) Types of Joints fibrous joints: Short connecting fibres which stitch bones together. These joints are responsible for holding teeth in their sockets. Cartilaginous joints: joints in which cartilage holds bones together Synovial joints: allow widest range of movement, and include: Hing joints: allow forearm and lower leg to swing back and forth Saddle joints: one bone sits astride the other that's shaped like a saddle Angular joints: small bones of the wrist form a curved surface that sits into a flattened u-shaped cavity Gliding joints: allow only limited movements such as the vertebra Pivot joints: allow rotary movement 1) Biology Revisited 2) Understanding Biology Author: Don Galbraith Faculty of Education University of Toronto 3) Understanding Biology Peter H.

Raven and George B. Johnson Proffesor of Botany and Professor of Biology.