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All the organisms present on earth survive on food, water, minerals and oxygen. Life is impossible if all these factors do not come into play. These are the basic requirements of any organism for its survival. However, these components must be transported to all parts of the body that require them. The body needs them for energy and growth. Additionally, even the waste materials need to be transported to excrete them out of the body.
The Human Circulatory System
Circulation is the process by which fluids are transported into the body. It is one of the key organ systems in human beings. The components that make up the circulatory system are blood, heart and blood vessels.
- Blood: It is the fluid or liquid that flows throughout our body. It flows through the blood vessels. Blood is composed of various components such as Red blood cells or RBCs, White blood cells or WBCs, and Platelets.
Blood flows through the veins in our body. Some of its important functions are as follows:
⮚ It helps in the transportation of food from the small intestine to other organs of the body.
⮚ It helps in transporting oxygen from the lungs to the other parts of the human body.
⮚ It also substitutes waste that is to be removed from the body.
Blood is composed of plasma. The plasma has different types of cells in it. Some of them are as follows:
⮚ The first type of cells present in the plasma is called Red Blood Cells or RBCs. It contains haemoglobin which is a red-coloured pigment. It is the source that binds with oxygen. Later, it helps in transferring oxygen to all parts of the body. The red colour of the blood is due to haemoglobin.
⮚ The second component present in the blood that flows through your veins is White Blood Cells (WBCs). They help in fighting against infections and pathogens. They define the immunity system of the body.
⮚ You may have noticed the formation of a brown-like clot around the surface where you get hurt. This is due to the presence of platelets in the blood. They help in blood clotting. If they do not exist, you may have bled to death.
- Blood Vessels: The tubes that allow the blood to flow through your body are known as blood vessels. The two types of blood vessels present in a human body are:
⮚ Arteries: They help in carrying blood that is rich in oxygen from the heart to all parts of the body. The blood flows at a high speed and pressure through the arteries. This results in thick elastic walls for the arteries.
⮚ Veins: These types of blood vessels help in carrying blood that is carbon dioxide-rich from the organs of the body. They take it back to the heart. The veins have thin walls. They have valves that direct the blood towards the heart.
⮚ The arteries are divided into smaller blood vessels. They are divided into further thinner tubes known as blood capillaries. These form veins together. They move further to enter the heart.
⮚ The throbbing movement in the blood vessels is known as the pulse. The number of beats that occur per minute is called the pulse rate. A normal person has a pulse rate that ranges between 72 and 80 beats per minute on average.
- Heart: The heart is the pumping organ of the body. It pumps blood all the time. It helps in transporting blood to all the parts of the body. Some of its chief characteristics are:
⮚ The heart is present in the left side of the chest cavity.
⮚ The heart is sized almost as big as your fist.
⮚ The heart contains four chambers. There is a partition between the chambers. Due to this, the oxygen-rich blood does not get mixed with carbon dioxide-rich blood. The two upper chambers are known as the atria (singular: atrium) and the two lower chambers are known as the ventricles.
You can understand the functioning of the heart through the diagrams mentioned above. Figure A shows the parts of the heart and its location. The second figure shows the direction of the circulation. It starts from the right side. The blood flows from the heart to the body and then back to the heart.
Heartbeat: The heart walls are made up of heart muscles. They move rhythmically. The contractions and relaxations take place rhythmically. That’s how a heartbeat occurs. A stethoscope is used to feel a heartbeat and hear it.
The Human Excretory System
The excretory system in humans has many parts. It consists of: kidneys, two ureters, a urinary bladder, and a urethra. The main functions of the excretory system in humans are:
- The excretory system in humans helps to filter the blood carried by the blood capillaries present in the kidneys.
- When the blood goes to the kidneys, there are useful and harmful substances present. The useful substances get absorbed back into the blood.
- The waste materials are removed from the body in the form of urine.
- Now, the urine moves into the urinary bladder through ureters in the excretory system in humans.
- The urine is stored in the urinary bladder and then passed through a urinary opening called the urethra.
- On average, an adult human passes about 1-1.8 L of urine in 24 hours. The urine contains 95% water, 2.5% urea, and 2.5% other waste products.
- One of the other ways in which our body excretes waste is through sweating. Our sweat contains water and salts.
- Sweating is also a form of excretion in humans. It contains water and salts and helps to cool our
If the kidney stops performing its tasks, it can result in the failure of the excretory system in humans. This means that waste products will start collecting in the blood. Kidneys will no longer remove the waste products out. An artificial kidney will be employed to do the work. This is known as dialysis.
Conclusion–
The circulatory system (cardiovascular system) pumps blood from the heart to the lungs to get oxygen. The heart then sends oxygenated blood through arteries to the rest of the body. The veins carry oxygen-poor blood back to the heart to start the circulation process over. circulatory system is critical to healthy organs, muscles and tissues.
