Blood

Blood is a vital fluid present in our body. It is considered important because life cannot exist without blood. This fluid flows through the blood vessels; supplying oxygen and essential nutrients to the body’s tissues and organs, as well as eliminating waste products from the organs.

Blood is located in the cardiovascular system. It is composed of several elements that are required in order to maintain the balance of the body. It also helps in protecting the body from pathogens and to facilitate different functions.

If there were no blood, the organs would not get the needed oxygen and nutrients. The body wouldn’t be able to control its temperature and the immune system would also be ineffective.

In this article, we will discuss what blood is and its composition, its different categories, role, blood diseases and other related topics.

Also Check: GK Quiz on Blood

Blood and its Components

Blood is a fluid connective tissue which is mesodermal in origin.

• It is an opaque red coloured fluid alkaline in nature and salty in taste.
• Its specific gravity is 1.050 – 1.060.
• The volume of blood in a healthy man is about 5 to 6 litres (about 6 to 8% of the total weight of the body).
• Blood contains two main components,

1. Fluid Part: The plasma
2. Solid part: The corpuscles.

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Plasma

• Plasma represents roughly 55 percent of blood’s whole volume;
• It is the liquid component of the blood
• It consists of water and dissolved substances.
• It is a pale yellow fluid formed mostly from 90% water
• It also possesses: proteins, electrolytes, hormones and metabolic wastes.

Function of Plasma

1. Plasma helps in the transportation of nutrients, hormones and proteins in the body.
2. It also plays an important role in the elimination of waste products during the cellular processes.

Corpuscles

They are the solid component of blood. They are of three types:

• Red Blood Cells (RBCs)
• White Blood Cells (WBCs)
• Platelets

Also Check: Blood Vessels

Red Blood Cells (RBCs)

1. RBC or erythrocytes are a most commonly found cell in the blood.
2. RBCs are biconcave in structure which
3. The biconcave shape provides flexibility and a large surface area for the exchange of gases.
4. RBCs are also called red corpuscles because they contain a protein called haemoglobin.
5. Haemoglobin has the ability to bind oxygen and provide the red colour to the blood.

Function

1. They are useful in carrying oxygen from lungs to all the other parts of the body.
2. They also carry carbon dioxide from the other parts of the body back to the lungs to be expelled out.

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White Blood Cells (WBCs)

1. They are also known as leukocytes.
2. They are large and nucleated blood corpuscles.
3. The nucleus may be spherical in shape or two to many lobed.
4. These are relatively lesser in number than RBCs.
5. They are colourless due to the absence of any pigment.
6. Their number is about 6000-8000 mm^–3.

Types of White Blood Cells

There are 5 types of WBCs which are discussed below.

1. Neutrophils: When an infection arises, they are the first to react, fighting and breaking down bacteria and other dangerous intruders.
2. Lymphocytes: They are essential to the immune system because they produce antibodies and kill malignant or contaminated cells.
3. Monocytes: By absorbing and decomposing bacteria, dead cells, and other detritus, monocytes aid in the battle against infections.
4. Eosinophils: They are involved in allergic reactions as well as the fight against parasites.
5. Basophils: During allergic reactions, they release substances like histamine, which aids in the body’s defence against allergens and diseases.

Functions of WBC’s

• WBCs are important in the immune system’s functioning.
• They defend the body against diseases by combating bacteria, viruses and other foreign bodies that might invade the body.

Also Check: Difference Between Blood and Lymph

Platelets

1. Thrombocytes also known as platelets
2. They are small cell fragments which participate in the blood clotting.
3. These have dense tubular systems.
4. Their lifespan ranges from 8 to 12 days.
5. Platelets are found only in mammals.

Function of Platelets

• Platelets are essential for the clotting process;
• When any blood vessel is injured, the platelets stick together to form a clog that prevents further bleeding.
• They also release substances that contribute to the clotting of blood so that the area is closed.

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Blood Types and Groups

Blood is categorised into groups depending on the presence or absence of antibodies on the red blood cells. The ABO Blood Group System is the most well-known classification. It divides the blood into four groups namely:

• A
• B
• AB
• O

Rh positive and Rh negative are other possibilities depending on whether Rh factor is present.

• Type A: Has anti-B antibodies in the plasma and A antigens on the surface of RBCs.
• Type B: Has anti-A antibodies in the plasma and B antigens on the surface of RBCs.
• Type AB is the universal receiver because it possesses both A and B antigens and neither anti-A nor anti-B antibodies.
• Type O: Known as the universal donor, it lacks antigens on RBCs but possesses both anti-A and anti-B antibodies.

The blood type is important for:

1. Compatibility of transfusion of blood
2. Receiving a transfusion of organ
3. Pregnancy management

Functions of Blood

Blood carries out vital tasks that are necessary for survival:

In Transportation

• It conveys nutrients and waste products.
• It eliminates carbon dioxide.
• It delivers oxygen from the lungs to tissues and organs.

In Regulation

1. Blood maintains pH equilibrium.
2. It also manages fluid levels inside the body
3. It distributes heat to assist control body temperature.

In immune system

• White blood cells perform a vital part in the immune system
• It provides protection from pathogens.
• Additionally, platelets and plasma proteins in blood help coagulate, reducing excessive bleeding and promoting wound healing.

FAQs on Blood

What is serum?

Blood plasma without coagulation factors is known as serum

What are some blood disorders?

Anaemia, Sickle cell anaemia, haemophilia, leukaemia, etc are some of the common blood disorders

How do blood types work?

Blood types are based on the presence or absence of antigens on RBCs. Therefore, knowing the ABO system & Rh factor are important in transfusions

Why is blood donation important?

Blood donation is important as it is used in saving lives. It is important for blood supply in emergencies, surgeries and blood disorders.

What is the difference between red and white blood cells?

Red Blood Cells help in the transport of oxygen while White Blood Cells have their vital roles in the body's immune system