FUNCTIONS OF THE SKELETAL SYSTEM 7th Grade THE SKELETAL SYSTEM Provides shape, strength, and support (3S s) Internal framework of the body Support and anchor for soft organs Protects soft internal organs Skull Rib cage Vertebral Column Aids in movement and provides flexibility FUNCTIONS OF THE CONT D Stores salts, minerals and fat Calcium (Ca) Phosphorus (P) Fat in the form of yellow bone marrow Produces blood cells in the red bone marrow (hematopoiesis) Red blood cells (RBC s) White blood cells (WBC s) QUICK ASSESSMENT: CONCEPT MAP CONCEPT MAP THE HUMAN SKELETON 2. 1. 3. 20. 4. 19. Skeletal System 18. 17. Sacrum (5) Ilium 5. 6. 7. Function 16. Coccyx (4) 8. Ischium 9. 10. 11. 12. 15. 13. 14. Name Mr. Mayorga 7 th Grade Science 1
BONE CLASSIFICATION Location/Function 206 Bones Shapes Axial (80) Appendicular (126) Long Short Flat Irregular DIVISIONS OF THE SKELETON Appendicular Skeleton (126) Axial Skeleton Cranium and face 22 Skull Associated 7 Vertebral column 26 (33) Ribs 24 Sternum 1 Total 80 Sacrum (5) Coccyx (4) AXIAL VS. APPENDICULAR Axial Skeleton: Located in the middle (axis) of the body. This section of the skeleton protects the internal organs (80). Appendicular Skeleton: Includes all the bones found in you upper and lower extremities. This section of the skeleton aids in movement (126). CLASSIFICATION OF BONES Long bones, e.g, femur, tibia, humerus, radius, etc. Short bones, e.g., phalanges, carpals, etc. Flat bones, e.g., the bones of the skull, sternum, etc. Irregular bones, e.g., vertebrae, ribs, mandible, etc. EXTERNAL STRUCTURES OF A LONG BONE Epiphysis Diaphysis (Shaft) Periosteum Articular Cartilage INTERNAL BONE STRUCTURES Compact Bone Endosteum Medullary (or Marrow) Cavity Yellow Bone Marrow Spongy Bone Mr. Mayorga 7 th Grade Science 2
MICROSCOPIC STRUCTURE OF COMPACT BONE Compact Bone Periosteum Osteocyte Blood vessel BONE CELLS Osteoblasts: bonemaking cells Make new bone Osteogenesis Osteocytes: mature bone cells found in compact bone Osteoclasts: bone destroyers that dissolve and reshape bone Haversian canal BONE DEVELOPMENT 300 ± bones when you were first born 206 as an adult Ossification (or osteogenesis) Most bones formed directly from cartilage (endochondral ossification). Others form directly from connective tissue (intramembranous ossification), such as the flat bones of the skull. SKELETAL JOINTS Pivot Ball-and-Socket Hinge Ellipsoid Saddle Gliding Fixed/Immovable TENDONS VS. LIGAMENTS Tendons are tough, solid band of connective tissue that connect muscle to a bone. Ligaments are also made of connective tissue, and they connect bone to bone. L T An Overview COMMON DISEASES OF THE SKELETAL SYSTEM Mr. Mayorga 7 th Grade Science 3
BONE FRACTURES A fractured bone is a partially or completely broken bone. A bone may be completely fractured or partially fractured in any number of ways (crosswise, lengthwise, in the middle). HOW FRACTURES HEAL DISLOCATION A dislocation is an injury to your joint in which the ends of your bones are forced to separate. The injury temporarily deforms and immobilizes your joint and may result in sudden and severe pain. SPRAIN A sprain occurs when ligaments are stretched, snapped, slightly torn or ruptured, all of which are more serious and require longer to heal. OSTEOPOROSIS Osteoporosis («porous bone») is a condition that develops when bone is no longer replaced as quickly as it is removed. Symptoms include the loss of normal bone density, mass and strength, leading to increased porousness and vulnerability to fracture, specifically of the hip, spine and wrist. OSTEOGENESIS IMPERFECTA (OI) OI lit. means «bones that were imperfectly made from the beginning of life». OI is a genetic disease commonly known as «brittle bone» disorder. It is characterized by bones that break easily, often from little or no apparent cause. A person with OI may break a rib while coughing, a leg while rolling over in their sleep. Mr. Mayorga 7 th Grade Science 4
OSTEOARTHRITIS (OA) OA is also known as the wear-and-tear kind of arthritis. OA is a chronic condition characterized by the breakdown of the joint s cartilage. The breakdown of cartilage causes the bones to rub against each other, causing stiffness, pain and loss of movement in the joint. RHEUMATOID ARTHRITIS (RA) RA is a chronic inflammatory disease that causes pain, stiffness, and swelling around the joints. RA is often confused with osteoarthritis. RA It is a disease known as an "autoimmune" disease in which your own immune system mistakenly attacks healthy tissue, causing inflammation that damages your joints. THE HUMAN SKELETON Scapula (Shoulder Blade) Sternum Cranium (skull) Mandible (jaw) Clavicle (collar bone) Humerus (funny bone) Vertebra Sacrum (5) Ribs Ilium Radius Ulna Phalanges Coccyx (4) Carpals Metacarpals Ischium Femur (thigh bone) Patella (knee cap) Tibia (shin bone) Fibula Metatarsals Tarsals Phalanges INVERTEBRATES VS. VERTEBRATES Invertebrates Animals that lack a backbone 99% of all species Includes sponges, cnidarians, worms, mollusks, insects, and echinoderms May have exoskeletons Vertebrates Animals that possess a backbone ±1% of all species Include fish, amphibians, reptiles, birds and mammals Have endoskeletons FUNCTIONS OF THE EXOSKELETON It enables the body to withstand the pull of gravity. This provides the organism the ability to get of the ground as it moves. It provides points of attachment for soft muscle tissue locomotion. It protects against desiccation or drying out. It protects against predators; the exoskeleton is the animal s armor. Mr. Mayorga 7 th Grade Science 5
EXOSKELETON VS. ENDOSKELETON Limited flexibility Heavy Nonliving tissue Chitin or CaCO3 Product of epidermis Limits growth Molting Vulnerability Extremely flexible Light and strong Living tissue Made of collagen and minerals Can repair itself Grows with the individual AXIAL VS. APPENDICULAR Axial Skeleton: Located in the middle (axis) of the body. This section of the skeleton protects the internal organs (80). Appendicular Skeleton: Includes all the bones found in you upper and lower extremities. This section of the skeleton aids in movement (126). Mr. Mayorga 7 th Grade Science 6