Source of pictures: pixabay.com
The first class on Wednesday afternoon is Natural Science. This is David's favorite course. "Jingle- jingle." The bell rang. The teacher walked in with a thick encyclopedia and the whole classroom immediately got quite. He gently put the book on the desk and turned his head to the door. Then pairs of little eyes followed him and gathered at the doorway with curiosity. At this point, the teacher said enthusiastically, "Boys and girls, today I have invited my friend, who is the attending physician of the Department of Nephrology in our municipal hospital. He will give you a medical lecture."
As the teacher finished his words, the classroom burst into applause. A young doctor walked in. He nodded slightly to the students. Then he picked up the chalk and turned to the blackboard. After writing down a word "kidneys", he asked, "Anybody knows what kidneys look like?"
The students shook their heads. The doctor patiently explained to them, "Kidneys are a pair of small organs. Their shapes look like beans and they are near our back. We have a pair of kidneys. However, our body can function normally even if there is only one healthy kidney. Kidneys are small, but they play many important roles, such as balancing body fluid, regulating blood pressure, generating red blood cells, and helping our body to clear wastes."
At this moment, David raised his hand to ask questions. The doctor nodded at him as permission. Then David asked, "'I want to know what is inside the kidney. You told us it looked like a bean. Are there a lot of beans-like stuff in it just like a pod?" The doctor smiled and replied, "You are half-right. You should know that a kidney is made up of about one million filtering units. We call this filtering unit as 'nephron'. Each nephron contains a group of small winding blood vessels. This group is named as 'glomerulus', which functions like a semipermeable membrane."
Another child raised his hand and asked, "What is the semipermeable membrane?" "You all are very good at thinking," the doctor replied, "The semipermeable membrane is like a magical gate. Only certain particles are allowed to pass through. For glomeruli, they only allow water and soluble wastes in the blood to traverse. These filtered wastes will be excreted in the form of urine eventually."
The student continued, "If the glomeruli have something wrong and can't filter out wastes normally, what would happen?" The doctor answered, "A good question. When glomeruli in nephron don't work, the wastes that should have been filtered out begin to accumulate in the body. Then, there will be damages to human body. Therefore, we should maintain a healthy lifestyle to keep healthy, such as having meals on time and doing exercise regularly."
Author: Lu An
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