PULMONARY FUNCTION - PowerPoint Presentation

PULMONARY FUNCTION & RESPIRATORY ANATOMY KAAP310

Respiratory Anatomy Larynx Hyoid bone Thyroid cartilageLateral cricothyroid ligamentsCricoid cartilage http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2020/2020%20Exam%20Reviews/Exam%203/larynx%20figure.jpg

Anatomy of the Lung Trachea Bronchi Upper lobeMiddle lobeLower lobeDiaphragm http://www.cancer.gov/Common/PopUps/popDefinition.aspx?id=270740&version=Patient&language=English

Anatomy of the Lung Terminal bronchiole Respiratory bronchiole Pulmonary veinPulmonary arteryAlveoliCapillary bed http://cnx.org/content/m46548/latest/2309_The_Respiratory_Zone.jpg

Surfactant A detergent-like complex of lipids and proteins produced by alveolar cells. Decreases the surface tension of the fluid that lines the walls of the alveoli. Less energy is required for breathing.Prevents alveoli from collapsing. http://hyperphysics.phy-astr.gsu.edu/hbase/fluids/imgflu/alveolicut.gif

Blood Circulation The heart pumps deoxygenated blood to the pulmonary capillaries for gas exchange to occur between blood and alveoli – air sacs in the lungs.This is known as the pulmonary circulation.Oxygenated blood returns to the heart, where it is pumped out through the aorta by the left ventricle to the rest of the body (systemic circulation). Red blood cells (erythrocytes) transport oxygen in the body. RBC concentration is higher in those living at high altitudes. http://www.lenoircc.edu/disted/med/medgif/med12111c.gif

Inspiration and Expiration During inspiration, the diaphragm and external intercostals contract to make the thoracic cavity larger.Active process – requires muscle action.During expiration, the diaphragm and external intercostals relax and the thoracic cavity becomes smaller.Passive process at rest Active process during exercise http://3.bp.blogspot.com/-oBzLa5UeiQM/TZyfGjrEHpI/AAAAAAAAAAQ/_IrQb_OSNSc/s1600/inspirationexpiration.jpg

Respiratory Volumes Tidal Volume (V T) – the amount of air that moves into and out of the lungs during normal, quiet breathing (~500 ml).Inspiratory Reserve Volume (IRV) – the amount of air that can be inspired forcibly beyond the tidal volume (2100-3200 ml).Expiratory Reserve Volume (ERV) – the amount of air that can be expelled from the lungs after a normal tidal volume expiration (1000-1200 ml). Residual Volume (RV) – the amount of air that remains in the lungs even after the most strenuous expiration (1200 ml).

Respiratory Capacities Inspiratory Capacity (IC) – the amount of air that can be inspired after a normal tidal volume expiration. IC = VT + IRVFunctional Residual Capacity (FRC) – the amount of air remaining in the lungs after a normal tidal volume expiration.FRC = RV + ERV Vital Capacity (VC, also called FVC, forced vital capacity) – the total amount of exchangeable air (~4800 ml).VC = V T + IRV + ERV Total Lung Capacity (TLC) – the sum of all lung volumes (~6000 ml). TLC = VT + IRV + ERV + RV

Spirogram http://www.austincc.edu/apreview/NursingPics/RespiratoryPics/Picture16.jpg Rate of breathing and tidal volume increase during exercise.

Dead Space Dead Space – some of the inspired air fills the conducting respiratory passageways and never contribute to gas exchange in the alveoli. Anatomical Dead Space (VD)– volume in conducting zone (~150 ml).Alveolar Dead Space – volume of air in alveoli that have ceased to act in gas exchange (due to alveolar collapse or obstruction by mucus, for example).Total Dead Space = anatomical dead space plus alveolar dead space. http://web.squ.edu.om/med-Lib/MED_CD/E_CDs/anesthesia/site/content/figures/2015f21.gif

Additional Terms Alveolar Volume: VA = volume of gas in the alveoli that participates in gas exchange.VA = VT – VD Breathing Frequency: f = number of breaths per minute. Minute Ventilation = Expired Ventilation: = total volume of air expired per minute . (Notice the over-dot.) Alveolar Ventilation: = volume of air fresh air reaching alveoli every minute . (Notice over-dot.)  

Spirometry Measurement of pulmonary function that is common in clinical medicine Involves measurement of the volume and rate of expired airflow FVC – forced vital capacity – amount of gas expelled when a person takes a deep breath and then forcefully exhales maximally and as rapidly as possible. FEV1 (forced expired volume in one second) – the amount of air exhaled in the first second of a maximal exhalation.Normally 75-85% of VC FEV1 /FVC ratio – used to assess and diagnose airway disorders Clinically significant when <75% https://www.nhlbi.nih.gov/health/health-topics/images/spirometry.jpg

It is used to diagnose airway disorders . Obstructive airway diseases – asthma, chronic bronchitis, emphysema, chronic obstructive pulmonary disease (COPD), etc.Reduced FEV1 Normal FVCReduced FEV1/FVC ratio http://www.rationalprescribing.com/images/illustrations/obstructive_vs_restrictive_lung_disease.gif Restrictive airway diseases – kyphoscoliosis, neuromuscular disease, pulmonary fibrosis, etc. Reduced FVC Reduced FEV 1 FEV 1 /FVC ratio may be normal, or not Why do spirometry?

Experiment 1 Using the handheld spirometers, ONE person from each group will be the subject, who will wear a nose piece to prevent air from escaping through the nasal passages.Subject will take a maximal inspiration, then quickly place their mouth around the mouthpiece creating a tight seal, and then exhale AS QUICKLY AND AS FORCEFULLY AS POSSIBLE until he/she cannot exhale anymore. The subject will perform 3 trials, allowing rest time between trials.Record your FVC and FEV 1 values in the data sheet. Calculate your FEV1 /FVC ratio

Spirometry Reference Value Calculator Go to the following website: http://www.cdc.gov/niosh/topics/spirometry/RefCalculator.html Select “Hankinson 1999” as your reference source.Enter your gender, race, age, and height and the highest numbers you recorded for FVC and FEV1 (leave the other boxes blank).Click calculate. Fill in the table in the lab packet. Answer and turn in the lab questions – either before the end of lab or next week.

Equations to Remember Minute Ventilation = breathing frequency × tidal volume VT = VA + VD Tidal volume = alveolar volume + dead space volume Alveolar Ventilation Rate = breathing frequency × alveolar volume Therefore, using the equation relating tidal volume and alveolar volume, AVR = breathing frequency × (tidal volume – dead space volume)  

Sample Calculations with the Equations to RememberA subject has a tidal volume of 700 mL (VT =700 mL) and is breathing 14 times per minute (f=14 breaths/min). What is her minute ventilation? The subject just described has a dead space volume of 150 mL. What is her alveolar ventilation rate?