Difference Between Bone And Cartilage

Difference Between Bone And Cartilage: Bone and Cartilage are two types of Skeletal connective tissues found in the human body. They both play crucial roles in supporting the body and protecting organs, flexibility, locomotion and movement. They both form the endoskeleton of the human body. There are several key differences between bone and cartilage in terms of structure, composition, and function. This article covers the key distinctions between these two in detail.

Difference between Bone and Cartilage

Features	Bone	Cartilage
Type	Hardest connective tissue	Harder than dense regular CT but softer than bone
Study	Osteology	Chondrology
Composition	Collagen fibres only	Collagen fibres and elastic fibres
Blood Supply	Highly vascularized	Avascular except for the outermost layer (Perichondrium)
Matrix	Solid, hard, and non-pliable	Solid, soft, and pliable (compressible)
Arrangement of Matrix	Matrix is arranged in the form of concentric layers known as Lamellae.	Matrix is Homogenous
Lacunae	Lacunae have canaliculi and one osteocyte is present in a lacuna	Lacunae do not have canaliculi and up to 8 chondrocytes can be present in a lacuna
Regeneration/ Healing Capacity	The abundant blood supply for nourishment and healing	Limited regenerative capacity
Sensation	Sensation present due to the presence of nerves	Sensation absent due to the absence of nerves
Cells	Osteoblasts, Osteocytes, Osteoclasts	Chondroblasts, Chondrocytes, Chondroclasts
Location of Osteoblasts and Chondroblats	Osteoblasts are present on the inner and outer periphery.	Chondoblasts are present on the outer periphery.
Matrix Components	Organic: Ossein protein, Chondroitin-4-Sulphate, Hyaluronic acid Inorganic: Calcium salts (Calcium carbonate, Calcium phosphate, etc.)	Organic: Chondrin protein, Chondroitin-6-Sulphate, Hyaluronic acid Inorganic: Rare deposition of minerals
Function	The skeletal framework of the body, provide structural support, protect organs, serve as muscle attachment points, and enables locomotion and movement.	Act as a shock absorber, reducing friction in joints.

What is Bone?

The study of bones is known as Osteology. Bone is the hardest connective tissue that forms the skeletal system of the body. Bones contain collagen fibres only which provides strength and hardness to bones. Bones are highly vascularized, which means they have an abundant blood supply for nourishment and healing. Blood is supplied into the interior of bone through Haversian (longitudinal) and Volksmann’s (Transverse) canals. Haversian and Volksmann’s canals are characteristic features of mammals. The Haversian canal contains an artery, vein, lymph vessel and nerve bundle. The presence of nerves in bones is responsible for sensation in bones. Its matrix is solid, hard and non-pliable. Bones provide structural support, protect vital organs, and serve as attachment points for muscles. Bone tissue has the ability to regenerate and repair to some extent, which allows healing of fractures.

Structure of Bone

Matrix of Bones

Matrix is arranged in the form of concentric layers known as Lamellae. Fluid-filled cavities in which osteocytes are present are known as Lacunae. Lacunae have branched radiating channels to adjust the cytoplasmic processes of osteocytes. These channels are known as Canaliculi. A single Osteocyte is present in a lacuna.

Matrix contains 30-40% organic and 60-70% inorganic matter. Organic matter consists of Ossein protein, Chondroitin -4-Sulphate, and Hyaluronic acid. Inorganic matter contains Calcium salts including calcium carbonate (10%), calcium phosphate (85%) and calcium hydroxide and ions like potassium and fluoride ions (5%). Calcium Phosphate is the most abundant salt in bones.

Cells in Bones

Bones contain three types of cells:

• Osteoblasts –Osteoblasts are immature continuously dividing cells present on the inner and outer periphery.
• Osteocytes- Osteocytes are mature non-dividing cells.
• Osteoclasts- Osteoclasts are macrophages of bone that are responsible for the resorption of bone to maintain blood calcium levels.

What is Cartilage?

The study of cartilage is known as Chondrology. Cartilage is harder than dense regular connective tissue but softer than bone. It is composed of both collagen fibres and elastic fibres which provide elasticity and cushioning properties to cartilage. Cartilage is avascular except the outermost layer called the Perichondrium is vascular. The Perichondrium is made up of dense irregular white fibrous connective tissue. Its matrix is solid, soft and pliable (compressible).

It acts as a shock absorber and reduces friction in joints, allowing smooth movement. Cartilage has limited regenerative capacity, which means it has a limited ability to repair and regenerate damaged tissue. It is found in joints, such as the knee and elbow, as well as in the nose, ears, rib cage, and respiratory passages.

Matrix of Cartilages

Matrix is homogenous. Matrix consists of only organic matter i.e. chondrin protein, Chondroitin -6-Sulphate, and Hyaluronic acid. Deposition of inorganic minerals in cartilage is rare. Chondrocytes are also present in lacunae but lacunae are without canaliculi. Also, up to 8 Chondrocytes can be present in one lacunae.

Cells in Cartilages

Cartilage also contains three types of cells:

• Chondroblasts- Chondroblasts are immature continuously dividing cells present on the outer periphery only.
• Chondrocytes- Chondrocytes are mature non-dividing cells.
• Chondroclasts- Chondroclasts are macrophages of cartilage that are responsible for the resorption/decalcification/ demineralisation of embryonic cartilage and convert it into bone after birth.

FAQs on Bones and Cartilage

Q: What are the main types of skeletal connective tissues found in the human body?

Answer:

The main types of skeletal connective tissues found in the human body are bones and cartilage.

Q: What roles do bones and cartilage play in the body?

Answer:

Bones and cartilage play crucial roles in supporting the body, protecting organs, and enabling flexibility, locomotion, and movement.

Q: How do bone and cartilage differ in terms of composition?

Answer:

Bone is composed of collagen fibres only, while cartilage is composed of both collagen fibres and elastic fibres.

Q: Do bones and cartilage have different blood supplies?

Answer:

Yes, bones are highly vascularized which means they have an abundant blood supply while in Cartilage, blood supply is restricted to perichondrium which is the outermost layer of cartilage.

Q: Can bones and cartilage regenerate or repair themselves?

Answer:

Bones have the ability to regenerate and repair to some extent, allowing the healing of fractures. While cartilage has limited regenerative capacity which means it has a limited ability to repair and regenerate damaged tissue due to its avascular nature.