Why is drinking water important for humans?
The human body is made up of 80% water, which is present in blood and other cells. Since we lose a lot of fluid through sweat, urine, and breath, we need to replenish it constantly. Drinking less water can cause immediate problems. The body cells become dry, and the skin wrinkles. Blood becomes thicker, and the heart has to make more effort to pump it through the body. Since the blood is responsible for transporting oxygen around the body, oxygen is not supplied adequately to the organs. The heart and the brain react immediately to a lack of oxygen-they get damaged in just a few minutes.
Why do we need blood?
Our body consists of millions of cells, which must be supplied with water properly. This supply is the responsibility of the blood. The red blood cells transport vital oxygen (O2) around the body. The blood also absorbs nutrients from the digestive tract, distributes them to the organs, and in return, takes away the waste products from the organs. Blood contains platelets that seal wounds and white blood cells that help us fight disease-causing germs.
How does the heart work?
The heart, a hollow organ with four chambers can be imagined as an unbelievably strong pump. It is about the same size as a fist. Electrical signals coming from the brain cause the heart muscle to contract about 70 times in a minute in an adult. The contractions are more frequent in children and while we are playing sports. These contractions pump the blood through the whole body through the circulatory system. This system consists of two types of vessels: arteries with blood rich in oxygen and veins with blood poor in oxygen. While the arterial blood supplies oxygen to every cell in the body, the venous blood is sent to the lungs where it is purified by removing the waste product carbon dioxide and absorbing new oxygen.
Where does the oxygen in the blood come from?
When we breathe, the oxygen reaches our lungs via the mouth, nose, and trachea. The lungs have a number of very tiny cavities known as air sacs which are covered by a network of very fine blood vessels. The exchange of gases takes place here. Impure blood reaches these capillaries and releases the waste gas carbon dioxide in the air sacs. This is exhaled out of the body, and freshly inhaled oxygen is absorbed into the air sacs. This oxygen is released into the blood via the capillaries.
The different cells of our body have very different tasks, but they are all similar in their structure. They have a cell wall or a cell membrane, which protects the inner matter of the cell and controls what goes in the cell and what comes out of it. The nucleus inside the cell controls all the processes in the cell. The energy for these processes comes from mitochondria, the powerhouse of the cell. They are responsible for cell respiration. The endoplasmic reticulum takes care of the conversion of substances and detoxifying the cells. All these organelles are embedded in the liquid cytoplasm inside the cell. If we drink fewer fluids, the cytoplasm will dry out and the cell may die.
What are organs?
Organs are parts of the body having specific tasks. An example is the intestine, in which food is broken down and the nutrients are absorbed in the blood. Another important organ is the liver, which utilizes the components of food. Other organs are the kidneys, the spleen, the heart, and our biggest organ, the skin. They are all made up of different kinds of tissues, such as muscular tissue, fatty or supportive tissue, and blood vessels. The tissue in each organ is specifically designed to perform the tasks assigned to that organ. Thus, the muscular tissue of the heart is different and performs different functions as compared to that in the upper thigh. Each organ interacts with other organs to keep the body healthy.