Cartilage And Bone Comparison Table

Table 5-1

Cartilage and Bone Comparison

Table 5-1

Cartilage and Bone Comparison

Characteristic

Cartilage

Bone

Ground substance

Chondroitin sulfate, keratan sulfate Chondronectin, chondrocalcin No mineralization High degree of hydration (75%)

Chondroitin sulfate, keratan sulfate Osteonectin, osteocalcin, osteoporin Hydroxyapatite, citrate, bicarbonate Low degree of hydration (7%)

Rbers

Type 1 collagen (fibrocartilage) Type II collagen (hyaline and elastic)

Type 1 collagen (provides tensile strength)

Vascularity

Avascular; nutrients received via diffusion

Highly vascular

Nerves

Absent

Present

Growth

Interstitial and appositional

Appositional only

Repair

Low

High

Mitosis

Chondrogenic—yes Chondroblasts—yes Chondrocytes—yes

Osteoprogenitor—yes Osteoblasts—no Osteocytes—no Osteoclasts—no

Communication

No junctions between chondrocytes

Gap junctions between osteocytes

Hormonal influence

T3, T4, testosterone. GH, cortisone, hydrocortisone, estradiol

PTH; 1,25-(0H)2 vitamin D; calcitonin; GH; estrogens; androgens; T3; T4; Cortisol

Vitamin influence

N/A

Vitamins D, C, and A

T3 = triiodothyronine; T4 = thyroxine; GH = growth hormone; PTH = parathyroid hormone; 1,25-(0H)2 vitamin D = 1,25-dihydroxyvitamin D3.

T3 = triiodothyronine; T4 = thyroxine; GH = growth hormone; PTH = parathyroid hormone; 1,25-(0H)2 vitamin D = 1,25-dihydroxyvitamin D3.

XI. SELECTED PHOTOMICROGRAPHS

A. Spongy bone and compact bone (Figure 5-1)

Figure 5-1. (A) Coronal scction through the epiphysis of an adult tibia. Gross anatomically, two different types of bone can be described: spongy bone (S) arranged as trabeculae that are adapted to mechanical forces, and compact bone (C ) forming a rigid outer shell. The dinted line is the site of the former epiphyseal plate. (Reprinted wirh permission from Rohen JW, Yokochi C, Lutjen-Drecoll E: Color Atlas of Anatomy, 4th ed. Baltimore, Williams and Wilkins, 1998, p 9.) (B) Light micrograph of spongy bone [hcmatoxylin-eosin (HE) stained section], Trabeculae of spongy bone are shown with a lamellar (layered linearly) arrangement of osteocytes (single arrows) and bone matrix. Osteoblasts (double arrows) can be observed on the surface of the rrabeculae. The interstices between the trabeculae are filled with bone marrow (BM). (C) Light micrograph of compact bone (ground bone section). An osteon or Haversian system of compact bone is shown with a lamellar (layered concentrically) arrangement of osteocytes within lacunae (single arrows) and bone matrix. Osteocytes have many cytoplasmic processes within canaliculi (double arrows) that extend throughout the bone matrix and communicate with other osteocytes. Within the center of an osteon is a Haversian canal (HC) that contains blood vessels and nerves.

Figure 5-1. (A) Coronal scction through the epiphysis of an adult tibia. Gross anatomically, two different types of bone can be described: spongy bone (S) arranged as trabeculae that are adapted to mechanical forces, and compact bone (C ) forming a rigid outer shell. The dinted line is the site of the former epiphyseal plate. (Reprinted wirh permission from Rohen JW, Yokochi C, Lutjen-Drecoll E: Color Atlas of Anatomy, 4th ed. Baltimore, Williams and Wilkins, 1998, p 9.) (B) Light micrograph of spongy bone [hcmatoxylin-eosin (HE) stained section], Trabeculae of spongy bone are shown with a lamellar (layered linearly) arrangement of osteocytes (single arrows) and bone matrix. Osteoblasts (double arrows) can be observed on the surface of the rrabeculae. The interstices between the trabeculae are filled with bone marrow (BM). (C) Light micrograph of compact bone (ground bone section). An osteon or Haversian system of compact bone is shown with a lamellar (layered concentrically) arrangement of osteocytes within lacunae (single arrows) and bone matrix. Osteocytes have many cytoplasmic processes within canaliculi (double arrows) that extend throughout the bone matrix and communicate with other osteocytes. Within the center of an osteon is a Haversian canal (HC) that contains blood vessels and nerves.

Figure 5-2. (A) Light micrograph of osteoclasts. Two osteoclasts are shown attached to hone matrix (BM). The ruffled border is shown (arrowheads). N = Nucleus. (Reprinted with permission from Holiiger J: Cartilage and bone. In: Color Adas of Histology, 2nd ed. Edited by Gartner LP, Hiatt JL. Baltimore, Williams and Wilkins, 1994, p 78.) (B) Electron micrograph of an osteoclast. The cell membrane contains calcitonin receptors and a ruffled border adjacent to the resorbing bone matrix. (Reprinted with permission from Garrant P: Bone. In: A Textbook of Histology, 12th ed. Edited by Fawcett DW. New York, Chapman Hall, 1994, p 210. Courtesy of P. Garrant.)

Figure 5-2. (A) Light micrograph of osteoclasts. Two osteoclasts are shown attached to hone matrix (BM). The ruffled border is shown (arrowheads). N = Nucleus. (Reprinted with permission from Holiiger J: Cartilage and bone. In: Color Adas of Histology, 2nd ed. Edited by Gartner LP, Hiatt JL. Baltimore, Williams and Wilkins, 1994, p 78.) (B) Electron micrograph of an osteoclast. The cell membrane contains calcitonin receptors and a ruffled border adjacent to the resorbing bone matrix. (Reprinted with permission from Garrant P: Bone. In: A Textbook of Histology, 12th ed. Edited by Fawcett DW. New York, Chapman Hall, 1994, p 210. Courtesy of P. Garrant.)

C. Epiphyseal growth plate (Figure 5-3; see VIII E)

Figure 5-3. Light micrograph of endochondral ossification at the epiphyseal plate. (A) Zone of reserve consists of hyaline cartilage and chondrocytes (arrows). (B) Zone of proliferation consists of hyaline cartilage and chondrocytes undergoing mitosis forming stacks of chondrocytes (bracket). (C ) Zone of hypertrophy consists of hyaline cartilage and hypertrophied chondrocytes (arrows) that are secreting alkaline phosphatase to increase calcium and phosphate levels in the ground substance. (D) Zone of calcification consists of dead chondrocytes and calcified cartilage matrix called spicules (asterisk). (E) Zone of ossification consists of osteoprogenitor cells in the marrow cavity that differentiate into osteoblasts (arrows). Osteoblasts deposit bone (black areas) on the surface of a spicule to form a mixed spicule (asterisk).

Figure 5-3. Light micrograph of endochondral ossification at the epiphyseal plate. (A) Zone of reserve consists of hyaline cartilage and chondrocytes (arrows). (B) Zone of proliferation consists of hyaline cartilage and chondrocytes undergoing mitosis forming stacks of chondrocytes (bracket). (C ) Zone of hypertrophy consists of hyaline cartilage and hypertrophied chondrocytes (arrows) that are secreting alkaline phosphatase to increase calcium and phosphate levels in the ground substance. (D) Zone of calcification consists of dead chondrocytes and calcified cartilage matrix called spicules (asterisk). (E) Zone of ossification consists of osteoprogenitor cells in the marrow cavity that differentiate into osteoblasts (arrows). Osteoblasts deposit bone (black areas) on the surface of a spicule to form a mixed spicule (asterisk).

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