AnaPhy Skeletal system

• Support


  Serves as the structural framework for the body by supporting soft tissues and providing attachment points for the tendons of most skeletal muscles
• Protection


  Protects the most important internal organs from injury
• Assistance in movement


  Most skeletal muscles attach to bones; when they contract, they pull on bones to produce movement
• Mineral homeostasis


  Stores several minerals, especially calcium, and phosphorus, which contribute to the strength of bone. Bone releases minerals into the blood to maintain critical mineral balances and to distribute the minerals to other parts of the body
• Blood cell production


  Within certain bones, a connective tissue called red bone marrow produces red blood cells, white blood cells, and platelets, a process called hemopoiesis
• Triglyceride Storage


  Yellow Bone Marrow consists mainly of adipose cells, which store triglycerides. The stored triglycerides are a potential chemical energy reserve
• Diaphysis


  The bone's shaft or body—the long, cylindrical, main portion of the bone
• Epiphysis


  The proximal and distal ends of the bone
• Metaphyses


  The regions between the diaphysis and the epiphyses
• Articular Cartilage


  A thin layer of hyaline cartilage covering the part of the epiphysis where the bone forms an articulation (joint) with another bone. Reduces friction and absorbs shock at freely movable joints
• Periosteum


  A tough connective tissue sheath and its associated blood supply that surrounds the bone surface wherever it is not covered by articular cartilage. The periosteum also protects the bone, assists in fracture repair, helps nourish bone tissue, and serves as an attachment point for ligaments and tendons
• Medullary cavity


  A hollow, cylindrical space within the diaphysis that contains fatty yellow bone marrow and numerous blood vessels in adults. This cavity minimizes the weight of the bone by reducing the dense bony material where it is least needed
• Endosteum


  A thin membrane that lines the medullary cavity. It contains a single layer of bone-forming cells and a small amount of connective tissue
• 4 types of cells in bone tissue

  • Osteoprogenitor cells (unspecialized stem cells)
  • Osteoblasts (building cells)
  • Osteocytes (Mature bone cells)
  • Osteoclasts (huge cells)
• Compact Bone Tissue


  The strongest form of bone tissue. It is found beneath the periosteum of all bones and makes up the bulk of the diaphyses of long bones
• Spongy Bone Tissue

  Also referred to as trabecular or cancellous bone tissue, does not contain osteons
• Periosteal arteries


  Small arteries accompanied by nerves, enter the diaphysis through many perforating (Volkmann's) canals and supply the periosteum and outer part of the compact bone
• Nutrient Artery


  Enters bone through a foramen and branches into a number of smaller arteries and arterioles to supply maximum regions of adult bone. It sustains high blood pressure to reach distant locations, usually terminating into capillaries present in the metaphysis and endosteum
• Metaphyseal Artery


  Enters the metaphyses of a long bone and, together with the nutrient artery, supply the red bone marrow and bone tissue of the metaphyses
• Fracture


  Any break in a bone. Fractures are named according to their severity, the shape or position of the fracture line, or even the physician who first described them
• Repair of bone fracture

  1. Reactive Phase - Fracture hematoma

  2. Reparative phase: Fibrocartilaginous callus formation - fibrocartilaginous (soft) callus

  3. Reparative phase: Bony callus formation - bony (hard) callus

  4. Bone remodelling - Resorption/Osteoclasts
• Short Bones


  Somewhat cube-shaped and are nearly equal in length and width. They consist of spongy bone tissue except at the surface, which has a thin layer of compact bone tissue
• Flat Bones


  Generally thin and composed of two nearly parallel plates of compact bone tissue enclosing a layer of spongy bone tissue. Afford considerable protection and provide extensive areas for muscle attachment
• Sesamoid Bones


  Develop in certain tendons where there is considerable friction, tension, and physical stress, such as the palms and soles
• Irregular Bones


  Have complex shapes and cannot be grouped into any of the previous categories
• Sutural Bones


  Small bones located in sutures (joints) between certain cranial bones. Their number varies greatly from person to person
• Divisions of Skeletal System

  • Cranial Bones - 8 Bones
  • Facial Bones - 14 Bones
• Frontal Bone


  Forms the forehead (the anterior part of the cranium), the roofs of the orbits (eye sockets), and most of the anterior part of the cranial floor
• Parietal Bones


  Form the greater portion of the sides and roof of the cranial cavity. The internal surfaces of the parietal bones contain many protrusions and depressions that accommodate the blood vessels supplying the dura mater, the superficial connective tissue (meninx) covering of the brain
• Temporal Bones


  Form the inferior lateral aspects of the cranium and part of the cranial floor
• Occipital Bones


  Form the posterior part and most of the base of the cranium
• Sphenoid Bone


  Lies at the middle part of the base of the skull. This bone is called the keystone of the cranial floor because it articulates with all the other cranial bones, holding them together
• Ethmoid Bones


  Is a delicate bone located in the anterior part of the cranial floor medial to the orbits and is spongelike in appearance
• Nasal Bones


  Are small, flattened, rectangular-shaped bones that form the bridge of the nose. These small bones protect the upper entry to the nasal cavity and provide attachment for a couple of thin muscles of facial expression. For those of you who wear glasses, they are the bones that form the resting place for the bridge of the glasses
• Lacrimal Bones


  Are thin and roughly resemble a fingernail in size and shape. These bones, the smallest bones of the face, are posterior and lateral to the nasal bones and form a part of the medial wall of each orbit. The lacrimal bones each contain a lacrimal fossa, a vertical tunnel formed with the maxilla, that houses the lacrimal sac, a structure that gathers tears and passes them into the nasal cavity
• Palatine Bones


  The two L-shaped palatine bones form the posterior portion of the hard palate, part of the floor and lateral wall of the nasal cavity, and a small portion of the floors of the orbits. The posterior portion of the hard palate is formed by the horizontal plates of the palatine bones
• Inferior Nasal Conchae


  Are inferior to the middle nasal conchae of the ethmoid bone, and are separate bones, not part of the ethmoid bone. These scroll-like bones form a part of the inferior lateral wall of the nasal cavity and project into the nasal cavity. All three pairs of nasal conchae (superior, middle, and inferior) increase the surface area of the nasal cavity and help swirl and filter air before it passes into the lungs
• However, only the superior nasal conchae of the ethmoid bone are involved in the sense of smell
• Vomer


  Is a roughly triangular bone on the floor of the nasal cavity that articulates superiorly with the perpendicular plate of the ethmoid bone and sphenoid bone and inferiorly with both the maxillae and palatine bones along the midline. It forms the inferior portion of the bony nasal septum, the partition that divides the nasal cavity into right and left sides
• Maxillae


  The paired maxillae unite to form the upper jawbone. They articulate with every bone of the face except the mandible (lower jawbone). The maxillae form part of the floors of the orbits, part of the lateral walls and floor of the nasal cavity, and most of the hard palate