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How does oxygen reach all parts of the body? How do the blood vessels get stuck little by little? Why is the respiratory system always invaded by germs...
Sometimes, medical and health care knowledge is boring, obscure, abstract and difficult to remember.
Since October, Life Times has set up a column of "Comic Painting Science" to paint images to make this knowledge "live", so that you can understand and learn at a glance.
The circular journey of the "Oxygen Courier"
With the heart constantly beating, blood circulates in a certain direction in the cardiovascular system, transporting oxygen (O2), nutrients, etc., while the metabolically produced carbon dioxide (CO2), urea and other waste products are transported to the respiratory organs and excretory organs, excreted.
Among them, oxygen is the key substance of human metabolism and the fundamental element of life activities. How does it circulate and be utilized in the human body? Life Times takes you to hear the "oxygen courier" self-description.
Audit specialists
Fu Bin, Professor of Hematology, Xiangya Hospital, Central South University
Lin Guoqiang, Associate Professor of Cardiac And Macrovascular Surgery, Xiangya Hospital, Central South University
Editors of this issue 丨 Xu Wenting Wang Xiaoqing
Drawing 丨 Ma Hongliang
My name is "Red Blood Cell" and I am a courier. Although I am small and unremarkable, my work is crucial and directly related to the health of human life.
I have a rounded appearance and a rich connotation:
The appearance is double concave disc-shaped, which is about 25% larger than the surface area of the spherical structure, which is conducive to faster gas exchange;
My interior is filled with hemoglobin, which has the function of binding and transporting oxygen and carbon dioxide.
In order to make the human body function properly, my partners and I work hard all the time. Every minute and every second of my life, I am constantly fulfilling one order after another:
As the heart beats, blood circulates in a certain direction through the cardiovascular system. I followed the blood flow through the human body, delivering "packages" along the way - oxygen, nutrients, etc., and taking away the waste of carbon dioxide, urea and other wastes produced by metabolism.
What is the effort to complete an order? Today I'm going to talk to you about my cyclical journey as an "oxygen courier."
"Ding-dong! You have a new delivery order"
Collection loading
My friends and I received one delivery message after another, and together we went to the warehouse to collect our respective "oxygen packages" and bind them to the hemoglobin in our bodies.
Countless red blood cells are assembled in the left ventricle of the "express distribution center", and the blood carrying oxygen (arterial blood, bright red) is ready to be fired, waiting in line to be shot out by a powerful heart pump.
Deliver packages
The contraction of the heart creates a strong momentum, shooting arterial blood out of the left ventricle, and at this point, our transport work begins. First, rush into the aorta with oxygen.
Subsequently, arterial blood enters the branches of the aorta. From here, everyone moves separately, each following different blood vessel branches, delivering packages to different tissues and organs.
For example, arterial blood enters the capillaries of tissues and organs such as the liver and kidneys, unloads the package full of oxygen, and at the same time "picks" from these organs and takes away carbon dioxide.
Prepare for the return journey
The companions who have just finished delivering the goods, with carbon dioxide, are constantly flowing back along the blood vessels, returning to the heart again, and preparing for the next express delivery.
At this time, the blood, because it carries carbon dioxide, becomes dark red venous blood. I joined countless of my buddies who had completed the oxygen delivery and followed the blood to the right atrium.
As the venous blood passes through the right atrium, we rush to the right ventricle.
When the heart contracts, it produces a strong momentum, and we follow the blood from the veins "squeezed" out of the right ventricle and into the pulmonary artery. After that, it passes through different branching paths to reach the pulmonary capillaries. This is the "only way" to reassemble packages.
Arriving inside the alveoli, we unloaded the carbon dioxide we had carried all the way and put back on the oxygen package to prepare to set off again, at which point the blood turned into arterial blood and flowed to the left atrium.
Go again
After the "transit" of the left atrium, we carrying the package followed the arterial blood and came to the left ventricle of the "express distribution center" again, ready to start the next round of delivery tasks.
- Ends -
Seemingly ordinary day, for the red blood cells, busy and full, only their struggle is not stopped, in order to achieve the cycle of oxygen, so that the human body has the "power" to continue to operate.
It should be reminded that malnutrition, lack of exercise, smoking, tight clothing, stress, atherosclerosis, etc. will cause poor blood circulation and can bring the risk of disease and even sudden death. ▲
Copyright notice: This article is the original of Life Times, and unauthorized reproduction is refused.