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257 Cards in this Set
- Front
- Back
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3 parts of gas exchange
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ventilation, gas diffusion into and uptake by blood, and gas transport by blood
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What is cellular respiration
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metabolic process that uses fuel molecular and oxygen to produce energy
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Is carbon dioxide a byproduct of cellular respiration
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YES
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What are 3 main section of Human respiratory system
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1. Ventilation and mechanics of breathing
2. gas transfer and transport 3. the control of breathing |
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Gas movment into and out of the cells is by
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simple diffusion
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Is the movment of blood to lungs and vice versa also diffusion
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YES
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What is beneifit of lungs have very thin walls
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diffusion occurs readily
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What is benefit that lugns have mosit surfaces
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so oxygen and CO2 can dissolve in fluid
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The thoracic cavity is bounded by
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rib cage and closed by diaphragm
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What are pleura
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sheets of epithelail tissue that line interior of thorax
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What does parietal pleura line
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interior of thorax
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What does visceral pleura line
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covers each lung
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What is the interplerual space
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between the partieal and ciseral pleura
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What is important of intrapleural space contains several ml of fluid
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minimizes friction between pleura, and important for pressure changes that cause breathing
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What is the main airway
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trachea
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What does trachea branch into
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two bronchi-one bronchus for each lung
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The bronchi branch into secondary and theriaty bronchi, then divide into
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bronchioles
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What do bronchioles divide into
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terminal bronchioloes
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After terminal bronchioloes, What strucutres make up the respiratory zone
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respiratory bronchioles, and avlerolvar sace
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Where is the start of gas exchange
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TERMINAL bronchioloes
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What is the acinus
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basic functinal unit for gas exchange
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What composes the acinus
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consists of terminal bronchiole, alveolar duct and alveoli and blood vessels
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Bronchi UP TO the terminal bronchioles are surrounded by and have
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incomplete rings of cartilage that prevent their collapse, and hav smooth muscle
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Do terminal bronchioles have rings
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NO, only smooth muscle
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The conduction zone carries gas by
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bulk flow into repriatory zone
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What are 3 functions of conducting zone
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move air to and from respiratory zone
2. warm and humidify air 3. serves as body defense aginat microbes |
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What keeps foreign matter from entering the alveoli
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mucociliary transport system
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What does the mucociliary transport system do?
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cilia that beat synchronsously, and move mucus and trapped particles up to trachea
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What does tobacco smoke to do mucocillary transport system
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distrupts beat of cilia, and allows mucus and particles to accumulate in lower airways
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How does air move into and out of the lungs
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down pressure gradients
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If air always moves down a pressure gradient,for INHALATION the air in the lungs must be
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at a lower pressure than atmosphereic pressure
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For exhaltion the presure in the lungs must
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exceed atmospheric pressure
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Changes in lung pressure is caused by cange in
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lung volume
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What does Boyle's law sate
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the volume is inversely proportional to its pressure
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Ultimately breathing is due to changes in volume of what,
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thoracic volme changes leading to change in lung volume and pressure in lungs
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Changes in thoracic vavity pressure can alter lung volume becuase
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the lung is very compliant
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The greater the complicance of the lungs
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the more the volume will increase witth a given pressure gradient
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For example a thick walled ballon does not increase in volume much with a slight pressure, but a thin walled ballon while
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readily infalte b/c it is more compliant
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The pressure gradient across a container's walls can be mediated in two ways
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internal pressure and external pressure
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How is internal pressure increased
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by forcing air into a container (inflating a ballon)
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What happens to the lungs when external pressure decreases
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leads to increased lung volume
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What happens to the lungs when external pressure increases
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leads to decreased lung volume
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The lungs itself is elastic, after being inflated, when pressure gradient is reduced what happens
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lungs recoil to orginal volume
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What are the most elastic portions of the lungs
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alveoli
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What volume of the lungs is the main change during breathing
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avlveoli
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THe bronchi do not collapse when removed from the thorax, what does collapse
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alveoli
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Is the chest cavity much less comliant, how are the lungs and chest wall linked
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by intrapleural fluid
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Why does the intrapleural fluid NOT expand or compress in response to pressure changes
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b/c the chest cavity volume is ALWAYS greter than that of the lungs
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Can the chest cavity expand
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YES
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Due to inward recoil of lungs, and outward spring of chest wall, the
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intrapleural pressure is lower than atmosperhic pressure by about 5 cm H20
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Does intrapleural pressure being lower than atmospheric pressure have to do with the greater growth of the thorax during early development
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YES
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What is benefit that intrapleural pressure is less than atmospheric pressure
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lungs will remain slightly distended and alveoli will not collapse
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What happens if the intrapleural space is punctrures
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air is pulled into the intrapleural space, b/c of its negative pressure, until equal with atmospheric pressure
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What happens when intrapleural space pressure equilibrates with atmosphereic pressure
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the lungs and chest cavity are no longer connceted
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Why does only the lung in the puncuted side collapse
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each lung is in a separate chamber separated by mediastnium
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How can pneumothroax be corrrected
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by resealing the intraplerual space and a connecting drain,used to create a new negative pressure during healing
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The thoracic cavity is airtight, and separated from the abdomen by
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the diaphragm
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The thoracic cage is made up of
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12 pairs of ribs and a stermum, and internal and external intercostal muscles
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The rib cage is hinged to the vertebral column allowing
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it to rise and lower during breathing
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Volume expansion of chest cavity is due to
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contraction of diaphragm and EXTERNAL intercostals
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What contacts during resting breathing
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diaphragm
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What contracts during more forceful breating
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diaphragm and EXTERNAL intercostals
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The volume reduction of the chest cabity is due to
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relaxation of diaphragm and contraction of INTERNAL intercostals
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What is needed for more forceful exhalation
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internal intercostal and contaction of abdominal muscles
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What are the 4 basic pressures in breathing
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1. atmospheric pressure
2. intralplueral pressure 3. transpulmonic pressure 4. aveolar pressure TIAA |
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What is atmospheric pressure
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760 mmHG or 1027 cm H20
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Is absolute pressure important
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NO--only pressure gradients
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What is inspriation
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flow of air into the lungs
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Inspiration is due to
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an INCREASE in thoracic volume and a decrease in pressure inside the lungs
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As volume of the thoracic cavity increase what happens to intrapleural pressure and volume
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intraplerual PRESSURE decreases, b/c VOLUME of intraplrual fluid stays constant
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What is transpulmonic pressure
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differance between intralpulmonary pressure and interpleural pressure
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B/c the lungs are connceted to thoracic cavity, as the volume of the thoracic cavity increases
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an increase in lung volume
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Essential all of the lung volume change is due to
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a change in the alveolar volume, the compliant region
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As lungs volume increases, what happens to pressure in lungs
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Decrease
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The rate flow into the lungs is dependent on the
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magnitude of pressure gradient, and airway resitance
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Air flow equation equals=
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(Patm-Palveoli)/resistance
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Increase resistance causes
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decrease flow
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What happens to lungs due to an increased transpulmonic pressure
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volume of lungs increases
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The decrease in lung pressure to subatmospheric presure causes
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air flow into lung
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Does expiration during quite breathing require any muscular contraction
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NO
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What happens to thoracic volume and intrapleural pressure when diagragm relaxes
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thoraic volume decreases, and increased intraplerual pressure
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The streching of lung due to expasion during inpriation, does what during expriation
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increases recoil force of lung
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A reduced transpulmonic pressure gradient does what
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decrease LUNG VOLUME
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A decrease in lung volume does what to the air brought into the lung during inspiration
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increases the pressure in the aveloi
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FINALLY What happens whent he pressure in the avleoi exceeds atmospheric
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air flows out of the lung
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What happens to intralpleural pressure as air leaves lung
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intralplerual pressure returns to normal, and cycle can start over
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Deeper inspiration due to greater increase in chest volume is due to
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contraction of external intercostal muscles
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What does contraction of the external intercostal muscles do
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lifts rib cage UP and OUT
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What does contraction of external intercostals do to interpleural and alveolar pressure, results in
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decrease, results in more air moving into lung that at rest
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More forecful expriation can be aceived with contraction of
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internal intercostal and abdominal muscle
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What do internal intercostal do to rib cage
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move down and IN
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What does contraction of abdominal muscles do
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push diaphragm upward
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A greater decrease in chest volume leads to a greater
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increase in alveolar pressure and mroe AIR movemtn OUT
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Where does tubulent air floow occur
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in trachea and large bronchi
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Flow is fast in tubuelnt air flow, the faster it morves
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the greater the turbulence, and the more noise of breathing is heard
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Is turbulence in the large airways a source of resistance to breathing
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YES
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Laminar air flow occurs in
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small peripheral airway
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Why is airflow in laminair airways silent
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slow rate of air flow
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Rate of air movemtn with laminar flow is greatly affected by
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airway diameter
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Laminar flow=
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radius^4
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What are major sites of airway resistance
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bronchi and bronchioles
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What does parasympathetic stimulation do to bronchi and bronchioles
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contraction and contraction of airways
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What does sympathetic stimulation or epinephrine do to bronchi and bronchioles
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relaxtion or dialtion
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Sympathetic stimulation is mediated by binding to a
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beta receptor
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What is spirometry used for
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to meausre changes in lung volume during inspritaion and expiration
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What is tidal volume
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volume of air entering of leaving lungs with a single breath at rest
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What is inspiratory reserve volume
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the volume of air that can be inhaled at the end of normal inspiration
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What is expiratory reserve volume
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maximal volume of air that can be exhaled at the end of a tidal volume
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What is vital capacity
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maxium amount of air that can be moved
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What is equation for vital capacity=
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tidal volume + IRV +ERV
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Does vital capcaity demonstarat that there is a great reserve capacity to increase vnetilation
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YES
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What is residual volume
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volume of air in lungs, even after maximal expiration
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What is functional residual capacity
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amoutn of air remaining in lungs after normal exhalation at rest
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What is forced expiratory volume in 1 sec (FEV1)
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volume forciliby exhaled in 1st second after maximum inhaltion
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What is timed forced expriatory volume in 1 sec normally (FEV1)
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80% of vital capacity
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What is Forced vital capacity
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volume of air that can be exhaled as forcily and rapidly as possible after maximal inspriation
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What does obsturctive lung disease such as emphysema and asthma do
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expiratory flow is obstructed
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What happens to FVC and FEV1 in obstuctive lung diseases
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FVC is reduced, but FEV1 is drastically reduced
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What happens to FVC and FEV1 with restictive lung diseases
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both equally reduced
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What happens with restrcive lung disease to lung
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lung inflation is restricted
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Gas exchange ONLY occurs in
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alveoli and terminal bronchioles
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Is the air in the conducting region involved in gas exchange
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NO
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What is dead space
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volume of inspired air "WASTED" in conducting region
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Why is only a fration of air reaching the alveoli is "FRESH"?
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during inspriation air present in conducting pathway and alveli (old air) is mixed with fresh air
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What happens if tidal volume does not exceed dead air space
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NO FRESH air enters alveoli
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Is deal space volume constant
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NO
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Change in alveolar ventilaiton is the most importatn variable for
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GAS exhange
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Alveolar minutes ventilation =
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(Tidal volumer xfreq/minute-Dead space freq/min
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What is the most effective breathing that increase alveolar ventialtion
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slow deep breath
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What is the worst type of breathing
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rapid shallow breating
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Becuase of dead space, what is more imporatn than rate of breathing
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DEPTH of breating
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How well the lung inflates and delated with changes in transpulmonic pressure is a measure of
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lung compliance
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Compliance =
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Change in volume/ change in pressure
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A steep slope in the pressure volume curve indicates
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HIGH complaicne of the lung
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What is wrong with lungs be excessively compliant
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there is little elastic recoil, so EXPIRATION takes lots of effort
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Suraface tension of water on the inner alveoli can greatly affect
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compliance of the lung
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What is surface tension due to
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attractive forces between water molecules
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What does the inner surface of alveoli look like
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it is moist and in contact with water
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The surface tension of water creates a forces that does what to alveoli
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pulls them inward and reduces their diameter
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THe surface tension of water contributes to 70% of
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the elastic recoil of alveoli
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Why is lung compliance REDUCED due to surface tension of water
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pull alveoli inward, more force required to inflate alveoli
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What lowers the surface tension in alveolar walls
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surfactant
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What does surfactant contain
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complex of phospholipids and proteins
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What secretes surfactant
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the epithelial cells lining the alveoli
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Do surfactant have both hydrophobic and hydrophilic ends, which do what
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YES, disrupt attractive forces between water
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Reducing the surface tension reduces the force required, what does it do to compliance
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to INFLATE the lungs--INCREASES LUNG COMPLIANCE
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Suface tension of water can affect lung compliance, but what also does it do
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also affects the PRESSURE inside the alveoli
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What is Law of Leplace
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Aveolar Presure P=2T/R
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Therefore according to Law of Leplace, what happens to an increase in pressure with a decreasing radius
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Presure increase with a decreasing radius
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WHen airflow into the lung is produced by pressure gradient, air will flow into
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the larger alveolus
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What prevents the collapse of small alveloi
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surfactant is more tightly packed, so SMALLER alveolo have lower surface tension than larger alveoli
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Is surface tension less in smaller alveloi
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YES
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Reducing the surface tension in smaller alveoli offsets the effects of
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smaller radius on pressure
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Premature infants that have an inadequate amount of surfactant, makes it difficult ot breath, why
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high surface tension of water on alveoli surfaces make it difficult to inflate lung
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What is needed for surfactant synthetisis before birth
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cortisol
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Pulmonayr circulation is a LOW pressure, low resistance system compared to
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systemic
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THe lungs have HIGHLY compliant vessels, does that mean the weak right heart can match the output of the left heart without a large increase in pulmonary pressure
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YES
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An increase in CO leads to an increase in MAP, and opeingm of collapsed vessels, which means what for lungs
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increased bloow flow to lungs, and increases SA available for gas exchange
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At rest, most why are most capillaries in lower lung open
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due to higher relative pressure
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Are most cappilaries in upper lung open at REST
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NO FEW.
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What is beneifit of few cappilaires in upper lung open at rest
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reserve capillaries
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Increase CO leads to flow leads to increase flow thorugh what portion of lung
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cappilaries in UPPER LUNG
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The ratio of alveolar ventilation to alveolar blood flow =
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ventilation/perfusion ratio
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Regional imbalances in lung in ventilation and perfusion lead to
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physiological dead space and physiological shunts
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WHat is physiological dead space
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alveoli with ventilation, but no perfusion
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What is a physological shunt
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perfusion of alveolus without ventilation
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Is there any gas exhanged in physiological dead spaces, and shunts?
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NO
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What is main effect on regional ventilation and perfusion (V/Q) in the lung
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is GRAVITY
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Blood pressure is greatest at what region of the lung due to gravity and hydostatic pressure
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at the base
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Blood pressure is greatest at the base, and vessels are very compliant, results in
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vessels are EXPANDED at base, and greater perfusion at BASE
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How does gravity affect intrapleural presure
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Gravity pulls LUNG down, making intralpleural pressure is much more negative in apex than in base
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If interpleural pressure is more negative in apex what happens to the avleoli in the apex
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tend to be more fully expanded BEFORE inspiration
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Since the alveoli are larger at the apex before inspiration, this means
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they expand less during inspiration (LESS AIR can get in) LESS COMPLIANT
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THE Greater perufsion and ventilation of base compared to the apex is generally associated with
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great alveolar ventilation and gravity on blood flow
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The relative effect of gravity is greatest on
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BLOOD flow, than ventilation
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THe V/Q ratio is much greater in the apex so Lungs compensate for this, What happens if lungs have greater ventilation than perfusion
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they decrease CO2, and increase oxygen
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How do lungs compensate for increase ventilation
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bronchiole constrction, and ateriole dialtion (local regulation)
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What is the result of bronchioloe contstion, and ateriole dialtion
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decrease in ventilation and increase in perfusion
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What happens if lungs have greater perfusion than ventilation
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increase CO2 and decrease O2
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How do lungs compensate for increased CO2 and decreased O2
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bronchile dilation and ateriole constriction
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What is the result of bronchiole dialation and ateriole constriction
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increase in ventilation and a decrease in perfusion
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These physiological adjustments tend to increase ventilation in the base, and decrease blood perfusion in the base of the lungs, which helps minimize
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V/Q gradient from apex to base
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The interior of the lungs is saturated with water vapor, do is change total pressure of the lungs
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NO--just menas the parial pressures of other gases are decreased
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The concentration of a gas that dissolves in a liquid depends on
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patial presure of gas, it solubility and temp
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Which is more soluble CO2 or O2
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CO2 21 times more soluble
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Why is partial pressure of oxygen in inspired air not as high as that in fresh air
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b/c inspired air mixes with old air from dead space
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Where is the partial pressure of CO2 higher
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inspired air
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The compostion of alveolar air depends on
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1. ventilation of alveoli
2. rate of oxyen uptake by blood 3. rate of CO2 release by blood |
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B/c of the low velocity of air, what is the main mechanism of exchange of air within the alveoli
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DIFFUSION--little bulk flow
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350ml of alveolar ventation with each breath is diltued into
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2 liters of alveolar space
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What are the driving forces for gas diffusion
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partial pressure gradients
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Blood gas content rapidly comes into equilibrium with alveolar gas, therefore the partial pressures of gasses
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partial pressure of gasses in pulmonary venous blood is equal to the partial pressures in alveolar air
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Why isnt sytemic arterial blood gas content that same as alveolar air (the differances are minimal and not important)
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b/c some pulmonary blood flow bypasses alveoli, and ventilation and perfusion are not perfectly matched
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Oxygen has a very low solubility, can dissolved oxygen alone meet the bodies needs
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NO
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How are our oxten supplies met
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by oxygen binding to hemoglobin, each hemoglobin can bind 4 oxygen
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Is 99% of blood carried by hemoglobin
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YES
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An increase in Oxygen partial pressure leads to an increased
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saturation
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In the lungs, the partial pressure of oxygen is typically high, and therefore the oxygen binds readily to hemoglobin that is present, leading to increase hemoglobin
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SATURATION
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What is P50
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the partial pressure an individal has, at which hemoglobin is 50% saturated with oxygen
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If an in individual has a decrease P50, what does that mean
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HIGHER affinity-b/c the individual needs a lower parital pressure to have hemoglobin 50% saturated
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Does decrease hemoglobin lead to decrease carrying capacity
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YES
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What is benefit that at pressures above about 60 mmHg, the standard dissociation curve is relatively flat,
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the oxygen content of the blood does not change significantly even with large increases in the oxygen partial pressure.--safety net
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What causes oxygen to be unloaded in the systemic capillaries
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reduce oxygen partial pressure in capillaries
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What is oxygen partial pressure in the systemic cappilaries
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40mm Hg
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In the steep part of the curve, small change in oxygen partial presure in systemic cappilarries can lead to
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big changes in the amount of oxygen unloaded
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The differance in oxygen conent of blood entering the capillaries and that of blood leaving the cappilares is equal to
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the amount of oxygen consumed by the tissues
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With extercise, there is a greater oxygen consumption by the tissue, what happens to partial pressure in tissues
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partial pressure drops in tissues increasing oxygen delivery to the tissues
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What are 3 major factors that affect hemoglobin affinity for oxygen--thus altering delivery to tissues
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1. Carbon dioxide/pH
2. Temperature 3. 2,3 diphosphoglycerate |
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An increase CO2 does what to pH
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decreases pH
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What does a increased in CO2 and/ OR decrease in pH do
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Bohr effect there is an increase oxygen release at tissues
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There is an increase in temperature of active muscles to about 43 Degrees Celcius, what does this do
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promotes increased oxygen unloading, b/c temperature in lung is 36 degrees
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What does 2,3, diphosphoglycerate do
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reduces hemoglobin affity for oxygen
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INCREASE in CO2, Temperature and 2,3 diphosphoglyercate all do what and decrease in pH
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shift curve to RIGHT (DECREASE AFFINTY FOR HEMOGLOBIN
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When is more 2,3DPG produced
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when there is LOW oxygen, so with decreased OXYGEN in tissues DPG unloads it from hemoglobin
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Carbon dioxide produced from CELLular metabolism readily diffuses from cells to interstital space to
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plasma
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Where does CO2 once is enters plasma
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diffuses into RBC
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What happens to CO2 in RBC
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CO2 combines with H20 and forms carbonic acid, which is then dissociates into HCO3 and H
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What happens to the H+ produced
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is accepted by hemoglobin, more H+ can bind
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What happens to the bicarb
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It is removed from the RBC in exchange for CL
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The majority of carbon dioxide is transported as
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bicarb
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The Haldane effects is
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the more hemoglobin is deoxygenated, the more CO2 can be taken up by RBCs
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Does oxygenated or deoxygenated hemoglobin bind protons better
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deoxyhemoglobin binds protons more readily
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As oxygen leaves hemoglobin, what happens
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it binds more protons, which means more carbon dioxide can be taken up by RBCs
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Do the haldane effect occur for both Oxygen unloading and CO2 unloading
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YES
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What favors CO2 unloading in LUNGS
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Low partial pressure in alveoi
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What is the result of oxygenation of hemoglbin releasing the H+
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HCO3 from plasma enters RBC forming carbonic acid, which splits and forms CO2, and H20
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Why does bicarb readily enter the RBC
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due to a reverse CL shift in lungs
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After carbonic acid is converted to H20 and CO2 in LUNGS by carbonic anhydrase what happens
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CO2 diffuses from blood into alveoli
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Is breathing an automatic process, does it occur without conscious effort
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YES
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We can voluntarily stop breathing for a period of time until
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carbon dioxide builds up in blood,will stimulate breating
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What contols the rhythm of breathing
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respiraotry center in MEDULLA
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Is only skeletal muscle involved in breathing
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YES
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The norma resting rate of breathing is
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14 breaths per minute
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What is odine's curse
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no automatic control breathing, only voluntary control--person must remember to breath
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What neruons expriatory or inspritory are responsible for breathing
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INSPRIATORY neurons only
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Where are pulmonary strech receptros located and respond to
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in smooth muscle airways--are activated when lung inflates
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What happens after pulmonary strech receptros in smooth muscle are acitvated
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send impulses via vagus nerve to medulla and INHIBIT respiraotry neurons
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What happens after pulmonary strech receptros inhibt respiratory neurons
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STOPS inspiration, helps regulate rhytm of breath and PREVENTS overinflation of LUNG
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Are the pulmonary strech receptors more important in newborns than adults
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YES
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Pulmonary strech receptros only play a role during periods of
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LARGE tidal volume such as intense exercist
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Does passive expriation require stimultion, if no when
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NO, only with force forceful breating with internal intercostals and abd muscles
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To maintain pH of blood and tissues, adequate AVLVEOLAR VENTILATION MUST BE MAINTAIN TO GET RID OF
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CO2 being produced
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Two Sets of chemorectpros detet changes in arerial Oxygen, CO2 and PH and send signals where
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Central and pheripheral chemoreceptors send to medulla respiratory center
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Where are central chemoreceptors
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located in medulla next to respiratory center
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Where are peripheral chemorecetpros
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arotic arch and carotid sinus
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Central chemoreceptors monitor only CO2 in
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cerbral spinal fluid
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How do central chemoreceptors montitor CO2 levels in cerebrospinal fluid
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CO2 diffuses into Cerbral spinal fluid with h20, forming carbonic acid, dissociates forms H+--stimulates chemoreceptors
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A decrease pH in the cerbrospinal fluid leads to
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INCREASE ventilation
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Control of ventiltion by changes in ATERIAL blood is mediated by
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peripheral chemoreceptors
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Can canges in arterial pH be dectected by central chemoreceptors
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NO---H+ cannot cross BBB
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What happens when pH decreases in arterial blood
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peripheral chemoreceptors are activated and send signals to respiratory medulla to increase ventilation
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What chemorecetpors can sense ketoacidosis
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peripheral chemoreceptors
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Central chemorecetpros only respond to increase CO2, what do perihperal chemoreceptors only respond to
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pH--peripheral chemorecptors onyl account for 15-20% of response to CO2
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What has the SMALLEST effect on control of ventilation
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OXYGEN
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The need to control oxygen levels is minor compared to the need to control
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CO2 adn pH
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The ONLY time oxygen is regulated is if oxygen parital pressure is <60 mmHG, what is activated
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peripheral chemoreceptors increase ventilation
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ALSO what happens to sentivity to oxygen levels WITH INCREASED CO2 LEVELS (people with emphesema)
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increased oxygen sensitivity
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