[Biology Class Notes] on Types of White Blood Cells Pdf for Exam

Blood is a fluid connective tissue which supplies oxygen and the mineral resources and carries out the waste products and carbon dioxide throughout the body. It is made up of different types of blood cells, which are produced in the bone marrow. It is about 80% water and 20% solids.

Types of Blood Cells:

The blood is made up of four different types of cells:

1.  Red blood cells (RBC)

2.  White blood cells (WBC)

3.  Plasma

4.  Platelets

The composition of blood is as follows:, ~55% of plasma and ~45% of blood cells. Now we will discuss briefly about WBC.

Red Blood Cells

Red blood cells are biconcave cells, and these do not have a nucleus in humans. These cells are also called erythrocytes. RBCs have a rich iron protein called haemoglobin that gives the blood its red colour. The primary and core function of these cells is to transport oxygen from various tissues and organs of the human body.

What are White Blood Cells?

WBC is a type of blood cell which helps us to fight against diseases. These WBC are produced by stem cells in the bone marrow and it is found in the blood and lymph tissue. WBC are also called leukocytes.

The lifespan of WBC is about 13 to 20 days. After this, they are destroyed inside the lymphatic system. The normal white blood cell count in blood is 4,500 to 11,000 per microlitre.

Plasma

Plasma is the extracellular and liquid portion of blood and is transparent or pale yellow coloured. Plasma in blood contains 80–90% water, and the remaining 10% is salts, enzymes, nutrients, lipids, and hormones.

Platelets

These are tiny fragments of blood cells that facilitate the formation of clots in our bodies to stop bleeding. Platelets help repair the damage and rush towards blood vessels whenever there is any damage in them. 

White Blood Cells Function

WBC are a part of the immune system, if there is a decrease in the immune power, then the body releases the WBC. The main function of these cells is to protect the body from getting affected by foreign particles. Whenever an infection or foreign particle invades the body, the WBC builds up the antibodies and attacks the germs to destroy it.

• White blood cells are also known as leucocytes or leukocytes. 

• It helps to stimulate the production of progesterone hormone in our body. 

• It is essential for our reproductive systems as it helps create a network of blood vessels in the ovary.

• If your body is struggling and a specific area is under attack, the white blood cells surge into the area to destroy the harmful substance and avoid illnesses.

Types of White Blood Cells and Their Function:

There are three different types of white blood cells:

1. Granulocytes: 

Granulocytes are a type of WBC, which has small granules made up of proteins. These are further divided into three types, and they are:

a. Basophils: Basophils helps to provide immune responses to parasitic infections. In addition to that, it has the following functions:

Prevents blood clotting: Basophil contains a substance called heparin, which is a blood-thinning substance, this avoids clotting of blood inside the body.

Mediates allergic reactions: When an immune system is exposed to an allergen, the basophil releases a substance called histamine which helps to kill the allergens, it is well known for its role to fight against asthma.

b. Eosinophils: Eosinophils are the special cells inside the immune system which are involved in inflammatory and anti-parasitic responses.

c. Neutrophils: Neutrophils help to heal damaged tissues, it also helps to fight against bacterial or viral infections.

Difference Between Basophils, Eosinophils, and Neutrophils:

2. Lymphocytes: 

The lymphocytes are further divided into three types:

1. B cells: The B cells are also referred to as B lymphocytes, which produce antibodies in the immune system.

2. T Cells: The T cells are also referred to as T lymphocytes, which helps to recognize and remove the infection-causing pathogens.

3. Natural Killer Cells: These cells are responsible for attacking and killing the pathogens, it also kills cancerous cells.

Difference Between B Cells and T Cells:

3. Monocytes:

Monocytes make up around 2–8% of the WBC, which helps to fight against chronic infections.

WBC Normal Range:

The WBC normal range is based on age.

What Happens When a Person has a High White Blood Cell Count?

If the WBC count increases in the body, then it may lead to the disease leukocytosis. Below are the medical conditions indicated dues to high white blood cell count:

1. Asthma attack

2. Heart attack

3. Rheumatoid arthritis, inflammatory bowel diseases

4. Leukaemia

What Happens When a Person has a Low White Blood Cell Count?

If the human body is producing lower numbers of  WBC, it leads to a disease called leukopenia.

Conditions for leukopenia are as follows:

1. Bone marrow disorders

2. Vitamin B-12 deficiency

3. Autoimmune conditions, HIV

Hence, we can conclude that blood cells play an important role in our life. It protects our body by keeping a track of foreign bodies. They also supply oxygen to cells and tissues and provide essential nutrients. Blood cells help to keep our body clean by removing the waste products through the kidney.