Text e. Respiratory System: Oxygen Delivery System

The primary function of the respiratory system is to deliver oxygen to all parts of the body. The respiratory system does this through breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. This exchange of gases in the respiratory system is the means of getting oxygen to the blood.

Respiration is achieved through the mouth, nose, trachea, lungs, and diaphragm, oxygen entering the respiratory system through the mouth and the nose. The oxygen then passes through the larynx (where speech sounds are produced) and the trachea which is a tube that enters the chest cavity. In the chest cavity, the trachea splits into two smaller tubes called the bronchi, each bronchus then dividing again forming the bronchial tubes. The bronchial tubes lead directly into the lungs where they divide into many smaller tubes which connect to tiny sacs called alveoli. The average adult's lungs contain about 600 million of these spongy, air-filled sacs that are surrounded by capillaries. The inhaled oxygen having passed into the alveoli, it diffuses through the capillaries into the arterial blood. Meanwhile, the waste-rich blood from the veins releases its carbon dioxide into the alveoli. The carbon dioxide follows the same path out of the lungs when you exhale.

The diaphragm's job is to help to pump the carbon dioxide out of the lungs and to pull the oxygen into the lungs. The diaphragm is a sheet of muscles that lies across the bottom of the chest cavity. As the diaphragm contracts and relaxes, breathing takes place. When the diaphragm contracts, oxygen is pulled into the lungs. When the diaphragm relaxes, carbon dioxide is pumped out of the lungs.

Home work.

Ex. 30. a). Read and translate text E. b). Answer the questions on the Respiratory System. Texts C, D, E will help you in your work.

1. What is the primary function of the respiratory system?

2. How does the respiratory system deliver oxygen to all parts of the body?

3. What processes take place in the body during the exchange of gases?

4. What does the exchange of gases in the respiratory system's mean?

5. How is respiration achieved?

6. How does oxygen seep into the bloodstream?

7. How is carbon dioxide removed from the body?

8. What is the diaphragm's job?

9. What happens when the diaphragm contracts?

10. What happens when the diaphragm relaxes?

Ex. 31. Look at pictures 3, 4 and 5 and answer these questions again without using the texts.

4.

Class work.

Ex. 32. Translate text G at sight.

Text g. Pulmonary Circulation: It's All in the Lungs

Pulmonary circulation is the movement of blood from the heart, to the lungs, and back to the heart again. This is just one phase of the overall circulatory system.

The veins bring waste-rich blood back to the heart, entering the right atrium throughout two large veins called vena cava. The right atrium fills with the waste-rich blood and then contracts, pushing the blood through a one-way valve into the right ventricle. The right ventricle fills and then contracts, pushing the blood into the pulmonary artery which leads to the lungs. In the lung capillaries, the exchange of carbon dioxide and oxygen takes place. The fresh, oxygen-rich blood enters the pulmonary veins and then returns to the heart, re-entering through the left atrium. The oxygen-rich blood then passes through a one-way valve into the left ventricle where it will exit the heart through the main artery, called the aorta. The left ventricle's contraction forces the blood into the aorta and the blood begins its journey throughout the body.

The one-way valves are important for preventing any backward flow of blood. The circulatory system is a network of one-way streets. If blood started flowing the wrong way, the blood gases (oxygen and carbon dioxide) might mix, causing a serious threat to your body.

You can use a stethoscope to hear pulmonary circulation. The two sounds you hear, "lub" and "dub," are the ventricles contracting and the valves closing.

Ex. 33. Read text H. Entitle it. Match the questions with the passages below. Order the questions in the correct order. Here question 1 corresponds to passage A.

1. What is the purpose of breathing?

2. How does the oxygen/waste exchange done?

3. Where does breathing begin?

4. What do the sacs do?

5. What happens to the carbon dioxide?

6. What are those tiny air sacs for?

7. What is the process of breathing?

Text H.

A. You have to breathe because all of the cells in your body require oxygen. Without oxygen, your body wouldn't move. It would be like a parked car without a battery. The car might have gas, but without a battery, forget it! So you might have blood in your body, but without oxygen, forget it! You receive oxygen from breathing in air and then the oxygen goes to your blood which is then circulated throughout your entire body.

B. You breathe with the help of your diaphragm (which is a dome-shaped muscle under your rib cage) and other muscles in your chest and abdomen. These muscles will literally change the space and pressure inside your body cavity to accommodate your breathing. When your diaphragm pulls down, it is making room for the lungs to expand. The lungs get bigger with air and push the diaphragm down. The diaphragm also lowers the internal air pressure. Outside of your body, the air pressure is greater and you suck in air when you inhale. The air then expands your lungs like two balloons being blown up. When your diaphragm relaxes, it moves up and the cavity inside your body gets smaller. Your muscles will then squeeze your rib cage and your lungs begin to collapse as the air is pushed up and out your body when you exhale. Cool huh?

C. About 18 - 20 times a minute, you breathe in. When a doctor puts her hand on your shoulder or back and looks at the clock, they are keeping track of how many times you breathe within one minute. This is how one of your vital signs is measured, called "respiration."

When you breathe, you inhale air and pass it through your nasal passages where the air is filtered, heated, moistened and enters the back of the throat. The esophagus (food tube) is located at the back of the throat and the trachea (windpipe) for air is located at the front of the throat. When you eat, a tiny flap called the "epiglottis" closes down to cover the windpipe so food won't go down the wrong pipe.

D. Air flows down through the windpipe, past the vocal cords (voice box), to where the lowest ribs meet the center of your chest. This is where your windpipe divides into two tubes which lead to each of the two lungs that fill most of your ribcage. Each lung feels just like a sponge. Inside each of your sponge-like lungs, there are tubes called bronchi which branch into even smaller tubes just like the branches of a tree. At the end of these tubes are millions of itty bitty bubbles or sacs called alveoli. If you were to spread out flat all of the air sacs in the lungs of an adult, the tissue would cover an area about the third of the size of a tennis court.

E. The alveoli sacs bring new oxygen from air you just breathed to your bloodstream. It is here that a phenomenal exchange takes place. The oxygen is exchanged for waste products, like carbon dioxide, which the cells in your body have made and can't use.

F. This phenomenal exchange works with the assistance of the red blood cells in your bloodstream. Your red blood cells are like box cars on a railroad track. They will show up at the sacs at just the right time, ready to trade in old carbon dioxide that your body's cells have made for some new oxygen you just breathed in. During this process, the red blood cells turn from purple to a sparkling red color as they start carrying the oxygen to ALL the cells in your body.

G. The carbon dioxide (waste) that your body made and now can't use will go through the lungs, back up your windpipe and out with every single exhale. This is a chemical exchange of breathing in and out (inhalation/exhalation). This is an automatic process that you don't even have to think about. Unless of course you smoke, then you'd be depriving ALL of your cells of oxygen.