The Lymphatic System: Definition and Fundamental Components

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  • 0:05 Infrastructural Immunity
  • 0:33 The Lymphatic System
  • 1:44 Tissues & Organs of…
  • 5:02 Lesson Summary
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Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

This lesson will cover something known as the lymphatic system. You'll learn about bone marrow, lymph, the thymus, lymph nodes, spleen, and much more as we explore this critical component of your immune system.

Infrastructural Immunity

In order for a country to function well, it needs some basic components. It needs roads connecting cities together as well as buildings in which citizens can live, work, and play. These are two very basic and fundamental parts of a healthy infrastructure. Likewise, your body needs an infrastructure by which its defense mechanism, the immune system, can travel, grow, and work. We'll be taking a look into a major part of this system.

The Lymphatic System

The system I am talking about is called the lymphatic system, and it is a collection of organs, tissues, ducts, and vessels that help to make or transport lymph. Lymph is a clear-to-white fluid circulating in the vessels and ducts of the lymphatic system that contains white blood cells, proteins, and fat.

This system is kind of simple to understand. Basically, the lymphatic capillaries and vessels help to transport cells and fluid from tissues back into general circulation. They also transport foreign invaders, such as bacteria, to organs of the lymphatic system, where white blood cells will destroy them. These white blood cells are like the emergency personnel of our country: firefighters, police, and ambulances that respond to a crime scene caused by a pathogen.

However, the cells (the emergency personnel) need a place to be trained, a place to be stationed, and a home to live in. The buildings that provide for such needs are akin to the tissues and organs of the lymphatic system.

Tissues and Organ of the Lymphatic System

One such major tissue is called the bone marrow. This tissue is located inside of many of the bones in your body and is a tissue that produces red blood cells, white blood cells, and platelets.

The bone marrow is like the hospital in our country, where little babies are born and taken care of during the first few days of their life.

Once the future emergency personnel (the white blood cells) are born in the bone marrow, some of them need to grow up a bit before they are ready for action. You know how that goes; some people just mature faster than others.

When white blood cells of the innate immune system, such as neutrophils, monocytes, eosinophils, and basophils, are released from the bone marrow, they are essentially ready for action right away. This is because they are nonspecific in the way they attack an invader. They basically go after anything that moves. You can liken these emergency personnel to police officers ready to respond to any problem.

This is in contrast to white blood cells of the adaptive immune system, called lymphocytes, which are very specific to the invader they try to kill, kind of like K9 officers. K9 officers must first become policemen, but they also need further maturation and training to deal with specific threats where a dog may need to be used.

Therefore, the cells of the adaptive immune system, called lymphocytes, need to mature and train a bit more before they are fully functional. For example, B-cell lymphocytes will mature in the bone marrow, while other lymphocytes will need to be transported to an organ called the thymus, which is an organ involved in the maturation of T-cells, a type of lymphocyte. This is really easy to remember; just recall that B stands for 'bone marrow' and T stands for 'thymus.' In any case, I'm sure you won't be surprised to learn that the thymus and bone marrow are considered to be the primary organ and tissue of the lymphatic system, because this is where white blood cells are made and mature.

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