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194 Cards in this Set
- Front
- Back
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Where does gas exchange occur?
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In alveoli
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inspiration
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movement of air from the external environment into the alveoli
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Expiration
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refers to movement of air from the alveoli to the external environment
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what conducts air between the external environment and the alveoli?
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Airways
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describe airway composition
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a continuous branching network of tubes that terminate in the alveolar sacs
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How many generations of branching occur in the airways?
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20
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What does upper airway consist of?
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nose mouth, pharanx, larynx
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What does larynx lead into?
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trachea which divides into multiple generations of bronchi
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walls of trachea and bronchi are composed of what? what is its function?
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cartilage which allows structural support and helps keep the airway open
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first airways that do NOT contain cartilage
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bronchioles. This is the level alveoli appear at
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Where do terminal airways end?
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at alveoli clusters
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two functional zones of respiratory tract
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1. conducting zone- it begins at the trachea and ends ant the begining of the respiratory bronchi. NO gas exchange occurs here.
2. Respiratory Zone- extends from the repiratory bronchioles down through the alveoli. ALL gas exchange occurs here. |
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In what zone does gas exchange occur?
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Respiratory Zone
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What surrounds alveoli?
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rich supply of blood vessels so respiratory gases like CO2 and O2 are rapidly exchanged across the repiratory membranes
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3 types of protection respiratory system has from particulate matter
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1. Cilia
2. mucus 3. water fluid 4. macrophages |
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Describe cilia location and function in respiratory tract
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epithelial surfaces of airways to the end of the repiratory bronchioles contain cilia that beat upward toward the pharanyx. These epithelial cells also have glands that secrete mucus. mucus traps particulate matter and is moved by cilia toward pharynx and swallowed.
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Function of watery fluid secreted by epithelial surfaces of airways
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mucus rides on it. Without the watery substance mucus layer becomes thick and dehydrated.
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Cystic fibrosis
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defect in the chloride channels. no watery fluid for mucus to ride on so causes drying
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When are macrophages and cilia drastically impaired?
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By smoking
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Alveoli
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hollow sacs whose open ends are continuous with the airway lumens. Usually lined in single, continuous layer with type I and interspered with Type II
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Type I alveoli
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lined continuous in single layer. Most alveoli
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Type II alveoli
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interspersed in monolayer. They produce surfactant
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Total surface area available for gas exchange
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70 squarre meters
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repiratory membrane
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entire pathway over which oxygen and carbon dioxide must travel. It consists of the alveoli wall epithelial cells, the interstiitial fluid, and the capillary wall. these are all v. closely related so that gas exchange can occur
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What promotes rapid exchange of the repiratory gases between the alveoli and the blood?
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combination of large surface area and a short diffusion path
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Where are lungs?
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in closed thorax
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What surrounds lungs?
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pleural sac, a thin sheet that consists of two membranes really close to each other (inner and outer membrane)
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inner membrane of pleural sac
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attached to thesurface of lung by connective tissue
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Outer membrane of pleural sac
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attached to the inner thoracic wall and the diaphragm by connective tissue
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what seperates the inner and outer membrane of the pleural sacs?
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intrapleural fluid to lubricate the pleural surfaces. changes in the hydrostatic pressure of this fulid are directly related to the movements of the lungs and the thoracic wall
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Are the pleural sacs for each lung the same?
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no the pleural sac for each lung is seperate
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are inner and outer pleural membrane attached?
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NO. they are seperated by intrapleural fluid
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steps of respiration
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1. ventilation: exchange of air between atmosphere and alveoli by bulkflow.
2. exchange of O2 and CO2 between alveolar air and blood in lung caps by diffusion 3. transport of O2 and CO2 through pulmonary and systemic circulation by bulk flow 4. Exchange of O2 and CO2 between blood in tissue caps and cells in tissue by diffusion 5. cellular uses O2 and makes CO2 |
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What causes pressure gradient at periphery?
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Cells use Oxygen and produce carbon dioxide. so puts hi CO2 and low O2 in blood that ways after blood goes through right heart (lungs) O2 will have gradient to move in and CO2 will have gradient to move out to alveoli
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Ventilation
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exchange of air between the external environment and the alveoli
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Bulk flow equation
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F = (Patm - Palv)/(R)
reistance to flow by lungs in v. low so the flow has lo pressure |
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What is the MOST important factor for determing airway resistance
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diameter or radius of the air passages.
remember that resistance is inversely proportional to the fourth power of the radius |
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Boyles law
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at constant temp, pressure exerted by fixed number of gas molecules varies inversely with the volume of the container.
Ex: Increase in volume of container decreases the pressure of the gas. decrease vol. increase press. increase vol. decrease press. |
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What alters the pressure gradient between the alveoli and the external environment?
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changes in alveolar pressure do to volume of lungs changing. Air flows into or out of the alveoli depending on direction of pressure gradient
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what does it depend on for air to go in or out of alveoli?
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Pressure gradient
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transpulmonary pressure
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measured between inside and outside of the lungs (NOT between the alveoli and outside the chest) Pal-Pip
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Inside pressure
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pressure of air in the alveoli (Palv)
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Outside pressure
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pressure of the intrapleural fluid (Pip)
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Transpulmonary equation
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alveoli P - intrapleural f. P
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For air to get into system what must have most pressure?
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For air to get in system atmospheric pressure must be greater in atmosphere than in intrapelural fluid
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What happens to lungs at the end of expiration?
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the lungs expand bc of the positvie transpulmonary pressure is exactly balanced by the elastic recoil force of the chest wall
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What allows diaphragm and inspiratory intercostals to contract?
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neurally induced. controlled by midbrain pacemaker cells
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chain of events that happens when the diaphragm and inspiratory intercostals contract
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thorax expands
Pip becomes subatmospheric bc vol increases so P decreases Increase in traspulmonary P Lungs expand Palv becomes subatomospheric bc pressure decreases when vol. increases Air flows into the alveoli |
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is inhalation active or passive?
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Inhalation is active while exhalation is passive
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inspiration process
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neurally induced contraction of the diaphragm and inspiratory intercostal m. between the ribs which increase vol. in thorax, the decrease in vol. increases transpulm. P. Lungs expand. Expanded lungs increase vol of alveoli and decrease the P causing movement of air into lungs
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Expiration process flow chart
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diaphragm and inspiratory intercostals stop contraction
chest wall recoil inward Pip moves to preinspiration value Transpulmonary pressure moves beack toward preinspiration lungs recoil to reg. size air in alveoli is compressed Palv becomes greater than Patm Air leaves lungs |
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Expiration proccess
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expiration is initiated by relaxation of diaphragm and inspiratory intercostal m. the chest wall is no longer being pulled out so vol. decreases due to elastic recoil
transpulm. P decreases bc vol of lungs decreases vol of alveoli decrease and pressure in alveoli increase increase in alveolar P increases the P gradient between the alveoli and the environment and air leaves lungs |
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Lung compliance
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magnitude of the change in lung volume produced by a given change in the transpulmonary pressure
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Compliance equation
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Change in lung vol./Palv-Pip
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What does lo lung compliance meant
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greater than normal transpulmonary pressure must be generated to produce a gain amount of lung expansion. Basically you need a greater Pip to increase the work of breathing
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2 determinants of lung compliance
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1. elasticity of connective tissue
2. alveolar surface tension |
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Purpose of surfactant
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reduces the surface tension forces within the alveoli therefore increasing the lung compliance
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What enhance secretion of surfactant by type II cells?
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Deep breaths
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What is airway resistance determined by
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physical, neural, and chemical factors.
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What is airways resistance normally/
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Very low and therefore there a small pressure gradient can cause large movement of air
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What does transpulmonary pressure do to airways?
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distends the airways mainly those without cartilage and reduces the resistance to air flow
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lateral traction
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produced by elastic connective tissue fibers that are attached to the exterior of airways. The forces exerted by there fibers help to destend the airways and further reduce resistance of airway.
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What neural factors effect airways?
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1. epinephrine relaxes airway smooth m. by binding to beta receptors and reduces airway resistance
2. Leukotrienes produced during inflam. contract airway smooth m. and increase airway resistance |
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Asthma
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diseae where airway smooth m. contracts strongly and increases resistance. treat with anti inflam drug (glucocorticoids) to reduce inflam or use bronchiodialtors to reduce excessive smooth m. contraction
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chronic obstructive pulmonary disease (COPD)
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causes difficulties with ventilation and with oxygenatin of the blood. v. common with smokers
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is increased smooth m. constriction responsible for COPD?
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NO it is due to ventilation
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2 types of COPD
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emphysema
chronic bronchitis |
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emphysema
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results from destruction of alveoli, enlarged alveoli air space which decrease SA, and loss of pulmonary caps. It is thought that lung produces proteolytic enzyme to destroy elastic tissue
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Chronic Bronchitis
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caused by excessive mucus production in bronchi and chronic inflam changes in small airways
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How many exclusive volumes can total lung vol. be divided into?
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4
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Tidal vol
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(resting vol) volume of air moved in and out of lungs during quiet breathing. Usually about 500 mL
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inspiratory reserve vol (IRV)
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additional vol of air that can be inspired by maximum exertion of the inspiratory m. following normal inspiration
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Expiratory reserve volume (ERV)
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additional vol of air that can be exhaled by maximal contraction of the expiratory m. following a normal expiration
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residual vol.
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amount of air that is left in the lungs at the end of a max expiration.
Cannot get all the air out of lung, EVER! So air remains in lungs even after expiration |
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inspiratory capacity
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tidal vol + inspiratory
reserve vol. it is amount of air that can be inspired from the end of a normal expiration |
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Functional residual capacity
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expiratory reserve vol
+ residual volume amount of air that remain in the lungs at the end of normal expiration |
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two capacities that make up lung
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inspiratory capacity
+ functional residual capacity |
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vital capacity
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total amount of air that can be inspired after performing a maximal expiration. Total amount of air that can be physiologically controlled
expiratory reserve vol + tidal vol + inspiratory reserve vol basically its the max expiration to the max inspiration |
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lung vol that make up the total lung capacity
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inspiratory reserve vol
+ resting tidal vol + expiratory reserve vol + residual vol |
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forced expiratory volume in 1 sec (FEV1)
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amount of air an indiviual can exhale in one sec by max respiratory exertion following a max inspriation. Imporant clinically to measure as a percentage to vidal cap (FEV1/Vital Cap)
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Normal percentage of FEV1
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80%
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FEV1 in obstructive lung disease
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way less than normal 80% due to narrowing or obstuction or respiratory airways.
These people have barrel chest bc air is traped in lung and have hi resistance with expiration |
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2 types of pulmonary disease
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obstructuve lung disease
restuctuve lung disease |
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FEV1 with restuctive lung disease
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airway resistance is normal by respiratory movements are impaired. Vital capacity is reduced but normal ratio of FEV1 to vital cap.
Seen in people w/ disease of diaphragm or inspiratory m. |
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minute ventilation
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total amount of air moved into and out of lungs over a one min. period
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minute vol calculation
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tidal vol X respiratory rate
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problem with minute vol calculation
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it does not tel us alveolus ventilation
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volume in conducting airways
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about 150 mL where no gas exchange takes place. so this is known as atomic dead space
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alveolar ventilaiton
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amount of fresh air that moves into the alveoli during a one min period
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alveolar ventilation calculation
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(tidal vol - dead space)
x respiratory rate |
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How shoud dr find efficacy of repiratory activity?
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focus on alveolar ninute ventiation.
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Alveolar dead space
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vol of air contained in alveoli that have little or no blood supply.
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physiological dead space
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total dead space. which is the sum of the anatomical dead space and the alveolar dead space
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alveolar dead space
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where some of alveoli have no or little blood supply
if healthy this should be zero |
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air in dead space at the end of inspiration
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fresh air
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air in dead space at the end of expiration
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alveolar air
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In steady state what does O2 consumed by tissues equal?
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vol of oxygen added to blood in the lungs. Same for CO2 produced by tissue is equal to rate at which CO2 leaves the blood and enters the lungs
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respiratory quotient (RQ)
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CO2 production/ O2 consumption
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RQ carbs
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1 so O2 production = CO2
consump. |
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RQ fat
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0.7
CO2 producion/O2 consumption is 7/10 |
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RQ protein
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0.9
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RQ for mixed diet
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0.8
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what is presure exerted by a agas on the walls of its containe due to?
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random motion of gas molecules
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what is random motion of gas molecules that cause pressure on a gas equal to?
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temp and conc of gas mol.
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Dalton's law
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in mix of gases the pressure exerted by one gas is independent of the pressure exerted by any of the other gases in the mixture. The total pressure of a gas mixture is the sum of the individual partial pressure of the seperate gases
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How shoud dr find efficacy of repiratory activity?
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focus on alveolar ninute ventiation.
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Alveolar dead space
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vol of air contained in alveoli that have little or no blood supply.
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physiological dead space
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total dead space. which is the sum of the anatomical dead space and the alveolar dead space
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alveolar dead space
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where some of alveoli have no or little blood supply
if healthy this should be zero |
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air in dead space at the end of inspiration
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fresh air
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air in dead space at the end of expiration
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alveolar air
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In steady state what does O2 consumed by tissues equal?
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vol of oxygen added to blood in the lungs. Same for CO2 produced by tissue is equal to rate at which CO2 leaves the blood and enters the lungs
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respiratory quotient (RQ)
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CO2 production/ O2 consumption
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RQ carbs
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1 so O2 production = CO2
consump. |
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RQ fat
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0.7
CO2 producion/O2 consumption is 7/10 |
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RQ protein
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0.9
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RQ for mixed diet
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0.8
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what is presure exerted by a agas on the walls of its containe due to?
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random motion of gas molecules
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what is random motion of gas molecules that cause pressure on a gas equal to?
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temp and conc of gas mol.
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Dalton's law
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in mix of gases the pressure exerted by one gas is independent of the pressure exerted by any of the other gases in the mixture. The total pressure of a gas mixture is the sum of the individual partial pressure of the seperate gases
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How shoud dr find efficacy of repiratory activity?
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focus on alveolar ninute ventiation.
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Alveolar dead space
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vol of air contained in alveoli that have little or no blood supply.
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physiological dead space
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total dead space. which is the sum of the anatomical dead space and the alveolar dead space
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alveolar dead space
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where some of alveoli have no or little blood supply
if healthy this should be zero |
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air in dead space at the end of inspiration
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fresh air
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air in dead space at the end of expiration
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alveolar air
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In steady state what does O2 consumed by tissues equal?
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vol of oxygen added to blood in the lungs. Same for CO2 produced by tissue is equal to rate at which CO2 leaves the blood and enters the lungs
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respiratory quotient (RQ)
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CO2 production/ O2 consumption
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RQ carbs
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1 so O2 production = CO2
consump. |
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RQ fat
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0.7
CO2 producion/O2 consumption is 7/10 |
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RQ protein
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0.9
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RQ for mixed diet
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0.8
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what is presure exerted by a agas on the walls of its containe due to?
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random motion of gas molecules
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what is random motion of gas molecules that cause pressure on a gas equal to?
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temp and conc of gas mol.
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Dalton's law
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in mix of gases the pressure exerted by one gas is independent of the pressure exerted by any of the other gases in the mixture. The total pressure of a gas mixture is the sum of the individual partial pressure of the seperate gases
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How shoud dr find efficacy of repiratory activity?
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focus on alveolar ninute ventiation.
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Alveolar dead space
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vol of air contained in alveoli that have little or no blood supply.
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physiological dead space
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total dead space. which is the sum of the anatomical dead space and the alveolar dead space
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alveolar dead space
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where some of alveoli have no or little blood supply
if healthy this should be zero |
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air in dead space at the end of inspiration
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fresh air
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air in dead space at the end of expiration
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alveolar air
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In steady state what does O2 consumed by tissues equal?
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vol of oxygen added to blood in the lungs. Same for CO2 produced by tissue is equal to rate at which CO2 leaves the blood and enters the lungs
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respiratory quotient (RQ)
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CO2 production/ O2 consumption
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RQ carbs
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1 so O2 production = CO2
consump. |
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RQ fat
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0.7
CO2 producion/O2 consumption is 7/10 |
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RQ protein
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0.9
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RQ for mixed diet
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0.8
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what is presure exerted by a agas on the walls of its containe due to?
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random motion of gas molecules
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what is random motion of gas molecules that cause pressure on a gas equal to?
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temp and conc of gas mol.
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Dalton's law
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in mix of gases the pressure exerted by one gas is independent of the pressure exerted by any of the other gases in the mixture. The total pressure of a gas mixture is the sum of the individual partial pressure of the seperate gases
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Atmospheric air composition
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79% Nitrogen
21% oxygen |
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henrys law
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amount of particular gas dissolved in the liquid is directly proportional to the partial pressure of that gas in the space above the liquid
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what will happen if the partial pressure of a gas is higher is the liquid phase than in the gas phase?
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gas wil diffuse out of the liquid phase into the gas phase
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What is partial pressure of a gas is higher in the gas phase than in the liquid phase?
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gas will diffuse into the liquid
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Oxygen pressure in atomospher and alveoli
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in atmosphere 160 mmHG
in alveolar 105 mmHG |
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pressure of CO2 in atomosphere and in alveoi
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atmosphere = 0.3
alveoli = 40 |
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Pressure of water in atmosphere and in alveoli
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atmosphere = 0
alveoli = 46 comes from air and air gets humidified in the lungs |
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pressure on N2 in atmosphere and in lungs
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atmospher 600 mmGH
alveolli is 569 mmHg |
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What happens to O2 pressure in alveolus if alveolar ventilation decrease?
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it will decrease
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What happens to alveolar O2 pressure if cellular O2 consumption is increased?
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it will be decreased
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Factors that determine the value of alveolar CO2 pressure
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rate of alveolar ventilation
rate of cellular CO2 production |
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what happens to alveolus CO2 pressure if alveolar ventilation is decreasedd?
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It increases
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What happens to alveolus CO2 pressure if rate of production of CO2 by cells increases
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it will increase
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What is alveolar O2 pressure determined by at any particular atmospheric O2 pressure?
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ratio of O2 consumption by tissues to alveolar ventilation
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What is alveolar CO2 pressure determined by at any particular atmospheric CO2 pressure?
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ratio of CO2 production by tissues to alveolar ventilation
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Hypoventilation
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increase in ratio of CO2 production to alveolar ventilation that causs increase in alvolar CO2 pressure above normal value of 40 mmHg
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Hyperventilation
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decrease in ratio of CO2 production to alveolar ventilation that causs decrease in alvolar CO2 pressure below normal value of 40 mmHg
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In normal circumstances, where does O2 and CO2 equilibrate?
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between the alveoli and pulmonary caps before the blood leaves the caps
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what does effient use of the lungs to supply oxygen to the blood in pulmonary caps and remove CO2 depend on?
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ensureing that alveoli have good blood supply and are well ventilated. Any mismatch is called a ventilation-perfusion ratio
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If alveoli is not well ventilated, what is optimum blood supply?
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it must be reduced as well
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what happens when alveolus is under ventilated?
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lack of oxygen in the alveolus and surrounding tissue casue vasoconstiction of pulmonary bv in that region in order to maintain normal ventilation perfusion ratio
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What does ventilation perfusion abnormalities cause?
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lower oxygen pressure in the systemic arterial blood. Elevation of CO2 pressure in the systemic arterial blood too sometimes
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2 forms of oxygen in arterial blood
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dissolved in blood plasm
reversibly bound to hemoglobin contained in the RBS |
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% of total O2 in arterial blood that is dissolved plasma
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3% bc its low solubility in water so majority of O2 (97%) is bound to hemoglobin and carried.
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How many oxygens can one hemoglobin carry/
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4
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percent saturation of O2
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amount of O2 bound to Hb/ maximal capacity of Hb to bind O2
x 100 |
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oxygen hemolglobin dissociation curve
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relationship between the oxygen pressure in arterial blood and percent saturation of Hb.
S shape curve steepest portion between partial pressure of O2 of 10-60 mmHg. plateus at O2 pressure of 60 mmHg |
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What initiates inspiration?
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action potentials in motor nerves to inspiratory m.
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only time expiratory m. are activated by action potentials
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forced expiration
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where is control of AP for respiratory m.?
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in medulla oblongata. medulary inspiratory neurons provide the rhythmicinput to motor neurons
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What is rhythmic activy of respiration result of?
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interactions w/ other medually neurons and intrinsic pacemaker potentials in inspiratory neurons themselves. these fire to start inspiration process
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what modulateds output of inspiratory neurons and may terminate inspiration by inhibiting the nuerons?
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the lower pons (apneustic center)
The upper pons (pneumotaxic center) modulates the lower pons |
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purpose of pulmonary stretch receptors
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limit inspiration. safety mechanism so you dont over inflate the lungs. ONLY IMPORTANT WHEN TIDAL VOL IS LARGE LKE W/ EXCERCISE
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What can be changed to control ventilation?
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respiratory rate and tidal volume
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most important inputs to medullary inspiratory neurons at rest come from where?
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come from periphereal chemoreceptors and central chemoreceptors
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peripheral chemoreceptors
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consist of carotid bodies and aortic bodies. their afferent fibers give excitatory input to the medullary inspiratory neurons
These receptors are primarily stimulated by decreases in arterial O2 pressure and increase in arterial H+ conc. |
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central chemorecptors
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in medulla and give excitatory input to medullary inspiratory neurons. They are stimulated by increases in the H+ conc of the brain's extracelluar fluid, largely as a result of changes in blood Co2 Pressure
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when does pulmonary ventilation increase significantly?
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when arterial Oxygen PRessure fall below 60 mmHg. the low Oxygen pressure increase the rate of firing of the peripheeral chemorectors which stimulates the medullary inspiratory neurons. the increase in ventilation increases the delivery of oxygen to the alveoli and increases the arterial Oxygen
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are small reduction of arterial oxygen a major stimuls for increasing ventilation?
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NO
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Flow chart. what happens when inspired oxygen pressure decreases?
|
decrease alveolar oxygen pressure
decrease arterial oxygen pressure increase firing of peripheral chemoreceptors reflex via medulllary respiratory neurons to increase contractions of resp. m. increase ventilation return of alveolare nad arterial oxygen pressure to normal |
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Does a small icrease in arterial CO2 pressure cause a big increase in ventilation?
|
YES
differs from O2 |
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what does control of ventilation related to changes in CO2 caused by
|
H+ conc. Increase H+ conc. increases rate of fining of both central and peripheral chemoreceptors
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FLOW CHART OF INDUCED HYPER VENTILATION
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decrease production of non CO2 acid (H+ w/o CO2)
increase arterial H+ peripheral chemoreceptors fire reflex via medulalry respiratry neurons cause respiratory m. to increase contraction increase ventilation decrease alveolar PCO2 decrease arterial PCO2 Return of aterial H+ to normal |
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How to distinguish where H+ comes from.
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metabolic acidosis does not stimulate central chemorectors bc H+ cant cross blood brain barrrier but Respiratory acidosis does stimulate central rectors bc CO2 can cross blood brain barrier
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