Lung Ventilation Lecture Notes PDF

Lecture 15 How is air moved in and out of the lungs for ventilation? - diaphragm. What happens during inspiration at rest? - Constrict the diaphragm to inspire - Bring the diaphragm down when contracting it to the region that expands our thoracic cavity What happens during expiration...

Lecture 15 How is air moved in and out of the lungs for ventilation? - diaphragm. What happens during inspiration at rest? - Constrict the diaphragm to inspire - Bring the diaphragm down when contracting it to the region that expands our thoracic cavity What happens during expiration at rest? - Relaxing the diaphragm - Move back into the thoracic cavity and decreases the volume of the cavity What changes the thoracic cavity to either increase or decrease? - Pressure What happens during inspiration during exercise? - Contraction during exercise is pivotal for moving air in and out - Use of sternocleidomastoid, scalenes, external intercostals - All of these muscles pull the ribs outwards and increase the volume What happens during expiration during exercise? - Relax the diaphragm and goes up - Use the other muscles to make it smaller - Internal intercostals, external abdominal obliques, internal abdominal obliques, transverse abdominis, and rectus abdominis - Internal intercostals associated with the ribs and bring the ribs in - The 4 other are associated with the abdomen How does contracting muscles in our abdominal region have an impact on our thoracic cavity size? - Constricting abdominal region pushes up all of the organs to move up which helps the thoracic cavity to be smaller What are the mechanisms used for ventilation? - Inspire: rib cage goes up, diaphragm goes down - Expire: rib cage goes down, diaphragm moves up - When the diaphragm relaxes it causes the pressure change in thoracic cavity to make the lungs get smaller What kind of system is used for ventilation? - Closed system - It will create a pressure change causing the air to go into the lungs What happens to the diaphragm during inspiration?  - Contract - The pressure goes to 763 mmHg which is greater than atmosphere so the air leaves our lungs into the air What happens to the diaphragm during expiration? - Relax What does the pressure create for ventilation? - A pressure gradient for air flow out of the lungs How does the pressure gradient work? - Pressure goes from high to low level gradient therefore air moves from high to low gradient and causes our lung tissue in the alveoli to expand Is the pleural connected to the rib cage? - No, it is just floating within it How does changing the diaphragm cause a pressure change in the pleural to cause the lungs to expand and decrease since they aren’t attached? - Intrapleural fluid that sits between the pleural - Slide side to side - Pleura in the lungs and the lining of the thoracic cavity, move against one another, they move together when there is pressure Where is oxygen being diffused into the blood? - Alveoli - Tubes leading to the alveoli don’t diffuse What is dead space ventilation (VD)? - “Unused” ventilation - Doesn’t participate in gas exchange - Conducting zone What is alveolar ventilation (VA)? - Volume of inspired gas that reaches the respiratory zone What is the equation for total ventilation? - V = VA + VD How do you measure lung volume? - Spirometry is the measurement technique used to measure lung volume What is tidal volume? - Volume inspired and expired per breath What is inspiratory reserve volume (IRB)?  - Maximal inspiration at the end of tidal inspiration - Breathing in as much as you can What is expiratory reserve volume (ERV)? - Maximal expiration at the end of tidal volume - Breathing out as much as you can What is residual lung volume? - The amount of air left trying to blow out as much air as possible Why can’t you breathe out all the air from your lungs? - It will be hard to expand alveoli - They can’t touch each other since they are sticking to each other What does surfactant do? - Helps alveoli to not collapse and not get stuck to each other Why is the air left in the lungs dirty? - It has byproducts from metabolisms and are diluted out What is total lung capacity (TLC)? - Volume in the lung after maximal inspiration - The biggest breath they can take How does acute exercise impact lung volumes? - Increases the frequency with each breath - Tidal reserve volume increases, amount of air going in and out - Inspiratory reserve volume decreases, breathing in as much as you can What are the effects of acute exercise in breathing frequency? - Breathing frequency increases with exercise - Tidal volume gets larger by cutting into inspiratory reserve volume and into expiratory reserve volume - Tap into inspiratory more when exercising What happens to the residual reserve volume? - Nothing happens to it since you have to keep that air in the lungs What are the effects of ventilation during exercise? - Breathe rate increases - Tidal volume increases - Pulmonary ventilation increases How does chronic endurance exercise training impact the lung volumes? - It doesn’t  - There isn’t a stimulus strong enough to do so - Highly over built so it can keep us alive What is the one sport that changes in volumes? - Swimming What are the mechanisms for increasing lungs from swimming? - Utilizing a lot of oxygen when you are swimming - Taking a breath and having to hold it - Alveoli changes in size and lung volume to change in size to be able to hold their breath for longer periods What leads to a reduced ventilation rate? - Changes in the cardiovascular, peripheral vascular, skeletal muscle - Not the lungs themselves How does O2 and CO2 diffuse? - Diffuse from the atmosphere into the lungs, into the alveoli and into the RBC the into the working skeletal muscle - Pressure gradient What is partial pressure? - The pressure exerted by oxygen in a mixture in the alveoli of the lungs - Fractional composition of gas absolute pressure What is absolute pressure? - Barometric pressure What happens to the pressure when you go above sea level? - The barometric pressure decreases What is the percentage of oxygen in the air? - 21% How do you measure barometric pressure? - Barometric pressure at sea level x the given percentage What is the partial pressure of oxygen at sea level? - 160 mmHg