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67 Cards in this Set
- Front
- Back
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The pressure generated by each sphere is determined by what law? |
Law of Laplace |
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P = ? |
2T/r |
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Having no surfactant does what to collapsing pressure? |
Increases it |
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Having surfactant does what to collapsing pressure? |
Decreases it |
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Smaller alveoli without surfactant will collapse. What is this called? |
Atelectasis |
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How does surfactant reduce the collapsing pressure? |
It disrupts intermolecular forces in the fluid lining the alveoli |
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In a developing fetus, synthesis of surfactant begins at what week? |
24 |
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In a developing fetus, at what week is surfactant always present? |
35 |
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When does an infant never have surfactant? |
When they are premature and born before 24 weeks |
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When do infants have varied amounts of surfactant? |
When they are born premature- between weeks 24 and 35 |
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Where is the major site of airway resistance? |
Medium sized bronchi (gens 5-10) |
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Without a pressure difference, what happens to air flow? |
It does not occur |
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What is the primary determinant of resistance? |
Airway radius |
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Resistance is determined by what law? |
Pouseilles Law |
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Resistance is __________ proportional to radius? |
Inversely |
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When is PNS cholinergic dominant? |
Dominant at rest |
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What happens when PNS cholinergic is dominant? When is it dominant? |
- constriction of bronchial smooth muscle -decrease in airway diameter -increase in airflow resistance -Dominant when at rest |
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What activates the constriction of bronchial smooth muscle? Example? |
muscarinic agonists Ex: muscarine/carbachol |
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What blocks the effects of the constriction of bronchial smooth muscle? Example? |
muscarinic antagonists Ex: atropine |
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What happens when SNS adrenergic is dominant? When is it dominant? |
-relaxation of bronchial smooth muscle -increase in airway diameter -decrease in airflow resistance -Dominant during exercise |
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What activates the relaxation of bronchial smooth muscle? Example? |
B2 receptors Ex: epinephrine/albuterol |
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What are conditions associated with Chronic Obstructive Pulmonary Disease? (COPD) |
-secretions -thickening -loss of airway support *All associated with airway resistance |
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Examples of COPD? |
Asthma and emphysema |
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What happens to airway resistance with asthma? |
it increases |
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What is this describing? -Thickening of walls from inflammation& histamine induced edema -plugging of airway by secretion of mucus -airway hyperresponsiveness, constricting spasms |
Asthma |
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Someone who has asthma has an increased sensitivity to? |
Smoke, cold air, and exercise |
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What are 3 treatments for asthma and what do they do? |
-B adrenergic agonists; Relax smooth muscle -Corticosteroids; decrease inflammation -Antileukotrienes; decrease inflammation |
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Collapse of airways and destruction of alveolar walls occurs in what disease? |
Emphysema |
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Explain what goes on with trypsin in someone who has emphysema |
-macrophages release trypsin -lungs are protected by a1 antitrypsin -but the increase in trypsin production overrides the protective ability of a1 antitrypsin |
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A man in his 50s with an increased shortness of breath for over 3 to 4 years would have what type of emphysema and what do they call them? |
Type A Pink puffers |
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Signs of Type A emphysema? |
-recent weight loss -no cyanosis -overexpanded chest -quiet breath sounds -normal jugular venous pressure |
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2 components of pink puffers? |
mild hypoxemia normal PCO2 |
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A man in his 50s with history of chronic cough& expectoration for several years would have what type of emphysema and what are they called? |
type B Blue bloaters |
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Signs of type B emphysema? |
-some cyanosis -rales -fluid retention and raised jugular veins |
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2 components of blue bloaters? |
hypoxemia hypercapnia (increase in PCO2) |
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clicking bubbling rattling sounds in lungs due to air opening closed air spaces; categorized as moist, dry, fine, and coarse |
rales |
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Gas transfer across cell membranes or capillary walls occurs via _________? |
diffusion |
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Fick Equation |
Vx = D x A x deltaP/ delta X |
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The rate of transfer of gas is directly proportional to? |
Diffusion coefficient Surface Area Pressure gradient |
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The rate of transfer of gas is inversely proportional to? |
membrane thickness |
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The driving force for the diffusion of gas comes from what? |
partial pressure difference of the gas (deltaP) |
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The diffusion coefficient of a gas (D) depends on what 2 things of the gas? |
molecular weight and solubility |
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D for CO2 is how many times higher than for O2? What does this mean? |
20 times for a given pressure, CO2 diffuses 20 times faster than O2 |
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The lung diffusing capacity (DL) combines what 4 things? |
1. the diffusion coefficient (D) of the gas 2. the SA of the membrane 3. the membrane thickness 4. the time taken for the gas to combine with proteins (ex: binding of O2 to Hb) |
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In emphysema, what happens to DL? Why? |
it decreases destruction of alveoli results in a decrease in SA for gas exchange |
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In fibrosis or pulmonary edema, what happens to DL? Why? |
it decreases the diffusion distance increases due to an increase in membrane thickness or an increase in fluid volume |
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In anemia, what happens to DL? Why? |
it decreases there is a decrease in hemoglobin in red blood cells |
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In exercise, what happens to DL? Why? |
it increases additional capillaries are perfused which results in an increase surface area for gas exchange |
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How many forms of gas are in alveolar air and how are they expressed? |
one form of gas expressed as partial pressure |
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In solutions such as blood, gas is carried in several forms, what are they called? |
-dissolved -bound -modified |
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gases in solution are carried in dissolved form |
dissolved gas |
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Henrys law? |
Cx = Px x solubility |
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Of the inhaled gases, which gas is carried only in dissolved form and never bound or modified? |
Nitrogen |
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O2, CO2, and CO are all bound to proteins in blood. This is known as? |
Bound gas |
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The conversion of CO2 to HCO3 in the RBC; most CO2 is carried in this form |
chemically modified gas |
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The partial pressure of a gas in a mixture of gases is the pressure that gas would exert if it occupied the total volume of the mixture |
Daltons law of partial pressures |
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Px = ? |
PB x F |
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If gas is humidified what is the Px equation? |
Px = (PB - PH2O) x F |
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what kind of blood goes from the tissues via the veins to the right heart; pumped from the right ventricle via the pulmonary artery to the pulmonary capillaries |
mixed venous blood |
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What are the P O2 and P CO2 values in the mixed venous blood? |
P O2 = 40 mmHg (Low) P CO2 = 46 mmHg (high) |
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What kind of blood is oxygenated and leaves the pulmonary capillaries; returns to the left heart; and is pumped from the LV into the aorta? |
systemic arterial blood |
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What are the P O2 and P CO2 values in the systemic arterial blood? |
P O2 = 100 mmHg (high) PCO2 = 40 mmHg (low) |
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Why does the blood leaving the capillary have the same PO2 as the alveoli? |
it is equilibrated |
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What 2 forms is O2 transported in the blood and what is the percentage? |
2% dissolved in blood 98% bound to Hb in RBC |
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O2 diffuses from alveoli to blood along its _____________________? |
Partial pressure gradient |
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Only ________ O2 produces a partial pressure. |
dissolved |
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Describe Henrys law |
The concentration of dissolved O2 is proportional to the partial pressure of O2 |
