Exam IV Final Study Guide Respiratory System o Major Functions of the Respiratory System To supply body w O2 and dispose of CO2 Respiration four distinct processes must happen Pulmonary ventilation moving air into out of the lungs External respiration gas exchange b n lungs and blood Exam IV Final Study Guide PET3322 Anatomy Physiology I Figueroa Fall 2011 Tubes include epithelial cells Cartilage to keep big tube lumen open keep diameter If no cartilage one would suffocate o Conducting Zone Bronchi Air reaching bronchi is Warm and cleansed of impurities Saturated w water vapor Bronchi is subdivide into secondary bronchi each supplying a lobe of the lungs Air passages undergo 23 orders of branching in the lungs Notes All tubes without alveoli are conducting zone Alveolis only place where gas exchanges no gas exchange in conducting Where does air become moist conducting zone Alveoli covered w capillary net will get 02 o Conducting Zone Bronchial Tree Bronchioles Consist of cuboidal epithelium Have a complete layer of circular smooth muscle Lack cartilage support and mucus producing cells o Respiratory Zone end of resp tract Presence of alveoli Begins as terminal bronchioles feed into respiratory bronchioles Respiratory bronchioles lead to alveolar ducts then to terminal clusters of alveolar sacs composed of alveoli Notes Large tubes epithelial and smooth muscle Small aveoli epithelial cells o Approx 300million alveoli provides tremendous SA for gas exchanges and accounts for most of the lungs volume alveoli have large SA compared to trachea Exam IV Final Study Guide PET3322 Anatomy Physiology I Figueroa Fall 2011 o Respiratory Membrane This air blood barrier is composed of Alveolar and capillary walls Their fused basal laminas Alveolar walls Area single layer of type I epithelial cells Permit gas exchange by simple diffusion Have angiotensin converting enzyme ACE converts angio 1 to 2 Breathing o Breathing or pulmonary ventilation consists of two phases Inspiration air flows into the lungs Expiration gases exit the lungs Respiration use of oxygen by cells Ventilation breathing in air Gas Pressure and Volume o Don t Need to know Boyle s Law o Diaphragm is skeletal muscle controlled by ANS voluntary o To move air or blood need pressure decrease space size increase Volume Pressure Relationships in the Thoracic Cavity o Respiratory pressure is always described relative to atmospheric pressure o Atmospheric pressure Patm Pressure exerted by the air surrounding the body Negative respiratory pressure is less than Patm Positive respiratory pressure is greater than Patm Ppul and Pip fluctuate with the phases of breathing Ppul always eventually equalizes itself with P atm Pip is always Ppul and P atm Atmospheric Pressure 760mm at sea level Exam IV Final Study Guide PET3322 Anatomy Physiology I Figueroa Fall 2011 Pressure Relationships o Two forces act to pull the lungs away from the thoracic wall promoting lung collapse Elasticity of lungs causes them to assume smallest possible size Surface tension of alveolar fluid draws alveoli to their smallest possible size o Opposing force elasticity of the chest wall pulls the thorax outward to enlarge the lungs o Caused by equalization of the intrapleural pressure with the intrapulmonary pressure o Transpulmonary pressure keeps the airways open Transpulmonary pressure difference between the intrapulmonary and intrapleural pressures Ppul Pip Lung Collapse Pulmonary Ventilation o A mechanical process that depends on volume changes in the thoracic cavity o Volume changes lead to pressure changes which lead to the flow of gases to equalize pressure Exam IV Final Study Guide PET3322 Anatomy Physiology I Figueroa Fall 2011 The Respiratory Muscles o At rest we only need the diaphragm In charge of inspiration and expiration at rest Responsible for movement volume and pressure o Relax expiration o Contract inspiration o Main expiratory muscles are the abdominal muscles Expiration o Inspiratory muscles relax and the rib cage descends due to gravity o Thoracic cavity volume decreases o Elastic lungs recoil passively and intrapulmonary volume decreases o Intrapulmonary pressure rises above atmospheric pressure 1 mm Hg o Gases flow out of the lungs down the pressure gradient until intrapulmonary pressure is 0 o Notes Small change 760 P decrease 759 757 increase 761 763 Contract inspiration diaphragm down Relax expiration diaphragm up note big tubes smooth muscle little tubes no smooth muscle Physical Factors Influencing Ventilation Airway Resistance o Friction is the major nonelastic source of resistance to airflow o The relationship between flow F pressure P and resistance R is F Physical Factors Influencing Ventilation Airway Resistance Exam IV Final Study Guide PET3322 Anatomy Physiology I Figueroa Fall 2011 o The amount of gas flowing into and out of the alveoli is directly proportional to DP the pressure gradient between the atmosphere and the alveoli o Gas flow is inversely proportional to resistance with the greatest resistance being in the medium sized bronchi Airway Resistance o As airway resistance rises breathing movements become more strenuous o Severely constricted or obstructed bronchioles Can prevent life sustaining ventilation Can occur during acute asthma attacks which stops ventilation o Epinephrine release via the sympathetic nervous system dilates bronchioles and reduces air resistance o PNS activity increases air resistance Only asking volume at rest move 500 in move 500 out Tidal Volume 150 Alveolar Ventilation 350 ml Alveolar ventilation rate AVR measures the flow of fresh gases into and out of the alveoli during a particular time Alveoli 17th and up resp zone Slow deep breathing increases AVR and rapid shallow breathing decreases AVR Conducting NO Alveoli fnx conduct air from outside to resp zone only function is to push air to resp zone Only 350 reaches resp zone 150 conducting zone and will not participate in air exchange dead space does not participate in gas exchange because it is lacking alveoli Total ventilation is 500x15 Orange conducting Blue resp Exam IV Final Study Guide PET3322 Anatomy Physiology I Figueroa Fall 2011 pP O2 160 mm Hg 104 mm Hg Know partial pressure in multiple areas 40 45 5 104 40 60 CO2 more soluble less P needed Change in P created force diffusion no change no diffusion Partial Pressure Gradients and Gas Solubilities o Although carbon dioxide has a lower partial pressure gradient It is 20 times more soluble
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