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Chapter 7 Notes

Chapter 7 Notes. Skeletal System: Tissue and physiology Skeletal tissue is the most distinctive form of connective tissue. Functions of Skeletal Tissue. Support Ex. Arch of foot, vertebral column, etc. Protection Ex. Skull protects the brain, rib cage protects lungs and heart. Movement

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Chapter 7 Notes

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  1. Chapter 7 Notes Skeletal System: Tissue and physiology Skeletal tissue is the most distinctive form of connective tissue.

  2. Functions of Skeletal Tissue • Support • Ex. Arch of foot, vertebral column, etc. • Protection • Ex. Skull protects the brain, rib cage protects lungs and heart. • Movement • Occurs with the help of joints - act as levers • Muscle contraction pulls on bones = movement

  3. Functions of Skeletal Tissue • Mineral reservoir • Calcium • Homeostasis of blood calcium levels • Hemopoiesis - blood cell formation • Occurs in red bone marrow • chest • spinal column in adults • base of skull • upper arm and thigh • In infants or child, all bone marrow is red. ADULTS

  4. Bone Shapes • Long bone- consists of 6 parts. Ex. femur, humerus • Short bone- ex. Carpals = fingers and toes • Flat Bone– scapula = back (shoulder blade) • Irregular bone- vertebrae

  5. Structure of Long Bone • Diaphysis • Main shaft • Strong support • Hollow = decrease in weight

  6. Structure of Long Bone • Epiphysis • Ends of long bone • Bulbous shape allows for muscle attachment and gives stability to joints • Contains spongy tissue • contains marrow - red or yellow Spongy bone Compact bone

  7. Structure of Long Bone • Articular cartilage • Covers joint surface of epiphysis • Cushions jars and blows

  8. Structure of Long Bone • Periosteum • Dense fibrous membrane • Covers bone except at joints • Tedons interlace with and anchor muscles • Contain many blood vessels (connects with haversian canal) • Osteoblasts (bone forming cells) compose inner layer

  9. Structure of Long Bone • Medullary Canal • Tube of diaphysis • Contains marrow • Endosteum • Membrane • Lines medullary cavity of long bone

  10. Long Bone Anatomy http://kidshealth.org/misc/movie/bodybasics/bone.html

  11. Haversian System • Identifies microscopic structure of compact bone in the diaphysis

  12. Haversian System Structure • Lamellae (Lah-Mel-e) • cylinder shaped layers of calcified matrix (non-living) • Lacunae (la-Kew-nah) • small spaces • contains tissue fluid where bone cells (osteocytes) live • imprisoned between lamellae

  13. Haversian System Structure • Canaliculi (Ka-NALi-ku-li) • ultra small canals • radiates out from lacunae to connect each other • connects also to haversian canal • Haversian canal • Contains blood vessels and lymphatic tissue • Gives nutrients to lacunae through canaliculi • Gives nutrients to osteocytes

  14. Haversian System

  15. Bone Development and Growth • Osteogenesis -the process of bone formation • At 12 weeks the skeleton has formed-made of cartilage and fibrous tissue.

  16. Bone Development and Growth • Fontanels - "soft spots" of an infant's skull

  17. Osteogensis • Intramembranous Development • Prebone structure of skull and mandible • Takes place within connective tissue • Connective tissue enlarges to form osteoblasts - bone forming cells. • Bone matrix is formed • Matrix is calcified by deposits of calcium and salts. • Flat bones grow by adding to their outside boarders.

  18. Osteogensis Continued • Endochondral (all other bones) • Begin as cartilage • Cartilage develops periosteum - enlarges into a ring • Cartilage calcifies • Ossification, hardening of bone, progresses toward each epiphysis. • During bone growth, ephiphyseal cartilage remains between ends and shaft = growth plate.

  19. Osteogensis Continued Major stages (a-d fetal, e child, f adult) in the development of the endochondral bone.

  20. Bone Growth • Diameter • Osteoclasts - enlarge diameter of medullary cavity by eating away wall. • Osteoblasts - build new bone at periosteum • Occurs throughout life

  21. Bone Growth Continued • Childhood • Bone ossification is greater than bone resorption (decomposition) = taller • Adulthood • Bone ossification and resorption equal one another. • At 35-40, bone ossification decreases and resorption is greater. • Become hollow • Vertebrae collapse = height decrease • Brittle bones = death

  22. Bone Growth

  23. Bone Fracture • Bone Fracture - break in continuity of bone. • Types • Simple - skin remains unbroken • Compound - broken ends protrude through skin • Easily infected - osteomyelitis

  24. Bone Fractures Continued • A complete fracture is when the bone has broken into two pieces. • A greenstick fracture is when the bone cracks on one side only, not all the way through. • A single fracture is when the bone is broken in one place. • A comminuted (say: kah-muh-noot-ed) fracture is when the bone is broken into more than two pieces or crushed. • A bowing fracture, which only happens in kids, is when the bone bends but doesn't break • An open fracture is when the bone is sticking through the skin.

  25. Bone Fractures Continued

  26. Bone Fractures Continued • Repair - fracture healing • Damage to blood vessels begins repair sequence. • Dead bone is removed by osteoclasts-resorption. • Osteoclasts used as framework for repair tissue called callus. • Callus tissue bonds broken ends of bone outside. • Callus tissue binds medullary cavity. • Callus tissue is molded and replaced with bone. • Electrically induced osteogenesis - uses electrical stimuli to heal fractures.

  27. Bone Fractures Continued • Major steps in the repair of a fracture.

  28. Osteoporosis • Loss of calcified matrix & callogenous fibers. • Occurs most frequently in elderly, white females. • Decrease levels of estrogen and testosterone. • Decreased osteoblast activity • Decreased maintenance of existing bone • Bone Degeneration • Spontaneous fractures • Curvature of the spine • Treatment • Estrogen therapy - after menopause • Dietary supplement of calcium and vitamin D.

  29. Cartilage • Cartilage - connective tissue • Types • Hyaline • Elastic Cartilage • Fibrocartilage

  30. Hyaline • Most abundant • Semi-transparent-bluish, opalescent • Covers articular surface of bone • Forms ends of ribs that join to sternum • Forms rings in trachea, bronchi of lungs, & nose

  31. Elastic Cartilage • Elasticity and firmness • Fibers form to external ear, epiglottis, tubes in ear, nasal cavity • Yellowish in color

  32. Fibrocartilage • Greatest tensile strength • Intervertebral disks, point of attachment of some large tendons to bones.

  33. Structure of Cartilage • Chondrocytes - cartilage cells. • Avascular - contain no blood vessels. • Receive oxygen and nutrients through diffusion. • Increase of collagenous fibers and matrix embedded in a gel (not calcified).

  34. Function of Cartilage • Shock absorption • Resists collapse of passageways • Allows bone growth

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