The Skeletal System. ï‚· Parts of the skeletal system ï‚· Bones...

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Transcript of The Skeletal System. ï‚· Parts of the skeletal system ï‚· Bones...

  • Slide 1
  • The Skeletal System
  • Slide 2
  • Parts of the skeletal system Bones (skeleton) 20% of your body mass Joints junction of 2 or more bones Cartilages - connective tissue Ligaments fasten bone to bone Divided into two divisions Axial skeleton skull, spine and thorax Appendicular skeleton limbs & girdles
  • Slide 3
  • 5 Functions of Bones Support of the body Protection of soft organs Movement due to attached skeletal muscles Storage Ca & P also K, Na, S, Mg, and Cu as well as adipose tissue Blood cell formation - hematopoiesis
  • Slide 4
  • Bones of the Human Body The skeleton has 206 bones Two basic types of bone tissue Compact bone Dense Homogeneous Spongy bone Small needle-like pieces of bone Many open spaces Figure 5.2b
  • Slide 5
  • 4 Classifications of Bones Long bones Typically longer than wide Have a shaft with heads at both ends Contain mostly compact bone Examples: Femur, humerus, bones of fingers
  • Slide 6
  • Classification of Bones Short bones Generally cube-shape Contain mostly spongy bone Examples: Carpals, tarsals
  • Slide 7
  • Classification of Bones Flat bones Thin and flattened Usually curved Thin layers of compact bone around a layer of spongy bone Examples: Skull, ribs, sternum
  • Slide 8
  • Classification of Bones Irregular bones Irregular shape Do not fit into other bone classification categories Example: Vertebrae and hip
  • Slide 9
  • Gross Anatomy of a Long Bone Diaphysis Shaft surrounds the medullary cavity Composed of compact bone Epiphysis Ends of the bone Composed mostly of spongy bone Bulbous shape provides space for muscle attachment. Figure 5.2a
  • Slide 10
  • Medullary cavity Center of long bones Contains yellow marrow (mostly fat) in adults Contains red marrow (for blood cell formation) in infants Figure 5.2a Gross Anatomy of a Long Bone
  • Slide 11
  • Epiphysis Line Found in adult bones Thin line of bony tissue spanning the epiphysis Epiphyseal plate Cartilage in young bone between the diaphysis and the epiphysis for long bone lengthening AKA : Growth Plate Gross Anatomy of a Long Bone
  • Slide 12
  • Periosteum Outside covering of the diaphysis Contains nerves, blood vessels, lymph vessels Fibrous connective tissue membrane contains osteoblasts Sharpeys fibers Secure periosteum to underlying bone Figure 5.2c Arteries - Supply bone cells with nutrients Gross Anatomy of a Long Bone
  • Slide 13
  • Endosteum Membrane in medullary cavity Contains osteoclasts and osteoblasts Figure 5.2c Arteries - Supply bone cells with nutrients Gross Anatomy of a Long Bone
  • Slide 14
  • Slide 5.8a Articular cartilage Covers the external surface of the epiphyses Made of hyaline cartilage Decreases friction at joint surfaces Figure 5.2a Gross Anatomy of a Long Bone
  • Slide 15
  • Hematopoiesis blood cell formation Occurs in red marrow cavities of spongy bone Red Marrow Cavities Newborn Medullary cavity and all cavities of spongy bone contain red bone marrow. Most Adults Confined to the cavities of spongy bone of flat bones and medullary cavity of some long bones Gross Anatomy of a Long Bone
  • Slide 16
  • Bone Markings Table 5.1 Surface features of bones Sites of attachments for muscles, tendons, and ligaments Passages for nerves and blood vessels Categories of bone markings Projections and processes grow out from the bone surface Depressions or cavities indentations
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  • Slide 18
  • Slide 19
  • On a separate sheet of paper and with a group, examine a collection of bones and determine their type (long, short, flat, irregular), their location, and name any bone markings. Make a data table and describe each bone. Bone Markings Table 5.1 BoneTypeLocationMarkings
  • Slide 20
  • What do you remember about this picture? What makes it a connective tissue? Microscopic Anatomy of Bone
  • Slide 21
  • Bone consists of a few different types of cells Osteoblasts bone building Osteocytes mature bone cells Osteoclasts bone destroying
  • Slide 22
  • Microscopic Anatomy of Bone Osteoblasts bone building Found in periosteum and endosteum Secrete matrix
  • Slide 23
  • Microscopic Anatomy of Bone Osteocytes mature bone cells Osteoblasts that have become trapped in lacunae Maintain the bone tissue
  • Slide 24
  • Microscopic Anatomy of Bone Osteoclasts bone destroying Giant cells that participate in bone resorption Mainly found in endosteum
  • Slide 25
  • Microscopic Anatomy of Bone Bone also is made up of a hard matrix Organic Component: collagen fibers and other organic materials Inorganic component: 2 salts: calcium phosphate and calcium hydroxide form hydroxyapatite.
  • Slide 26
  • Microscopic Anatomy of Bone The tissue consists of many units working together Osteon (Haversian System) A unit of microscopic bone; concentric circle & matrix rings
  • Slide 27
  • Slide 28
  • Microscopic Anatomy of Bone Osteon (Haversian System) Cells = osteocytes Matrix = lamellae
  • Slide 29
  • Microscopic Anatomy of Bone Each Osteon contains: Central (Haversian) canal Opening in the center of the osteon Carries blood vessels and nerves
  • Slide 30
  • Microscopic Anatomy of Bone Each Osteon contains: Lacunae Cavities containing bone cells (osteocytes) Arranged in concentric rings Lamellae Rings around the central canal All collagen fibers run in the same direction Figure 5.3
  • Slide 31
  • Microscopic Anatomy of Bone Each Osteon contains: Canaliculi Tiny canals Radiate from the central canal to lacunae Form a transport system
  • Slide 32
  • Microscopic Anatomy of Bone Each Osteon contains: Volkmanns canal Canal perpendicular to the central canal Connect blood vessels and nerves of periosteum to Haversian canal
  • Slide 33
  • Make a concept map of the microscopic structure and anatomy of a long bone. Each section should be connected with a phrase. For example, osteon = contains osteocytes and lacunae Microscopic Anatomy of Bone Osteon Osteocytes Lamellae Contains cells and matrix
  • Slide 34
  • Changes in the Human Skeleton In embryos, the skeleton is primarily hyaline cartilage During development, much of this cartilage is replaced by bone Cartilage remains in isolated areas Bridge of the nose Parts of ribs Joints
  • Slide 35
  • Bone Growth Epiphyseal plates allow for growth of long bone during childhood New cartilage is continuously formed Older cartilage becomes ossified Cartilage is broken down Bone replaces cartilage
  • Slide 36
  • Hormonal Effects on Bone Growth hormone, produced by the pituitary gland, and thyroxine, produced by the thyroid gland, stimulate bone growth. GH stimulates protein synthesis and cell growth throughout the body. Thyroxine stimulates cell metabolism and increases the rate of osteoblast activity.
  • Slide 37
  • Hormonal Effects on Bone At puberty, the rising levels of sex hormones (estrogens in females and androgens in males) cause osteoblasts to produce bone faster than the epiphyseal cartilage can divide. This causes the characteristic growth spurt as well as the ultimate closure of the epiphyseal plate. Estrogens cause faster closure of the epiphyseal growth plate than do androgens. Estrogen also acts to stimulate osteoblast activity.
  • Slide 38
  • Hormonal Effects on Bone Parathyroid hormone and calcitonin are 2 hormones that antagonistically maintain blood [Ca 2+ ] at homeostatic levels. Since the skeleton is the bodys major calcium reservoir, the activity of these 2 hormones affects bone resorption and deposition.
  • Slide 39
  • Growth in Bone Length Epiphyseal cartilage (close to the epiphysis) of the epiphyseal plate divides to create more cartilage, while the diaphyseal cartilage (close to the diaphysis) of the epiphyseal plate is transformed into bone. This increases the length of the shaft.
  • Slide 40
  • As a result osteoblasts begin producing bone faster than the rate of epiphyseal cartilage expansion. Thus the bone grows while the epiphyseal plate gets narrower and narrower and ultimately disappears. A remnant (epiphyseal line) is visible on X- rays (do you see them in the adjacent femur, tibia, and fibula?) At puberty, growth in bone length is increased dramatically by the combined activities of growth hormone, thyroid hormone, and the sex hormones.
  • Slide 41
  • Bone Fractures A break in a bone Types of bone fractures Closed (simple) fracture break that does not penetrate the skin Open (compound) fracture broken bone penetrates through the skin Bone fractures are treated by reduction and immobilization Realignment of the bone
  • Slide 42
  • Common Types of Fractures
  • Slide 43
  • Repair of Bone Fractures Hematoma (blood-filled swelling) is formed Break is splinted by fibrocartilage to form a callus Fibrocartilag