Cartilage in the Human Body

Cartilage is a connective tissue that provides support and protection for the body's joints. Cartilage located in the human body is found in joints between bones, ends of the ribs, and between the vertebrae in the spine. Cartilage is made from specialized cells called chondrocytes that produce a combination of collagen, proteoglycans, and other non-collagenous proteins. The three types of cartilage in the body are hyaline cartilage, elastic cartilage, and fibrocartilage. It acts as a shock absorber and reduces friction in joints, allowing smooth movement. 

What is Cartilage?

Cartilage Definition: Cartilage is a flexible connective tissue that provides structural support and covers the ends of bones at joints, reducing friction and enabling smooth movement.

Cartilage in the human body is a flexible, non-vascular supporting connective tissue. It is made up of chondrocytes that are scattered in a matrix containing fibrous tissue and various combinations of proteoglycans and glycosaminoglycans. Cartilage found throughout the human body is of three types: hyaline, fibrous, and elastic cartilage.

Hyaline cartilage occurs in embryos, fibrous cartilage in intervertebral discs and pubic symphysis, and elastic cartilage in the external ear and epiglottis. Cartilage has many roles in the human body including the ability to resist compressive forces, enhance bone resilience, and provide support and flexibility to bony areas.

Also Read: Overview and Types of Connective Tissue

Cartilage in Human Body Diagram

The diagram of cartilage found in human body is given below:

Where is Cartilage Located in the Human Body?

Cartilage is found in the human body where two bones meet. It is also found at the ends of all joint bones which includes the following.

• Joints bones e.g. the elbows, knees, and ankles
• Ends of the ribs
• Between the vertebrae in the spine
• Ears and nose
• Bronchial tubes or airways

Also Read: Anatomy & Physiology of Human Skeletal System

Cartilage Example

Some example of cartilage present in human body is even below:

1. Bronchial Cartilage
2. Tracheal Rings
3. Epiglottis
4. Intervertebral Discs
5. Nasal Cartilage
6. Articular Cartilage

What is Cartilage Made of?

Cartilage is made up of specialized cells such as chondrocytes and chondroblasts, and a matrix containing extracellular materials. It is composed of:

• Chondrocytes: Chondrocytes are immobile specialized cells present within the spaces of lacunae and surrounded by the matrix. One or more chondrocytes can be present in a single lacuna. Chondrocytes have different functions depending on the cartilage type. They increase joint articulation in joint cartilage, regulate epiphyseal plate growth, and maintain the extracellular matrix.
• Chondroblasts: Chondroblasts are free cells that produce the elements of the extracellular matrix. During embryonic development, at first, they form a matrix of hyaluronic acid, chondroitin sulfate, collagen fibers, and water which eventually become immobile and surrounded by the matrix. These cells are then called chondrocytes.
• Fibroblasts: Fibroblasts produce type I collagen. In some cases, fibroblasts transform into chondrocytes.
• Extracellular Matrix: The extracellular matrix consists of three elements which include the following.
  • Collagen: It is a protein-based mesh-like structure of fibrils. It provides strength to cartilage tissue.
  • Proteoglycans: The monomers of proteoglycans bond to hyaluronic acid by linking proteins. The large molecules of proteoglycans then bind with water to provide flexibility and cushioning qualities.
  • Noncollagenous Proteins: Noncollagenous elements play an important role in maintaining the organization of the macromolecular structure of cartilage.

Also Read: Difference Between Endoskeleton And Exoskeleton

Types of Cartilage

There are three types of cartilage in the human body which are as follows.

Hyaline Cartilage

Cartilage most abundant in human body is Hyaline Cartilage. It consists of bluish-white, shiny ground elastic material within closely packed collagen fibers containing matrix. It has a smooth surface and solid matrix which makes it tough but slightly flexible. This cartilage is surrounded externally by a fibrous membrane called perichondrium except at the articular ends of bones where it is surrounded by skin. In the embryo, hyaline cartilage forms first before ossifying to develop bones. Hyaline cartilage is present in:

• the ends of joint bones
• Between ribs
• Nasal passages

Fibro Cartilage

Fibrocartilage is the toughest cartilage and consists of dense masses of white collagen fibers (Type I and Type II) embedded with chondrocytes in a matrix. It lacks perichondrium. Fibrocartilage is present in:

• Intervertebral discs in the spine
• meniscus of the knee joint.
• Between the pubic symphysis, tendons, and ligaments throughout your body.
• Callus formed at ends of fractured bones

Elastic Cartilage

Elastic cartilage connective tissue is abundant with a network of threadlike elastic fibers and chondrocytes and surrounded by perichondrium. It has a yellowish appearance. It plays an important role in providing support, flexibility, and shape. Elastic cartilage is present in:

• Outer ears (Auricles)
• Eustachian tubes
• Larynx

Also Read: Pivot Joints -Definition, Diagram, & its Examples

Functions of Cartilage in the Human Body

The important functions of cartilage in the human body are stated below.

• Structure for bony skeleton: During embryonic development, cartilage forms a model that in later stages of life grows into a bony skeleton.
• Movements of joints: Articular and fibrous cartilage help the joints to function normally.
• Protection of knee joints: A strong layer of cartilage in the knee joint separates the thigh bones and provides a protective cushion. Knee joints can move smoothly with the help of this cartilage.
• Smooth movements of bones: Articular cartilage allows ease of movement of bones. Without it, the bones will rub each other and cause extreme pain.
• Moisturizing joints: Synovial fluid present in articular cartilage acts as a moisturizer for the joints. During movement, the fluid disperses through the joint and helps it remain flexible.
• Shock absorber: Fibrous cartilage bands outside of the bones act as a shock absorber. It helps to disperse the heavy load of the weight of the upper part of the body.
• Shape of organs: The cartilage gives shape to organs such as the ear and nose.
• Flexibility: Cartilage provides the flexibility to ribcage during the expansion of the chest while breathing. It keeps the trachea open and flexible.

Also Read: How Many Chest Bones are in the Human Body?

Clinical Significance of Cartilage in the Human Body

Several diseases and disorders can affect cartilage in the human body. Thus the cartilage has many clinical significance which include the following.

• Cartilage can be damaged by several causes such as injury to the joints, degeneration with age, being overweight, excessive physical activities, inflammation, and infections.
• Some diseases and disorders like rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, spinal disc herniation, achondroplasia, costochondritis, and neoplasm can cause severe damage to the cartilage.
• Damaged cartilage does not cause pain itself as it does not contain nerves. But damaged cartilage leads to friction between the joints of bones which results in discomfort, pain, and inflammation.

Also Read: Difference Between Bone And Cartilage

Conclusion: Cartilage in the Human Body

Cartilage in the human body is a specialized flexible connective tissue. Different types of cartilage serve different structural and functional purposes and are present in joints, bones, spine, lungs, ears, and nose. Cartilage in the human body provides natural protection to bones. But when it is damaged, it often can not heal naturally. Researchers are exploring innovative methods to heal and treat damaged cartilage along with increasing blood supply and grafting cartilage.

Also Read:

• Types Of Joints - Classification of Joints in the Human Body
• Areolar Connective Tissue | Function and Location