Topic: The build of the heart. Cardiac cycle.

Author: Elżbieta Szedzianis

Target group

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

Core curriculum

Lesson plan overview (Process)

The students recognize the build of a heart and its work cycle.

Key Success Criteria

• you will describe the build of a heart and its location;

• you will talk about the cardiac cycle.

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

Programmed method, observation.

Individual work, work in pairs and work in groups.

Teaching measures

• abstract;

• interactive or traditional whiteboard;

• tablets/computers;

• stethoscopes;

• watch with a stopwatch option.

Lesson plan overview (Process)

Introduction

1. The teacher plays a recording of how heart works from the Internet titled: *”Usypiające BICIE SERCA - biały szum” https://www.youtube.com/watch?v=38_OFXKhJgs. He asks the students to imitate its rhythm. Next, the teacher explains that during this lesson, the students will learn how the mechanism of heartbeat works.

2. The teacher tells the topic of the lessons, defines the purpose of the course using simple language and shows students the criteria for success.

Realization

3. The teacher informs the students about what is planned for this lesson: they will work individually, at their own pace - they will read an abstract, complete exercises and conduct observations. He gives detailed information to his students. He announces that he will supervise their work and help them if necessary.

4. The students read the fragment titled “The build of the heart” twice. They analyze the illustration that represents the location of the heart and a simplified schematic drawing of how the heart is build. They write down the most important notions. If they do not understand some, they check their meaning in the “Glossary”.

5. The students complete in writing “Exercise 1”, and then they complete the interactive exercises no. 1, 2, and 3.

6. The students read the fragment titled “The work of the heart” twice. They conduct “Observation no. 1”.

7. They complete in writing “Exercise 2” and “Exercise 3”.

8. The students look for the radial artery in the wrist area, if necessary, they can use the illustration “Place where you should measure the pulse”. They draw a point where you can feel the pulse on the skin. Then, they count heartbeats per minute. In writing, they answer the question: “What conclusion do you draw from comparing the number of heart beast and the pulse?”.

9. The students complete the interactive exercise no. 4, 5, 6, and 7.

10. Then, they discuss their solutions - first in pairs, then in groups of four.

Summary

The teacher asks the students to finish one of the following sentences:

• “I like learning things using the programmed method, because...”.

• “I don’t like learning things using the programmed method, because...”.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

The build of the heart, cardiac cycle

Cardiovascular system is a closed transporting system, which is composed of the heart and blood vessels. Heart has the shape of a cone and the size of a closed fist. It is found in the middle of the chest, behind the sternum, and its tip is pointed to the left. It is composed of striated muscle tissue, which contracts regularly, forcing the blood to flow in blood vessels. There are 4 chambers of the heart: 2 atria (right and left) and 2 ventricles (right and left). There are walls between particular parts of the heart. The walls of the ventricles are thicker and more muscular than the walls of the atria. This happens because the atria transport the blood only to the ventricles, and the ventricles transport it into all the arteries. The pressure of the blood pushed out by the ventricles must be this high in order for the blood to reach even the cells that are located the furthest from the heart. Veins enter into the atria and transport blood into the heart, whereas arteries start from the ventricles and they transport the blood from the heart. Between the atria and the ventricles and at the place where the vessels exit the ventricles there are valves. They open in one direction only, which means they force the blood to flow in one direction and prevent it from regressing.

In order to describe how heart works using a schematic drawing, we must first establish, which part is left and which part is right. In order to do this, we put the piece of paper with the schematic drawing of a heart to our own torso, as if we wanted to show the model of our own heart. The parts of the schematic drawing of the heart on our left side are the left ventricle and left atrium, and those on our right side – right ventricle and right atrium.

If blood isn’t reaching an organ for several minutes, that place suffers from irreversible changes and necrosis of tissues, which is why the heart beats non‑stop. Heart beat is composed of contractions of the organ, one after the other. A doctor listens to cardiac cycle when putting stethoscope to our chest. He pays attention e.g. to the tones, which approximately are identical with contractions of the ventricles and them unflexing.

First, blood transported by the veins fills both atria. When the atria contract, they push blood into the chambers. Then, both ventricles contract, pushing the blood from the heart into the arteries. After that, heart has a short period of rest. When it is relaxed, the atria become filled with blood again.

The heart contracts between 60 and 80 times per minute, pushing around 80 cmIndeks górny 3³ of blood during every contraction. The pressure of the blood flowing from the heart can be felt in the arteries as pulse and measured with a blood‑pressure device. This device shows you the values of systolic pressure (120 mm Hg) and diastolic pressure (80 mm Hg). Blood pressure is measured during rest, because it becomes elevated during effort. The values of the pressure can change, depending on the physical activity, emotional state, temperature and food that we consumed.

Contracting heart works, which is why it requires large amounts of energy. This is why it has its own network of blood vessels called coronary arteries. They provide each cell of the heart muscle with elements necessary for cellular respiration. Cardiac cycle does not depend on us. The heart has a natural pacemaker, composed of highly specialized cells, which have the ability to move the heart muscle and make it contract.

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

• Heart is the suction and forcing pump, that makes the blood move in the vessels.

• Human heart is divided into 4 parts: 2 atria and 2 ventricles.

• Valves that are present in the heart and in veins force the blood to flow in one direction only.

• 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.