Chapter 6

What are the functions of the axial skeleton?

-Long axis of the body and include the bones of the skull, vertebral column, and rib cage. Functions: (protect, support, carry other body parts)

Explain the 7 functions of bones.

-Support -Protection -Anchorage -Mineral Storage -Blood cell formation -Triglyceride (fat) storage -Hormone Production

What is a sesamoid bone?

-a specialized short bone that occurs within a tendon, such as the patella (kneecap). -used to reduce the stress if the direction or pull of a tendon to reduce abrasion or tearing.

Explain how cartilage grows.

Appostional Growth: -Cartilage forming cells in the surrounding perichondrium and secrete new matric against the external face of the existing cartilage tissue. Interstitial Growth: -The lacunae bound chondrocyte divide and secrete new matrix, expading the cartilage iwthin.

Distinguish between the appendicular and axial skeletons.

Axial Skeletons: -Long axis of the body and include the bones of the skull, vertebral column, and rib cage. Functions: (protect, support, carry other body parts) Appendicular Skeleton: -Consists of the bones of the upper and lower limbs and the girdles that attach the limbs to the axial skeleton. Bones of the limbs help us move from place to place and manipulate our environment.

What is the difference between calcified cartilage and bone?

Cartilage: -Surrounded by Perichondrium -No blood vessels or nerves (only in periochondrium) -Chondrocytes in lacunae -Flexible extracellular matrix -Extracellular matrix made by chondroblasts -Appositional growth and interstitial growth Bone: -Surrounded by Periosteum -Blood vessels and nerves throughout -Osteocytes in lacunae -Rigid extracellular matirx (due to inorganic calcium salts). -Extracellular Matrix (organic part) made by osteoblasts -Appositional growth only

Describe the three different types of skeletal cartilages. State where each type is found.

Hyaline Cartilage: -Look like freshly frosted glass when exposed, provide support with flexibility and resilience. -Chondrohydrates are spherical and the only fiber type in their matrix is fine collagen fiber. -Location: costal cartilage, articular cartilage of joint, cartilage in the external ear, cartilages in nose, thyroid cartilage, trachea, cricoid cartilage, respiratory tube cartilages in neck and thorax). Elastic Cartilage: -Resembles Hyaline Cartilages, but they contain stretchy elastic fibers and so are better able to stand up to repeated bending. -Location: Found in only two skeletal locations (the external ear and the epiglottis). Fibrocartilage: -Highly compressible with great tensile strength. -Consist of roughly parallel rows of chondrocytes alternating with thick collagen fibers. -Location: occurs in sites that are subjected to both pressure and stretch, such as the padlike cartilages of the knew and the discs between vertebrae. (Pubic symphysis, Meniscus, Cartilage in intervertebral disc)

Name and give the function of each of the cells of bone tissue. What cell line gives rise to each of these cell?

Osteoprogenitor cells (Osteogenic cells): -Mitotically active stem cells found in the membranous periosteum and endosteum. -In growing bones, they are flattened cells (squamous) -When stimulated, these cells differentiate into osteoblasts, while others persist as osteoprogenitor cells Osteoblasts: -Bone forming cells that secrete the bone Matrix -Actively mitotic -

Compare the histological structure and location of compact and spongy bone.

Spongy Bone: -Has a mesh of bony spines called trabeculae. -Internal Layer. -Honeycomb of small needle like or flat pieces called trabeculae. Compact Bone: -looks smooth and solid -smooth and solid -External Layer

Explain the four classes of bone "shape."

a. Long Bone (Humerus) b. Irregular bone (vertebra) c. Flat bone (sternum) d. Short bone (talus)