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74 Cards in this Set
- Front
- Back
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5 things to be accomplished with pulmonary physiology
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1. Ventilation- getting air into and out of the lungs** Most important.
2. External respiration- gas exchange between alveoli and the pulmonary capillary blood. 3. Gas transport- gas physically moved by the blood stream. 4. Internal respiration- gas exchange between the systemic capillaries and metabollically active tissues of the body. 5. cellular respiration- metabolic use of oxygen of all cells- mitochondria. |
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Conducting structures of the pulmonary system
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Composed of all the anatomical structures that provide a conduit through which the air must travel in order to get to the respiratory division. Includes: nose, oral cavity, trachea, bronchi.
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Does the conducting system have a role in EXTERNAL respiration?
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NO.
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What is the anatomical dead space?
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Volume of air within the conduction pathways.
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Definition of breathing rate
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Breaths per minute
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Define tidal volume
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volume of air breathed in or out each minute.
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V = BR x TV
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volume of air breathed in and out each minute is equal to the breathing rate multiplied by the tidal volume
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What is the average volume of air breathed in per breath?
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500 mL/br
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What is the average volume of air breathed in each minute?
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6000 mL/min
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In respiratory distress, is the breathing rate increased or decreased?
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Increased.
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When breathing rate increases, what happens to the tidal volume?
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Tidal volume falls.
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Respiratory structures
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respiratory bronchioles, alveolar ducts, alveoli
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What occurs within the respiratory end of the pulmonary system?
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Location of EXTERNAL respiration. Gas exchange between pulmonary capillaries and alveoli.
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What is the function of the nose?
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Moisten air, filter air, warm air.
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What are the 3 functions of the pleura?
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Secrete serous fluid to ensure smooth lung movement. Adhere lung to thoracic wall. isolate thoracic organs from the lungs.
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At rest, is exhalation passive?
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YES
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What makes the diaphragm contract and increase the superior inferior space of the thorax?
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Inspiration
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How does P = 1/V relate to respiration?
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As the volume increases within the lungs, the pressure decreases thereby forcing the air to move into the lungs.
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Inspiratory reserve volume
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maximal amount of air that can be drawn into the lungs with determined effort after normal inspiration.
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Expiratory reserve volume
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additional amount of air that can be expired from the lungs by determined effort after normal expiration.
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Functional residual capacity
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The amount of gas left within the lungs at the end of a normal expiration
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Residual capacity (volume)
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The amount of gas left within the lungs after the most forcible expiration amounting to 60-100 cc.
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Vital capacity
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The amount of air that is forcibly exhaled after a forcefull inspiration.
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Total lung volume
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Amount of gas in the lungs after a maximal inspiration.
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Tidal volume
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Volume of air inhaled with each breath.
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Distinguish capacity from volume.
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Capacity = maximal amount
Volume = amount filled that is not necessarily the maximal amount. |
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Define intrapulmonic pressure
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Pressure inside the lung. INtrapulmonic pressure < atmospheric pressure = inspiration during quiet breathing.
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What does a lack of air within the intrapleural space produce?
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Subatmospheric pressure to be lower than intra pulmonary pressure creating a vacuum- lung surface adheres to the thoracic wall. Facilitates inflation of the lung.
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What is elasticity?
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Property of the structure to return to its inital size after being distended
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What is the result of elasticity of the lungs?
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Lungs will resist distention.
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When does tension increase?
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During inspiration. Tension decreases during expiration.
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What is the proper term for elastic tension?
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Recoil tendency
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How is surface tension created in the lungs?
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Water molecules on the surdace of the alveoli are attracted more to other water molecules than air which in turn creates pressure inside of the alveoli.
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What is the pressure created by the surface tension on the alveoli called?
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Intra-alveolar pressure
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What is surfactant?
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Glycoprotein. Surface active agent. Synthesized and secreted by type II alveolar cells. Located in the alveoli. Not S/S until later in fetal life.
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What is hyaline membrane disease?
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Premature delivery complication. The child is born too early and the synthesis and secretion of surfactant has not yet occurred. Called hyaline membrane disease because lungs have hyaline cartilage like appearance.
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What is compliance?
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Change in lung volume over the change in transpulmonary pressure. Ability of something to expand when it's stretched.
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Pathway of inspiration of air
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Oral cavity/nose -> pharynx -> larynx -> trachea ->bronchi -> bronchioles -> alveolar ducts -> alveoli.
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Partial pressure
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Pressure of a gas within a mixture of gases with the plasma of the blood. Indirectly related to solubility.
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Describe the exchange of gases within the alveoli
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CO2 moves into the alveolus from the blood because of the concentratoin of the pressures. O2 moves out of the alveolus to oxygenate blood.
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2 ways to transport oxygen
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Dissolve in plasma, combine with hemoglobin
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What is the solubility of oxygen within plasma?
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0.3 mL of oxygen/100 mL of blood
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What is the metabolic requirement of the solubility of oxygen in the plasma?
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200 mL/min on average
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How is MET calculated?
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MET = 3.5 mL O2/kg body weight/min
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How do you calculate cardiac output?
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Q = SV x HR
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What is the average cardiac output?
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5000 mL/min
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What is oxygen carrying capacity?
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The amount of oxygen that a HgB molecule can carry
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What is the average amount of HgB found in the blood at one time?
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15 g HgB/100 mL blood
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What is the molecular weight of carbamino HgB?
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450,000
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What are the 2 groups of neurons in the medulla that are clustered which are critically important in respiratory control?
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DRG (dorsal respiratory group), VRG (ventral respiratory group)
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Describe the dorsal respiratory group.
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Located near vagus nerve, responsible for integrating input from the peripheral strech receptors and from the chemoreceptors and sends information to the VRG
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Describe the ventral respiratory group
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Responsible for basic respiratory rhythm. Network of neurons that runs in the brainstem from the medulla all the way up to the medullary-pontine border. Smooths transition from inspirtation to expiration
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What kinds of neurons does the ventral respiratory group have?
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inspiratory and expiratory
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What is the function of inspiratory neurons?
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fire and send impulses along the phrenic and intercostal nerves to innervate the diaphragm and external intercostal muscles.
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Describe active breathing
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Muscles contract => volume increases => pressure decreases => you breath in
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What is the function of expiratory neurons?
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fire and inhibit the inspiratory neurons which stop the impulses to muscles of respiration.
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Describe passive breathing
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Muscles rebound, volume decreases, pressure increases, you breathe out. * NO BRAIN ACTIVITY
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What is the function of the pneumotaxic center (pontine respiratory group)?
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Send impulses to VRG, monitor respiratory rhythm for activity being performed.
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How is inspiratory depth determined?
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By how actively the respiratory center stimulates the motor neurons serving the respiratory molecules. Greater the inspiration, the greater # motor units, greater the breath.
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How is breathing rate determined by the body?
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by how quickly the inspiratory center is turned on and off.
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Where are the chemoreceptors for inspiraton located? What partial pressures are they sensitive to?
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They are located in the medulla, aortic arch, carotid arteries at the point of bifurcation. They are sensitive to PCO2, pH, and PO2
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Which chemoreceptors are for periphery and which ones are central?
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The medulla is central. Aortic/carotid is peripheral.
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What is the optimum partial pressure for PCO2?
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40 +/- 3 mmHg
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Describe the chemical process of increasing ventilation in response to PCO2
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PCO2 increases, CO2 diffuses into CSF and combines with water to form H2CO3 --> H + HCO3. Hyperkapnia excites receptors in CSF. Synapse with VRG and increase rate and depth of breathing.
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How large of a raise in pressure will cause alveolar ventilation to double?
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5 mmHg
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What excites the chemoreceptors to increase ventilation?
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H ion
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What partial pressure are the chemoreceptors most sensitive to in regard to increasing ventilation?
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PCO2
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Where are the cells which are sensitive to PO2?
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Periphery
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How large of a drop must there be in PO2 to increase ventilation?
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The pressure level must drop to 60 mmHg or lower.
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If there is a decrease in pH in the blood, what will result?
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The breathing rate will increase even if there is not a significant raise in PCO2. This could be a result of poor fatty acid metabolism, or increasing lactic acid levels.
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Waht is atelectasis?
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Collapsed lung. Pneumonal thorax.
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What is empyema?
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Pus accumulation within the pleural space.
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What is emphysema?
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loss of elasiticity within the alveoli
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What is bronicectasis?
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Inflammation of the bronchi and bronchioles.
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