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CH.6 - Bones and Skeletal Tissues - Anatomy & Physiology

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Terms in this set (24)

  • What is skeletal cartilage and its main characteristics?
    Skeletal cartilage is made of resilient cartilage tissue primarily composed of water. It contains no blood vessels or nerves and is surrounded by a dense connective tissue layer called the perichondrium which provides nutrients and resists outward expansion.
  • Name the three types of cartilage and a key feature of each.
    Hyaline cartilage: most abundant, provides support and flexibility.
    Elastic cartilage: contains elastic fibers, found in external ear and epiglottis.
    Fibrocartilage: thick collagen fibers, great tensile strength, found in menisci and intervertebral discs.
  • What are the two ways cartilage grows?
    Appositional growth: new matrix laid on cartilage surface, increasing length.
    Interstitial growth: chondrocytes divide within lacunae, secreting new matrix, increasing thickness.
  • List the seven functions of bones.
    1. Support for body and organs
    2. Protection of brain and vital organs
    3. Movement as levers for muscles
    4. Mineral and growth factor storage
    5. Blood cell formation (hematopoiesis)
    6. Triglyceride (fat) storage
    7. Hormone production (osteocalcin)
  • How are bones classified by location?
    Bones are divided into the axial skeleton (skull, vertebral column, rib cage) and the appendicular skeleton (limbs and girdles attaching limbs to axial skeleton).
  • What are the four bone shapes and an example of each?
    Long bones: longer than wide, e.g. femur.
    Short bones: cube-shaped, e.g. talus.
    Flat bones: thin and curved, e.g. sternum.
    Irregular bones: complex shapes, e.g. vertebrae.
  • What tissues make up bones, making them organs?
    Bones contain osseous (bone) tissue, nervous tissue, cartilage, fibrous connective tissue, muscle cells, and epithelial cells in blood vessels.
  • Describe the difference between compact and spongy bone.
    Compact bone is dense and smooth forming the outer layer.
    Spongy bone consists of a honeycomb of trabeculae with spaces filled with red or yellow marrow.
  • What membranes cover bones and their functions?
    Periosteum: double-layered membrane covering external bone surfaces except joints, contains osteogenic cells.
    Endosteum: delicate membrane covering internal bone surfaces and trabeculae, also contains osteogenic cells.
  • Where is red marrow found and what is its function?
    Red marrow is found in trabecular cavities of spongy bone and diploƫ of flat bones. It is the site of hematopoiesis, the formation of blood cells.
  • What are the three types of bone markings?
    Projections: sites of muscle and ligament attachment.
    Depressions: grooves or indentations for vessels or joints.
    Openings: holes or canals for blood vessels and nerves.
  • Name the five major types of bone cells and their functions.
    Osteogenic cells: stem cells that differentiate.
    Osteoblasts: bone-forming cells secreting osteoid.
    Osteocytes: mature cells maintaining matrix.
    Bone-lining cells: maintain matrix on bone surfaces.
    Osteoclasts: bone-resorbing cells breaking down matrix.
  • What is an osteon and its components?
    An osteon is the structural unit of compact bone, consisting of concentric lamellae around a central (Haversian) canal containing blood vessels and nerves.
  • What are canaliculi and their role in bone?
    Canaliculi are tiny canals connecting lacunae, allowing osteocytes to communicate and exchange nutrients and wastes.
  • What is the chemical composition of bone?
    Bone is composed of organic components (cells and osteoid with collagen for strength) and inorganic components (hydroxyapatites, calcium phosphate crystals providing hardness).
  • What is ossification and its two types?
    Ossification is bone tissue formation.
    Intramembranous ossification: bone develops from fibrous membrane.
    Endochondral ossification: bone replaces hyaline cartilage.
  • Describe the process of endochondral ossification in long bones.
    Bone collar forms around diaphysis, cartilage calcifies and deteriorates, periosteal bud invades, spongy bone forms, secondary ossification centers appear in epiphyses, and cartilage remains only in epiphyseal plates and articular cartilage.
  • How do long bones grow in length and width?
    Length growth occurs by interstitial growth at the epiphyseal plate.
    Width growth occurs by appositional growth with osteoblasts adding bone matrix on the surface and osteoclasts resorbing bone inside.
  • What is bone remodeling and which cells are involved?
    Bone remodeling is the continuous process of bone deposit and resorption involving osteoblasts (deposit) and osteoclasts (resorption) to maintain bone strength and mineral homeostasis.
  • How does parathyroid hormone (PTH) regulate blood calcium?
    PTH is released when blood calcium is low, stimulating osteoclasts to resorb bone and release calcium into blood, raising calcium levels and stopping PTH secretion when balanced.
  • What is Wolff's law regarding bone?
    Wolff's law states that bones grow or remodel in response to the mechanical stresses placed on them, becoming thicker and stronger where stress is greatest.
  • What are the classifications of bone fractures?
    Classified by position (nondisplaced or displaced), completeness (complete or incomplete), and skin penetration (open/compound or closed/simple).
  • What are the four stages of bone fracture repair?
    1. Hematoma formation
    2. Fibrocartilaginous callus formation
    3. Bony callus formation
    4. Bone remodeling
  • What is osteoporosis and its risk factors?
    Osteoporosis is a disease where bone resorption exceeds deposit, leading to decreased bone mass and fractures. Risk factors include age, postmenopausal women, low estrogen, poor diet, smoking, and lack of exercise.