The Functions of Blood and How it Works in The Body

Inside the body, nutrients and certain substances are been absorbed into the blood for biochemical processes and cell activities. The blood helps the body perform various functions like nutrient absorption, cell mitosis, oxygen transport and excretion of waste. In this post, we’ll talk about the functions of blood and how it works in the body.

How The Blood Works

Table of Contents

Blood is a transport liquid pumped by the heart to all parts of the body, after which it is returned to the heart to repeat the process.

Blood is both a tissue and a fluid. It is a tissue because it is a collection of similar specialized cells that serve particular functions.

These cells are suspended in a liquid matrix called plasma, which makes the blood a fluid. If blood flow stops, death will occur within minutes because of the effects of an unfavorable environment on highly susceptible cells.

In other words, blood is an aqueous body fluid containing water with a whole range of substances like oxygen and carbon dioxide. It is contained in a complex network called the cardiovascular system and is pumped around the body by the heart.

Blood Components

In humans, blood is an opaque red fluid, freely flowing but denser and more viscous than water.

The characteristic color is imparted by hemoglobin, a unique iron-containing protein.

Hemoglobin brightens in color when saturated with oxygen and darkens when oxygen is removed.

For this reason, the partially deoxygenated blood from a vein is darker than oxygenated blood from an artery.

The red blood cells constitutes about 45 percent of the volume of the blood, and the remaining cells such as leukocytes and platelets are less than one percent.

the blood cells

The fluid portion, plasma, is a clear, slightly sticky, yellowish liquid. After a fatty meal, plasma appears turbid. Within the body the blood is permanently fluid, and turbulent flow assures that cells and plasma are fairly homogeneously mixed.

The blood is a fluid that consists of:

  • Plasma
  • Leukocytes
  • Erythrocytes
  • Platelets

Plasma: Serves as a transport medium for delivering nutrients to the cells of the various organs of the body.

Erythrocytes: Red blood cells also called erythrocytes carries oxygen to the lungs and tissues.

Leukocytes: Leukocytes known as white blood cells fights infections and diseases.

Platelets: Promotes clotting to reduce blood loss when there’s injury in the blood vessels.

The Functions of Blood

Blood plays an important role in many functions of the cardiovascular system.

The functions of blood include:

  • Blood contains DNA that signals the presence of certain diseases, such as cancer, and indicates chemical imbalances like iron deficiency.
  • Blood transports nutrients from their site of absorption in the digestive tract to the cells that require these nutrients.
  • Blood carries waste products from the cells’ activities to the kidneys for disposal from the body.
  • It distributes hormones to organs that the endocrine system uses to coordinate physiological functions in our bodies.
  • Our blood carries clotting factors and platelets to help prevent the blood loss that often occurs with injury.
  • Blood also carries heat generated in the body core to other parts of the body.
  • It distributes water and electrolytes to all of our tissues as well.


The blood helps in transporting substances through the blood vessels, and it also facilitates the absorption of nutrients, cell activities and biochemical processes. It has four main components such as plasma, erythrocytes, leukocytes, and platelets. Each blood component has it’s specific functions. Plasma delivers nutrients to the tissues and organs of the body, leukocytes fights infections, erythrocytes transports oxygen and platelets promotes blood clotting when there’s injury.

If you like this post then subscribe to our YouTube channel for more updates.