HUMAN SYSTEMS Skeletal System SKELETAL SYSTEM Bones and

HUMAN SYSTEMS: Skeletal System

SKELETAL SYSTEM � Bones and cartilage � Alive and active � 206 bones in humans � Support and protection � Helps maintaining homeostasis � Store minerals, make blood cells

SKELETAL SYSTEM � Functions 1. 2. 3. 4. of bones Protect organs (ribs protect heart and lungs) Store minerals Role in movement Bone marrow (making blood cells)

SKELETAL SYSTEM

BONE STRUCTURE � 1. 2. 3. 4. � 1. 2. Bone is a living organ made up of different types of tissues Connective tissue and minerals Osteoblast cells – mineral deposition Spongy bone – open spaces in bone Compact bone – no visible open spaces Bone marrow – two types Red marrow – red and white blood cells synthesis Yellow marrow – stores fats

BONE STRUCTURE

BONE GROWTH During development most bones are soft � Bone formation initiates as flexible tissue cartilage � As development occurs cartilage is replaced by bone � During growth, bones also increase in size � During childhood, most bones still have growth plates of cartilage � These growth plates provide a place for bones to continue to grow �

JOINTS � � � A place where two or more bones meet is called a joint Some joints, such as fixed joints, allow little or no movement Many of the joints in the skull are fixed joints Other joints, such as your shoulder, allow a lot of movement Joints can be classified based on how the bones in a joint move 1. Gliding or sliding joints 2. Hinge joints 3. Ball and socket joints

JOINTS

JOINTS Joints are often placed under a great deal of stress � But they can withstand a lot of wear and tear because of their structure � Joints are held together by ligaments � Ligaments are strong elastic bands of connective tissue � They connect the bones in a joint � � Also, cartilage covers the ends of many bones. Cartilage helps cushion the area in a joint where bones meet.

INJURIES AND DISEASES 1. 2. 3. Fracture Dislocation of joint Sprain – ligament stretched or torn 4. Osteoporosis � Bone density decreases � Bones become weak 5. Arthritis - joints may swell or stiffen 6. Gout – accumulation of uric acid 7. Nutrition and bone heath