Commonly taught anatomy is often simplified for various reasons. Perhaps the pupils are too young, perhaps there is only so much time, perhaps different aspects are considered more important than others. In any case, one common factor often left out is how much impact you have on the processes going on inside you. The way we learn about the digestive system, the urinary system, the circulation system often creates the feeling that our organs simply carry on their business regardless of what’s going on outside. Whether you are sitting there in class or out playing soccer, what’s the difference?
I’d like to explain a bit about the circulation system and lymphatic system and how we can easily help these systems function well if we understand how they work.
The lymphatic system plays a number of important roles in the body including a large part of immune responses as well as fluid return. The part of fluid return you are likely most familiar with is when you have swelling, such as a sprained ankle. The lymphatic system is responsible for clearing away all that extra fluid so that as you heal, your ankle is no longer swollen.
The lymphatic system works hand-in-hand with the cardiovascular system. In the cardiovascular system, blood flows in a cycle. In the lymphatic system, lymph fluid only flows in one direction: into the cardiovascular system.
In capillaries, blood is filtered so that oxygen, nutrients, fluid, etc. can be delivered to tissues and wastes can be carried away. The movement of these things is driven by concentration and pressure gradients. Due to the nature of these pressure differences, not all the fluid is returned to the capillaries to continue on through the veins. The initial vessels of the lymphatic system pick up this leftover fluid and return it at the subclavian veins (just under your clavicles).
Forces that drive fluid flow:
Arteries: blood flow is mainly driven by the pumping of the heart.
Capillaries: pressure created from the pumping heart is diffused during the filtration processes.
Veins: flow is driven mainly by skeletal muscle (muscles you consciously control) as well as respiration (inhalation/ exhalation creates pressure changes in abdominal cavity).
Lymph vessels: flow is driven by the siphon effect, angion contraction, as well as skeletal muscle contraction and respiration.
Think of when you show off your big biceps to your friends. As you “flex” the muscle, it bulges. Whenever muscle bellies bulge as they are working, they push against tubes that run near them or through them, thus helping to squeeze the fluid inside the tubes in the same way you squeeze out the last bit of toothpaste.
This means that every single muscle contraction contributes to keeping blood and lymph circulating the body, providing nutrients in a timely fashion to the tissues that need them, and carrying away waste (such as damaged cells from sites of injury) so that tissue can heal efficiently. It also means that not all exercise is equal. If you go for a jog, some muscles will be working harder than others, meaning that different parts of your body will experience replenishing blood circulation and revitalizing lymph flow more than others.
To keep all parts of you well nourished, you need to use all your parts. Seek variety in the way you move, and if you are healing from an injury, don’t feel prohibited from movement that feels safe and pain-free. Wiggling your toes at the end of a cast, stretching out muscles on the opposite side, and moving a limb within the range of motion available before pain are all ways to increase circulation and encourage the healing process.
Furthermore, not all breathing is the same. If your body is constantly restricted to the shallower, higher-up-in-the-torso kind of breathing that occurs when life is stressful, the fluid in your tubes will have less pressure change from you breathing in and out to help push up against gravity back towards the heart. If you can find ways to expose your body to less stressful situations or give your body time to process the stress it encounters, your tubes will feel the difference.
I’m not suggesting that you start breathing really hard and wriggling your whole body around constantly, but being aware that movement has more consequences than simply burning calories can put every action into a new perspective. Your body needs you!