-
Hyaline cartilages
Provide support, flexibility, and resilienceMost abundant type
-
Elastic cartilages
Similar to hyaline cartilages, but contain elastic fibers
-
Fibrocartilages
Collagen fibers—have great tensile strength
-
Skeletal Cartilages
Contain no blood vessels or nerves
Surrounded by perichondrium
contains blood vessels for nutrient delivery to cartilage via diffusion
-
There are two main catagories in the Skeletal system
Axial skeleton
Appendicular skeleton
-
Classification of Bones by Shape
Long bonesLonger than they are wide
Short bonesCube-shaped bones (in wrist and ankle)
Sesamoid bones (within tendons, e.g., patella)Flat bonesThin, flat, slightly curved
Irregular bonesComplicated shapes
-
Function of Bones
- StorageMinerals (calcium and phosphorus) and growth factors
- Blood cell formation (hematopoiesis) in marrow cavities
- Triglyceride (energy) storage in bone cavities
-
Structure of Long Bone
- Diaphysis (shaft)Compact bone collar surrounds medullary (marrow) cavity
- Medullary cavity in adults contains fat (yellow marrow)
- Epiphyses
- Expanded ends Spongy bone interior
- Epiphyseal line (remnant of growth plate)
- Articular (hyaline) cartilage on joint surfaces
-
Membranes of the Bones
PERIOSTEUM
- Periosteum
- Outer fibrous layer
- Inner osteogenic layer
- Osteoblasts (bone-forming cells
- Osteoclasts (bone-destroying cells)
- Osteogenic cells (stem cells
- )Nerve fibers, nutrient blood vessels, and lymphatic vessels enter the bone via nutrient foraminaSecured to underlying bone by Sharpey’s fibers
-
ENDOSTEUM
- Endosteum
- Delicate membrane on internal surfaces of spongy bone lining diaphysys
- Also contains osteoblasts and osteoclasts
-
Location of
Hematopoietic Tissue
Red Marrow
- Red marrow cavities of adults
- Trabecular cavities of the heads of the femur and humerus
- Trabecular cavities of the diploë of flat bonesRed marrow of newborn infants
- Medullary cavities and all spaces in spongy bone
-
MICROSCOPIC STRUCTURE OF COMPACT BONE
- Haversian system, or osteon—structural unit
- LamellaeWeight-bearing
- Column-like matrix tubesCentral (Haversian) canal
- Contains blood vessels and nerves
(CONTINUE ON NEXT CARD)
-
COMPACT BONE
Perforating (Volkmann’s) canals
At right angles to the central canal
Connects blood vessels and nerves of the periosteum and central canal
Lacunae—small cavities that contain osteocytes
Canaliculi—hairlike canals that connect lacunae to each other and the central canal
-
Trabeculae
- Align along lines of stress
- No osteons
- Contain irregularly arranged lamellae, osteocytes, and canaliculi
- Capillaries in endosteum supply nutrients
-
CHEMICAL COMPOSITION OF BONE
- Osteogenic cells, osteoblasts, osteocytes, osteoclasts
- Osteoid—organic bone matrix secreted by osteoblasts
- Ground substance (proteoglycans, glycoproteins
- Collagen fibersProvide tensile strength and flexibility
- Hydroxyapatites- (mineral salts)65% of bone by mass
- Mainly calcium phosphate crystals
- Responsible for hardness and resistance to compression
|
|
