Respiratory System Biology 11 S.Dosman

Respiration all processes involved in the exchange of oxygen and carbon dioxide between cells and the environment. Respiration includes breathing, gas exchange, and cellular respiration.

Breathing the movement of gases between the respiratory membrane of living things and their external environment.

Respiratory Membrane The living membrane where the diffusion of oxygen and other gases occurs. Gases are exchanged between the living cells of the body and the external environment (the atmosphere or water).

Trachea the windpipe; connects the pharynx and larynx to the bronchi.

Cilia tiny hair-like protein structures found on some cells that sweep foreign debris from the respiratory tract.

Epiglottis a structure that covers the glottis (opening of the trachea) during swallowing.

Larynx The voice box; contains vocal cords.

Bronchi the passage from the trachea to either the left or right lung

Bronchioles The smallest passageways of the respiratory tract.

Alveoli sacs of the lung in which the exchange of gases between the atmosphere and the blood occurs.

Pleural Membrane a thin, fluid-filled membrane that surrounds the outer surface of the lungs and lines the inner wall of the chest cavity.

Inspiration Air moving into lungs; occurs when pressure inside the lungs is less than that of the atmosphere.

Expiration Air moving out of lungs; occurs when pressure inside the lungs is greater than that of the atmosphere.

Diaphragm a sheet of muscle that separates the organs of the chest cavity from those of the abdominal cavity.

External Intercostals Muscles muscles that raise the rib cage, decreasing pressure inside the chest cavity.

Internal Intercostals Muscles muscles that pull the rib cage downward, increasing pressure in the chest cavity.

1. Why is oxygen considered vital to life? Humans cannot survive more than a few minutes without oxygen or death will occur. Also, oxygen is needed in cellular respiration during a process called oxidation; when organic compounds are broken down using oxygen. Without oxygen, not enough energy can be obtained and life processes in humans cannot be maintained.

2. Identify and describe the four processes involved in respiration (hint, use figure 2 page 282). The four processes involved in respiration are: Breathing: process by which air enters and leaves the lungs. External respiration: involves the exchange of gases (oxygen and carbon dioxide) between the air and the blood. Internal respiration: involves the exchange of gases between the blood and the tissue fluids. Cellular respiration: involves the production of ATP in body cells.

3. Give 4 examples of respiratory membranes (systems) and identify an organism that uses each type. Four examples of respiratory membranes are: Skin: organisms such as earthworms use the moist surface of their skin to diffuse gases. Gills: organisms such as fish, salamanders, clams, starfish and crayfish exchange gases using gills; folded extensions of the outer surface of the body. Tracheal system: insects have a system of branching respiratory tubes with openings called spiracles. Lungs: large land animals such as humans have an internal membrane called lungs. Their respiratory system has a trachea that branches into smaller tubes that carries air to the lungs.

4. What is the function of the nasal cavity in mammalian respiratory systems? The nasal cavity of mammals blocks foreign particles from entering the respiratory system through the use of tiny hairs (cilia). It also warms and moistens the incoming air.

5. Why are there mucus producing cells in your trachea? The mucus producing cells in your trachea produce mucus that can trap any debris that may have been missed by the nasal cavity.

6. What happens when food goes “down the wrong way”; what part of your respiratory system did not do its job? When food goes “down the wrong way” it has entered the trachea because the epiglottis has not done its job. During swallowing, the muscular action causes the epiglottis to close over the trachea so food slides the esophagus.

7. How does your larynx work? The larynx is commonly called the voice box. It contains two thin sheets of elastic ligaments known as vocal cords which vibrate and produce sounds as air passes over them. The more air you pass over the vocal cords the louder your voice will be!

8. What is the function of the cartilage rings in the trachea and bronchi? The cartilage rings in the trachea and bronchi keep the smooth muscle of the airways open.

9. Fully explain how the alveoli function in gas exchange. The alveoli are tiny air sacs located at the end of the bronchioles. They are surrounded by capillaries and gases are exchanged via diffusion through the thin walls of the capillaries and alveoli. The oxygen and carbon dioxide will diffuse from high concentration to low.

10. What is the function of the pleural membrane? The pleural membrane surrounds that outer surface of the lungs and lines the inner wall of the chest cavity. It is filled with fluids that reduce friction between the lungs and the chest cavity during inhalation (when the lugs increase in size and fill the chest cavity).

11. Explain how differences in pressure between the atmosphere and your chest cavity control the movement of air into and out of your lungs. The differences in pressure (high – low) between the atmosphere and the chest cavity are what allow air to move in and out of the lungs. Gases will move from high pressure to low pressure. The pressure in the atmosphere remains relatively constant but the pressure in the chest fluctuates as we increase and decrease the size of our chest cavity when inhaling and exhaling. When we inhale our chest cavity increases which decreases pressure and air rushes in to our lungs. When we exhale the chest cavity decreases which increases pressure and air rushes out of our lungs.

12. Explain the role of the diaphragm and the intercostals muscles in the breathing process? The diaphragm and the intercostals muscles play a key role in increasing and decreasing the size of the chest cavity so that air may enter and leave the lungs. During inspiration, the diaphragm contracts and flattens out and the external intercostals muscles pull the ribs upward and outward. These actions increase the volume (size) of the chest cavity which lowers the pressure and air rushes in. The opposite muscular actions occur during expiration. The diaphragm relaxes and moves upward and the intercostals muscles relax and the ribcage falls. This decreases the volume of the chest cavity and increases pressure and as a result air rushes out of the lungs.