Why Tooth Enamel Is the Hardest Tissue in Human Body Structure and Function
The human body gets its shape from the skeleton, which consists of bone and cartilage. Vital organs such as the lungs, heart, and brain are enclosed within the skeletal system. Enamel is the hardest substance in our body, but if we talk about which tissue is the hardest, it will be the Femoral and Temporal bone of the skull. Teeth and bone are the main substances in our body but the striking difference being teeth aren't actually bone though more than 99% of the calcium in our body is found in bones and teeth.
Sensitive Organ in Our Body
Our human body is made up of five sense organs- eyes, ears, nose, tongue and skin. An interesting fact is that there is a “sixth sense”, which is known as proprioception or the body's awareness of its place in space.
The skin is our body's most sensitive organ consisting of water, nutrients, lipids, and mineral deposits. The skin protects us from any kind of physical harm and, most importantly, reduces the harmful effects of UV radiation. The skin synchronises our body temperature. As most of our body is covered with skin, the most sensitive heat receptors are our elbows, nose and fingertips. The cold receptors are found on the chest, chin, nose, fingers, and upper lip. The skin covers 22 square feet of the surface area of a human body and is about 16% of total body weight.
Besides being a sensitive organ, it plays a vital role in providing immunity and protection against any kind of germs too. The skin, besides containing pain, and heat receptors, also contains hair follicles for the growth of hair. The skin, besides being the most sensitive, has varying degrees of thickness and thinness, for example, the skin below the eyes is the most sensitive, but it's thicker on the soles of feet and palms.
Weakest Part of Human Body
The human body comprises 206 bones which provide shape and form. The vital organs are also shielded by the bones, the femur being the longest, thickest and strongest, and the weakest and softest bone in our body is the clavicle which is the collar bone.
Interestingly the weak part of the body is dependent on the fact that what kind of force is operated on it, like the femur being the strongest bone, will handle impact before it cracks, but the ribs will break under much lesser impact of external force. If the impact is more than eyes, throat, knee joints, etc. will be considered weak depending on the force involved.
Hardest Cartilage of Body
Cartilage is a connective tissue found all over the body. It is a vital structural component and consists of chondrocyte cells mixed with collagen, thus, making it softer than bone. It provides support and structure to the tissue and cushions the joints. There are three types of cartilage found in our body, that are, Hyaline cartilage, Elastic cartilage, and Fibrocartilage.
Hyaline is found at the ends of joints, between the ribs and inside the nose.
Elastic is found in the external ear, epiglottis and larynx.
Fibrous is the hardest cartilage in intervertebral discs, joint capsules, and ligaments.
Fibrous cartilage is the strongest because of the presence of one after another layer of hyaline cartilage, matrix and layers of collagen fibres. It has strong resistance to ductile stresses and is tough and inflexible. It is found within the knee, in the intervertebral discs and in the pubic symphysis. Being the hardest cartilage, it forms the lining of the bony grooves of the tendon.
Interesting Fact
An interesting fact is that the thigh bone (Femur) is the strongest and longest bone in the human body and takes a lot of force to break it motor vehicle accidents are the major cause of femur fractures.
Important Questions
1. Which is the second hardest tissue in the body?
Ans. The dentin lies beneath enamel and cementum, it's harder than bone but softer than enamel. It being the second hardest tissue and possessing a softer texture than enamel, helps absorb the pressure from chewing. Dentine is denser than bone and has a yellowish colour seen through the tooth enamel Is the second hardest tissue.
2. What is the strongest bone in the human skull?
Ans. The mandible is the largest and strongest bone forming the face, the lower part of the jaw and major part of the mouth, as it holds the lower teeth in their position, assists in chewing food and is composed of the left and right halves of the lower jaw or mandible.
Key Features of Hardest Tissue of Human Body
The fibrocartilage is the strongest, specialised type in areas requiring tough support and strength.
The skin stores water and fats in its tissues providing insulation when needed.
Skin is the most sensitive and the largest organ of our body, the liver is the second largest.
The Mohs hardness scale is a qualitative ordinal scale. Tooth enamel ranks as hard as steel.
FAQs on Hardest Tissue in the Human Body and Why It Is Enamel
1. What is the hardest tissue in the human body?
The hardest tissue in the human body is tooth enamel.
- Enamel is the outermost layer of the tooth crown.
- It is composed of about 96% hydroxyapatite crystals (calcium phosphate).
- It is harder than bone and provides protection against chewing forces and decay.
2. Why is tooth enamel the hardest substance in the human body?
Tooth enamel is the hardest substance because it contains a very high concentration of mineral salts, mainly hydroxyapatite.
- About 96% of enamel is inorganic mineral.
- The tightly packed crystal structure increases strength and resistance.
- It has very little organic material compared to other tissues.
3. Is enamel harder than bone?
Yes, enamel is harder than bone.
- Enamel contains about 96% mineral content.
- Bone contains about 65–70% mineral content and more collagen.
- Bone is flexible and living, while enamel is non-living and extremely rigid.
4. Is enamel a living tissue?
No, tooth enamel is not a living tissue.
- It does not contain living cells.
- It has no blood vessels or nerves.
- Once damaged, it cannot regenerate naturally.
5. What is enamel made of?
Enamel is primarily made of hydroxyapatite crystals, a crystalline form of calcium phosphate.
- About 96% inorganic mineral (hydroxyapatite).
- About 1–2% organic material.
- About 2–3% water.
6. What is the function of enamel in teeth?
The main function of enamel is to protect teeth from mechanical damage and decay.
- Shields inner layers like dentin and pulp.
- Resists wear during chewing and biting.
- Protects against temperature changes and acids.
7. How does enamel compare to dentin?
Enamel is harder and more mineralized than dentin.
- Enamel: Outer layer, 96% mineral, hardest tissue.
- Dentin: Beneath enamel, about 70% mineral, contains microscopic tubules.
- Dentin is softer and more sensitive.
8. Can enamel repair itself if it is damaged?
No, enamel cannot fully repair itself because it is a non-living tissue.
- It lacks living cells and blood supply.
- Minor mineral loss can be reversed by remineralization using fluoride and saliva.
- Severe damage requires dental treatment.
9. What makes bone strong but not as hard as enamel?
Bone is strong but less hard than enamel because it contains more collagen fibers and less mineral content.
- Bone has about 65–70% mineral salts.
- Collagen provides flexibility and shock absorption.
- Bone is a living tissue that remodels and repairs.
10. Which is the second hardest tissue in the human body?
The second hardest tissue in the human body is dentin, located beneath enamel.
- It forms the bulk of the tooth structure.
- It is less mineralized than enamel but harder than bone.
- It contains microscopic tubules that connect to the pulp.
