The circulatory system is one of the important system consisting of heart, blood vessels and blood. It transports respiratory gases, nutrients, hormones and waste materials within the body. It protects the body from harmful pathogens and also regulates the body temperature.
Heart is located in the thoracic cavity between the two lungs. The heart is four chambered and is surrounded by a double layered membrane called pericardium. The heart pumps blood continuously throughout our life time.
Three types of blood vessels are present in the body. They are arteries, veins and capillaries. They form a closed network through which the blood is circulated.
Blood is a fluid connective tissue of red colour containing plasma and blood cells. There are three types of blood cells namely, Red blood corpuscles (RBCs), White Blood corpuscles (WBCs) and Blood Platelets. RBCs are produced in the bone marrow.
Activity 6: Place the middle and index fingers of your right hand on the inner side of your left wrist. Can you feel a throbbing movement. Why do you feel the throbbing? This throbbing is called the pulse and it is due to the blood flowing in the arteries. Count the number of pulse in one minute.
How many pulse beats could you count in one minute? The number of beats per minute is called the Pulse rate. A resting person usually has a pulse rate between 72 to 80 beats per minute.
Find other places in your body where you can feel the pulse. Record your own pulse beats and your classmates as beats per minute; Compare the values.
Hospitals have blood banks where blood can be temporarily stored before it is given to the patients in need. Every healthy person over 18 years of age can donate blood. So that, it can be given to persons in need during emergencies of accidents or operations. Blood donation saves their life.