You can start this unit by evaluating your students’ skills; to determine how much information your students either know or remember from past experiences, a pre-test or questionnaire can be used. For example:
1. What is the Circulatory System?
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2. Name the main parts of the system.
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3. What is blood?
4. How is blood pumped through the body?
These types of answers can be reviewed by the teacher and a final analysis can be made to determine the amount of information you need to cover for each specific class.
I. History and Discoveries
Concept:
Ancient myths revealed stories of bloodletting, a process of cutting a vein to drain out some of the evil spirits which have strickened the body with illness.
You can begin by reading some of these ancient myths about the circulatory system to your class. In ancient Greece, people believed that a person became ill when the evil spirits entered the body, and there was no way for these spirits to leave unless some type of cut was made. Sick people were brought to the local barber, who would cut a vein and let some of the person’s blood drain into a pan to let some of the “bad blood” out. This “bad blood” was enriched with the evil spirit and when the barber thought enough blood was let out, he would patch up the wound and send the patient off. This process, termed “blood-letting” caused many people to bleed to death and to die from infections.
At this point a discussion about bloodletting can encourage the students to reach conclusions about the dangers of the process. See if the students can answer, “Why was this process dangerous?” Other discussions can lead to the term “bad blood” which is still used today in regards to “bad blood between families”. Talk about the role that the barber played as a surgeon. In conclusion, as a homework assignment, have students go to a local barber and ask what the red, white, and blue stripes mean on the barber pole. They should learn to identify the red with blood, blue with vein and white for bandages. Students at this age love to listen to myths. They can get an idea of the foolish ideas medicine had in those days. It can also show in their minds the progress science and medicine have made from that time period to now.
Concept:
The heart, by repeated contraction, produces a continuous flow of blood throughout the body which continually returns to the heart in one complete cycle.
Acquire William Harvey’s best written novels or pieces of work that he developed around 1625. Read to your class some of Harvey’s discoveries he made about the heart and blood. Describe to your students the time, classroom settings and equipment that Harvey used and worked by. Explain how his discoveries were so important and how they became the basis for modern physiology. Also, explain how Harvey could have gotten killed for publishing his work. After completing the readings try and receive some feedback from the students by setting up the following activity:
Lesson
: (Writing assignment, listening skills) “Close your eyes and pretend that you are sitting in William Harvey’s classroom back in 1628. You are one of Mr. Harvey’s students. Answer these questions, first in your mind, then in story form on a piece of paper.”
1. What kind of clothes are you and your classmates wearing?
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2. Describe your classroom to me.
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3. What kind of lab equipment are you using?
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4. What are some of the lectures Mr. Harvey gave to your class?
5. Draw a portrait of Mr. Harvey (what do you think he looked like?)
You now have the basis or foundation of your unit. Your class has their feet wet. They understand a little history of the circulatory system and they had fun building their foundation.
II. Blood and its Parts
Concept:
Blood is the fluid of the circulatory system. It is essential to life. It consists of a solid part, the cells, and the liquid part, plasma. Blood carries oxygen and food substances to the cells.