PHIS 206 1st EditionLecture 16Outline of Last Lecture I. Circulation in the HeartII. Heart Failure (congestive)III. ShockIV. Why Heart is Not Working?Outline of Current LectureI. Respiratory System FunctionsII. RespirationIII. Respiratory System OrganizationIV. Mechanics of RespirationV. Inspiration/Expiration in ThoraxVI. How To Change VolumeVII. PipesVIII. Categories of Pulmonary DisordersIX. La Passe’s LawCurrent LectureI. Respiratory System Functions-allow you to exchange gasses (carbon dioxide out, oxygen in)-Secondary Functionscleanse ,warm, and humidify airlittle capillary beds are exposed to air on one side: alveoliimportant for speechhelps water balanceregulate body temperatureII. Respiration: use O2 and get rid of CO2-Includes ventilation (breathing) and the exchange of gasses in capillaries trachea lungsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. alveoli: spheres open on side; bunches of grapes attached to bronchiole terminals NOT SHOWN IN DIAGRAMbronchioles: have muscles (constrict and dilate) bronchus-Case of fluids flowing through pipes, so usual laws apply Flow down, Pressure up v. Flow up and Resistance down-Alveoli and respiratory bronchioles referred to as respiratory zone where gas change occurs-Lungs have 2 sets of airways1. conducting zone: no exchange of gasses; air moves2. respiratory zone: exchange of gasses occursIII. Respiratory System Organization-mucociliary system when cilia beats, mucous moves up extension stroke pushes fluid up (periodically swallow) Function: when air is brought in, particles, dust, etc.. get stuck on the mucous and cilia moves fluid up1st line of defense in alveoli IV. Mechanics of Respiration-air is a fluid, and the conducting zone are pipes-air goes down alveoli if the alveoli is at a lower pressure than the air-need downhill pressure-greater pressure difference = greater flow-pressure down if cavity expands-pressure up if cavity volume down-Lungs surrounded by a pleural membrane that separates them from a chest wallpleural membrane: allows the lungs to expand and constrict-pressure down when thoracic goes up and lungs expand, alveoli pressure goes down, so air will go in: inspiration-volume down, pressure up, lungs constrict, alveoli pressure up, so air will go out: expiration V. Inspiration/Expiration in Thorax-air in thorax is always (-) or less than atmospheric pressure (1 atm= 760 mm Hg) inhaling: pressure down exhaling: pressure not as (-) in the thorax-When below atmospheric pressure, it stays there WHY? elasticity of the lungs forces out when muscles relaxThoracic cavityAbdominal cavity (below)o elastic wall will make lungs collapse, but air-tight box stops it with the (-) pressure outsideo La Place’s Law: if you make spheres with openings, smaller sphere equals greater pressure inside of it increase pressure in alveoli, air will be injected, and alveoli willget small Balloons: small and big connected by glass rode (air will go to the bigger one)VI. How To Change Volume-At rest, inspire by contracting diaphragm causes reduction in volume in thoracic cavity and increase in pressure-When walking, we increase air in and out by contracting the diaphragm and contracting internal and external intercostals external intercostal: raises the ribs and expands the thorax-When running, we increase air in and out by contracting the diaphragm and external/ intercostal muscles increase activity by increasing contraction of intercostal muscles change volume of lungs by increasing the contracting muscles-Decrease volume by contracting abdominal musclesVII. Pipes-Increase diameter by 16 inches, then the pressure is reduced by 1/16th VIII. Category of Pulmonary Disorders-Bronchioles have ability to change air resistance-Two Categories 1. Obstructive disorders: diameter decreases, obstruction of airway- Asthmao bronchiole (smooth muscles): contractions and airway resistance increases, so need to use muscles to exhale (NOT NORMAL)o We use 3-5% caloric intake, and asthmatics use 30% to breatheo Expiration is hard for them, so effort needed to expire air bronchioles constricting pressure on lungs when exhale- bronchioles reduce in size Symptoms: wheezing (sound of air)2. Restrictive disorders: lung volume decreased Example: pneumonia o pneumonia: fluid accumulates in alveoliIX. La Passe’s Law-resistance of surface tension in air/liquid interphase-surface tension is why spheres collapse-pulmonary surfactant: reduce surface tension between 2 phases Ex.) detergent our lung detergent (pulmonary surfactant) prevents alveoli from
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