What Is Blood And What Are Its Different Components? » Science ABC

For the longest time, people have been intrigued by blood, and this fascination has manifested in many fascinating methods. For instance, back in the day, Greek soldiers drank the blood of different fallen troopers, considering that it might give them the lifeless man’s power! Nevertheless, rather a lot has modified since then; we now know much more concerning the foundational fluid of life—blood!

Blood is a life-saving fluid that, in greater advanced animals like humans, moves throughout the circulatory system. It’s a elementary element of the human body, and an adult body carries close to 4 or 5 liters of blood. Blood from arteries is scarlet purple in colour, while blood from the veins is purple-red, as a consequence of its carbon dioxide content material. Nevertheless, should you see somebody harm and oozing blood, you’ll only see the primary pink colour, so that you won’t be capable of decide if it’s from the arteries or veins. This blood moves from the central pump (the guts) to the complete body by means of an enormous network of arteries, veins, and capillaries. Whereas doing so, it is available in contact with near 4.5 trillion cells of the human physique, offering them with oxygen and nourishment, and functioning as a transport medium for his or her waste merchandise to be excreted.

Blood and its many names and features!

Blood carries out a number of features in our body and is known as the fluid of life, provided that it carries oxygen from the lungs to all of the cells and transports carbon dioxide again to the lungs. It transports vitamin from the digestive system and hormones from the endocrine system. Vitamins and hormones are answerable for progress, so blood may also be referred to as the fluid of progress. If an infection attacks the physique, blood ensures that the white blood cells or fighter cells of our physique reach the location and kill the an infection, so blood may also be the fluid of health. Blood acts as a reservoir of water, glucose, sodium and potassium; each time our bodies are beneath stress or misery, in situations comparable to electrolyte loss or starvation, these substances may be pulled from the blood. The water content material in blood is quickly interchangeable with interstitial fluid, so blood helps in regulating the water content material of our our bodies.

What is blood made from?

Blood is actually connective tissue in fluid type and consists of a liquid portion referred to as the plasma, as well as different parts or blood cells. Blood cells are available 3 varieties:

  1. Pink blood cells (erythrocytes)
  2. White blood cells (leukocytes)
  3. Platelets (thrombocytes)

These blood cells are shaped within the stem cells of the bone marrow; once shaped, they’re launched into the bloodstream to perform their designated specialised features. There are different organs, such because the spleen and liver, that help regulate the formation/destruction of blood cells. The method of the formation of blood cells known as hematopoiesis and the stem cells they are shaped from known as the hematopoietic cell. Fun reality—grownup marrow incorporates about 1,000,000,000,000 hematopoietic cells!


For those who acquire blood and retailer it in a check tube for 30 minutes, it’ll separate into 3 layers of plasma, white blood cells, and purple blood cells.

(Photograph Credit score : KnuteKnudsen /Wikimedia Commons)

Plasma is a clear, straw-colored liquid during which the blood cells are suspended. It makes up about 54% of our blood. The composition of the plasma is 91%-92% water, whereas the remaining is made from natural and inorganic compounds mandatory for sustaining life. These strong materials embrace proteins, carbohydrates, enzymes, fats, sodium, calcium, potassium, chloride, phosphate, iodide, iron and copper, amongst others. All these compounds are required in the suitable quantities for bodily stability to be maintained.

Pink blood cells or erythrocytes

red blood cell view

Purple blood cells (RBCs) are the most typical sort of blood cell, with every cubic mm of blood containing about 4-6 million cells! To match this big amount of RBCs, our stem cell manufacturing unit produces about 2-Three million RBCs each second! It’s troublesome to even think about this sort of speedy manufacturing occurring in some tiny stem cell of our body, nevertheless it’s true! RBCs are also referred to as erythrocytes, as erythros means “red”. This pink shade of the RBCs is because of the presence of a coloring pigment referred to as hemoglobin. Hemoglobin is an iron-bearing protein that helps to transport oxygen and thus helps RBCs transport respiratory gases. In other phrases, RBCs are an army of oxygen-carrying soldiers that take oxygen to all elements of the physique.

Let’s speak just a little concerning the shape and construction of a RBC. Now, an RBC just isn’t a daily round-shaped cell; as an alternative, it intently resembles a dumbbell and has a biconcave form. Why, do you ask? Properly, the biconcave shape helps the RBCs carry out a variety of features with ease, akin to:

  1. Equal and quick diffusion of oxygen by means of its surface.
  2. Potential to squeeze by means of capillaries without turning into damaged
  3. Providing a big floor space for absorption and removing of drugs.

Now, in mammals, aside from the camel, RBCs are and not using a nucleus, and since there isn’t a nucleus, there’s also no DNA, mitochondria, Golgi our bodies or different organelles. Because of the absence of mitochondria, the power that RBCs want will come from the glycolytic means of the body.

Why can we even need RBCs?

RBCs represent about 45 % of the blood, in order that they have to be there with some objective to serve. A number of the most necessary reasons are under.

  1. Transport of respiratory gases – As mentioned earlier, RBCs include hemoglobin, which combines with oxygen and varieties oxyhemoglobin. Virtually 97 % of oxygen is transported as oxyhemoglobin. Hemoglobin, similarly, combines with carbon dioxide and varieties carbhemoglobin; about 30 % of CO2 is transported in that type.
  2. Willpower of blood groups – RBCs carry blood group antigens, which help us decide blood groups and in addition prevents deadly, ghastly reactions on account of incompatible blood transfusions. Imagine what a catastrophe that may be!

What happens to previous RBCs? – oh, wait they have a graveyard!


RBCs are undoubtedly not immortal; their common lifespan is a mere 120 days. After 120 days, the previous or “senile” RBCs have cell partitions which are growing older and increasingly fragile. Often, the capillaries that RBCs cross via have a diameter that’s less than or equal to the RBCs. Youthful RBCs often haven’t any drawback passing by way of these tiny capillaries; the older ones, nevertheless, endure injury while passing via these tiny vessels, owing to their fragile cell walls, and sometimes die. This often occurs within the capillaries of the spleen, as they’re extraordinarily small, so the spleen can also be known as the graveyard of RBCs!

White blood cells or leukocytes

white blood cell

(Photograph Credit : Cancer Research UK uploader/Wikimedia Commons)

White blood cells (WBCs) are the colorless shaped parts of the blood. They differ from RBCs in that they are larger in measurement, however fewer in quantity (4,000-11,000 cells/cubic mm of blood). They have a nucleus, in contrast to RBCs, and exist in several styles and sizes. Regardless of variations in shape and measurement, WBCs play a very essential position in our our bodies. They are our protection mechanism and rise to the event once we’re attacked by any infection and can defend our system. You’ll be able to think of WBCs because the vacuum cleaners of our body. They transfer to the location of infection and suck up all of the dust (on this case, the dangerous guys like disease-causing micro organism/viruses). WBCs are broadly divided into two classes

type of white blood cells

(Photograph Credit : BruceBlaus/Wikimedia Commons)

  1. The granulocytes, which embrace the neutrophils, eosinophils, and basophils. They’ve a lobed nucleus and granulated cytoplasm.
  2. The agranulocytes, which embrace lymphocytes and monocytes.

White blood cell & bacteria

The granulocytes are often the first response workforce to the location of an an infection. Neutrophils include enzymes that digest bacteria. There are two forms of lymphocytes—T cells and B cells. As soon as an an infection triggers these cells, the B cells produce highly specific antibodies that assist combat the an infection, whereas the T cells, additionally referred to as helper T cells, secrete chemical compounds that stimulate different immune cells to arrange a coordinated assault. Monocytes, however, turn into macrophages and engulf pathogens.

Why do we’d like WBCs?

Think about being struck down by a viral infection or a extreme bout of bacterial gastroenteritis. The first cells of the physique to be alerted are the leukocytes. They shield our our bodies from invading pathogens by both destroying them or inactivating them. Neutrophils and monocytes work collectively as the primary line of defense towards invading microorganisms. Eosinophils play an necessary position towards parasites and in addition assist battle allergic reactions. Basophils improve in quantity every time there’s a healing process initiated in the physique, as they contribute to the healing course of in a constructive means. All kinds of WBCs, indirectly or one other, are chargeable for our good well being, immunity and well-being.

Platelets or thrombocytes


(Photograph Credit : BruceBlaus/Wikimedia Commons)

Platelets are colorless, non-nucleated parts of the blood that exist in numerous shapes. They could be spherical, rod-shaped, oval, comma-shaped and even cigar-shaped! For every cubic mm of blood, the traditional platelet rely ranges from 200,000 – 400,000 platelets. Platelets additionally originate from stem cells, which differentiate into megakaryocytes after which shed platelets into the bloodstream. These platelets flow into in the blood in an inactivated state and execute their features solely when triggered. The typical lifespan of platelets is about 9 days, until they’re triggered by an damage, they usually sometimes die a natural dying in the spleen.

Why do we’d like platelets?

bleeding and platelets saying we will stop you from bleeding

Ever questioned what happens whenever you get your hand pricked for a blood check or once you harm your self and begin bleeding? How does blood know when to cease oozing out? If you harm yourself, you bleed, but you don’t bleed endlessly. Your blood all the time clots and prevents you from bleeding out. This life-saving mechanism in place because of the platelets. Each time there’s an damage, the inactivated platelets are triggered into motion they usually rush to the location of damage. Once they arrive, they stick with the injured website and type a clot, thereby stopping additional bleeding. Briefly, you’ll be able to consider platelets as pure Band-Aids in our our bodies that persist with the world of damage with a view to stop blood loss. Clot formation just isn’t the one approach by which they cease bleeding; platelets are additionally chargeable for hemostasis (prevention of blood loss) by secreting chemical compounds like 5-HT, which cause blood vessels to close down or constrict. Platelets also include platelet-derived progress elements (PDGF), which assist to repair the ruptured blood vessels.

What do these blood cells signal about our well-being?

Typically, once we’re sick or low on power, one of many first blood exams our docs will advise us to take is the Complete Blood Rely (CBC). A CBC is a screening check for any sort of dysfunction associated to our blood cells and it will possibly instantly indicate or assist diagnose a medical condition we may be suffering from. For example, if a CBC indicates that you’ve a low quantity of RBCs, you could be affected by some type of anemia through which your body’s capacity to ship oxygen could be compromised, owing to decreased RBC quantity. Abnormalities in the form, measurement and variety of WBCs signifies that your body is preventing an an infection that might be as small as an allergy, or as giant as a life-threatening situation like leukemia. Problems with platelets indicate bleeding issues, wherein you may bleed excessively in response to even a minor damage.

To conclude, although these blood cells and elements are tiny elements in our body, they have very particular features that assist sustain life. Having a basic overview of those blood elements will help paint a more full image of our health by way of a simple process like the entire blood rely blood check!


  1. Essentials Of Medical Physiology By Okay Sembulingam
  2. Blood: Physiology and Circulation edited By Kara Rogers Senior Editor
  3. College Of Rochester