EXAM 4 STUDY GUIDE The Respiratory System control exchange of gases to provide oxygen for the body and expel carbon dioxide As you can see in the diagram the trachea leads to the bronchi and then to bronchioles then to the alveoli Pulmonary ventilation moving air into and out of the lungs External respiration gas exchange between the lungs and the blood Lungs Bronchi have cartilage these are the larger tubes extending from the trachea windpipe the function is to conduct air to smaller tubes smaller tubes are the bronchioles that have alveoli Alveoli are where gas exchange occurs between alveolus and capillaries because there are over 300 million alveoli in the lungs there is a much larger area for gas exchange to take place Conducting zones DO NOT have alveoli so the bronchi is a conducting zone Respiratory Zones DO have alveoli so the bronchioles are a respiratory zone The Respiratory Membrane is the site of gas exchange it consists of wall of alveolus have epithelial cells gas exchange by simple diffusion wall of capillaries have endothelial cells interstitial fluid is in between Look at the picture below the exchange off gas is CO2 from blood to alveolus and 02 from the alveolus to the blood Breathing has two phases in class he emphasize that breathing is the same as ventilation In spiration inhalation air into the lungs Ex piration exhalation air exits the lungs Inspiration and expiration are the terms for breathing that will used on the exam The thoracic cavity includes the heart and lungs these correlate in that as blood moves into and out of the air air is moving in and out of the lungs Our ribs function to protect internal vital organs muscle between the ribs intercostal allow rib cage to expand during inhalation Atmospheric Pressure is 760mmHg it takes GREATER than the atmospheric pressure 760mmHg to move air from inside of the lungs to the outside air expiration Diaphragm skeletal muscle Pressure Relationship In Thoracic Cavity when diaphragm comes down contraction pressure DECREASES when it comes up relaxation pressure INCREASES at rest the diaphragm is doing all of the work The muscles of the abdomen are the main expiratory muscles needed when we are not at rest ex Imagine blowing up a balloon with your mouth contraction of the abdomen increases pressure and pushes the diaphragm up causing expiration relaxing theses muscles causes a decreases in pressure EXHILATION DIAPHRAGM COMING UP INCREASES PRESSURE INSPIRATION DIAPHRAGM COMING DOWN DECREASED PRESSURE 1 at rest the diaphragm is relaxed 2 during inspiration the diaphragm is contraction 3 during expiration the diaphragm is relaxing F air flow P change in pressure R resistance to airflow Increased resistance decreased airflow Example mucus in the air tube is causing resistance airflow decreases and as air tries to flow through the resistance causes us to cough up the mucus Tidal Volume 5oomL this is volume of air moving in and out of the lungs during normal inspiration expiration ventilation is what s occurring inside of the lungs anatomical dead space 150mL of air does not reach alveoli alveolar air 350mL of air per breath that is needed from the tidal volume AVR alveolar ventilation AVR frequency x tidal volume dead space The frequency is how many breaths For exam purpose this would be however many breaths x 350 Remember that the most important gases in the air are NITROGEN AND OXYGEN Volume is directly related to pressure meaning that that when volume increases pressure also increases Partial Pressure Gradients and Gas Solubilites Internal Respiration The partial pressure oxygen PO2 of venous blood is 40 mm Hg the partial pressure in the alveoli is 104 mm Hg In class he said that on the exam the partial pressure of the alveoli is anything closest to 100 P change in pressure for oxygen is about 60 mmHg 100 40 60 Carbon dioxide has a lower partial pressure gradient than oxygen It is 20 times more soluble membranes than oxygen It diffuses in equal amounts with oxygen but with a lower partial pressure It requires lower pressure to get the same amount of diffusion P is 5mmHg 20 times more soluble membranes Oxygen 104 mmHg blood leaving the capillaries has the same pressure of the alveoli so it has the same pressure as the previous tissue CO2 40 mmHg lower partial pressure Pressure of alveolar sac air is the SAME as the oxygenated blood leaving the pulmonary capillaries Venous blood has the same partial pressure as the cells 0 40 CO2 45 compare these points with the diagram below to understand this conceptually Oxygen Loading into the blood hemoglobin hb is the oxygen transport protein in the red blood cells Each hemoglobin can transport 4 molecules of oxygen saturated hemoglobin means that all four hemes are bounded to oxygen 02 98 saturated arterial blood contains 20 ml oxygen per 100 ml blood This is 20 of the volume As arterial blood flows through capillaries 5 ml oxygen are released to tissues Oxygen hemoglobin saturation curve I recommend looking at the curve on the slides 33 37 of the respiratory PowerPoint to get an idea of the relationship between saturation and partial pressure of oxygen normal concentrated hemoglobin is 15 grams and each gram can transport 1 3 mL of hemoglobin 15 x 1 3 20 mL O2 per 100 mL of blood 75 saturation 15mL of oxygen Metabolism will affect the oxygen hemoglobin dissociation curve Increased body temperature increased delivery of oxygen to the cells the source of increased body temp doesn t matter it can be from fever or from exercise Transport and Exchange of CO2 Co2 H2O H2CO3 H HCO3 more H increased acidity reaction proceeds to the LEFT more CO2 reaction proceeds to the RIGHT SO If H begins decreasing carbonic acid will dissociate releasing H bicarbonate is the most common way to transport CO2 from systemic capillaries CO2 is the most important stimulus for Breathing bicarbonate is the main form of transporting in plasma ALSO CO2 is mainly travels to the lungs in the form of bicarbonate Bohr effect At the tissues as more CO2 enters the blood more O2 dissociates from hemoglobin Haldane effect the lower the PO2 partial pressure of oxygen and hb saturation the more CO2 can be carried in the blood Respiratory Center medulla oblongata has the inspiratory and expiratory areas the inspiratory area is innervated by the diaphragm Expiratory area is innervated by the abdomen AREAS IN PONS WILL NOT BE ON EXAM CHEMORECEPTORS in medulla oblongata function to control respiration Peripheral
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