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 walkedin with a thick encyclopedia and the whole classroom immediately gotquite.Hegently put the book on the desk and turnedhis head to the door. Then pairs of little eyesfollowed him andgatheredat the doorway with curiosity. At this point, the teacher saidenthusiastically,"Boys and girls,todayI have invitedmy friend, who is the attending physician of the Department of Nephrology in our municipal hospital. He will giveyoua medical lecture."
As the teacher finishedhis words, the classroom burst into applause. A young doctor walkedin. He noddedslightly to the students. Thenhe pickedup the chalk and turnedto the blackboard.Afterwritingdown a word "kidneys",heasked, "Anybodyknows what kidneys look like?"
The students shooktheir heads. The doctor patiently explained to them,"Kidneys are a pair of small organs. Their shapeslooklike beans and theyare nearour 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 raisedhis handto ask questions. The doctor noddedat himas permission. Then David asked, "'I want to know what is insidethe kidney. You told us it looked like a bean. Are there a lot of beans-likestuffin it justlike a pod?" The doctor smiled andreplied, "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 functionslikeasemipermeable membrane."
Another child raisedhis 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 totraverse. These filtered wastes will be excreted in the form of urine eventually."
Thestudent continued,"If the glomeruli have something wrong and can'tfilter out wastesnormally, what would happen?"The doctor answered, "A good question. When glomeruli innephron don't work, the wastes that should have been filtered out begin to accumulate in the body. Then, there will bedamagesto human body. Therefore, weshouldmaintain a healthy lifestyleto keep healthy, such ashaving mealson timeand doing exercise regularly."
Author: LuAn
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