2. THE MUSCULOSKELETAL SYSTEM : Part 1

3. Structure and Function Forms the body framework Enables the body to move Protects and supports internal organs

4. Bones Composed of osseous tissue Consists of a rich supply of blood vessels and nerves Osteoblasts are bone-forming cells Osteoclasts are responsible for reabsorbing dead bone tissue Osteocytes are mature bone cells

5. Ossification Bones The development of osteocytes and the hardening process is called ossification calcium phosphorus vitamin D Ossification depends on:

6. Epiphyseal Plates “Growth Plates” Located on the ends of long bones Where osteoblasts increase bone length After adolescence the plates dissolve and the bone fuses, ending bone growth

7. Common Bone Categories The adult skeleton has 206 bones. Common Bone Categories Long bones (Femur) Short bones (Wrist bones) Flat bones (Skull) Irregular bones (Vertebrae) Sesamoid bones (Kneecap)

8. Parts of Long Bones Parts of long bones: Diaphysis Longest portion Hollow shaft Epiphysis Bulbous ends Covered by cartilage

9. 8 Parts of Long Bones Part 2 Articular cartilage: thin flexible substance that provides protection at movable points Medullary cavity: hollow space that contains yellow bone marrow Parts of a Long Bone Femur Distal epiphysis Diaphysis Proximal epiphysis Epiphyseal disks Spongy bone Articular cartilage Space containing red marrow Compact bone Medullary cavity Yellow marrow Periosteum

10. Bone Marrow: specialized flexible tissue found inside bones Yellow Bone Marrow Found in medullary cavity Major storage for fat within the body Red Bone Marrow Where hematopoiesis occurs (blood cell formation) Found in cavities of –Flat & short bones –Vertebrae –Sternum –Ribs –Ends of long bones 9

12. Cranial Bones

13. Spinal Column Also called: Spine Vertebral column Backbone Vertebrae Cervical = 7 Thoracic = 12 Lumbar = 5 Sacrum = 5 fused Coccyx = 4 fused **Intervertebral Discs made of fibrocartilage provide cushioning between vertebrae**

14. Bones of the Chest The Thoracic Cage Clavicle Scapula Sternum Costal Cartilage True ribs False ribs Floating ribs The thoracic cage surrounds the heart and lungs in the thoracic cavity.

15. The Pelvic Girdle The pubic symphysis is where both coxal bones join. Coxal Bones Sacrum Coccyx

16. Bones of the Extremities Bones of the Arm Upper Arm Humerus Lower Arm Ulna Radius Hand and Fingers Carpals (wrist) Metacarpals (palm) Phalanges (fingers)

17. Bones of the Extremities Part 2 Bones of the Leg Upper Leg Femur Lower leg Tibia (shin) Fibula Patella (kneecap) Feet and Toes Tarsals Calcaneus (heel) Metatarsals Phalanges

18. Joints Types of Joints Amphiarthroses Moves slightly Ex: Pubic Symphysis Diarthroses Moves freely Ex: What you tend to think of as “joints” Synarthroses No movement Ex: Sutures of the skull

19. Tendons and Ligaments Tendons are bands of fibrous tissue that connect muscles to bone Ligaments connect bones to other bones Movement occurs at joints with the assistance of muscles, tendons, and ligaments Tendons and Ligaments

20. Muscles Muscles contract (shorten) and extend to provide body movement Types of Muscles 1. Voluntary (skeletal) 2. Involuntary (smooth or visceral) 3. Cardiac (heart)

21. 20 Muscles - Fascia Muscles Most muscles are covered by a band of connective tissue called fascia, that supports the muscle

22. Skeletal Muscle Attach to bones and are responsible for body movements “Striated Muscle” “Voluntary Muscle” Muscle fiber: an individual skeletal muscle cell Born with your # of muscle fibers, can only increase fiber diameter!

23. Smooth Muscle “Involuntary Muscles” or “Visceral Muscles” Found in the walls of many internal organs (stomach, intestines, bladder, respiratory pathways) Peristalsis: Wavelike contractions that move food through the digestive tract

24. Cardiac Muscle Found only in the walls of the heart Involuntary muscle with branching Intercalated discs: structures that join together many cardiac muscle cells for simultaneous contraction (heartbeat)