Chapter 11: The Skeletal System Flashcards
(35 cards)
What are the functions of the skeletal system?
Support framework, movement anchor, protection, mineral storage, fat storage, blood cell production.
Compact Bone
Highly organized and composed of tubular units called osteons.
Osteocytes
Bone cells lie in tiny chambers arranged in concentric circles around a central canal (Lacunae)
Matrix
Fills the space between the rows of the lacunae (cells), hard from mineral salts, flexible from collagen.
Spongy Bone
Unorganized appearance, contains thin plates (trabeculae) separated by unequal spaces, lighter but designed for strength, lattice work, spaces often filled with red bone marrow.
Cartilage
Less strength than bone but more flexible, cells are scattered in a gel-like matrix, no nerves or blood vessels, three types.
Hyaline Cartilage
Firmer with a lot collagen, found at the ends of bones, nose, larynx, and trachea.
Fibrocartilage
Strong from rows of thick collagen fibers, found where a lot of support is needed (disks of spine and knee).
Elastic Cartilage
More flexible with a lot of elastin fibers in the matrix. Found in the ear flaps and the epiglottis.
Five Major Steps of Ossification or Bone Development
Cartilage model, bone collar, primary ossification center, secondary ossification, growth plate.
1st step in ossification: Cartilage model
In the embryo, chondrocytes lay down hyaline cartilage, which is shaped like the future cells. (cartilage models of future bones)
2nd Step of Ossification: Bone Collar
Osteoblasts secretes the organic matrix, and the matrix undergoes calcification. Bone collar is composed of compact bone.
3rd Step of Ossification: The Primary Ossification Center
First center for bone formation, blood vessels bring osteoblasts to the interior and start to lay down spongy bone.
4th Step of Ossification: The Medullary Cavity and Secondary Ossification Sites
The spongy bone of the diaphysis is absorbed by osteoclasts and creates the medullary cavity. Shortly after birth, the second site is formed in the epiphyses.
5th Step of Ossification: The epiphyseal (growth) Plate
A band of cartilage called a growth plate remains between the primary and secondary ossification center. Bones continue to grow as long as the plate is present. The growth plate eventually disappears from the cartilage thinning.
Hormones
Regulate bone growth with GH in childhood and sex hormones in puberty.
How are bones maintained by BONE REMODELING?
Renewal and recycling, old cells broken down and new cells formed, allows regulation of Ca2+ in blood, thickens and strengthens bones that get a lot of use or stress, bone loss can occur with older age.
What are the 4 steps of bone repair and the functions?
- Hematoma: Clotted blood forms within hours
- Fibrocartilage callus: fills the space between the ends of the broken bone for about 3 weeks
- Bony callus: convert fibrocartilage callus to bony callus that joins broken bones together (lasts 3-4 months)
- Remodeling: Osteoblasts build new compact bone. osteoclasts absorb the spongy bone, creating a new medullary cavity. (last for years).
Axial Skeleton
Skull, backbone, and rib cage.
Appendicular Skeleton
Pectoral girdle, pelvic girdle, arms, legs.
Fibrous Joint
Fibrous connective tissue, immoveable. (cranial joints)
Cartilaginous Joint
Hyaline or fibrocartliage, slightly moveable. (ribs to sternum, intervertebral disks)
Synovial Joint
Flexible and moveable, cavity with synovial liquid that cushions and lubricate, cartilage decreases friction, reinforced with ligaments, hinge joints, ball and socket joints.
Flexion
Joint angle decreases
