Blood is a fluid connective tissue composed of plasma, blood cells, and platelets. It circulates throughout our bodies, supplying oxygen and nutrients to different cells and organs. It accounts for about 8% of our body weight. It is made up of blood cells suspended in blood plasma invertebrates.

The heart’s pumping function circulates blood through blood arteries throughout the body. In animals with lungs, arterial blood transports oxygen from breathed air to the tissues, and venous blood transports carbon dioxide, a waste product of cell metabolism, from the tissues to the lungs to be expelled. An average adult has about 5-6 liters of blood.

What are the components of blood and their functions?

Blood is composed of plasma and the formed elements. The generated elements are two types of blood cells or corpuscles: red blood cells (erythrocytes) and white blood cells (leukocytes), as well as platelets, which aid in clotting. Red blood cells account for approximately 45 percent of total blood volume, plasma for around 54.3 percent, and white cells for around 0.7 percent.

Formed Elements: We’ve seen that blood is made up of cells known as formed constituents of blood. These cells each have their own set of duties and duties to fulfill in the body. The following are the blood cells that circulate throughout the body:

Red Blood Cells (Erythrocytes): In humans, RBCs are biconcave cells with no nucleus; they are also known as erythrocytes. RBCs contain hemoglobin, an iron-rich protein that gives blood its red color. RBCs are the most abundant type of blood cell produced in the bone marrow. Their primary role is to move oxygen from and to different tissues and organs. The hematocrit is the percentage of blood occupied by red blood cells, which is generally around 45 percent. The surface area of all red blood cells in the human body would be approximately 2,000 times that of the body’s external surface.

White Blood Cells (Leucocytes): Leucocytes are blood cells that are colorless. They are colorless because they lack hemoglobin. Granulocytes and agranulocytes are two types of lymphocytes. WBCs primarily aid in immunity and defense mechanisms. They assault pathogenic agents (pathogens) and foreign substances, as well as kill and eliminate old or abnormal cells and cellular waste. Leukemia is a type of malignancy that affects leukocytes.

Platelets (Thrombocytes): Tiny disc-shaped cells that assist regulate blood flow when any portion of the body is damaged, allowing for faster recovery through blood clotting. Platelets, also known as thrombocytes, are minute, colorless blood cell fragments that form clots and stop or prevent bleeding. Platelets are produced in the bone marrow, the sponge-like substance found within our bones. Stem cells in bone marrow turn into red blood cells, white blood cells, and platelets.

Plasma: Blood plasma is a yellowish liquid component of blood that suspends blood cells, proteins, and other components of whole blood. It accounts for approximately 55% of the total blood volume in the body. It is the extracellular fluid’s intravascular component. It is primarily water (up to 95 percent by volume) and contains dissolved proteins (e.g., serum albumins, globulins, and fibrinogen), glucose, coagulation factors, electrolytes (Na+, Ca2+, Mg2+, HCO3, Cl, etc.), hormones, carbon dioxide, and oxygen.

What are the components of plasma?

Plasma is 90% water, with the remaining 10% made up of ions, proteins, dissolved gases, nutritional molecules, and wastes.

Antibody proteins, coagulation factors, and the proteins albumin and fibrinogen, which maintain serum osmotic pressure, are all found in plasma.

What are the components of Blood Plasma?

The blood plasma is made up of some specific components. Their names and functions are as follows:

Plasma Proteins

  1. Albumin: Albumin aids in the maintenance of the blood’s colloid osmotic pressure. It is the smallest of the plasma proteins yet accounts for the highest percentage. The blood’s colloid osmotic pressure is critical for maintaining a balance between the water inside the blood and the water in the tissue fluid surrounding the cells. Albumin also aids in the transfer of several molecules, including medicines, hormones, and fatty acids.
  2. Globulin: Globulins are classified into three types: alpha, beta, and gamma, with the smallest being alpha and the largest being gamma. Antibodies are gamma-globulins. The alpha globulins contain high-density lipoproteins (HDL), which are vital in transporting fats to cells for the construction of numerous compounds as well as energy metabolism. The most well-known function of HDL is its role in preventing plaque formation by retaining cholesterol in the bloodstream. Low-density lipoproteins (LDL) are beta globulins that transport fat to cells for the creation of steroid and cell membranes. It also stimulates the creation of cholesterol plaques, which is a risk factor for arterial and heart disease. Immunoglobulins are another name for antibodies or gamma globulins. They are produced by B lymphocytes, a type of immune cell. Antibodies are in charge of the body’s humoral immune response, identifying pathogens through specific receptors and neutralizing them through a variety of processes.


Fibrinogen is a soluble plasma clotting factor precursor that, when it comes into touch with a sticky surface, converts to fibrin, a threadlike protein. The fibrin threads generated in this manner trap platelets, forming the primary platelet clot upon which a stable blood clot is produced by the coagulation process.

Clotting Factors And Inhibitors

Plasma clotting factors cause a blood clot to develop at any rupture in the smooth endothelium lining of the blood arteries. This not only stops blood loss but also defends the body from invading microorganisms.

Coagulation inhibitor proteins keep blood from clotting in unfavorable places or at unfavorable times.

Other Proteins

  • Cytokines are cellular signaling molecules that cells create in order to interact with one another and regulate critical cellular processes.
  • Hormones are substances secreted by one organ or cell type to act on another in a remote area via the bloodstream, resulting in long-distance effects.


Sodium is the most abundant ion in plasma and accounts for the majority of plasma osmolarity.

Amino Acids

Tissues or plasma proteins can be broken down and the amino acids reused in the production of other biological structures. This may involve macrophages in the gastrointestinal tract, the lymphatic system, and the lungs.

Nitrogenous Compounds

Nitrogenous waste products, such as urea, are formed in the body as a result of the breakdown of numerous substances. These are transported by plasma to the kidneys for excretion.


Plasma contains nutrients absorbed from the gut or other organs of origin, such as glucose, lipids, amino acids, minerals, and vitamins.

Dissolved Gases

In addition to dissolved oxygen and carbon dioxide, plasma includes a considerable amount of nitrogen.

What are the types of blood?

The ABO blood group system categorizes blood types based on the distinct types of antigens found in red blood cells and antibodies found in plasma. They employ the ABO system in conjunction with the RhD antigen status to decide which blood type(s) will match for a safe red blood cell transfusion.ABO is divided into four groups:

  • Group A: A antigen is found on the surface of red blood cells, and an anti-B antibody is found in plasma. Anti-B antibodies would assault blood cells containing the B antigen.
  • Group B: B antigen is found on the surface of red blood cells, and anti-A antibody is found in plasma. Anti-A antibodies would assault blood cells containing the A antigen.
  • Group AB: The red blood cells contain both A and B antigens, but there are no anti-A or anti-B antibodies in the plasma. Individuals with ABO blood type AB are eligible for any ABO blood type.
  • Group O: The plasma includes both anti-A and anti-B antibodies, but the red blood cell surface lacks either A or B antigens. Because these antigens are not present, this type of blood can be received by anyone with any ABO blood type.

The Rhesus Factor

Rh factor, commonly known as the RhD antigen, is found in some red blood cells. The Rhesus grouping offers a new dimension. RhD positivity occurs when red blood cells have the RhD antigen. They are RhD negative if they do not.
When assessing blood types, doctors must consider both ABO and Rh. This indicates that the ABO/Rh blood group system has eight major blood types.

What are the components of Blood Pressure?

Blood pressure (BP) is the force exerted by blood on the walls of blood vessels, which aids in the movement of blood throughout the body.

The components of blood pressure include systolic and diastolic pressure.
The amount of pressure that blood puts on vessels while the heart is pumping is measured as systolic blood pressure.

Systolic blood pressure should be no more than 120 mmHg. The pressure in the vessels between heartbeats is measured by diastolic blood pressure. The ideal diastolic blood pressure is 80 millimeters of mercury. Hormones, stress, exercise, eating, sitting, and standing are all factors that might impact blood pressure.

The number of blood vessels, the movement of smooth muscle, one-way valves, and the fluid pressure of the blood itself all influence blood flow through the body.

When new blood enters the arteries during systole, the artery walls expand to accommodate the increased pressure of the extra blood; during diastole, the walls return to normal due to their elastic qualities.

For example, 120/80 denotes a systolic blood pressure of 120 mm Hg and a diastolic blood pressure of 80 mm Hg. The blood continues to drain into the arterioles at a rather uniform rate throughout the cardiac cycle.

Diastolic blood pressure has long been thought to be the essential component of blood pressure and the primary focus of antihypertensive medication. Important epidemiological studies highlighted the significance of systolic blood pressure, and research in the 1990s reinforced this perspective.

In contrast to diastolic blood pressure, systolic blood pressure rises gradually with age, and in aging societies, high systolic blood pressure is the most frequent form of hypertension.

During strenuous exercise, the blood arteries relax and dilate, compensating for the increased heart rate and ensuring that adequate oxygenated blood reaches the muscles. Stress causes a decrease in blood vessel diameter, which leads to an increase in blood pressure. These variations can also be produced by nerve signals or hormones, and simply standing or lying down can have a significant impact on blood pressure.

What causes hemolytic anemia?

Hemolytic anemia occurs when the breakdown of red blood cells outpaces the synthesis of these cells by your bone marrow.

Extrinsic and intrinsic hemolytic anaemia are both possible.

  1. Extrinsic hemolytic anemia can develop in a variety of ways, including when the spleen captures and destroys healthy red blood cells or when an immunological reaction occurs. It can also be caused by the loss of red blood cells as a result of; an infection, cancerous growth, autoimmune conditions, adverse effects of medicine, cancer of the bone marrow, lymphoma.
  2. Intrinsic hemolytic anemia occurs when your body’s red blood cells fail to work normally. This disorder is frequently hereditary, as evidenced by those who have sickle cell anemia or thalassemia and have defective hemoglobin.

Other times, an inherited metabolic anomaly, such as G6PD deficiency or red blood cell membrane instability, such as hereditary spherocytosis, can cause this illness. Hemolytic anaemia can affect people of any age.


It is possible that a doctor will be unable to identify the cause of hemolytic anaemia. This condition, however, can be caused by a number of disorders and even some drugs. The above-mentioned reasons are some of the causes that can result in this disease.

In some cases, taking certain drugs causes hemolytic anaemia. This is referred to as drug-induced hemolytic anaemia. One of the most severe types of hemolytic anaemia is induced by obtaining the wrong blood type red blood cell transfusion.

Everyone has a unique blood type (A, B, AB, or O). If you acquire an incompatible blood type, antibodies, which are specialised immune proteins, will assault the alien red blood cells. As a result, red blood cells are destroyed exceedingly quickly, which can be fatal. This is why, before providing blood, healthcare providers must thoroughly check blood types.

Some of the causes of hemolytic anaemia are just transient. Hemolytic anaemia may be treatable if the underlying cause is identified and treated.