Human Anatomy Quiz 2 (chapter 5) Flashcards
Appendicular skeleton
that portion of the skeleton associated with the limbs. It includes the clavicles, scapulae, ossa coxae, and all of the bones in the free parts of the limbs.
Articular cartilage
the hyaline cartilage that covers those load bearing surfaces of bones that are involved in synovial joints. Some hyaline cartilage is not involved in joints (costal cartilage), some is not involved in synovial joints (epiphyseal cartilage), and cartilaginous structures found in some synovial joints are not composed of hyaline cartilage (e.g. articular discs and menisci).
Axial skeleton
the sternum and ribs, and the bones of the vertebral column and head. These bones are all flat or irregular in shape.
Compact (cortical) bone tissue
bone tissue that is “solid” (i.e, not in the form of small spicules separated by bone marrow tissue). Compact bone tissue is also called “dense” bone tissue.
Epiphysis
either end of a long bone. Specific landmark names are applied to epiphyses depending on the anatomic features located there (head of the humerus, base of a metacarpal bone, tuberosity of a distal phalanx, etc.).
Flat bones
those bones that are obvioulsy flattened in one dimension (sternum, ribs, scapulae, clavicles, assa coxae, and many bones in the skull).
Hydroxyapatite
the principal inorganic component of bone tissue. Hydroxyapatite is a complex calcum phosphate salt that has the chemical formulation Ca10(PO4)6(OH)2 and it is also the primary mineral in the enamel, cementum and dentin of teeth.
Irregular bones
the vertebrae and several bones of the head which have jutting processes. Exact numbers of irregular bons and flat bones are typically not stated because some bones have parts that are flat and other portions that are irregular (temporal and occipital bones).
Long bones
those bones designated as such by convention. The 88 long bones are found in the free parts of each superior limb (humerus, radius, ulna, five metacarpal bones, and 14 phalanges) and each inferior limb (femur bone, tibia, fibula, five metatarsal bones and 14 phalanges).
Medullary cavity
the space within a bone that contains bone marow tissue, adipose tissue, and blood. The connective tissue proper that lines the medullary cavity (thinner but similar to periosteum) is called endosteum.
Osseous lacunae
the timy spaces within bone tissue that contain osteocytes. Osteocytes in neighboring lacunae communicate physically and metabolically by extending cytoplasmic processes through tiny passageways called osseous canaliculi.
Osseous lamella
a layer of mineralized osteoid. Those parallel and adjacent to the periosteum and endosteum are called external and internal circumferential lamellae. Those in the intervening compact bone are called concentric (osteonal) and interstitial lamellae.
Osteoblast
a bone tissue forming cell. Osteoblasts secrete the organic part of the extracellular matrix of bone tissue and become osteocytes when they become trapped therein.
Osteoclast
a multinuclear bone cell involved in bone tissue absorption. Osteoclasts dissolve the mineral with acidic secretions and hydrolyze the osteoid enzymatically.
Osteoid
the non-cellular organic portion of bone tissue. It is manufactured by osteoblasts and consists of collagenous fibers embedded in a protein/polysaccaride ground substance.
Osteology
the study of bone tissue and of bones. Bones are organs that contain all of the various connective tissues as well as smooth muscle tissue, nervous tissue, and simple squamous epithelium.
Periosteum
the dense, irregular connective tissue proper that forms the outer encasement of bones. Periosteum covers all of the external surfaces except for articular surfaces, attachments of tendons, ligaments, retinacula, joint capsules, and ports of entry for nervs and vessels.
Sesamoid bones
“seed-like” bones that are embedded in a few tendons and serve as bearing surfaces for them. The patellae (kneecaps) are the largest sesamoid bones, and two smaller ones are typically found at the base of each thumb and big toe.
Shot bones
the carpal and tarsal bones. There are 30 short bones total (8 in each wrist and 7 in each ankle). Some short bones are physically longer than some of the long bones.
Spongy (trabecular) bone tissue
bone tissue formed of small spicules between intervening regions of bone marrow tissue. This form of bone tissue is often found within the ends of long bones and is also called “cancellous” bone tissue.
Discuss the organic and inorganic components of bone tissue
Organic portion: Cells, fibers and ground substance (same as other connective tissues).
Inorganic component: Hydroxyapatite C10(PO4)6(OH)2. Calcium and phosphate ions.
Discuss the three kinds of cells found in bone tissue
Osteoblasts: single nucleated active cells. secrete fibers and organic part of the ground substance. Fibers - collagenous. Ground substance - protein-polysaccaride.
Osteocyte - former osteoblasts that are entrapped in their own secretion.
Osteoclasts - cells that are active in bone reabsorption.
Discuss the 4 kinds of lamellae of bone tissue
Concentric (osteonal) Lamellae - surround neurovascular channels within the cortex of bone.
Interstitial - incomplete remnants of concentric and external circumferential lamellae
external circumferential lamellae - several layers of lamellae that surround a whole bone
Internal circumferential lamellae - several layers that surround the medullary cavities
Explain why interstitial lamellae are always “older” than adjacent concentric lamellae.
Osteoclasts do not stay within osteonal boundaries when they reabsorb bone. they leave partial remnants of existing lamellae next to the channels that they form. So in the process of making concentric lamellae, interstitial lamellae is always “older”.
