Difference Between Bone and Cartilage

Bones and cartilages are types of connective tissue present in the body. The connective tissues connect and support other body tissues. This type of tissue is made up of loosely packed cells surrounded by the Extracellular Matrix or the ECM. This matrix has living cells that make up the connective tissue. Bones and cartilages are both needed to protect the vital internal organs of the body. They also provide binding and support and help our body organs in movement. It is essential to know the difference between cartilage and bone.

A Cartilage is thin, flexible and resistant to compressive forces. Bones are hard, brittle and lack elasticity. They are highly vascularized and very strong. While cartilages provide cushion-type padding for long bones, bones provide skeletal support. Bones and cartilages differ in their cellular structure, density, types and functions.

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We will now have a brief discussion about bone and cartilage and learn to distinguish between bone and cartilage.

What is a Bone?

Bones are living, growing tissue. They build up the skeletal system in the vertebrates. They are made up of collagen, which is a protein. Bones protect the various organs of the body and provide a support framework for the body. They can also produce red and white blood cells and store minerals. They have a complex internal and external structure. 

An adult human body consists of 206 bones. Which include bones from the:

• The jawbone is part of the skull.

• Cervical, thoracic, and lumbar vertebrae, as well as the sacrum and tailbone, are all parts of the spine 

• Ribs and breastbone are located in the centre of the chest (sternum)

• Scapula, clavicle, humerus, radius, and ulna

• Carpals, metacarpals, and phalanges are the bones of the wrist.

• Hip bones (pelvis).

• The femur (thigh bone), patella (kneecap), tibia (shin bone), and fibula (fibula) are the bones that make up the legs.

• Tarsals, metatarsals, and phalanges are the bones that make up the feet.

• The different kinds of bones

Bones are made up of dense connective tissue and contain special bone cells known as osteoblasts, osteocytes, and osteoclasts. Bones have a rich supply of blood through a proper vascular system. They have high compressive strength and can create and replace themselves. Bones also contain an essential mineral called Calcium Phosphate. They can store the calcium and release a part of it into the bloodstream. The thigh bone or Femur is the longest bone in the human body. The stapes is the human ear is the smallest bone.

There are Four Different types of Bone in the Human Body:

Long bone:

This type of bone is long and thin. The bones of the arms and legs are two examples (excluding the wrists, ankles, and kneecaps). Long bones act as levers, allowing movement, with the support of muscles.

Short bones:

The shape is squat and cubed. The wrists and ankles are made up of short bones. 

Flat bone:

A flattened, wide surface characterizes a flat bone. Ribs, shoulder blades, the breastbone, and the bones of the cranium are just a few examples.

Irregular bone:

It has a shape that isn't one of the three types mentioned above. The bones of the spine are a good example (vertebrae).

Bone tissue

The dense, rigid outer shell that houses blood vessels and nerves is known as the periosteum. The firm, smooth layer that surrounds and protects the tissue within is known as compact or thick tissue. Spongy or cancellous tissue is a porous, honeycombed structure found inside most bones that permits them to be strong while remaining lightweight.

Bone marrow is a jelly-like material that creates blood cells and can be found inside the spaces of some bones (particularly the pelvic). The strength and health of bones are influenced by a number of things. The following factors of bone density:

Calcium in the diet is consistent, Sunlight and diet provide enough vitamin D, A vitamin and mineral-rich diet, Parathyroid hormone, growth hormone, calcitonin, oestrogen, and testosterone are among the hormones that can be found in the body. Weight-bearing exercises on a regular basis are recommended.

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What is Cartilage?

Cartilage is a flexible type of connective tissue found in various parts of the body. It is capable of bending but resists stretching. The primary function of cartilage is to connect the bones of a body together. Cartilages are found in the joints between bones like elbows, knees, ankles, rib cage, discs of the spine, ear, nose, throat, and bronchioles.

Cartilage is a semi-rigid supporting tissue that is robust, flexible, and flexible. It has the ability to bear compression while also being able to bend. Extracellular matrix, made up of around 10% aggrecan, 75% water, and a combination of collagen fibres and other elements, is formed up of chondroblasts and chondrocytes (chondro - cartilage). Cartilages keep the joints in motion by cushioning bones against impact. They are not as hard as bones, but they are stiffer and less flexible than normal muscle tissue. 

Types of cartilage

There are 3 types of cartilage, namely Fibrocartilage, Hyaline and elastic cartilage.

• Fibrocartilage

Fibrocartilage is the tough material that makes up the intervertebral discs, as well as the intra articular cartilages of the knee, wrist, and temporo-mandibular joints, as well as the articular cartilage of the temporo-mandibular joint and the clavicle-sternum joint.

• Hyaline cartilage

A form of cartilage tissue is hyaline cartilage tissue. It's the most prevalent form of cartilage, with a lustrous, smooth look. Around the bones of free-moving joints, hyaline cartilage is found. Articular cartilage is what this is called. The tissue found in the walls of the respiratory tract is another example of hyaline cartilage. The bronchi, nose, trachea rings, and rib tips all fall into this category.

•  Elastic cartilage

The chondrocytes are present within the matrix of elastic cartilage in a threadlike network of elastic fibres. Elastic cartilage gives a structure like the external ear its strength and flexibility while also maintaining its shape. A perichondrium can be found on it.

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Cartilages are made up of specialized cells known as chondrocytes. An essential feature of the cartilage is that it has no blood vessels. Due to the lack of blood vessels, cartilage cannot heal itself. It also grows at a slow pace in comparison to other tissues. When chondrocytes divide in growing cartilage, the daughter cells stay close together in clusters, producing a 'nest' of 2-4 cells. Lacunae are the matrix-enclosed cubicles where they sit. (lacunae = tiny lakes or pits) Because they have a lot of rough endoplasmic reticulum, active chondrocytes are big secretory cells with basophilic cytoplasm. Fat droplets can be found in older chondrocytes. 

Cartilage can develop in one of two ways

Interstitial growth - inside the current cartilage, chondrocytes grow and divide, laying down an additional matrix. This is most common in childhood and adolescence. Additional chondroblasts from the perichondrium add new surface layers of the matrix to the pre-existing matrix during appositional growth. Let us now differentiate between cartilage and bone. Below is a table listing out the difference between bones and cartilages on the basis of specific parameters.

Difference Between Cartilage and Bone

This cartilage vs. bone comparison will be helpful to distinguish between bone and cartilage. Both bones and cartilage are types of connective tissue but have a different structure, nature, and functions in the body.