THE ANATOMY OF THE RESPIRATORY SYSTEM
Instructions: Read the following paragraphs and statements. Then use the information to help you answer the questions and label the diagram.
The lungs are the main organs of respiration; their job is to help gases (mainly oxygen and carbon dioxide) to trade places. When you inhale, your lungs take in the oxygen that your cells need; blood circulating in the tissues of the lungs take the oxygen to cells all over your body. At the same time, the blood has been collecting carbon dioxide waste from cellular respiration in your cells. That waste goes into your lungs, and you expel it when you exhale.
In this gas-exchange process, the lungs need help from the internal and external intercostals, the diaphragm, as well as from other structures and organs. All together, these structures and organs make the respiratory system. The following statements will help you to learn more about this system.
Statements
1. The diaphragm is a large sheet-like muscle that divides the body cavity into two smaller cavities: the thoracic cavity, which contains the lungs and heart, and the abdominal cavity, which houses the organs and glands of digestion, excretion, and reproduction. “A” on the diagram points to the thoracic cavity and “B” points to the abdominal cavity. Locate these cavities and label them.
2. As you inhale, the muscle fibers of the diaphragm contract and the muscle moves downward. At the same time, the external intercostals contract causing the ribs to expand. Both of these actions expand the thoracic cavity which leads to a decrease in pressure. To fill this space, air rushes in through your nose (from high pressure) into the lungs. Red blood cells pick up oxygen from the “new” air, and carbon dioxide leaves the blood and mixes with the air in the lungs.
3. As you exhale, the diaphragm and the external intercostals relax while the internal intercostals contract. The diaphragm assumes it’s convex “at rest” shape and the ribs move inward. This increases the pressure, compressing the air and forcing it out through the nose expelling carbon dioxide. “N” points to the diaphragm; label the diaphragm.
4. To reach the lungs, air from the atmosphere follows a system of tubes and spaces called the respiratory pathway, which begins at the nose. On either side of the nose are small openings called nostrils. As incoming air passes through the nose itself, small, stiff hairs trap dust and other foreign particles. “C” points to the nose; label it.
5. Directly behind the nose, within the bone of the skull, is a space called the nasal cavity. It is lined with a membrane containing specialized cells that release a thick, clear liquid called mucus. Mucus and the mucous membrane help to warm and moisturize the air. “D” points to the nasal cavity; label the nasal cavity.
6. Additional fluid drains into the nasal cavity from the sinuses, which are also lined with mucous membrane. Like the nasal cavity, the sinuses are spaces in the bones of the skull; there are sinuses above and below the eyes. If you have allergies, you know that sometimes your mucous membranes can swell and prevent your sinuses from draining causing pressure build up and giving you a sinus headache. “E” points to the frontal sinus; label it.
7. On the walls of the nasal cavity are three rounded plates that look like scrolls; they are called “conchae” (plural for concha). Their job is to form channels that direct air into a space called the pharynx. When you open you mouth and look at your throat in a mirror, you will see a dangling piece of tissue called the uvula; the space behind the uvula is the oral pharynx. “F” points to the conchae; “G” points to the pharynx (label).
8. The pharynx directs air into the larynx. When you swallow, you can see the larynx move in your neck; this protruding part of the larynx is sometimes called the “Adam’s apple.” Another name for the larynx is the “voice box”; inside it are the vocals cords- thin bands of tissue that vibrate when exhaled air rushes past them. This enables you to make sounds when you speak or sing. “H” points to the larynx; please label “H.”
9. The larynx has a flap of tissue called the “epiglottis” that protects its opening. When you swallow, this flap closes, making a slight noise that you can hear. The purpose of this flap is to prevent food from entering and blocking the respiratory pathway. “I” points to the epiglottis; label it.
10. From the larynx, air passes into a large tube called the trachea or “windpipe.” The trachea is about 4.5 inches long. It is protected by rings of cartilage that help to keep it open so that air can travel through it freely. “J” points to the trachea, label it.
11. The trachea branches to make two smaller tubes called bronchi (the plural of bronchus), which direct air into the lungs. “K” points to the left bronchus; label it “left bronchus.”
12. The bronchi divide to make smaller tubes called bronchioles. The bronchioles, the bronchi, and the trachea are lined with small hair-like structures called cilia. Cilia wave back and forth as they trap foreign particles and push them back toward the throat or pharynx. “L” points to the bronchioles; label them.
13. The bronchioles continue to divide, making smaller and smaller tubes. They may divide up to twenty times before becoming air ducts. (Because these divisions are so small they have not been included in the diagram.) Air ducts are minute tubes that direct air into small, thin sacs called alveoli (the plural of alveolus). Collectively, the alveoli are sometimes called the respiratory membrane because respiratory gases diffuse through these thin sacs while entering and leaving the blood. “M” points to the alveoli; label them.
Level One Questions:
1. What are the main organs of respiration?
2. What is the function of the lungs?
3. The body cavity above the diaphragm is the ______cavity and below the diaphragm is the ______cavity.
4. What happens in the diaphragm when you breathe in?
5. To reach the lungs, air follows a system of ______and ______called the respiratory pathway.
6. What happens to incoming air as it passes through the nose?
7. How is the air warmed and moistened as it passes through the nasal cavity?
8. What is the job of the conchae?
9. The larynx is also called the ______.
10. What structures are in the larynx?
11. From the larynx, air passes into a tube about 4.5 inches long called the ______.
12. What keeps the tube open so that air can pass freely through it?
13. The bronchi divide to make smaller tubes called ______.
14. What are these smaller tubes lined with?
15. Collectively, the alveoli are sometimes called the ______.
Level Two Questions:
16. How does the diaphragm help to bring air into the lungs?
17. What causes sinus headache?
18. Why are the alveoli sometimes called the respiratory membrane?
Level Three Questions:
19. Smoking tobacco products destroys the cilia in the respiratory pathway. Why is the absence of cilia harmful?
20. Tar from cigarettes and other tobacco products can absorb gases that are known to be harmful when we encounter them as factors in air pollution. Can you make some assumptions about why this contributes to lung disease?
21. Imagine a hole through the skin and muscle into the thoracic cavity. Can you explain why it would make the lungs collapse?