Ch. 6 A&P: Cartilage and Bone Tissue

Perichondrium

• like a corset for cartilage, supports and protects

• Dense CT, some vascularity

Hyaline cartilage

• Surface of bones and joints, costal cartilage, tip of nose

• Reduces friction, absorbs shock, provides structural support

Elastic cartilage

Similar to hyaline cartilage, but has more elastic fibers for flexible suppor

Fibrocartilage

More fibers for stronger support

Appositional growth

• Building cartilage on top of existing cartilage

• Pushing perichondrium further away

Interstitial growth

Growth within tissue

Functions of bone tissue

• Support and protection

• Movement

• Reservoir for minerals and growth factors

• Site of blood cell formation

• Triglyceride storage

• Hormone production

Bone classification

• By location (Axial/Appendicular)

• By shape (Long, short, flat, irregular)

Periosteum

• Resilient membrane on outside of bone

• Has a fibrous layer and an osteogenic (bone-creating) layer

• Nutrient foramen for blood vessels

Endosteum

• Inner membrane of bone

• Also has osteogenic cells

Diploe

Spongy bone in a non-long bone

Bone marrow types

• Yellow for fat storage, usually in adults

• Red for blood cell formation, usually in children/teens

• Adult bone marrow can become red if activity level increases drastically

Osteogenic cells

• Stem cells

• Actively mitotic

• Daughter cells can differentiate

Osteoblast

• build bone tissue

• Secrete osteoid?

  • 90% collagen fibers as well as Calcium binding proteins

• Actively mitotic

• May build themselves into lacunae

Osteocyte

• Bone maintaining cell

• Has projections for communication purposes

Bone-lining cells

• Flatter, on external and internal surfaces

• Help maintain bone matrix

• Periosteal and endosteal cells

Osteoclast

• does not come from osteogenic cell, comes from macrophage

• Large and multinucleate

• Function is bone resorption (breakdown)

• Ruffled border increases surface area for enzymes to degrade bone

Osteon

• Structural unit of compact bone

• Pillars that run parallel to bone

Lamellae

Layers of osteon

Function of collagen fibers in osteon

Give bone resistance to force in all directions

Central canals

Center of osteon, site of nerves and blood supply

Perforating canals

• Allow central nerves and blood supply to reach all of the osteons in the bone

Canaliculi

Projections from osteocyte/lacunae to allow for communication

Circumferential lamellae

Layers around bone that don’t line up with osteons

Interstitial lamellae

• between osteons

• Provide structure/support

Trabeculae

• Structural support of spongy bone

• Organized along stress patterns to resist stress

Organic composition of bone

• Osteogenic cells, osteoblasts, osteocytes, bone-lining cells, osteoclasts

• Osteoid

• Sacrificial bonds

Sacrificial bonds

Collagen fibers will break in order to prevent the whole bone from breaking

Inorganic composition of bone

• Hydroxyapatites: Provide hardness and resistance to compression

Endochondral ossification

Inside cartilage; long bones

Intramembranous ossification

• Bone is developing from a fibrous membrane

Resting zone

• Closest to epiphyseal plate

• Not much happening