Skeletal System Flashcards
5 Types of Bones
1) Long
2) Short
3) Flat
4) Sesamoid
5) Irregular
5 Skeletal Functions
1) Supports the body
2) Protects soft body parts
3) Produces blood cells (in red bone marrow)
4) Stores minerals (calcium and phosphate) and fat (yellow bone marrow)
5) Permits flexible body movement (via attached muscles)
Long Bones
Longer than they are wide - e.g., femur
Short Bones
Generally cube-shaped, e.g. carpals
Flat Bones
Thin bones consisting of spongy bone sandwiched between two parallel layers of compact bone (e.g. skull bones)
Sesamoid Bones
Embedded in tendons and increase muscle leverage (e.g., patella)
Irregular Bones
Bones that don’t fit into any other category
A long bone is comprised of…
Compact bone and spongy bone
Epiphysis
End of a bone
Diaphysis
Shaft of a bone
Medullary Cavity
Space in compact bone, especially in the diaphysis (shaft)
Compact Bone
Living tissue composed of tubular units called osteons
Osteocyte
Bone cells, housed in the lacunae.
Lacunae
Spaces in which osteocyte reside
Lamella
Layer of matrix made with calcium phosphate and collagen fiberfs
Spongy Bone
Lighter than compact bones, but still strong. Composed of numerous thin plates called trabeculae, separated by uneven spaces, which often contain red bone marrow.
Cartilage
Not as strong as bone, but more flexible, composed of many collagenous and elastic fibers. Lack of nerves allows for suitable “padding”, but a lack of blood vessels results in slow healing.
Chondrocytes
Cartilage forming cells that lie within lacunae
Hyaline Cartilage
Firm but somewhat flexible; found in ends of long bones, nose, larynx, trachea
Fibrocartilage
Stronger than hyaline; found in disks between vertebrae
Elastic Cartilage
More flexible than hyaline cartilage. Found in ear flaps.
Ossification
Formation of bone
Intramembraneous Ossification
Bone development between sheets of fibrous connective tissue (used in flat bones)
Endochondral Ossification
Cartilage provides a “template” that is replaced by bone (used by most bones)
Mesenchyme
Undifferentiated connective tissue
Osteoblasts
Bone-forming cells