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.

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.