26 Physiology of the Respiratory System Answers to Pre- Lab Assignments Pre-Lab Activity 1: 1. bell jar 2. b 3. active 4. passive Pre-Lab Activity 2: 1. b 2. c Pre-Lab Activity 3: 1. a. 1 b. 3 c. 4 d. 2 2. a. 1 b. 3 c. 4 d. 2 Pre-Lab Activity 4: 1. e 2. rise; fall 3. fall; rise 4. depth of breathing Answers to Activity Questions Activity 1 1. a. wall of plural cavity b. trachea c. bronchus d. lungs e. pleural cavity f. diaphragm 2. a. inflated b. increased c. decreased d. because intrapulmonary pressure decreases below atmospheric pressure 3. a. deflated b. decreased c. increased d. because intrapulmonary pressure increased above atmospheric pressure 4. They collapse because they lose the negative pressure that draws air into the lungs. Answers to Post-Lab Assignments Post-lab quizzes are also assignable in PART I. Check Your Understanding Activity 1: Analyzing the Model Lung and Pulmonary Ventilation 1. Name the component of the bell jar lung model that corre- sponds with each of the following respiratory structures. a. Lungs ballons b. Diaphragm rubber membrane c. Pleural cavity interior of jar d. Trachea straight part of Y-shaped tube e. Bronchi branched parts of Y-shaped tube 2. The pressure of a gas in a closed container is inversely proportional to the volume of the container. 3. What is a pneumothorax and what does it cause? A pneumo- thorax occurs when air enters the pleural cavity. It causes the lungs to col- lapse. Activity 2: Measuring Respiratory Volumes in a Human Subject Using 1. Why does the predicted vital capacity vary with height? As height increases, lung volume increases. 2. Explain how age and gender might affect the lung capacity. Lungs lose elasticity as we age, thus reducing lung volumes and capacities. Males typically have larger lungs than females; therefore, males will have higher volumes and capacities. 3. How would the volume measurements change if the data were collected after vigorous exercise? Tidal volume would increase. _________________________________________________________ _______ 4. What is the difference between volume measurements and capacities? Volumes can be measured, whereas capacities must be calcu- lated. Activity 3: Determining Respiratory Volumes and Capacities at Rest and Fol- lowing Exercise 1. Respiratory volumes can be ( measured /calculated), whereas respiratory capacities are (measured/calculated ). Circle the correct answers. 2. Identify the various lung volumes and capacities in the follow- ing diagram. a. inspiratory reserve volume b. tidal volume c. expiratory reserve volume d. residual volume e. inspiratory capacity f. functional residual capacity g. vital capacity h. total lung capacity 3. Describe the effects of exercise on each of the following quan- tities. a. ERV: It decreases. b. IRV: It decreases. c. TV: It decreases. Activity 4: Investigating the Control of Breathing 1. Explain the relationship between blood CO2 levels and blood pH. As blood CO2 levels rise, pH decreases because CO2 combines with wa- ter to form carbonic acid, which dissociates into hydrogen ion and bicar- bonate ion. As hydrogen ion concentration goes up, pH goes down. 2. Based on your experimental results, complete the following chart. Did Breathing Rate Did the Amount of Exhaled CO2 Breathing Increase or De- Increase or Decrease? How Do You Pattern crease? Know? Hyperventila- Student data Student data tion Rebreathing Student data Student data PART II. Putting It All Together A. Review Questions Answer the following questions using your lecture notes, your textbook, and your lab notes. 1. List and briefly describe the five processes involved in provid- ing body cells with oxygen and ridding body cells of carbon dioxide. pulmonary ventilation = inhaling and exhaling external respiration = exchange of gases between air and blood gas transport = transport of gases by cardiovascular system internal respiration = exchange of gases at capillary bed cellular respiration = breakdown of food to produce ATP in the cell 2. How is most oxygen transported in the blood? a. It is dissolved in plasma. b. It is transported as bicarbonate ions. c. It is bound to hemoglobin. d. It attaches to the red blood cell’s membrane. e. None of these statements is correct. 3. The following equations can be used to predict vital capacity in males and females: Males: VC = (0.052 H) − (0.022 A) − 3.60 Females: VC = (0.041 H) − (0.018 A) − 2.69 where VC = vital capacity in liters, H = height in cm, and A = age in years. a. Brian is a 38-year-old male who is 186 cm tall. Calculate his predicted vital capacity: 5.2 L b. If Brian’s actual measured vital capacity is 2.80 L, suggest some possible reasons for the discrepancy between the predicted value and the actual value. Brian could be suffering from a respiratory disorder such as COPD or he could be an extremely overweight smoker in poor physical shape. 4. What are chemoreceptors, and how are they involved in the regulation of respiratory rate? Chemoreceptors are receptors located in blood vessels (peripheral chemoreceptors) and the brain (central chemoreceptors) that respond to chemicals. An increase in hydrogen ions, for example, can stimulate the respiratory center in the medulla oblongata to in- crease the breathing rate. .