Challenge Problem Gas exchange occurs in the _________ During a heart attack, fluid can back up and fill the lungs. Why is that so dangerous? Be specific In the trachea and bronchi the walls are lined with ciliated cells. Smoking can damage those cells. What would result if enough of the ciliated cells did not work? Get a 13b from the front

Respiratory Physiology I 13b

Bottle Model Read the instructions and material list In pairs create a model of a lung or lungs On the back of your Bottle Model instruction sheet Draw your model and explain how each part compares to real lungs and also how it functions like real lungs.

Gas Exchange Gas crosses the respiratory membrane by diffusion Oxygen enters the blood Carbon dioxide enters the alveoli Macrophages add protection Surfactant coats gas-exposed alveolar surfaces Slide 13.19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Events of Respiration Pulmonary ventilation – moving air in and out of the lungs External respiration – gas exchange between pulmonary blood and alveoli Respiratory gas transport – transport of oxygen and carbon dioxide via the bloodstream Internal respiration – gas exchange between blood and tissue cells in systemic capillaries Slide 13.20a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quick Quiz Where in the body does Pulmonary Ventilation occur? Why is the gas exchange at the alveoli called “external” while the gas exchange at the body tissues is called “internal”?

Challenge Problem Explain the image below in as much detail as possible. Think about the model you built Friday

Mechanics of Breathing: Pulmonary Ventilation Completely mechanical process Depends on volume changes in the thoracic cavity Volume changes lead to pressure changes, which lead to the flow of gases to equalize pressure Slide 13.21a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Mechanics of Breathing (Pulmonary Ventilation) Two phases Inspiration – flow of air into lung Expiration – air leaving lung Slide 13.21b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Inspiration Breathing IN Diaphragm and intercostal muscles contract Thoracic cavity size increases External air is pulled into the lungs due to an increase in intrapulmonary volume Slide 13.22a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Inspiration Slide 13.22b Figure 13.7a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Expiration Breathing OUT Largely a passive process which depends on natural lung elasticity As muscles relax, air is pushed out of the lungs Forced expiration can occur mostly by contracting internal intercostal muscles to depress the rib cage Slide 13.23a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Expiration Slide 13.23b Figure 13.7b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quick Quiz Describe the process of Inspiration Describe the process of expiration

Challenge Problem List the events that would occur when someone sneezes. 2. Why do they say to cover your mouth when sneezing?

Nonrespiratory Air Movements Can be caused by reflexes or voluntary actions Examples Cough and sneeze – clears lungs of debris Laughing Crying Yawn Hiccup Slide 13.25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Respiratory Volumes and Capacities Many factors that affect respiratory capacity A person’s size Sex Age Physical condition Slide 13.26 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Respiratory Volumes and Capacities Tidal Volume (TV) The amount of air moved with each normal breath Typically about 500ml of air in adults Slide 13.26 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Respiratory Volumes and Capacities Inspiratory reserve volume (IRV) Amount of air that can be taken in forcibly over the tidal volume Usually between 2100 and 3200 ml Expiratory reserve volume (ERV) Amount of air that can be forcibly exhaled Approximately 1200 ml Slide 13.27a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Respiratory Volumes and Capacities Residual volume Air remaining in lung after expiration About 1200 ml Slide 13.27b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Respiratory Volumes and Capacities Vital capacity The total amount of exchangeable air Vital capacity = TV + IRV + ERV Dead Space Volume Air that remains in conducting zone and never reaches alveoli About 150 ml Slide 13.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Respiratory Volumes and Capacities Functional volume Air that actually reaches the respiratory zone Usually about 350 ml Respiratory capacities are measured with a spirometer Slide 13.29 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Respiratory Capacities Figure 13.9 Slide 13.30 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Respiratory Sounds Sounds are monitored with a stethoscope Bronchial sounds produced by air rushing through trachea and bronchi Vesicular breathing sounds soft sounds of air filling alveoli Slide 13.31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quick Quiz Name 2 factors that can affect respiratory capacity What is Tidal Volume? What is Vital Capacity?