Chapter 6: The skeleton bone-Bone tissue Flashcards
What 7 tissues make up the bone?
1) bone
2) cartilage
3) dense connective tissue
4) epithelium
5) various blood-forming tissues,
6) adipose tissues
7) nervous tissue
What 2 things make up the skeleton system?
1) Bone
2) Cartilage
Is a bone an organ? Does it stop changing?
Yes; No
What are the 5 functions of the bone?
1) supporting & protecting soft tissues
2) Attachment site for muscles making movement possible
3) Storage of the minerals, calcium & phosphate – mineral homeostasis
4) Blood cell production occurs in red bone marrow (hemopoiesis or hematopoiesis)
5) Energy storage in yellow bone marrow
What is diaphysis?
Shaft
What is epiphysis?
One end of a long bone
What is metaphyses? What does it include.
metaphyses are the areas between the epiphysis and diaphysis and include the epiphyseal plate in growing bones.
What is articular cartilage over? What is its functions?
Articular cartilage over joint surfaces acts as friction reducer & shock absorber
What is the medullary cavity?
marrow cavity
What is endosteum?
The lining of the marrow cavity
What is periosteum?
the tough membrane covering bone but not the cartilage
What are the 2 layers of the periosteum? What are they made up of?
1) fibrous layer = dense irregular CT
2) osteogenic layer = bone cells & blood vessels that nourish or help with repairs
What is the % makeup of bone tissue?
Matrix of 25% water, 25% collagen fibers & 50% crystalized mineral salts
What is osseous?
Bone
What is bone tissue consists of?
Widely separated cells surrounded by large amounts of matrix.
What does the matrix of bone contain?
Inorganic salts, primarily hydroxyapatite and some calcium carbonate, and collagen fibers.
What is the process of calcification or mineralization?
salts are deposited in a framework of collagen fibers
Where does the process of calcification occur?
Only in the presence of collagen fibers.
What do mineral salt and college fibers do?
Mineral salts confer hardness on bone while collagen fibers give bone its great tensile strength.
What are the 4 cells in the bone tissue? What do they do?
1) Osteogenic (Osteoprogenitor) cells undergo cell division and develop into osteoblasts.
2) Osteoblasts are bone-building cells.
3) Osteocytes are mature bone cells and the principal cells of bone tissue.
4) Osteoclasts are derived from monocytes and serve to break down bone tissue.
What fills up the spaces in bones? Describe the spaces in spongy and compact bones
Bone is not completely solid since it has small spaces for vessels and red bone marrow; spongy bone has many such spaces and compact bone has very few such spaces
compact bone is arranged in what units?
osteons or Haversian systems
What did osteons contain?
Osteons contain blood vessels, lymphatic vessels, nerves, and osteocytes along with the calcified matrix.
How are osteons aligned?
Osteons are aligned in the same direction along lines of stress. These lines can slowly change as the stresses on the bone changes.
Where does compact or dense bone make up of?
Makes up the shaft of long bones and the external layer of all bones
What is an osteon?
Osteon is concentric rings (lamellae) of calcified matrix surrounding a vertically oriented blood vessel
Where are osteocytes found?
Osteocytes are found in spaces called lacunae
How do osteocytes communicate?
Osteocytes communicate through canaliculi filled with extracellular fluid that connect one cell to the next cell
What is Interstitial lamellae?
Interstitial lamellae represent older osteons that have been partially removed during tissue remodeling
What is the structure of spongy bone?
Spongy (cancellous) bone does not contain osteons. It consists of trabeculae surrounding many red marrow filled spaces .
Where does spongy bone forms?
It forms most of the structure of short, flat (hipbones, sternum, sides of skull, and ribs) , and irregular bones, and the epiphyses of long bones.
What is the function of spongy bone?
protects the red bone marrow.
What is trabeculae? Where is it?
Latticework of thin plates of bone called trabeculae oriented along lines of stress
What is in spaces between the structs of spongy bone?
Spaces in between these struts are filled with red marrow where blood cells develop
What do periosteal arteries do?
supply periosteum
How do nutrient arteries enter? What does it do?
enter through nutrient foramen and supplies compact bone of diaphysis & red marrow
What is fetal skeleton constructed of before week 8?
Prior to week 8, fetal skeleton is constructed of fibrous membranes and hyaline cartilage
What did embryonic connective tissue begin as?
mesenchyme
What is bone formation? When does it begin?
Bone formation is termed osteogenesis or ossification and begins when mesenchymal cells provide the template for subsequent ossification.
What are the 2 types of ossification that occurs? What are they from?
Intramembranous ossification- the formation of bone directly from or within fibrous connective tissue membranes.
Endochondrial ossification- the formation of bone from hyaline cartilage models.
What bones does intramembranous ossification form?
Intramembranous ossification forms the flat bones of the skull, the mandible, and the clavicles .
what did mesenchyme differentiate into?
osteogenic progenitor cells & then osteblasts
What did osteoblasts secret?
osteoblasts secrete osteoid: unmineralized matrix
woven bone is remodeled into what?
Woven bone is remodeled into spongy/ diploe & compact bone
what are fontanels?
fontanels (soft spots) that ossify later in development
What are the 4 parts of intramembranous ossification?
- Ossification centers appear in the fibrous connective tissue membranes
- Osteoid is secreted within the fibrous membrane that calcifies
- Woven bones and periosteum form
- Lamellar bone replaces woven bone, just deep to the periosteum. Red marrow appears.