Subtitles section Play video Print subtitles Smart Learning for All What causes body odor? Obviously sweat. No. Sweat is odorless. What? But how is that possible? Our skin contains two types of sweat glands, eccrine glands and apocrine glands. Eccrine glands are present all over our body. They produce sweat which is mostly water. Whereas, apocrine glands are concentrated in regions such as ear canals, armpits, etc. They produce thicker sweat which has proteins. Can I eat these proteins and become a bodybuilder? Just listen. We know that millions of bacteria are normally found all over our skin. When apocrine glands produce sweat, the bacteria on our skin breakdown the proteins in that sweat. Releasing unpleasant smell which we call as body odor. Why does water go stale overnight? Because you left it alone overnight. No. In water purification plants, chlorine is added to water. Chlorine kills microorganisms in water, thus keeping it clean and safe to drink. This chlorine gives our drinking water a slightly different taste. However, if we keep the water open for a long time or overnight, the chlorine will dissipate into air. As a result, the taste of water alters. Also, water is a universal solvent. It can dissolve almost anything. Hence, if we keep water open for quite a long time, the atmospheric carbon dioxide gets dissolved in it. This results in the formation of mild carbonic acid. What? Acid is formed in water? Indeed. However, it is not harmful. But the presence of carbonic acid. Slightly lowers the pH of water making it slightly acidic and thus, unpleasant to taste. What makes tattoos permanent? Glue sticks. No. Our skin has three layers, epidermis, dermis and hypodermis. Epidermis sheds thousands of skin cells every day. Hence, when we get a tattoo. The tattoo needles which are coated with colored pigment. Are inserted through the epidermis into the dermis. Thus, preventing the tattoo pigment from getting shed away. However, it is mainly our body's immune response which makes tattoos permanent. What? But how? The tattoo needles create wounds in the skin, activating the immune response. Immune cells like macrophages. Reach the wounded site and start to eat the small particles of colored pigment and clean the area. Bigger pigment particles that cannot be eaten by macrophages. Are absorbed by fibroblasts present in the dermis. These fibroblasts along with some macrophages remain at the site making the tattoo permanent. Where does the fat go when you lose weight? Santa Claus takes it away. No. Our food contains nutrients like carbohydrates, fats and proteins. When we eat food, these nutrients give us energy and help us to grow. However, when we eat excess amount of these nutrients. Our body stores them as triglycerides in fat or adipose cells for later use. This ultimately results in weight gain. Now, according to a prevailing research, when we try to lose weight. We actually breakdown these triglycerides in the presence of oxygen. Converting them into carbon dioxide, water and energy. What? My fat turns into carbon dioxide, water and energy? Yes. We exhale the carbon dioxide gas. Water is given out in the form of urine, sweat or tears. Whereas, we use the energy to perform various activities. Why do we get sunburn? Because sun is jealous of my skin. No. Sunburn is a term for red and inflamed skin. It is caused by ultraviolet radiation present in sunlight. Sunlight consists of three types of ultraviolet radiation, UVA, UVB and UVC. Does it contain UVZ as well? Just listen. Our skin is made up of cells. These cells have DNA. When we are in the hot sun for very long. The UVB radiation enters into our skin cells and starts to damage the DNA. DNA damage can lead to cancer. Thus, to reduce the risk of cancer, the damaged skin cells kill themselves. This programmed cell death is called apoptosis. Apoptosis activates the immune response. As a result, the blood flow increases to that area to heal the skin. This leads to red and inflamed skin which we call as sunburn. For more educational videos please visit http://www.SmartLearningforAll.com Also, don't forget to subscribe to our YouTube channel.