SKELETAL SYSTEM
Functions of the Skeletal System Support: Internal framework that supports and anchors all soft organs. Protection: Bones protect soft body organs Body movement skeletal muscle attached to bones by tendons. Use a levers. Storage: Storehouse for minerals ex. Ca & P. Fat Blood cell formation (bone marrow) - hematopoiesis
BONE STRUCTURE - Long Bone Epiphysis end of bone. Covered with cartilage Diaphysis between epiphyses Articular Cartilage hyaline on ends of bone. Periosteum outer covering, contains osteoblasts
Types of Bone (Osseous) Tissue Compact (wall of the diaphysis) dense outer layer Spongy (cancellous, epiphysis) red/yellow marrow Honeycomb like and filled with marrow
Inside the Long Bone Medullary Cavity hollow chamber filled with bone marrow (red, yellow) Red Marrow (blood) Found in spongy bone Yellow Marrow (fat) Found in diaphysis Endosteum lining of the medullary, contains osteoclasts
Structure of a Long Bone Figure 6.3a-c
Review the Structure of a Long Bone Matching quiz at http://www.mhhe.com/biosci/a p/holehaap/student/olc2/chap 07matching01.html
Microscopic Structure MATRIX - where the bone cells live OSTEOCYTES - mature bone cells, enclosed in tiny chambers called LACUNAE OSTEOCYTES form rings (LAMELLAE) around a HAVERSIAN CANAL which houses blood vessels Osteocytes are linked by CANALICULI for communication Haversian Canals are linked by VOLKMAN's CANALS
Osteocytes Volkmann s Canal Haversian Canal
Compact Bone BONE COLORING!
Test Yourself Find the... Haversian Canal Volkman's Canal Lamellae Spongy Bone Compact Bone
BONE DEVELOPMENT & GROWTH 1.Intramembranous bones flat, skull 2. Endochondral bones all other ALL BONES START AS HYALINE CARTILAGE, areas gradually turn to bone PRIMARY OSSIFICATION CENTER (shaft) SECONDARY OSSIFICATION CENTER (ends)
Bone Development & Growth EPIPHYSEAL DISK (growth plate) is a band of cartilage between the epiphysis and diaphysis These areas increase bone length as the cells ossify Cartilage becomes OSTEOBLASTS become OSTEOCYTES
RESORPTION OSTEOCLASTS - dissolve bone tissue to release minerals, process is called RESORPTION
Bone Growth
Bone Growth
Abnormal Bone Conditions BONE SPURS: abnormal growth. Can occur on any bone (e.g. heel). OSTEOPOROSIS: Increased activity of osteoclasts cause a break down bone, and the subsequent fewer minerals in the extracellular matrix make it fragile. The spongy bone especially becomes more porous. Men get it as well as women. What s the best way to prevent osteoporosis? Exercise! What does exercise do? Makes bones bigger. The most common bone used for a bone graft is the iliac bone of the hip.
Osteoporosis Figure 6.15
ORGANIZATION About 206 bones 2 Main Divisions Axial & Appendicular
Types of Bones Long bones Longer than they are wide (eg. femur, metacarpels) Short bones Cube-shaped bones (eg. wrist and ankle) Sesamoid bones (within tendons eg. patella) Flat bones Thin, flat, slightly curved (eg. sternum, skull) Irregular bones Complicated shapes (eg. vertebrae, hips)
Axial Skeleton Head, neck, trunk Skull Hyoid Bone Vertebral Column Thoracic Cage (ribs, 12 pairs) Sternum
Axial Skeleton
BONES OF THE SKULL (22 bones) 1. Frontal - 2. Parietal - 3. Occipital - 4. Temporal - 5. Sphenoid - 6. Maxilla - 7. Mandible - 8. Zygomatic -
Sutures - connection points 1. Coronal - between frontal and parietal bones 2. Lambdoidal - between occipital and parietal bones 3. Squamosal - between temporal and parietal bones 4. Sagittal - between parietal bones
Suture - refers to any connection between large bones (in fetal skulls, these are called fontanels) Fissure - any wide gap between bones
Fontanels are soft spots on an infant s skull
TOPOGRAPHY OF THE SKULL Foramen - refers to any opening in the skull, nerves and blood vessels leave this opening to supply the face Foramen Magnum Mental Foramen
Figure 6.10
Foramen Magnum
Figure 6.10
Hyoid Bone Supports tongue. Not in contact with any other bones.
Vertebrae (26) Neck = cervical (7) 1 st atlas 2 nd axis 3-7 C-3 thru C-7 neck Middle Back = thoracic (12) Articulate with ribs T-1 thru T-12 in chest Lower Back = lumbar (5) Largest vertebrae L-1 to L-5 Sacrum between hips Coccyx tail bone
Thoracic Cage
ABNORMALITIES OF THE SPINE ABNORMALITIES OF THE SPINE SCOLIOSIS is a lateral curve in the spine KYPHOSIS is a hunchback curve LORDOSIS is a swayback in the lower region. ANKYLOSIS is severe arthritis in the spine and the vertebrae fuse.
SCOLIOSIS
Kyphosis
LORDOSIS
ANKYLOSIS
Rheumatoid arthritis is an autoimmune disease which causes joint stiffness and bone deformity Source: http://www.thetimes.co.uk/tto/public/article3233439.ece
FUN FACTS ABOUT BONES Bone is made of the same type of minerals as limestone. Babies are born with 300 bones, but by adulthood we have only 206 in our bodies. The giraffe has the same number of bones in its neck as a human: seven in total. The long horned ram can take a head butt at 25 mph. The human skull will fracture at 5mph.
Warning: Next slide is graphic!
Broken Bones