Topic: How the blood vessels are build, how blood circulates

Author: Elżbieta Szedzianis

Target group

7th grade students of an eight‑year elementary school.

Core curriculum

Lesson objective

How the blood vessels are build and how blood circulates.

Key Success Criteria

• you will compare the build and the functions of arteries, veins and capillaries;

• you will explain the blood circulation in the body.

Key Competences

• communicating in the mother tongue;

• communicating in a foreign language;

• Mathematical competence and basic competences in science and technology;

• digital competence;

• learning to learn;

• social and civic competences.

Methods/Forms of work

work with text, instant information method, workshop method.

Individual work.

Teaching measures

• abstract;

• interactive or traditional whiteboard;

• tablets/computers;

• blood‑pressure monitor;

• disposable aprons;

• red and blue permanent markers.

Lesson plan overview (Process)

Before classes

The teacher invites a school nurse to classes

Introduction

1. The teacher tells the topic of the lessons, defines the purpose of the course and gives students the criteria for success.

2. The teacher asks a selected student to explain the heart work cycle.

Realization

1. The students read the fragment titled “The build of blood vessels” and in their notebooks, they prepare a table comparing the features (their lumen, the thickness of the muscle tissue, the presence of valves) and functions of all types of blood vessels.

2. Using the instant information method, the students talk about the build and functions of veins, arteries and capillaries.

3. The lecturer invites you to a school nurse classes, which will show students how to correctly measure their heart rate. The teacher instructs the pupils to write down the research question and the hypothesis in the form in the abstract. Then the students perform the experiment, record their observations and conclusions. The teacher indicates the person who shares his insights and explains the reasonableness of the conclusions he has made.

4. Next, volunteers, instructed by the teacher, measure their blood pressure while resting and after some physical effort. They compare the results and explain, why after some physical effort the blood pressure and the pulse increase.

5. The students analyze the illustration “Blood circulation” and describe the blood circulation in a closed system of vessels.

6. The teacher informs the students that their next task will be to demonstrate the blood circulation on themselves. He asks them to prepare, drawing on disposable aprons, the large and small blood circulation. When the drawings are ready, the students analyze them and show, how blood circulates in our body.

Summary

The students complete the interactive exercise no. 1 and interactive exercise no. 2.

Optional homework

The students prepare a comic strip which presents blood vessels - a vein, an artery and capillaries - which have a discussion about which one of them is the most important.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

How the blood vessels are build, how blood circulates

Blood is distributed all over the body using 3 types of blood vessels: arteries, veins and capillaries. Their walls are composed of 3 layers of tissues. The outer layer protects the blood vessels, the middle layer, composed of smooth muscle tissue, shrinks them or widens them, meaning that it regulates the blood flow. The internal layer, called endothelium, is thin and smooth, which allows blood to flow.

In arteries, blood circulates under high pressure, which is why the muscle layer and the internal membranes are thick. Veins transport blood under low pressure. Their muscularis is thinner, and internal membrane creates valves. They prevent the blood from flowing backwards and allow it to pump against the law of gravity. There are connections between the arteries and the veins. The network of very thin blood vessels is called the capillaries. Their walls are build of only one layer of cells: simple squamous epithelium. This type of a structure allows the gas exchange to take place and allows various substances to penetrate to and from the vessels.

Blood flows in a closed circuit of vessels which is composed of 2 circulations: systemic and pulmonary.

In pulmonary circulation blood that has a lot of carbon monoxide and very little oxygen is introduced from the right chamber to pulmonary arteries. These arteries are divided into smaller ones until they become thin capillaries that wrap around the alveoli. Between the blood in the capillaries and the alveoli the gas exchange happens. Diffusion happens and blood gives away the carbon monoxide and absorbs oxygen. Oxygenated blood goes back via the capillaries which become bigger veins. Pulmonary veins conduct the oxygenated blood into the left atrium.

During the contraction of the left atrium, the blood flows into the left chamber, where the systemic circulation begins. Next, from the left chamber, it flows to the biggest artery of the body – aorta. This is divided into smaller arteries coming closer to the cells of the body and forming the network of capillaries. Through them, oxygen and nutrients are transported towards the cells, whereas the products of metabolism are absorbed. Diffusion of respiratory gases takes place in the cells. It is also called the internal gas exchange: oxygen enters the tissues, whereas the carbon dioxide is transferred from the tissues into the capillaries. Deoxygenated blood is taken to the vein capillaries, which form bigger veins. Main veins from upper and lower part of the body transport the blood with carbon dioxide into the right atrium.

• Cardiovascular system includes the heart and blood vessels: Veins, arteries and capillaries.

• Arteries lead blood from the heart, whereas veins lead blood to the heart.

• Capillaries are wrapped around cells, provide them with nutrients and participate in gas exchange.

• Blood circles in 2 circulations: systemic and pulmonary.