DOC PREVIEW
VCU PHIS 206 - Respiratory Mechanics
Type Lecture Note
Pages 3

## This preview shows page 1 out of 3 pages.

View full document
Do you want full access? Go Premium and unlock all 3 pages.
Do you want full access? Go Premium and unlock all 3 pages.

Unformatted text preview:

PHIS 206 1st EditionLecture 17Outline of Last Lecture I. 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 LawOutline of Current Lecture I. Thoracic CavityII. Volume in LungsIII. Gas ExchangeIV. BloodV. How Things WorkCurrent LectureI. Thoracic Cavity-always at a slightly (-) pressure prevents lungs from collapsing-pneumothorax: condition where the lungs collapse-pulmonary surfactant: reduces tension b/w lining of lungs and air in the alveoli  results in low surface tension, so there is a lower tendency of the alveoli to collapseII. Volume in Lungs-5700 mm when you take a breath-1200 mm when you exhale air left in alveoli residual-Amt. we breathe = 500 mL Tidal volume-Normally operating b/w: 2200-2700 mL-You can increase by nearly 10-fold (inspiratory + expiratory reserves)-Capacitors: sums of volumes Total Lung Capacity: sum of allThese 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.Vital Capacity: sum of all except residual volume-FEV1 (force expiratory volume in 1 sec) inspire and expire at maximumwill exhale 80% of vital capacity in 1 sec-If obstructive pulmonary disorder, airway resistance increases, FEV1 will be less than 80% (vital capacity same) EX. asthma-If restrictive pulmonary disorder, vital capacity decreases, but still exhale 80% (vital capacity down) EX. pneumonia-conducting zone (no gas exchange) volume = 150 mL= ANATOMICAL DEAD SPACE 1st breathe taken already in alveoli, trachea, and bronchioles 1st breathe taken out ends up in alveoli, trachea, and bronchioles anatomical dead space: alveoli only gets (350/500) mL fresh air o alveoli ventilation rate: (TITLE VOLUME- DEAD SPACE) = RATE rate at which you get fresh air can increase or decrease by changing title volume or rate if TV gets small enough, alveoli ventilation rate will fall to 0 and you DIE (no fresh air!) same thing will happen if dead space gets changedIII. Gas Exchange-In alveoli, gas exchange going from gas to liquid phases-Air= 80% N and 20% O= 760 mmHg -Pressure exerted on a gas mixture is independent of what gas it is  pressure result of molecules banging against beaker (O and H same pressure)o driven by thermal agitation larger molecule = larger velocity PO2 = 150 mmHg (pressure exerted on O2)o insoluble in water: molar conc. is relatively small o “P” unit used to show direction of diffusion -Alveoli only comes out w/ less PO2 in mmHg-Capillaries = 150 mmHg of PO2 b/c O2 diffuses into themIV. Blood-circulates in systemic capillaries and alveoli systemic capillaries: low PO2 (40 mmHg) using up O2 and entering ≈ 100 mmHgo net diffusion: out of capillaries and into cells-capillaries: ONLY place things can change pulmonary capillaries: PO2 enter -HOW WE GET OXYGEN: starts at 150 mmHg to 100 mmHg in alveoli to 200 mmHg pulmonary blood to systemic capillaries oxygen diffuses out V. How Things Work- PO2 = 100 mmHG- O2 in water = 3 mL/L -15 mL/min in plasma (cardiac output is 5L (min)) not enough to live most O2 is not in plasma o in a red protein: hemoglobin reversibly binds O2 can bind 4 molecules of O2 when hemoglobin put in low PO2 : O2 comes off “unloads” most O2 in hemoglobin in red cellso myoglobin (in muscles) can also bind O2 Hemoglobin: 40 mmHgby 100 mmHg PO2, hemoglobin is ≈ 99% saturated % Saturated100PO25700Inspiratory Reserve: increase 3 L when you breatheTotal Lung CapacityLung 2700Expiratory Reserve: extra L you can force outResidual

View Full Document

# VCU PHIS 206 - Respiratory Mechanics

Type: Lecture Note
Pages: 3
Documents in this Course