Specialised Connective Tissue: Bone - Components and Functions, Difference Between Bone and Cartilage and Haversian Canal System

You have seen people meeting with accidents on roads. Sometimes they may break their bones. Any of your friends or relatives met with an accident and fractured their bones?

Yes.

Why does this fracture occur?

Yes, fracture occurs when any of the bone breaks. 

Do you know what bone is? 

Why does this fracture occur? 

What is its chemical composition?

Bone is a type of connective tissue. There are 206 bones present in the human body that collectively form the skeleton. Bones provide strength and flexibility to a person.

The major chemical elements present in bone are calcium and collagen fibres. Due to the presence of calcium, we are always recommended to take calcium rich foods. 

Now, you can relate this to why our mothers always force us to drink milk. This is because it is considered as a good source of calcium. Let’s discuss more about bone.

Table of Contents

• Skeletal tissue
• Bone
• Components of bone
• Functions of bone
• Practice Problems
• FAQs

Skeletal Tissue

It forms the endoskeleton of vertebrates. It supports the body and protects all the vital organs from external injuries. It is of two types as follows:

• Cartilage
• Bone

Bone

Bone is hard and non-pliable tissue. The ground substance is rich in calcium salts and collagen fibres that provide strength. The structural functional unit of bone is called the Haversian canal system. 

Components of Bone

Bone consists of the following components:

• Periosteum
• Matrix
• Endosteum
• Bone marrow

Periosteum

Bone is covered externally with a periosteum. It is a tough sheath of collagen fibres.

Matrix 

It is formed of ossein. Matrix possess calcium phosphate, calcium carbonate, magnesium phosphate etc. Matrices possess cells called osteocytes.

Endosteum

It is present outside the bone marrow cavity. It possesses white fibrous tissue and bone forming cells.

Bone marrow

Bone marrow cavity which is present inner to the endosteum possesses bone marrow. It possesses two types of bone marrow as follows:

Red bone marrow

It appears red in colour. It is present in the spongy part of the bone and produces RBCs and WBCs.

Yellow bone marrow

It appears yellow in colour. It is composed of adipose tissues and it stores fats.

Haversian Canal System

The Haversian canal with its surrounding lamellae and osteocytes constitute the Haversian canal system. It is the structural and functional unit of bone tissue. The matrix of bone occurs in layers called Lamellae. A central Haversian canal is surrounded by lamellae. Each Haversian canal contains an artery, a vein, a lymph vessel, a nerve and some bone cells. The cells of bone are known as osteocytes and these are present in spaces referred to as lacunae. Lacunae possess fine radiating channels called canaliculi. The Haversian canals are interconnected by the transverse channels named Volkmann’s canal or perforating hole.

Functions of Bone

The major functions of bone are as follows: 

• Bone is the main tissue that provides the structural framework to the body. 
• They support and protect the soft tissues and internal organs of the body. 
• It helps in the movement of the body.
• The long bones, such as limbs, bear the body weight.
• Long bones consist of bone marrow which is considered as the site of production of blood cells.

Difference between Bone and Cartilage

Practice Problems of Specialised Connective Tissue: Bone

Question 1. Which of the following isn't a bone's function?

a. Provides a structural frame to the body
b. Site of production of blood cells
c. Helps in body movement
d. Helps in conduction of impulses

Solution: Bones are connective tissues that have a hard, non-pliable ground substance that is high in calcium salts and collagen fibres. This gives bone its strength, making it an appropriate tissue for providing the body with a structural framework. Softer tissues and organs are also supported and protected by bones. Bones and skeletal muscles work together to create movement. The formation of blood cells takes place in the marrow of long bones. Hence, the correct option is d.

Question 2. In which spaces, bone cells are found?

a. Lacunae
b. Lamella
c. Canaliculi
d. Collagen fibres

Solution: In the bone matrix, there are spaces called lacunae where bone cells, or osteocytes, can be found. Hence, the correct option is a.

Question 3. Bones are mainly made up of

a. calcium and phosphorus
b. calcium and sulphur
c. calcium and magnesium
d. calcium and iron

Solution: The largest component of the vertebrate endoskeleton is bone, which is highly calcified (mineralized), hard, and inflexible connective tissue. Calcium phosphate and calcium carbonate minerals, as well as collagen fibres, make up the intercellular matrix, which is embedded in an elastic mucopolysaccharide ground substance. The majority of bones are made up of calcium and phosphorus. Hence, the correct option is a.

Question 4. The cells of bone are known as ________________.

a. Osteocytes
b. Chondrocytes
c. Neuron
d. Myofibril

Solution: Osteocytes are the cells that make up bone, and they exist in spaces called lacunae. Canaliculi are fine radiating channels seen in lacunae. Hence, the correct option is a.

FAQs of Specialised Connective Tissue: Bone

Question 1. Write down the difference between red bone marrow and yellow bone marrow?

Answer: 

Question 2. Haversian canals are interconnected by the transverse channels called __________?

Answer: Haversian canals are interconnected by the transverse channels called Volkmann’s canal.

Question 3. What is skeletal tissue?

Answer: The endoskeleton of vertebrates is made up of skeletal tissue. It protects and maintains the body's critical organs. It is divided into two types: bone and cartilage.

Question 4. The matrix of bone and cartilage is composed of which structures?

Answer: The matrix of bone is composed of ossein whereas the matrix of cartilage is composed of chondrin.

Related Topics to Connective Tissue Bone in Biology

• Connective Tissues
• Connective Tissue Blood
• Epithelial Tissue
• Connective Tissue Cartilage

NCERT Class 11 Biology Chapters