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53 Cards in this Set
- Front
- Back
Ventilatory system |
Responsible for maintaining efficient gas exchange between internal and external environment |
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Functions of ventilatory system |
Supply O2 required in metabolism, eliminate CO2 produced in metabolism, regulate hydrogen ion concentration to maintain acid base balance |
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Ambient air |
Outside air |
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2 parts of ventilatory system |
Conductive zone and respiratory zone |
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Conductive zone |
Mouth, nose, trachea, and 2 primary bronchi. Humidify, warm, and filter the air |
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Respiratory zone |
Bronchioles and alveoli (functional part of respiration) |
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Alveoli capillary membrane |
Where the gas exchange occurs |
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How much O2 leaves alveoli each minute in a resting state |
250 ml or 4.1 ml a second Trained endurance athletes can increase this uptake 20x during intense aerobic exercise |
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How much CO2 diffuses into alveoli each minute |
200 ml or 3.3 ml a second |
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Mechanics of inspiration |
Diaphragm contracts, flattens out, moves downward. Air in lungs expand reducing the pressure. Pressure differential sucks air in. Pressure starts to decrease until it's equal with the environment and then you expire |
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Mechanics of expiration |
Air moves out from the recoil of stretched lung tissue and relaxation of inspiratory muscles. Sternum and ribs swing down while diaphragm moves toward thoracic cavity. All this decreases chest cavity volume forcing air out |
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Static lung volume test |
Evaluates dimensional component for air movement within the pulmonary tract and impose no time limitation on the subject |
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Dynamic lung volumes |
Evaluates power component of pulmonary performance during different phases of ventilatory excursion |
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Tidal volume |
Amount of air expired in a single breath .4-1 L of air |
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Inspiratory reserve volume |
Maximum inspiration, additional volume of 2.5-3.5 L above TV |
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Expiratory reserve volume |
Max expiration. Additional 1-1.5 L of air can be exhaled after normal expiration |
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Forced vital capacity |
Maximum inspiration and expiration. Total air moved for max both. 4-5 L in men and 3-4 L in women |
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Residual lung volume |
Minimum amount of air left in lungs after maximal exhalation. 1.2-1.6 L in men. 1.0-1.2 for women |
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Anatomic dead space |
Portion of inspired air that doesn't participate in gas exchange. Usually 150-250mL or 30% of resting TV. |
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Physiologic dead space |
Portion if alveolar volume that doesn't participate in gas exchange due to some of the alveoli not functioning properly. Can increase due to: underperfusion of blood or COPD |
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Gas concentrations |
Reflect amount of gas in a given volume. Gas concentration = gas partial pressure x solubility |
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Solubility |
Dissolving power of gas |
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Gas pressures |
Force exerted by gas molecules against the surfaces they encounter |
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Henry's Law |
Solubility of the gas is equal to the pressure above the liquid. If the pressure is greater above the liquid, it will have greater solubility and diffuse into the liquid |
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Ambient air gas mixture |
Nitrogen (79%) Oxygen (21%) Carbon dioxide (<1%) |
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Daltons Law |
Partial pressure is the pressure each gas applies to it's surrounding **** |
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Barometric pressure |
Atmospheric pressure, pressure exerted by the weight of the gas contained in the atmosphere |
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Partial pressure of O2 |
Computed by 760 x .2093 = 159 |
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Tracheal air |
Air is humidified here. Total pressure of air decreased to 713. Decreases PO2 to 149 |
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Alveolar air |
This air is very different than ambient air. 14.5% O2 and 5.5% CO2. PO2 is equal to 100mmhg |
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Gas exchanges in the body (lungs) |
Alveolar PO2 = 100 Venous PO2 = 40
Alveolar PCO2 = 40 Venous PCO2 = 46 |
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Gas exchange in body (tissue) |
Arterial blood PO2 = 100 Tissue PO2 = 40 Arterial blood PCO2 = 40 Tissue PCO2 = 46 |
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Oxygen combined with Hb |
Hb is an iron protein. Increases RBC carrying capacity of oxygen 65-70 above what is dissolved in the plasma. Each Hb molecule has 4 iron atoms that combine with 1 oxygen molecule to form oxyhemoglobin. |
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Loading phase |
when O2 combines with hemoglobin, also known as saturating phase |
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Oxygen carrying capacity of hemoglobin |
Each 100 mL of blood contains roughly 15-16g of Hb in men. Each gram of Hb can combine with 1.34 mL of oxygen |
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Calculating oxygen carrying capacity of Hb |
Assumes 100% saturation Oxygen carrying capacity = Hb (g per 100 ml of blood) x oxygen caoacity of Hb |
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Oxyhemoglobin dissociation curve |
Explains loading and unloading of O2 in regards to PO2. As PO2 decreases, so does % concentration of Hb and extraction rate from Hb. When PO2 drops below 60, a sharp decrease occurs in how much oxygen combines with Hb |
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Bohr effect |
Increases to acidity and blood temperature causes the curve to shift downward and to the right (enhanced unloading of O2). It weakens the bonds. In intense exercise this is seen resulting in unloading of O2 |
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Hb saturation |
At alveolar capillary membrane the PO2 is 100. Hb is 98% saturated. 19.7 mL of O2 is bound to Hb At tissue capillary level of PO2 is 40. Hb is 73% saturated. 15 mL of O2 is bound to Hb |
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Carbon dioxide transport in blood |
1. Plasma: 7-10% it stays while the rest diffuses 2. Loose combination with Hb 20% 3. Combined with water to form bicarbonate 70% |
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CO2 in plasma |
Establishes PCO2 of the blood |
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CO2 and Hb |
Diffuses from tissue and combines with Hb to form a carbamino acid. It's transported to lungs and expired |
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Haldane effect |
Facilitates CO2 removal from the body and explains the interaction between oxygen unloading and carbon dioxide release |
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ventilatory control: neural factors |
Respiratory cycle comes ruin automatic activity of inspiratory neurons. Neural input to the respiratory control center comes from both the high brain centers and afferent pathways |
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Ventilatory control during rest: humoral factors |
Chemical state of blood largely regulates pulmonary ventilation at rest. Arterial PCO2 provides the MOST IMPORTANT respiratory stimulus at rest. Chemoreceptors: structures that stimulate ventilation in response to increased carbon dioxide, temperature, and acidity |
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Ventilatory control: chemical factors |
Arterial PO2, in exercise does not decrease to the point that stimulates ventilation by chemoreceptor activation. Also PCO2 and H ions Chemical stimuli can't fully explain hyoerpnea (fast breathing) during physical activity |
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Pulmonary ventilation |
Process of breathing (minute ventilation) Physical activity provides greatest stimulus for increases in pulmonary ventilation |
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Ventilatory equivalent for oxygen |
Ratio of minute ventilation to oxygen uptake. Represents breathing economy. Reflects amount of air breathed (VE) per oxygen consumed (VO2) VE/VO2 |
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Ventilatory equivalent for carbon dioxide |
Ratio of minute ventilation to carbon dioxide produced VE/VCO2 |
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Ventilation during non steady state exercise |
As VO2 increases there is a point where minute ventilation increases disproportionately. This is at the ventilatory threshold |
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Ventilatory threshold |
Point at which Pulmonary ventilation increases disproportionately. Relates to carbon dioxides increases output from the buffering of lactate that begins to accumulate from anaerobic metabolism |
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Onset of blood lactate accumulation |
Indicated by sharp upswing in pulmonary ventilation related to VO2 during exercise. Imbalance between BL appearance and disappearance. Occurs between 55-60% of VO2max in healthy untrained individuals and 80% of VO2max in highly trained endurance athletes |
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Buffering |
Chemical buffers consist of a weak acid and a salt of that acid. Bicarbonate is main one. Anaerobic exercise increases demand for buffering |