Skeletal System. Chp. 5. Skeletal System Composed of 3 Types of Connective Tissue. Recall that connective tissue consists of a matrix with cells suspended w/in it--the type of matrix & cells determine type of tissue. Bones - hard elements of skeleton.
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Skeletal System Chp. 5
Skeletal SystemComposed of 3 Types of Connective Tissue Recall that connective tissue consists of a matrix with cells suspended w/in it--the type of matrix & cells determine type of tissue. • Bones- hard elements of skeleton. • Ligaments - dense, fibrous connective tissue that serves to bind bone-to-bone. • Cartilage - collagen & elastin fibers suspended in gel-like matrix [ground substance].
5 Functions of Bones • Support • Movement • Protection • Formation of blood cells • Mineral storage
Skeletal Systemcont. 1. Bone: hard inorganic matrix of calcium salts • Compact Bone: • Dense - extracellular deposits of calcium phosphate matrix w/ living cells • Osteocytes- living mature bone cells that maintain structure of bone • forms shafts & covers ends of long bones • filled with yellow marrow • Yellow marrow = Primarily fat for energy reserves • Contains blood vessels & nerves
Skeletal Systemcont. b. Spongy Bone: • porous bone found inside enlarged knobby ends of bones [knob = epiphysis] • Internal latticework makes bones lighter & stronger • Trabeculae = latticework of bones made of calcium minerals + living cells • red marrow - found in spaces of trabeculae w/in long bones of upper arms & legs Stem cells w/in red marrow produce RBC’s
Osteons [Haversian Systems]Cylindrical Structures (see text Fig 5.1) Osteons - as compact bone develops & hardens (ossifies) the osteocytes are trapped in hollow chambers within cylindrical osteons in such a way as to maintain contact with other osteocytes yet provide them a strong matrix to support them. Blood vessels traveling through the central Haversian canal feed the osteocytes via cell-to-cell diffusion. Waste products Diffuse away from cells, back to blood vessels.
Periosteum Tough Connective Tissue covering bones • Contains bone formingOsteoblast cells
* * Structure of Bone * Human Biology Figure 5.1 *Make note of these
Cartilage and Ligaments Cartilage - fibers of cartilage & elastin in gel-like matrix Function: support Types: • Fibrocartilage - between vertebral disks, in knee joint • Hyaline - embryonic “model” for bones, covers ends of mature bones found in joints. • Elastic cartilage - outer ear, part of epiglottis Ligaments- attach bone to bone
Bone Development[see Fig. 5.2 from text] Prenatal: cartilage model Fetus: some conversion to bone Childhood: primary & secondary ossification sites formed Adolescence: cartilage growth plate elongates
Bone Development (cont.) Figure 5.2
Mature Bone Remodeling and Repair Changes in: (1) shape, (2) size, (3) strength • Dependent on diet, exercise, age Bone cells regulated by hormones • Parathyroid hormone (PTH): removes calcium from bone • Calcitonin: adds calcium to bone Repair: hematoma and callus formation
Skeletal System: Frontal View Blue = Axial Skeleton [skull,vertebral column, ribs, Sternum] Black = Appendicular Skleton [pectoral girdle, pelvic girdle, limbs] Figure 5.5
Axial Skeleton: The Skull [Just make note of the number of bones in the skull] Figure 5.6
Axial Skeleton: Vertebral Column 5 areas of Axial skeleton: cervical, thoracic, lumbar, scarum, coccyx Figure 5.7
Axial Skeleton: Vertebral Column (cont.) Vertebral column • Regions: cervical, thoracic, lumbar, sacral, coccygeal • Intervertebral disks: cushion vertebrae; assist in movement, flexibility Ribs • Twelve pairs • Bottom two pair floating Sternum: Breastbone • Three bones fused
Appendicular Skeleton Pectoral girdle: shoulder • Clavicle, scapulas Pelvic girdles: hip • Coxal bones, sacrum, pubis, ilium, ischium Limbs • Arms: humerus, radius, ulna, wrist and hand bones • Legs: femur, tibia, fibula, ankle and foot bones
Joints (Articulations) Classified by degree of movement • Fibrous joint: immovable (e.g., fontanels) • Cartilagenous joint: slightly movable, cartilage connection (e.g., backbone) • Synovial joint: freely movable (e.g., knee)
Synovial Joints Figure 5.12A
Synovial Joints (cont.) Joint capsule: synovial membrane + hyaline cartilage Synovial membrane secretes synovial fluid as lubricant Hyaline cartilage cushions
Diseases and Disorders of the Skeletal System Sprains: stretched or torn ligaments Bursitis and tendinitis: inflammation of bursae or tendons Arthritis: inflammation of joints