The Human Body Class 3 Science
- The human body consists of different living and non-living components that together form a living structure that includes a variety of cells, tissues and organs.
- Similar organised cells form tissues that work together to make an organ. Different organs working to do similar functions form organ systems.
- The human body shows specific unique structures that are very essential for the life of any human.
Facts About Human Body
What Are the Main Non-living Components of the Human Body?
Non-living components of the body comprise water, gases like oxygen and carbon dioxide, and nutrients like sodium, potassium, iron etc.
What Causes Shivering in a Freezing Environment?
- The sensation of shivering arises due to constant contraction and relaxation of muscles.
- It is an action of our body to produce enough heat to bring the body's temperature to an optimum level.
What Causes Bruising?
- We get a bump or bruise due to the effect of the tiny blood vessels present below our skin.
- These blood vessels get ruptured and bleed under the skin, leading to a red bruise that slowly darkens and fades away in a few days.
What Is a Stethoscope Used for? The Doctor Places Their Stethoscope on the Chest and Back. They Also Tap the Chest and Back of the Body. Why Do They Do That?
- A stethoscope is used to hear the changes in the sound of the heart and lungs.
- They tap the chest and back to check if there is any liquid inside the lungs, as normal lungs are filled only with air; when filled with water, they sound differently.
Body Organs and Their Functioning
When We Are Injured, It Starts Bleeding, but After Some Time, the Bleeding Stops. How Does It Happen?
- Blood comprises various cells which perform different functions.
- Platelets in blood help to clot and make a dense covering at the site of injury to reduce the blood loss from our body which may otherwise prove fatal.
When We Touch Our Chest Part, It Feels Hard and Bony, but Why Not the Abdomen Part Feels the Same?
- The structure of particular bones protects the chest part (thoracic region) called the rib cage.
- A bony rib cage protects the heart and lungs and allows these organs to contract and relax.
- No such bony structure is present in the abdominal region; hence we do not feel any hardness there.
What Is the Function of the Liver in the Human Body?
- The liver plays an essential role in the digestion of fats.
- The blood circulated through the liver undergoes key processes like removing unwanted substances, regulating blood sugar levels, releasing nutrients or enzymes required by the body, e
Why Do Kids Have Less Number of Teeth Than Adults?
- Kids start developing their teeth after the age of 7-8 months and develop their primary teeth up to the age of 3 years.
- Until now, the buccal cavity is not big enough to develop other teeth.
- As children grow, the buccal cavity size increases, enabling it to accommodate 32 permanent teeth.
It Does Not Pain When We Brush Our Teeth. Then Why Does It Pain Badly While the Dentist Cleans Them?
- Teeth are dead and the hardest part of our body. But like hair and nails, the roots of the teeth are connected to the nervous system and blood vessels.
- When the germs reach the root part of the teeth, we feel pain.
- So, while the dentist cleans the teeth, we feel pain as the instruments reach the root of our teeth, where we can feel sensations.
What Connects Bones and Muscles Together? How Are Bones Attached to the Other Bones?
- Bones are attached to the other bones and muscles with the help of connective tissues.
- The ligaments join bones to bones.
- The tendons join muscle to bone.