1. INTRODUCTION: Blood is the life force of every animal that lives on this planet. It is a colloidal fluid that transports life supporting oxygen and nutrients to the cells besides carrying away carbon dioxide and other waste products for removal. The blood that runs throughout the veins, arteries and capillaries is often called as “whole blood”. It is a mixture of 55% liquid plasma and 45% solid blood cells. About 7 to 8% of our total body weight is blood. From the histological point of view blood is considered as a liquid connective tissue and in average a normal healthy person has about 5 to 5.5 liters of blood in his body.
2. ORIGIN OF BLOOD:
The most precious fluid of our body that is our blood cells like RBC, WBC, Platelets etc. develop from the hematopoietic stem cells and are formed in the bone narrow.
3. COMPONENTS OF BLOOD: Hematological analysis of blood reveals that it is composed of liquid plasma and the solid blood cells such as RBC, WBC and platelets.
a) PLASMA: The plasma part of the blood is a yellowish fluid that contains nutrients, proteins, hormones and the waste products. Due to presence of this component, blood is viscous and can run throughout the body of the animals.
b) RBC: The RBCs are the non-nucleated matured blood cells which constitute about 40% to 45% of the total blood volume. They are though biconcave in shape, have a special ability to change their shape so as to fit themselves inside the blood vessels. RBCs have a special protein called as hemoglobin which gives the identical red colour to blood. They can survive on an average upto 120 days.
c) WBC: WBCs are nucleated cells of blood which take part in a key role by protecting us from the attack of pathogens and give us immunity. They are of several types and their life span varies from few hours to several months. WBCs are mainly formed in the bone marrow. However in some other parts of our body like spleen, thymus and lymph nodes can also produce the WBCs. Depending on the shape of the nucleus and composition of the cytoplasm, the WBCs are of different types, such as eosinophil, neutrophil, basophil, lymphocyte and monocytes. They all are involved in our immune system.
d) PLATELETS: The tiny oval shaped fragments of blood cells that help in the coagulation of blood are called as platelets. These platelets gather around the site of an injury and remain stick to the blood vessels to form a fibrin coat to stop bleeding from there. Platelets survive in
Our blood stream for about 9 days and are constantly being replaced by new platelets formed in the bone marrow.
4. CIRCULATION OF BLOOD: Heart is the pumping organ to supply the necessary kinblood. With each heart beat, blood is pumpedetic energy to out to the tissues through the arteries to carry oxygen, food, hormones etc. After delivering these necessary substances, blood returns carrying the excretory materials, carbon dioxide etc through the veins. As the heart beats, the blood travelling through the vessels can be felt as regular “pulse” in the different regions of our body like wrist and neck etc. 5. BLOOD GROUPS: Not all blood is alike. Depending on the chemical composition like antibody and antigen present in the blood, it has been classified into 4 different categories and they are named after the ABO system as Blood group A, Blood group B, Blood group AB and Blood group O. Each group of blood may be further divided into +ve and –ve on the basis of Rh factor. For example, Blood group A +ve and Blood group A -ve etc.
6. GENERAL PROPERTIES OF BLOOD:
Being a special type of colloidal solution, blood exhibits some unique properties.
Some of the important properties of blood are:
a) Blood is a denser and viscous solution with a slight sticky nature.
b) Blood maintains its optimum temperature within 38 degree Celsius.
c) Blood is slightly alkaline in nature.
d) Colour of blood may be different depending on the pigment molecules present.
e) Colour of blood may vary on the dissolved oxygen content in the blood plasma.
f) Blood contains about 90% water.
g) Remaining 10% of blood is different organic and inorganic compounds
7. IMPORTANCE OF BLOOD:
Sometimes tears of relatives and well wishers cannot save the life of a patient, but the blood can. Blood is needed to keep us alive and it plays some vital roles in our body to function normally.
Blood is important for regulation of the body system and homeostasis. It maintains homeostasis by stabilizing the pH, body temperature, osmotic pressure and also by eliminating the excess heat from our body. Blood supports our physical growth by distributing nutrients and hormones besides removing the waste products from our body.
The RBC of blood contains hemoglobin which can bind oxygen to deliver it to the tissues for oxidation of food. It can also remove the unwanted carbon dioxide from the tissues formed after the cellular oxidation of food.
Blood plays a very important protective role by transporting clotting factors and platelets to prevent excessive blood loss from an injury. The heparin molecules produced by the blood can prevent the blood from clotting inside the blood vessels.
Blood can also transport the disease fighting agents, WBCs to the site of infection for an immune response. The plasma part of the blood acts as a medium to transport various substances within our body. The plasma part of the blood is also associated with the acid-base balance in our body.
WBCs surround the infected or injured area of our body to form the fibroblasts and help the process of tissue repair. They are also responsible for the formation of a special protein called ‘Trephone”, which influences the nutrition, growth and cell division in our body.
The lymphocytes of our blood can produce antibody to play some crucial role in the defensive mechanism of our body. The phagocytic WBCs play an important role in protecting our body from the microorganisms as they can eat the foreign pathogens that invade our body. There are many more functions that blood can carry out in our body. Less amount of blood in the body of a person can be a serious issue. Due to some physical illness or because of some accidents people lose blood and there are many people having this kind of problem all around the globe. In that condition, the life of the patient can be saved only with a blood transfusion. But, blood cannot be manufactured outside the body. That is the reason why these patients are cured by the blood donated by other people. Thus, the blood donors play a vital role in the healthcare of those patients. The blood donated by other people can save the life of a patient. In the hospitals the patients who are undergoing the treatment of cancer, undergoing orthopedic surgery or cardiovascular surgery etc are always served with the donated blood. The case is even applicable to many other health conditions like accident cases and people with inherited blood disorders. There is no end of the benefits of blood and blood donation. However, one thing we should always keep in our mind that donation of blood does not just benefit the recipient, but there is always a benefit for the donors as well.
According to Healthline Magazine, Mental Health Foundation, UK, June, 2019, donating blood always benefits a donor emotionally and physically. The report says that donation of blood can reduce mental stress, can improve our emotional well being, help us to get rid from negative feelings, provides us with a sense of belonging besides helping our physical health. ( https://www.healthline.com ).
Reference: Overview of Blood Donation : Santos A, Alana B , Healthline Magazine, June, 2019
Everyday people lose blood in accidents and injuries and desperately they require fresh blood to survive. Thus, it is our duty to make the common people understand the importance of blood and blood donation to keep our nation healthy mentally and physically. “A single pint can save three lives; A single gesture can create million smiles.”
- Written by: Sri Shivamjyoti Das (Winner of 'Call for Writers' Essay Competition by KhoonKhas in KIDS category) Class 6, Age 11 Years Tangla,Assam " Reading Shivamjyoti’s essay reminds us how important it is to channelize discourse around blood donation, especially since we, as a nation, must work together to overcome the shortage of blood. Khoon has always believed in sharing knowledge via interactive sessions and spreading awareness about blood donation. Khoon has held workshops in educational institutions such as the National Public School and Tata Institute of Social Sciences (TISS). Khoon aims to continue this tradition of working together to ensure we are more informed by the day and assume a collective responsibility to donate blood. "