U5-6H

Flashcard 1:
Question: What are the characteristics of cartilaginous tissue?
Answer: Tough, durable supporting connective tissue; ECM rich in GAGs, proteoglycans, collagen, & elastic fibers; firm consistency allows bearing mechanical stress without permanent distortion; provides cushioning in joints, facilitates bone movement, and guides long bone growth.

Flashcard 2:
Question: Where is cartilaginous tissue localised?
Answer: Structural framework in organs like the trachea; articular surfaces of bones, synovium, ligaments, synovial fluid, and the fetal skeleton.

Flashcard 3:
Question: How is cartilaginous tissue organized?
Answer: Chondrocytes embedded in ECM within lacunae; no vascular or nerve supply; nutrients diffuse from surrounding connective tissue (perichondrium); ECM properties depend on type II collagen, hyaluronan, and sulfated GAGs.

Flashcard 4:
Question: What is the structure of the perichondrium?
Answer: Outer region: collagen type I fibers and fibroblasts; inner layer: mesenchymal cells (chondrogenic cells) that differentiate into chondroblasts and chondrocytes.

Flashcard 5:
Question: What are the main cells in cartilaginous tissue?
Answer: Chondrogenic cells, chondroblasts (immature), and chondrocytes (mature).

Flashcard 6:
Question: What are the main components of the ECM in cartilaginous tissue?
Answer: GAGs (chondroitin sulfate), proteoglycans, type II collagen, and adhesive proteins.

Flashcard 7:
Question: Where is hyaline cartilage found?
Answer: Articular surfaces of movable joints, walls of larger respiratory passages (nose, larynx, trachea, bronchi), ventral ends of ribs, and epiphyseal plates of long bones.

Flashcard 8:
Question: What is the composition of hyaline cartilage ECM?
Answer: Type II collagen, aggrecan, chondroitin sulfate, keratan sulfate, and hyaluronan.

Flashcard 9:
Question: What is unique about the perichondrium in hyaline cartilage?
Answer: Present in most hyaline cartilage, except in articular cartilage.

Flashcard 10:
Question: What are isogenous aggregates in hyaline cartilage?
Answer: Groups of up to eight chondrocytes formed from mitotic divisions of a single chondroblast.

Flashcard 11:
Question: What is elastic cartilage, and where is it found?
Answer: Similar to hyaline cartilage but with abundant elastic fibers; found in the auricle of the ear, external auditory canals, epiglottis, and upper respiratory tract.

Flashcard 12:
Question: What is fibrocartilage, and where is it found?
Answer: A mix of hyaline cartilage and dense connective tissue; found in intervertebral discs, ligament attachments, and the pubic symphysis.

Flashcard 13:
Question: What is the main difference between fibrocartilage and other cartilage types?
Answer: Fibrocartilage has no distinct perichondrium and a more acidophilic matrix due to fewer proteoglycans.

Flashcard 14:
Question: What are the two types of growth in cartilaginous tissue?
Answer: Interstitial growth (mitotic division of chondrocytes) and appositional growth (differentiation of chondroblasts from perichondrium).

Flashcard 15:
Question: Why does damaged cartilage repair slowly?
Answer: Due to its avascularity and low metabolic rate; repairs often form dense connective tissue scars.

Flashcard 16:
Question: What are the main functions of bone tissue?
Answer: Provides solid support, protects organs, encloses medullary cavities, and serves as a reservoir for calcium and phosphate.

Flashcard 17:
Question: What are the main cells in bone tissue?
Answer: Osteoblasts (bone-forming cells), osteocytes (mature osteoblasts), and osteoclasts (bone-resorbing cells).

Flashcard 18:
Question: What is the composition of bone matrix?
Answer: 50% inorganic material (calcium hydroxyapatite, non-crystalline calcium phosphate); 90% organic matter (type I collagen, proteoglycans, glycoproteins like osteonectin and osteocalcin).

Flashcard 19:
Question: What is the function of osteoblasts?
Answer: Synthesize organic components of bone matrix (type I collagen, proteoglycans, glycoproteins) and deposit inorganic components.

Flashcard 20:
Question: What is the function of osteocytes?
Answer: Maintain calcified matrix; located in lacunae and connected by canaliculi.

Flashcard 21:
Question: What is the function of osteoclasts?
Answer: Resorb bone matrix; essential for bone growth and remodeling.

Flashcard 22:
Question: What is the structure of the periosteum?
Answer: Outer fibrous layer (type I collagen, fibroblasts, blood vessels) and inner cellular layer (osteoprogenitor cells).

Flashcard 23:
Question: What are the two types of bone based on structure?
Answer: Compact (cortical) bone (80% of bone mass) and spongy (cancellous) bone (20% of bone mass).

Flashcard 24:
Question: What is the structure of compact bone?
Answer: Organized into osteons (Haversian systems) with concentric lamellae, central canals, and canaliculi.

Flashcard 25:
Question: What is the structure of spongy bone?
Answer: Network of trabeculae with osteocytes, lacunae, and canaliculi; no Haversian systems.

Flashcard 26:
Question: What is intramembranous ossification?
Answer: Direct differentiation of osteoblasts from mesenchyme; forms flat bones.

Flashcard 27:
Question: What is endochondral ossification?
Answer: Replaces hyaline cartilage with bone; forms most bones, especially long bones.

Flashcard 28:
Question: What are the steps of endochondral ossification?
Answer: Cartilage model → bone collar → primary ossification center → secondary ossification centers → epiphyseal plate → bone elongation.

Flashcard 29:
Question: What is appositional bone growth?
Answer: Osteoblasts in periosteum deposit bone; osteoclasts in endosteum enlarge medullary cavity.

Flashcard 30:
Question: What are the stages of fracture repair?
Answer: 1. Hematoma formation; 2. Fibrocartilaginous callus formation; 3. Hard (bony) callus formation; 4. Bone remodeling into compact and cancellous bone.

Flashcard 31:
Question: What is the role of osteonectin in bone matrix?
Answer: A glycoprotein that mediates the adherence of osteoblasts to the ECM.

Flashcard 32:
Question: What is the role of osteocalcin in bone matrix?
Answer: A calcium-binding protein that promotes calcification of the matrix.

Flashcard 33:
Question: What is the role of matrix vesicles in bone formation?
Answer: Release phosphatases that promote calcification of the matrix.

Flashcard 34:
Question: What is the role of the epiphyseal plate in bone growth?
Answer: Provides for continued bone elongation during childhood.

Flashcard 35:
Question: What is the difference between woven and lamellar bone?
Answer: Woven bone is immature and disorganized; lamellar bone is mature and organized into concentric layers (lamellae).