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Anatomy & Physiology Review Question

Short Answer Essay
Chapter 13. The Respiratory System
20090609 Lee Kwang Ryeol

8. Clearly explain the difference between external and internal respiration.
External respiration : gas exchange between the pulmonary blood and alveoli must take place. Gas exchanges are being made between the blood and the body exterior.
Internal respiration : Atsystemic capillaries, gas exchanges must be made between the blood and tissue cells. Gas exchanges are occurring between the blood and cells inside the body.

9. Trace the route of air from the nares to an alveolus.
Nares – nasal cavity – nasopharynx – oropharynx – laryngopharynx – larynx – trachea – bronchi - alveolus

10. Why is it important that the trachea be reinforced withcartilaginous rings? What is the advantage of the fact that the rings are incomplete posteriorly?
The solid portions support the trachea walls and keep it open, in spite of the pressure changes that occur during breathing. The open parts of the rings abut the esophagus and allow it to expand anteriorly when we swallow a large piece of food.

11. Where in the respiratory tract is the air filtered, warmed,and moistened?
The nasal cavity is lined with a mucosa, which warms, filters, and moistens incoming air. The mucosa also contains receptors for sense of smell.

12. The trachea has goblet cells that produce mucus. What is the specific protective function of the mucus?
The sticky mucus produced by the mucosa’s gland (goblet cells) moistens the air and traps incoming bacteria and other foreigndebris, and lysozyme enzymes in the mucus destroy bacteria chemically. The ciliated cells of the trachea beat continuously and in a direction opposite to that of the incoming air. They propel mucus, loaded with dust particles and other debris, away from the lungs to the throat, where can be swallowed or spat out.

13. In terms of general health, what is the importance of the fact that thepharyngotympanic tubes and the sinuses drain into the nasal cavities and nasopharynx?
The pharyngotympanic tubes, which drain the middle ear, open into the nasopharynx. The mucosae of these two regions are continuous, so ear infections may follow a sore throat or other types of pharyngeal infections.
Also, because the nasal mucosa is continuous throughout the respiratory tract and extends tentaclelike into the nasolacrimal ducts and paranasal sinuses, nasal cavity infections often spread to those regions as well.

14. What is it about the structure of the alveoli that makes them an ideal site for gas exchange?
The walls of the alveoli are composed largely of a single, thin layer of squamous epithelial cells. Alveolar pores connect neighboring air sacs and provide alternative routes forair to reach alveoli whose feeder bronchioles have been clogged by mucus or otherwise blocked. Alveoli have large surface to exchange the gas with external environment, so it makes them an ideal site for gas exchange.

15. What do TV, ERV, and VC mean?
TV (tidal volume) is the volume of gas in the normal quiet breathing. It is about 500ml of air. ERV means expiratory reserve volume, isapproximately 1200ml. After a normal expiration, more air can be exhaled. The amount of this air is ERV. VC means Vital capacity. This is the total amount of exchangeable air which is approximately 4800ml in healthy young men.

16. Name several nonrespiratory air movements, and explain how each differs from normal breathing.
Movement | Mechanism and result |
Cough | Taking a deep breath, closingglottis, forcing air superiorly from lungs against glottis. Cough act to clear the lower respiratory passageways. |
Sneeze | Similar to cough, except that expelled air is directed through nasal cavities instead of through oral cavity. Sneezes clear upper respiratory passages. |
Crying | Inspiration followed by release of air in a number of short expirations. |
Laughing | Essentially same as...