Cardiorespiratory System Part 2 PDF

Cardiorespiratory System: Part 2 Respiratory System Learning Objectives 1. Describe the structure and function of the Respiratory System 2. Discuss the mechanics of ventilation 3. Explain pulmonary volumes and capacities 4. Describe gas exchange including differentiating processes for interna...

Cardiorespiratory System: Part 2 Respiratory System Learning Objectives 1. Describe the structure and function of the Respiratory System 2. Discuss the mechanics of ventilation 3. Explain pulmonary volumes and capacities 4. Describe gas exchange including differentiating processes for internal and external respiration and describing ventilation-perfusion ratio 5. Summarize the processes for transport of respiratory gases 6. Explain the regulation of respiration A lot can happen from.. VENTILATION Function of the Lungs Primary purpose is to provide a means of gas exchange between the external environment and the body Ventilation refers to the mechanical process of moving air into and out of lungs Diffusion is the random movement of molecules from an area of high concentration to an area of lower concentration Conducting and Respiratory Zones Conducting zone Respiratory zone Conducts air to respiratory Exchange of gases zone between air and blood Humidifies, warms, and Components: filters air Respiratory bronchioles Components: Alveolar sacs Trachea Bronchial tree Bronchioles  Respiratory Structure: Bronchial Tree (Conducting zones) Terminal bronchioles Respiratory bronchioles (Respiratory unit) Conducting Zone: Mucociliary Clearance Removal of particles from the airways as the result of a mucous coating and cilia Primary innate defense mechanism of the lung Nasal conchae ↔ bronchioles Three components: Ciliated epithelial cells Periciliary layer Lubricates airways Low viscosity Creates environment where cilia can move! Mucus layer Traps foreign particles and pathogens Conducting Zone: Mucociliary Clearance Cell Functions: Ciliated epithelial cells Cilia located on apical (inside/towards lumen) side of cell Move in a metachronal rhythm (sequential, not synchronous) 60% of trachea lining Goblet Cells Principal secretory cell: secret mucus 20% of trachea lining Serous and Club Cells Secrete watery secretions Why does your nose run in cold Copyright © 2010 Pearson Education, Inc. environments? Respiratory Zone FOUR MAIN FUNCTIONS Gas exchange with blood Surfactant production Immune function: Macrophage Clotting function Gas Exchange with the Blood Respiratory Zone: Alveoli Alveoli- smallest functional unit of the respiratory system, where gas exchange occurs (external respiration) Two types of alveolar cells: Type I - simple squamous cells, where gas exchange occurs Type II - secret surfactant (lines alveoli, reduces surface tension; prevents atelectasis) Mechanics of Breathing Inspiration Diaphragm pushes downward, lowering intrapulmonary pressure Expiration Diaphragm relaxes, raising intrapulmonary pressure Resistance to airflow Largely determined by airway diameter Boyle’s Law Gases move from areas of high pressure to areas of low pressure Ventilation: Pleurae Thin, double layered serous membrane; divides thoracic cavity into two pleural compartments and mediastinum Parietal pleura on thoracic wall, superior face of diaphragm, around heart, between lungs Visceral pleura on external lung surface pleural sac forms a double membrane Pleural fluid fills pleural cavity surrounding the lung, similar to a fluid filled Provides lubrication and surface balloon surrounding an air-filled balloon tension assists in expansion and recoil Ventilation: Pressures Pressure Relationships in the Thoracic Cavity: Atmospheric Pressure Intrapulmonary Pressure Inrapulmonary Pressure Ventilation: Pressures Atmospheric Pressure (Patm): Pressure exerted by air surrounding body 760 mm Hg at sea level = 1 atmosphere Convention is to describe respiratory pressures relative to Patm, which is considered 0 Negative respiratory pressure-less than Patm Positive respiratory pressure-greater than Patm Zero respiratory pressure = Patm Intrapulmonary Pressure (intra-alveolar) (Ppul): pressure exerted by gases in alveoli Fluctuates with breathing Always eventually equalizes with Patm Ventilation: Pressures Intrapleural Pressure (Pip): Pressure in pleural cavity Fluctuates with breathing Always a negative pressure (