ECAP BIOL The Respiratory System Mrs. Riel

ECAP BIOL The Lung Main function is to transfer oxygen from the atmosphere to the blood - and carbon dioxide from the blood to the atmosphere

ECAP BIOL More Facts on the Lungs u The narrower portion of each lung is called the apex u The bases rest on the diaphragm u The left lung has two lobes u The right lung has three lobes

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5 Discuss the Anatomy of the Airway u The Upper Respiratory Tract includes the Nose, Nasal Cavity and the Pharynx u The Lower Respiratory Tract includes the Larynx, trachea, bronchi, bronchioles, alveolar ducts, and alveoli.

ECAP BIOL The Vocal Cords u Part of the mucous membrane of the larynx forms a pair of folds called the true vocal cords. u Vibration that results in speech

ECAP BIOL The Right Primary Bronchus u It is wider than the left bronchus u It is shorter than the left bronchus u It is straighter than the left bronchus u It is the more common site for an inhaled object to become lodged

ECAP BIOL Cilia u Hair like projections which acts like an escalator u The cilia of the nasal mucosa move contaminated mucus toward the pharynx for swallowing

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ECAP BIOL Define Simple Diffusion u Movement of molecules from an area of high concentration to an area of lower concentration u No energy involved

ECAP BIOL Explain gas exchange in the Alveolus u O 2 diffuses across the A/C membrane into the blood u CO 2 diffuses from the blood across the A/C membrane into the alveolus u Gas exchange occurs by simple diffusion

ECAP BIOL Events of Respiration Respiratory gas transport – transport of oxygen and carbon dioxide via the bloodstream Internal respiration – gas exchange between blood and tissue cells in systemic capillaries

ECAP BIOL 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

ECAP BIOL Mechanics of Breathing (Pulmonary Ventilation) Two phases Inspiration – flow of air into lung Expiration – air leaving lung

ECAP BIOL Inspiration Diaphragm and intercostal muscles contract The size of the thoracic cavity increases External air is pulled into the lungs due to an increase in intrapulmonary volume

ECAP BIOL Inspiration

ECAP BIOL Exhalation   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

ECAP BIOL Exhalation

ECAP BIOL Pressure Differences in the Thoracic Cavity Normal pressure within the pleural space is always negative (intrapleural pressure) Differences in lung and pleural space pressures keep lungs from collapsing

ECAP BIOL Carbon Dioxide u CO2 is one of the most important stimuli leading to increased rate and depth of breathing

ECAP BIOL Respiratory Volumes and Capacities Normal breathing moves about 500 ml of air with each breath (tidal volume [TV]) Many factors that affect respiratory capacity A person’s size, sex, age, & physical condition.

ECAP BIOL 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

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

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