Biology HL 11/12 Gas Exchange PDF

Biology HL 11/12 Colin Guy  Gas Exchange allows organisms to obtain importantgases and remove waste gases produced in metabolic reactions through diffusions Surface Area to Volume Ratio Organisms with a very high surface area to volume ratio relies...

Biology HL 11/12 Colin Guy  Gas Exchange allows organisms to obtain importantgases and remove waste gases produced in metabolic reactions through diffusions Surface Area to Volume Ratio Organisms with a very high surface area to volume ratio relies on diffusion across body surface to obtain and release gases Specialized structures like lungs with highly folded branched surfaces have evolved in larger organisms to exchangegases in body Properties of effective gas exchangesurfaces LargeSurface Area more membrane space available for gases to diffuse across Permeability exchange surface must have pores or openings that allow gas exchange across surfaces vi e Stomata in plants open and close for gas exchange Thin tissue layer there is a short distance across which gases need to move  Having amoist surface helps to dissolve gases before diffusing across exchange surface for ex alveolar fluid in the alveoli Concentration Gradient diffusion occurs throug a difference in concentration of gas between 2 areas Gas mores from higher to lower concentration Concentration Gradient difference in concentration between 2 areas an Cno pportunity for substance to be exchanged between surface and blood Continuous Blood Flow as soon as substances move into the blood they are transported away by continuous blood flow Ventilation ensures air or water in desired gas is moved across exchange surface Mammal inhale airin to the lungs and exhale to remove at from lungs Lungs In mammals lungs responsible for exchange of gases between air and bloodstream Alveolar fluid surfactant type I Pneumocytes secrete alveolar fluid moistening the surface of the alveoli allowing gases to dissolve into the surfactantbefore diffusing across the wall of the alveoli and capillary into the blood Alveolar fluid contains surfactant a mixture of lipidsand proteins Bronchiole Network Each bronchiole branches into many alveoli and is made up of many separate bronchi Bronchi Airways from thetrachea to bronchioles Alveoli tiny sacs where and EQ are exchanged between air and blood Many alveoli create a larger surface in the lungs This means thereis more area across which CO2 and Oxygen can be exchanged Nasal Cavity Allows air to enter respiratory systemthrough nose filters air for pathogens andallergen and warms the air Buccal Cavity the mouth works with nasal cavity to allow passage of air into trachea Pharynx the throat is the passage which air travelsfrom the mouth and nose into the trachea Epiglottis A flap of cartilage that covers the trachea when swallow so food doesn't down the trache  y Larynx the voice box is a hollowtube that lets air pass from pharynx throat through to the trachea Also contains the Vocal cords Trachea the windpipe is an airway that carries air into lungs from nasal and buccal cavities Contains C shaped cartilaginous rings for structural strength smooth muscle helps regulate airflow mucous membrane lining traps dust debris and bacteria before reachinglungs Ventilation process of breathing including both inspiration and expiration I Ñaphragm a sheet of muscle below the ribs Intercostal muscles group of muscles anchored to the ribs There are 2 types Internal which are external antagonistic due to opposing actions on the ribs while breathing Abdominal Muscles During inhalation volume of your thoracic cavity increases the space within your chest As volumeincreases particles have more space to move colliding less frequently with each other and the walls  g of the lungs Pressure decreases allowing air from outside body to rush into lungs During Inspiration Diaphragm contracts moves downward External intercostal muscles contract and internal intercostal muscles relax causes rib cage to move up and out Increases volume of thoracic cavity decreases pressure in lungs Air moves down During Expiration quiet breathing Diagram relaxes moves upward and inward External and internal intercostal muscles also and in relax causing ribcage to move down , · Decreased volume in thoracic cavity and ·increasedpretreatesure gradient outof longs During forced breathing expiration · Diaphragm relaxes , moves upwardt inward · External intercostal / muscles relax internal intercostal , muscles contract rib cage moves up/down forcefully , · Decreased volume in thoracic cavity and increased pressure · Air moves forcefully down pressuregradientoutoflongs. Total lung volume total volume of air in y our lungs after inhaling maximum air. Any long capacity 6 liters = Forced vital capacity total volume ofair can forcibly exhale you Residual volume volume of air in longs that cannot beforcibly exhaled Tidal volume volume of air thatmoves in and outof lungs with every normal breath Inspiratory reserve