(1) How many capillaries are there in the body?
There are about 10 billion capillaries in the body.
80 % of the body except the muscle and the bone is the blood vessel and 99 % of the blood vessel is the capillaries. If 10 billion of the capillary are connected, the length becomes two and a half rounds of the earth, about 100 thousand km.
(2) What does capillary do?
The artery is the blood vessel to pump out the blood from the heart.
The vein is the blood vessel to return the blood to the heart.
The capillary is the blood vessel to provide nutrition and oxygen to the cells and to collect carbon dioxide (CO2) and wastes from the cells between the artery and the vein. The capillary trades unnecessary things for necessary things.
The capillary has a lot of holes and there is proper amount of leakage from the holes to provide nutrition and oxygen to the cells around. But if the wall cells which protect the capillary are damaged, the amount of the leakage increases, drying up the capillary and losing the function of the capillary. If the blood flow continuously stops in the capillary, the capillary itself disappears. This is ghost vessels.
(3) How old does the capillary easily decrease from?
The capillary easily decreases from 40s.
According to a research, the number of capillaries of 60s is 40 % less than 20s.
The capillary and dangerous diseases
Q1 Which is worsened by the decrease of the capillary?
(A) Effect of medicine (B) Quality of sleep
A1. (A) Effect of medicine
Even if the medicine is very effective, the decrease of the capillary makes the effect of the medicine drastically reduced.
An anticancer agent was administrated to a mouse developing cancer. The anticancer agent reached only some of the area. The leakage from the capillaries leaks the anticancer agent as well, so the anticancer agent doesn’t reach the required area.
Q2. Which can be caused by the decrease of the capillary?
(A) Easily having an attack of anemia (B) Easily catching a cold
A2. (B) Easily catching a cold
The decrease of the capillary causes the decline of the immune system, resulting in catching a cold easily. White blood cells which are immune cells and protect the body from the pathogens, but they can’t go to the place where they need to fight against the pathogens because of the disappearance of the capillary, resulting in catching a cold easily.
Q3. Aging of the skin is closely related to the decrease of the capillary. Which are not spread all over the cells of the skin and becomes the main reason of the aging of the skin?
(A) Oxygen and nutrition (B) Oxygen and water
A3. (A) Oxygen and nutrition
New cells are produced by the oxygen and nutrition delivered by the capillary. Healthy skins exchange old cells to new cells, which is the metabolism of the skin. Water is necessary, but the cell has the ability to produce water from the oxygen and nutrition.
The thickness of the capillary is 5 to 10 micron so a red cell which is 8 micron can pass through somehow (Fig.1 ). The thickness of the capillary is about one tenth of a hair.
Q4 Which is the reason that the risk of stroke and heart attack rises by the decrease of the capillary?
(A) Because high blood pressure tends to happen (B) Because thrombosis tends to happen
A4. (A) Because high blood pressure tends to happen
If the blood flow of the capillary is not good, nutrition and oxygen are not provided sufficiently. The heart detects the abnormality and rises the blood pressure to provide more blood. The blood vessel becomes hard to bear the high pressure of the blood from the heart. That makes the pressure even higher. High blood pressure rises the risk that the blood vessel ruptures. If the rupture happens near the brain, it causes stroke and if the rupture happens near the heart, it causes heart attack.
Q5. Which risk becomes higher due to the decrease of the capillary?
(A) Alzheimer’s disease (Dementia) (B) Pneumonia
A5. (A) Alzheimer’s disease (Dementia)
The brain which requires 15 % of all the body’s blood is filled with capillaries.
If the blood flow becomes poor and oxygen and nutrition are not delivered, the function of the brain declines, resulting in dementia.
Bones contain a lot of capillaries, so if the capillary decreases and required nutrition is not delivered, the density of the bone decreases and becomes easily broken.
The oxygen and nutrition are not delivered to all the body so the surplus nutrition taken from the meals remains in the blood vessel as excessive sugar. As a result, blood sugar is elevated, causing diabetes.
Sensitivity to cold:
The capillary delivers oxygen, nutrition, immune substance and temperature. Our body temperature is maintained by the blood delivered by the capillary. So the decrease of the capillary can cause sensitivity to cold.