2 2 Divisions The human skeleton has two divisions Axial skeleton – Consist of the skull, vertebrate column, and the rib cageThe Appendicular Skeleton - Consist the bones of the arms and legs, shoulder, and the pelvic girdle .The Skeleton of Humans is composed of a special connective tissue called BONEThere are 206 bones in the human body
4 Functions of the Skeletal System support - it forms the body's framework to support the muscles and organs.protection - the skeletal systems protects by1) forming the bony cavities around organs,the thoracic cavity protects the heart and lungsthe cranial cavity protects the brain.2) the yellow marrow in bones produces white blood cells which protect against invading microorganisms.movement - bones form joints which provide levers for movement such as walking, lifting, etc.hematopoiesis (blood cell production) - the red marrow produces red blood cells.mineral storage and homeostasis - the skeleton forms a reservoir of minerals, especially calcium, for maintenance of homeostasis.
5 2 Basic types of bone tissue: 1. Compact bone - dense, smooth. Contains few spaces. Covers spongy bone tissue. Provides protection and support and helps long bones resist stress of weight.2. Spongy bone - composed of small needle-like pieces and open spaces filled with red marrow. Makes up most of short, flat and irregular shaped bones and most of the epiphysis of long bones.Bones are classified by their shape1. Long bones (humerus, femur) 2. Flat bones (skull) 3. Short bones (fingers) 4. Irregular bones (vertebrae)
7 Joints JOINTS WHERE TWO BONES MEET Cartilage is responsible for keeping bones far enough apart so they do not rub against each other as they move. At the same time, joints hold the bones in place.Joints work by attaching muscles which work in in pairs - ANTOGONISTIC MUSCLES - flexors & extensorsMuscles attach to bone via connective tissue called TENDONSBones attach to bones via connective tissue called LIGAMENTS
8 There are two kinds of joints: IMMOVABLE JOINTTHEY ARE OFTEN CALLED FIXED JOINTS, AND ALLOW NO MOVEMENT BETWEEN BONES.These joints are interlocked and held together by Connective Tissue, or they are fused together.The places where the bones of the SKULL meet (SUTURE) meet are examples of immovable joints.Immovable joints are located in bones of the skulls and the ribs2. MOVABLE JOINTSMOST OF THE JOINTS OF THE BODY ARE FREELY MOVABLE JOINTS.In Freely Movable Joints, the ends of the bones are covered with a layer of Cartilage that provides a smooth surface at the joint. Joints are a place where two or more bones come together.Examples are the ball-and-socket, pivot, hinge, and gliding
10 Moveable Joints Ball-and-socket joint Ball-and-socket joints allow the greatest range of motion. They can be found in the shoulder where the top of the arm bone fits into the deep, bowl-like socket of the scapula (shoulder blade).This joint allows you to swing your arm freely in a circle, your hips also have ball-and-socket joints
11 Moveable Joints Hinge joint Permits a back-and-forth motion.The Knee enables your leg to flex and extend.The Elbow, which allows you to move your forearm toward and away from your body.
12 Moveable Joints Pivot Joint A pivot joint allows one bone to rotate around anotherA pivot joint can be found in the top of your neck, which gives you limited ability to turn your head from side to side
13 Moveable Joints Gliding Joint A gliding joint allows one bone to slide over another boneThe joint located in your wrist is an example of a gliding joint this joint enables you to bend and flex your wrist, as well as make limited side-to-side motions.
14 Joint ActivityWhat types of joints are involved in the following activities:1. Move your arm in a circle2. Push open a door3. Lift a book off the table4. Kneel down5. Wave your hand6. Twist your head from side to sideAnswers:1. Arm = ball-and-socket joint2. Door = hinge joint (elbow)3. Book = Gliding joint (wrist)4. Kneeling = hinge joint (knee)5. Hand = gliding joint (wrist)6. Head = Pivot joint (neck)