The Anatomy and Physiology of the Respiratory System

The cells of the human body require a constant stream of oxygen to stay alive. The respiratory system provides oxygen to the body’s cells by removing carbon dioxide. It is the respiratory system that is responsible for the respiration, the process by which our organism exchanges gases with its environment. The act of breathing with the lungs is called ventilation and includes inhalation (breathing in) and exhalation (breathing out).

There are 3 major parts of the respiratory system: the airway, the lungs, and the muscles of respiration.

The airway includes the nose, mouth, pharynx, larynx, trachea, bronchi, and bronchioles.

The nose and nasal cavity form the main external opening for the respiratory system through which air moves. The nasal cavity is a hollow space within the nose and skull that is lined with сilia, which are very fine hairs, which warm, moisturize and filter air. These hairs are coated with mucus that captures any germs and pollutants that are in the air we breathe before it enters the lungs. This foreign matter is then expelled from the body through swallowing, coughing or sneezing.

The mouth or the oral cavity is the secondary external opening for the respiratory tract. It can be used to supplement or replace the nasal cavity’s functions when needed.

The pharynx, also known as the throat, is a muscular funnel. It extends from the nasal cavity to the larynx and esophagus.

The larynx, also known as the voice box, is a short section between the pharynx and trachea.

The trachea is a tube which extends from the base of the larynx to the lungs, where it divides into two bronchi.

The bronchi are two tubes which begin at the trachea. The left bronchus is longer than the right one as it passes around the heart to reach the left lung. Each bronchus leads into a lung. In the lungs, the bronchi divide into bronchioles. The bronchioles end in fine alveolar ducts leading to the alveoli.

The alveoli, or air sacs, are the ends of the air passages. Each alveolus is closely surrounded by blood capillaries.

The lungs are paired, spongy organs located in the chest. They are not identical in shape and size. The left lung is smaller than the right one because it shares space in the chest with the heart. They are divided into lobes - the right lung has three lobes and the left lung has two lobes. The vital capacity of the lungs in the adult is about 3-4 liters.

When one breathes normally not all the alveoli and capillaries of the lungs are opened. When respiration becomes deep, the number of the opened alveoli and capillaries increases. The flow of blood into the lungs increases when one breathes in and it decreases when one breathes out.

Exercise 8. Find corresponding equivalents:

1. oral cavity & nasal cavity 2. a hollow space within the nose and skull 3. to capture germs 4. external opening 5. to be lined with hairs and mucus membrane 6. to remove carbon dioxide 7. to be surrounded by blood capillaries 8. to expel foreign matters

a) виводити вуглекислий газ b) виділяти інородні речовини c) бути оточеним кров’яними капілярами d) ротова та носова порожнини e) бути покритим волосками та слизовою оболонкою f) схоплювати мікроби g) порожнина в носі та черепі h) зовнішній отвір

Exercise 9. Match the terms with their definitions:

1. oral cavity 2. trachea 3. larynx 4. bronchus 5. alveolus 6. lung 7. pleura 8. cilium

a) either of the two main branches of the trachea that lead to the lungs, where they divide into smaller branches; b) a membrane that encloses each lung and lines the chest cavity; c) either of the two saclike respiratory organs in the thorax of humans and the higher vertebrates; d) a microscopic hairline process extending from the surface of a cell or unicellular organism; e) the opening through which food is taken in and vocalizations emerge; f) any of the tiny air-filled sacs arranged in clusters in the lungs, in which the exchange of oxygen and carbon dioxide takes place; g) a muscular and cartilaginous structure lined with mucous membrane at the upper part of the trachea in humans, in which the vocal cords are located. h) a tube that connects the pharynx and larynx to the lungs, allowing the passage of air;

Exercise 10. Answer the questions:

1. What is the respiratory system responsible for?

2. What are the main parts of the respiratory system?

3. What is the nose covered with?

4. What do the cilia do?

5. How do people expel foreign matters from the respiratory tract?

6. What are pharynx and larynx?

7. Which bronchus is larger and why?

8. How many alveoli are there in the lungs?

9. What are the lungs? What is their vital capacity?

10.When does the number of opened alveoli increase and decrease?

Exercise 11. Approve or contradict the following statements:

1. The respiratory system is responsible for supplying our body with oxygen and removing carbon dioxide, useful for our bodies.

2. All foreign matters are expelled from the body through swallowing, talking or sneezing.

3. Respiratory system is a biological system consisting of specific organs and structures used for the process of respiration.

4. The principal muscle of respiration in the human body is the diaphragm, a thin sheet of skeletal muscle that forms the floor of the thorax.

5. The right lung is smaller because it shares space in the chest with the heart.

6. When respiration becomes deep, the number of the closed alveoli and capillaries increases.

7. Hairs and mucus lining the nasal cavity help to trap dust, mold, pollen and other environmental contaminants before they can reach the inner portions of the body.

8. Our nose warms, moisturizes, and filters air we breathe out.

Exercise 12. Fill in prepositions from the box below where necessary:

With; into; in; of; through; for; to; out;

1. Respiration is a process which provides body ……. oxygen for growth and other metabolic activities and removes waste products in the form …… carbon dioxide.

2. The lungs are the main organs involved ……… the respiration process.

3. Air passes ……. the lungs …… the nostrils and the air flows down the trachea …….. the lungs.

4. The lungs have alveoli which are small air sacs filled …….. tiny capillaries.

5. The respiration process is carried …….. in two ways in living organisms: aerobic and anaerobic respiration.

6. Some ……. the common diseases related …….. respiration are common cold, tonsillitis and laryngitis.

7. Asthma and pneumonia are diseases associated ……… respiration along with lung cancer.

8. The respiratory system is responsible ….. supplying our body with oxygen.

Exercise 13. Fill in the gaps with the words and word-combinations from the box: