ANPH - Skeletal System & Tissues CH 11, 12, & 13 Flashcards
Functions of Bone
~Support → bones form the framework of the body and contribute to shape, alignment, positioning of body parts; ligaments help hold bones together
~Protection → bony “boxes” protect delicate structures they enclose
~Movement → bones with their joints constitute levers that move as muscles contract
~Mineral storage → bones are the major reservoir for calcium, phosphorus, and other minerals
~Hematopoiesis → production of blood, blood cell formation is carried out by myeloid tissue
Types of Bones
~Long bones → cylindrical ~Short bones → box like ~Flat bones → broad, sheetlike ~Irregular bones → various shapes ~Sesamoid bones → located in the middle of the tendon (seed like) (patella)
2 Types of bone Tissue
~Size, shape, and appearance of bones vary to meet the various needs served
~Bones vary in the proportion of compact and cancellous (spongy) bone
● Compact → bone is dense and solid in appearance
● Cancellous bone → characterized by open space partially filled with a lattice of thin branched structures supporting soft tissue
6 Features of Long Bones
~Diaphysis
● Main shaft of a long bone and is a hollow, cylindrical shape and thick compact bone
● Function → to provide strong support without cumbersome weight
~Epiphyses
● Both ends of a long bone, filled with cancellous bone and red marrow
● Bulbous shape
● Function → to provide attachments for muscles and give stability to joints
~Articular cartilage
● Layer of hyaline cartilage that covers the articular surface of epiphyses
● Function → to cushion jolts and impact
~Periosteum (micro circulation, nerves, stem cells → osteoblasts/osteoclasts, nutrition)
● Dense, white fibrous membrane that covers bone
● Attaches tendons firmly to bones and contains cells that form and destroy bone
● Contains blood vessels important for growth and repair
● Contains blood vessels that send branches into bone
● Essential for bone cell survival and bone formation
~Medullary → marrow cavity
~Endosteum → thin fibrous membrane that lines the medullary cavity
~Inner portion is cancellous bone covered on the outside with compact bone
Flat Bones
● Cranial flat bones have an internal and external table of compact bone and an inner cancellous region called the diploe → sandwich structure
● Bones are covered with periosteum and line with endosteum as in a long bone
● Other flat bones, short bones, and irregular bones have features similar to the cranial bones
Spaces inside the cancellous bone of short, flat, irregular and sesamoid bones are filled with red marrow
True/False
True
~Most distinctive form of connective tissue
~Extracellular components are hard and calcified
~Rigidity of bone allows it to serve its supportive and protective functions
~Rigid (tensile???) strength nearly equal to that of cast iron at less than one third of the
Bone Tissue
Composition of Bone Matrix
● Hydroxyapatite → crystals of calcium and phosphate contribute to bone hardness (osteoblasts make hydroxyapatite)
● chondroitin sulfate
names of cylinder shaped structural units of compact bone?
osteons, or Haversian systems
-osteons are the functionional unit of bones
canals that run lengthwise through bone and are connected by?
transverse (Volkmann) canals
Types of Lamellae (Compact Bone)
● Concentric → cylinder shaped layers of calcified matrix around the central canal
● Interstitial → layers of bone matrix between the osteons left over from previous osteons
● Circumferential → few layers of bone matrix that surround all the osteons; run along the outer circumference of a bone and inner circumference (boundary of medullary cavity) of a bone
ultra small canals radiating in all directions from the lacunae and connecting them to each other and to the central canal
Canaliculi
small spaces containing tissue fluid; bone cells are located between hard layers of the lamella. Each ______ contain 1 osteocyte
Lacunae
