Difference Between Blood and Lymph

Main Difference – Blood vs Lymph

Blood and lymph are the two circulating fluids in the animal body. Blood belongs to the circulation system whereas lymph belongs to the lymphatic system. Blood contains pigments which carry oxygen. Therefore, blood can be found in different colors in different types of organisms. But, lymph is a colorless fluid. Blood is composed of red blood cells, white blood cells, platelets and a fluid called plasma. Lymph is composed of white blood cells and a watery fluid. Both blood and lymph possess a circulatory function as well as an immune function. The main difference between blood and plasma is that blood circulates inside blood vessels whereas lymph circulates inside lymphatic vessels.

Key Areas Covered

1. What is Blood
      – Definition, Components, Function
2. What is Lymph
      – Definition, Components, Function
3. What are the Similarities Between Blood and Lymph
      – Outline of Common Features
4. What is the Difference Between Blood and Lymph
      – Comparison of Key Differences

Key Terms: Blood, Blood Vessels, Chyle, Circulatory System, Lymphatic System, Lymphatic Vessels, Lymph

What is Blood

Blood refers to the red liquid which circulates inside the arteries and veins, carrying respiratory gases and nutrients throughout the body. Red blood cells, white blood cells, platelets, and plasma are the components of the blood. Blood runs through the arteries, veins, and capillaries. It contains 55% of plasma and 45% of blood cells. The main function of the blood is to transport respiratory gases, nutrients, and metabolic wastes to their target organs. Oxygen is transported to the metabolizing tissues from lungs with the aid of respiratory pigments such as hemoglobin. Carbon dioxide is transported back to the lungs from tissues. Nutrients are transported to the tissues and metabolic wastes are transported to the excretory organs. Based on the type of components transported by the body, two types of blood can be identified: arterial blood and venous blood.

Figure 1: Arterial blood (brighter) and venous blood (darker)

White blood cells in the blood fight against the pathogens that invade the body. Blood also regulates the body temperature and maintains the pH.

What is Lymph

Lymph refers to a colorless fluid which bathes tissues and drains through the lymphatic system. It originates from the tissue fluid, connecting tissue fluid to the blood. Within tissues, a scattered network of lymphatic vessels occurs, collecting the tissue fluid and draining it back to the circulatory system. The lymph capillaries in the tissue spaces are shown in figure 2.

Figure 2: Lymph Capillaries

Lymph is composed of white blood cells and a watery fluid. The major function of the lymph is to maintain the fluid balance of the body. The composition of the lymph changes with its origin. For example, the lymph produced in the intestine contains a high concentration of fats. This lymph is called the chyle and it is milky-white in color.

Similarities Between Blood and Lymph

Both blood and lymph are two types of circulating fluids in the body.
Both blood and lymph circulate inside vessels.
Both blood and lymph circulate compounds in the body.
Both blood and lymph possess an immune function in the body.

Definition

Blood: Blood is the red liquid which circulates inside the arteries and veins, carrying respiratory gases and nutrients throughout the body.

Lymph: Lymph is a colorless fluid which bathes tissues and drains through the lymphatic system.

Color in Humans

Blood: Blood is red color in humans.

Lymph: Lymph is colorless.

Circulation

Blood: Blood circulates through arteries, veins, and the heart.

Lymph: Lymph circulates through lymph capillaries, lymph nodes, and lymph vessels.

Transporting Fluid

Blood: Blood is the main transporting fluid of the body.

Lymph: Lymph is the parallel transporting fluid, which connects tissue fluid to the circulatory system.

Red Blood Cells

Blood: Blood contains red blood cells.

Lymph: Lymph does not contain red blood cells.

Protein Concentration

Blood: Blood consists of a high protein concentration.

Lymph: Lymph consists of a low protein concentration.

Nutrients and Wastes

Blood: Blood contains more nutrients and wastes.

Lymph: Lymph contains fewer nutrients and wastes.

System

Blood: Blood belongs to the circulatory system.

Lymph: Lymph belongs to the lymphatic system.

Role

Blood: Blood regulates body temperature and maintains pH.

Lymph: Lymph transports fat and fat-soluble vitamins and stores lymphocytes.

Clotting

Blood: Blood clots rapidly due to the presence of fibrinogen.

Lymph: Lymph clots slowly due to the presence of less fibrinogen.

Conclusion

Blood and lymph are the two circulatory fluids in the body. Blood circulates through blood vessels and lymph circulates through lymphatic vessels. Blood carries respiratory gases, nutrients, and metabolic wastes throughout the body. Lymph is the draining of the tissue fluid to the circulatory system. The main difference between blood and lymph is their function in the body.

Reference:

1. “American Society of Hematology.” Blood Basics, 8 Sept. 2017, Available here.
2. “What is a Lymph? – Definition & Anatomy.” Study.com, Available here.

Image Courtesy:

1. “Venous and arterial blood” By Wesalius – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Illu lymph capillary” By SEER – U.S. National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) Program(Public Domain) via Commons Wikimedia