Bone and Cartilage tissue

What is the supporting connective tissue or tissue types in skeletal system

Cartilage and bone

Explain cartilage tissue?

Consists of chondrocytes embedded in a matrix of collagen and elastic fibers with a ground substance. Avascular and lacks nerve but is covered with a dense irregular connective tissue (perichondrium)

What are the types of cartilage

• Hyaline cartilage

• Fibrocartilage

• Elastic cartilage

Explain hyaline cartilage?

It is the most abundant type of cartilage and has collagen fibers in the matrix. It reduces friction at joints as articular cartilage and also located in wall of trachea and nose

Explain fibrocartilage?

Strongest type of cartilage that has dense bundles of collagen fibers causing rigidity and strength

Explain elastic cartilage?

Contains a network of elastic fibers to maintain shape after deformations. Located in the auricle of the ear and epiglottis

Long bone

E.g., humerus and femur, greater length than width

Short bone

E.g., carpal and tarsal bones, cube shaped and nearly equal in length, width, and depth

Flat bone

E.g., sternum, thin and composed of two parallel plates

Irregular bone

E.g., vertebra, complex shapes that cannot be grouped with other types

Sesamoid bone

E.g., patella, develop in certain tendons

Diaphysis of long bone

Shaft or body

Epiphysis of long bone

Proximal and distal ends of long bone

Metaphysis of long bone

Growth plate region

Medullary cavity of long bone

Marrow cavity

Endosteum of long bone

Lining of marrow cavity

Periosteum of long bone

Tough membrane covering the bone

• Fibrous layer—dense irregular connective tissue

• Osteogenic layer—bone cells and blood vessels that nourish or help with repair

What is compact bone?

Looks like a solid hard layer of bone that makes uf the shaft of long bones and external layer of all bones. It resists stressed produced by weight and movement

What is spongy bone? (cancellous, trabecular bone)

Latticework of thin plates of bone called trabeculae oriented along lines of stress. The spaces in between these struts are filled with red marrow where blood cells develop.

Where is spongy bone found

In the ends of long bones and inside flat bones

Since bone is a type of connective tissue, what is the matrix composed of?

Collagen fibers and crystalized mineral salts called hydroxyaptite

What are the cell types of bone

• Osteoprogenitor cells

• Osteoblasts

• Osteocytes

• Osteoclasts

What are osteoprogenitor cells?

Undifferentiated bone stem cells that can divide to replace themselves or become osteoblasts

What are osteoblasts?

Bone building cells that form matrix and collagen fibers but cannot divide

What are Osteocytes?

Mature cells that no longer secrete matrix but maintain it

What are osteoclasts?

Huge cells derived from fused monocytes that function in bone resorption by release of lysosomal enzymes

What is an osteon?

Structural unit of compact bone. Made up of concentric rings called lamellae of calcified matrix surrounding a vertically oriented blood vessel called the Haversian canal

What are lamellae?

Concentric rings of calcified matrix surrounding the Haversian canal in compact bone

What are lacunae?

Spaces in osteons where osteocytes are found

How do osteocytes communicate?

By slender processes with each other and with the central canals through canaliculi filled with extracellular fluid

What is interstitial lamellae?

Older osteons that have been partially removed during tissue remodeling

How to read a bone scan?

Hot spots are increased metabolic activity that may indicate cancer

What is intramembranous bone formation?

Formation of bone directly from mesenchymal cells

What is endochondral ossification?

Formation of bone within a hyaline cartilage model