HUMAN CIRCULATORY SYSTEM

BLOOD

Blood is a fluid connective tissue. The colour of blood is red because it contains a pigment called  haemoglobin in its red cells. There are  four main components of blood is:

PLASMA

The liquid part of the blood is called plasma. The plasma contain about 90% of water in it. The plasma also contain dissolved substances such as common salt, proteins, and hormones etc. Plasma carries all the dissolved substances from one part to the other part of the body.

RED BLOOD CELLS

Red blood cells are red in colour because it contains a red pigment called haemoglobin inside them. Red blood cells carries oxygen. Red blood cells carries oxygen from lungs to all the cells of the body. Red blood cells carries some carbon dioxide from tissue to  the lungs. Red blood cells do not have a nuclei.

WHITE BLOOD CELLS

White blood cells fight against infection and protect us from disease. This is because white blood cells fight against germs and foreign bodies. White blood cells make a chemical called 'Antibodies, in the human body. So, it is called soldiers of the body.

PLATELETS

Platelets are formed in the bone marrow. Platelets help in the coagulation of blood in a cut or a wound. When a cut or a wound starts bleeding, the platelets help clot the blood due to each the bleeding stops within a very short period of time.

FUNCTIONS OF BLOOD

1] Blood carries oxygen from lungs to the parts of the body.

2] Blood carries carbon dioxide from the cells of body to the lungs.

3] Blood carries hormones from the endocrine gland to the several body parts.

4] Blood protects the body from the diseases. This is because white blood cells kills the bacteria which cause diseases.

5]  Blood regulates the body temperature constant at about 37 degree Celsius.

HUMAN CIRCULATORY SYSTEM 

The various organs of human circulatory system are: Heart, Arteries, veins and capillaries. Blood is also a part of circulatory system. In the circulatory system the heart push out the blood. The arteries, veins, and capillaries work as a pipe through which the blood is flow. The heart is triangular in shape and it is made up of special muscle called cardiac muscle. The heart has four chambers. The upper two chambers of heart are called atria and the lower two chamber called ventricles. The two atria receive blood from the two main veins. and the two ventricles transport blood in the whole body. The heart beats nonstop all the time.