Term
| The rate of O2 diffusion from the alveolus into pulmonary capillaries is influence by what 4 factors? |
|
Definition
1. Difference in partial pressure of O2 across the respiratory membrane
2. Diffusion of coefficient of O2
3. Thickness of the respiratory membrane
4. Surface area of the respiratory membrane |
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Term
| PO2 in the alveolus is __mmHg, and PO2 in the arterial capillary blood is __mmHg. |
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Definition
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|
Term
| The initial pressure difference between PO2 in the alveolus and capillary blood is 60mmHg so O2 diffuses into the __. The PO2 in the arterial blood rises almost to the level of __ __. |
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Definition
|
|
Term
| The diffusion coefficient of O2 in higher in air than in a dissolved state, so it moves into the __. |
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Definition
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|
Term
| The diffusion coefficient for CO2 is higher in solution than in air, so movement is into ___ |
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Definition
|
|
Term
| Name 3 factors that can change the thickness of the respiratory membrane. |
|
Definition
Edema
Fibrosis of lungs
Mucus secretion |
|
|
Term
| The rate of diffusion is __ proportional to the thickness of the membrane, so increases in thickness will ___ diffusion rate of O2 |
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Definition
|
|
Term
| If you increase thickness of the respiratory membrane, how will this affect diffusion? |
|
Definition
|
|
Term
| Surface area of the respiratory membrane can be greatly decreased by certain conditions. Name 2. |
|
Definition
Lung Removal
Emphysema (destruction of alveolar walls) |
|
|
Term
| Sigificant decreases in surface area can lead to serious __ in gas exchange - even in resting conditions. |
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Definition
|
|
Term
| If you decrease surface area how will this affect gas exchange? |
|
Definition
|
|
Term
| The capacity of diffusion across a membrane can change with different conditions. Name 2. |
|
Definition
1. Exercise increases diffusion capacity of membrane of O2
2. Exercise increases diffusion capacity of CO2 |
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|
Term
| Because when exercising, vessels dilate, it increases the diffusion capacity of membrane to O2. This is partially du to what? |
|
Definition
| Increased perfusion of alveolar capillaries with blood |
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|
Term
| With exercise, alveolar ventilation is __ and so is diffusion capacity. |
|
Definition
|
|
Term
| Overall, exercise leads to an __ in blood oxygenation |
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Definition
|
|
Term
| Blood travels thru the lung much quicker during exercise than rest. This __ the amount of time for diffusion. The fact that diffusion increases during exercise helps insure that blood remains saturated with O2 |
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Definition
|
|
Term
| How much air is being ventilated to alveolus and how much blood is being perfused. |
|
Definition
| Ventilation-perfusion ratio |
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|
Term
| A concept that describes both the ventilation of the alveoli (Va) within a particular region of the lung AND the blood flow, or perfusion (Q) to that region. |
|
Definition
| Ventilation - Perfusion Ratio |
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|
Term
| When there is normal ventilation and perfusion in the alveoli, Va/Q ratio is said to be __ |
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Definition
| Normal (no particular value) |
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|
Term
| If there is zero ventilation, but still perfusion, then Va/Q ratio is __ |
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Definition
|
|
Term
| What might cause zero ventilation but still perfusion? |
|
Definition
| Obstruction of the bronchioles |
|
|
Term
| Conditions of below normal Va/Q ratio is termed what? |
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Definition
|
|
Term
| The lower regions of the lungs are examples of normal physiologic shunts. How? |
|
Definition
| Because ventilation is less than perfusion |
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|
Term
| If there is adequate ventilation, but no perfusion then what is Va/Q ratio? |
|
Definition
|
|
Term
| How might you have adequate ventilation but no perfusion? |
|
Definition
| Destruction of the alveolar wall, such as chronic smoking |
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|
Term
| In regions where you have adequate ventilation but no perfusion, there is no gas exchange from the alveoli to the blood, so Va/Q ratio is __ normal. |
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Definition
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|
Term
| Regions where no perfusion occurs is called what? |
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Definition
|
|
Term
| The apices of the lungs are examples of normal physiologic dead spaces because why? |
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Definition
| Perfusion is less than ventilation |
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|
Term
| In some conditions, there can be regions of both physiologic shunts and dead spaces. What might cause this? |
|
Definition
| Chronic obstructive lung dz |
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|
Term
| Exercise can also affect the Va/Q ratio - such as in the upper regions of the lungs. Perfusion to these areas __ with exercise, so Va/Q __ and approaches normal. |
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Definition
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|
Term
| About 98% of blood that enters the left atrium is from where? |
|
Definition
| Pulmonary arterial capillaries |
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|
Term
| What happens to blood that enters the left atrium? |
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Definition
| It gets oxygenated for systemic circulation |
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|
Term
| What happens to the other 2% of blood that didn't go to the left atrium? |
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Definition
| It passed from the aorta to the bronchial circulation to supply the tissues of the lungs (not exposed to alveolar air) and then returned to the left atrium. |
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Term
| Blood that goes to supply the tissues of the lungs is called __ and is deoxygenated once returned to the left atrium. |
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Definition
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|
Term
| Shunt flow blood is mixed with oxygenated blood and lowers the PO2 in the left atrium to about __mmHg for systemic circulation. |
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Definition
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|
Term
| About 3% of systemic arterial blood travels in the __ state. The other 97% is bount to __ and taken to the tissues. |
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Definition
|
|
Term
| When PO2 levels are high O2 does what? What does O2 do when PO2 levels are low? |
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Definition
Binds to hemoglobin
Dissociates from hemoglobin |
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|
Term
| When PO2 levels are high O2 does what? What does O2 do when PO2 levels are low? |
|
Definition
Binds to hemoglobin
Dissociates from hemoglobin |
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|
Term
| The amount of bound hemoglobin with O2 |
|
Definition
| Percent saturation of hemoglobin |
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|
Term
| Percentage of saturation of hemoglobin is high in systemic arterial blood __% and low in venous blood from peripheral tissues __% |
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Definition
|
|
Term
| Under normal conditions, about __mls of O2 are delivered to the tissues for every __mls of blood flow. |
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Definition
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|
Term
| During strenuous exercise, up to __ml of O2 per 100ml blood can be delivered to the muscle tissue. |
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Definition
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|
Term
| During extreme exercise, up to 15ml of O2 per 100 ml of blood is delivered to muscle tissue. This, combined with increased CO (up to 7x) can result in a __ fold increase in O2 delivery to muscle during extreme exercise. |
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Definition
|
|
Term
| The amount of O2 given up in the tissues. |
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Definition
|
|
Term
| What is the utilization coefficient normally? |
|
Definition
| 25% (decrease from 97% to 75% saturation) |
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|
Term
| During exercise, the coefficient for the entire body can rise to as much as __% |
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Definition
|
|
Term
| Each globin molecule binds _ heme groups, each heme group can bind to _ oxygen molecule. |
|
Definition
|
|
Term
| In addition to transporting O2, hemoglobin acts as a ___ in the tissues to maintain PO2 at __ mmHg regardless of the condition (rest/exercise) |
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Definition
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|
Term
| The fact that hemoglobin acts as a buffer is a very tightly controlled system and helps protect the tissues from changes such as what? |
|
Definition
| Decreased atmospheric O2 levels |
|
|
Term
| Name all of the ways in which you can get a curve shift to the right (decreases in saturation levels) |
|
Definition
Increased H+ (acidic pH, 7.2)
Increased CO2 concentration
Increased blood temperature |
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|
Term
| Decreases in saturation levels decreases the __ of hemoglobin for O2. |
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Definition
|
|
Term
| All of the conditions that cause a curve shift to the right occur in the tissues and facilitate what? |
|
Definition
| The dissociation of O2 from hemoglobin |
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|
Term
| What shifts the curve to the left (increases saturation levels)? |
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Definition
|
|
Term
| Exercise can also shift the curve to the __. It delivers more O2 from hemoglobin. |
|
Definition
|
|
Term
| When blood reaches the tissues, PO2 is still __mmHg. |
|
Definition
|
|
Term
| When blood reaches the tissues, the interstitial fluid is only ___mmHg. Therefore, O2 very rapidly diffuses in the interstitial fluid, and PO2 of capillaries drops to __mmHg for venous return. |
|
Definition
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|
Term
| The PO2 of cells is ler than the capillaries and the interstitial fluid (__mmHg), but still sufficient for normal metabolic functions. |
|
Definition
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|
Term
| Under normal conditions, the rate of O2 consumption by the cells is determined ultimately by the rate of __ __. |
|
Definition
| Energy Expenditure (ADP converted to ATP) |
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|
Term
| When O2 is used by the cells, virtually all of its converted to CO2, and this __ the intracellular PCO2. |
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Definition
|
|
Term
| CO2 has a much __ diffusion rate than O2, so the pressure difference required for diffusion is __ than for O2 |
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Definition
|
|
Term
| A significant increase in intracellular metabolism will __ PCO2 |
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Definition
|
|
Term
| A significantly increasing blood flow will __ PCO2 |
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Definition
|
|
Term
| A significantly decreasing blood flow will __ PCO2 |
|
Definition
|
|
Term
| The majority of CO2 diffuses out of the cell in dissolved form. Once in the capillaries, __% almost instantaneously catalytically reacts with water to form carbonic acid by an enzyme in RBCs. |
|
Definition
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|
Term
| When CO2 form carbonic acid, it then undergoes another very quick reaction and dissociates into what? |
|
Definition
|
|
Term
| Most of the __ ions bind to hemoglobin in the RBC |
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Definition
|
|
Term
| Many of the __ ions diffuse from the RBC into the plasma in exchange for __ ions |
|
Definition
|
|
Term
| The remaining __% of CO2 binds to hemoglobin (carbaminohemoglobin) to be transported to the alveoli. |
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Definition
|
|
Term
| Is the combination of carbaminohemoglobin reversible? |
|
Definition
|
|
Term
| The binding of O2 to hemoglobin dissociates CO2. Therefore, CO2 is easily released into the __. |
|
Definition
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|
Term
| Most H+ ions generated from carbonic acid (fromt he CO2 and H20) bind to what? |
|
Definition
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|
Term
| As blood flows thru the lungs, H+ ions are released from hemoglobin and combine with __ to yield what 2 things? |
|
Definition
|
|
Term
| Name the 3 groups of neurons located bilaterally within the medulla and pons |
|
Definition
1. Dorsal Respiratory Group
2. Pneumotaxic Center
3. Ventral Respiratory Group |
|
|
Term
| Where is dorsal respiratory group located? |
|
Definition
| Dorsal portion of the medulla (nucleus of tractus solitarius) |
|
|
Term
| Where is the pneumotaxic center located? |
|
Definition
| Dorsally in the superior pons |
|
|
Term
| Where is the ventral respiratory group located? |
|
Definition
| Ventrolateral part of medulla (nucleus ambiguus) |
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|
Term
| The dorsal respiratory group mainly causes __ |
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Definition
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|
Term
| This group contains sensory terminal of vagal and glossopharyngeal nerves from the peripheral chemoreceptors, baroreceptors, and receptors within the lungs. |
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Definition
|
|
Term
| Fire action potentials rhythmically on their own that initiate inspiration reflex |
|
Definition
|
|
Term
| What kinds of cells does the dorsal respiratory group use? |
|
Definition
|
|
Term
| Which group regulates the dorsal respiratory group? |
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Definition
|
|
Term
| Controls length, depth, and duration of inspiration |
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Definition
|
|
Term
| What would happen in there was no pneumotaxic center? |
|
Definition
| Lungs could overinflate and cause injury |
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|
Term
| This group mainly controls rate and depth of breathing |
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Definition
|
|
Term
| This group sends it signals to the dorsal respiratory group to "switch off" the inspiratory action potentials. This helps to control the during of the filling phase of the lung cycle. |
|
Definition
|
|
Term
| With the pneumotaxic center, you can get a strong signal that leads to __ duration or a weak signal that leads to __ duration. |
|
Definition
|
|
Term
| This group in inactive til needed. |
|
Definition
| Ventral Respiratory Group |
|
|
Term
| This group is used mostly during exercise |
|
Definition
| Ventral Respiratory Group |
|
|
Term
| This group mainly causes expiration |
|
Definition
| Ventral Respiratory Group |
|
|
Term
| With the ventral respiratory group, neurons remain almost intirely inactive when? |
|
Definition
|
|
Term
| This group does not appear to play a role in normal rhythmic oscillations |
|
Definition
| Ventral Respiratory Group |
|
|
Term
| With the ventral respiratory group, excess respiratory signals tend to "spill over" and activate the ventral group to provide powerful excitation of abdominals and aid in what? |
|
Definition
|
|
Term
| Modulates the extent to which lungs are inflated |
|
Definition
|
|
Term
| Located in the muscular portions of the bronchioles throughout the lungs transmit signals via the vagi to the dorsal respiratory group when the lungs become overstretched (>3X TV) |
|
Definition
|
|
Term
| Help to "switch off" inspiration as protective mechanism against injury to the tissue |
|
Definition
|
|
Term
| Increased CO2 and H+ levels stimulate a specialized __ area of the brainstem. This in turn sends signals to the respiratory centers diretly. |
|
Definition
|
|
Term
| Decreased O2 levels stimulate __ areas of the brainstem. |
|
Definition
|
|
Term
| O2 acts almost entirely on chemoreceptors located in what 2 places? |
|
Definition
| Carotid and Aortic Bodies |
|
|
Term
| Decreased O2 levels stimulate __. This in turn sends signals to the brainstem respiratory centers. |
|
Definition
|
|
Term
| Strenuous exercise can increase O2 consumption and CO2 formation by as much as __ fold |
|
Definition
|
|
Term
| Alveolar ventilation ordinarily increases almost exactly in step with increased level of __ metabolism |
|
Definition
|
|
Term
| During strenuous exercise what 3 values remain almost exactly normal? |
|
Definition
|
|
Term
| If PO2 and PCO2 levels remain the same, what triggers the increase in alveolar ventilation? |
|
Definition
| One theory is that signals are sent to the respiratory centers from higher cortical centers simultaneously with increased motor output. Same mechanism as activation of vasomotor centers to increase arterial pressure with exercise |
|
|
Term
| Is the theory about the trigger of alveolar ventilation when PO2 and PCO2 levels stay the same plausible? |
|
Definition
| Yes, given the timing of ventilation changes. They correlate with the initiation of exercise - before changes in the cellular metabolism and blood chemicals occur |
|
|
Term
|
Definition
| Chronic Pulmonary Emphysema |
|
|
Term
| Usually refers to an obstructive and destructive process of the lungs caused by many years of smoking. |
|
Definition
| Chronic Pulmonary Emphysema |
|
|
Term
| Chronic pulmonary emphysema can lead to chronic infection. How? |
|
Definition
| Causes paralysis of cilia = buildup of mucus in passageways = triggers stimulation of more mucus = leads to chronic obstruction of many smaller airways |
|
|
Term
| With chronic pulmonary emphysema, the obstruction makes it difficult to expire, thus causing entrapment of air in the alveoli and overstretching them. This, combined with infection can cause what? |
|
Definition
| Destruction of the alveoli |
|
|
Term
| With chronic pulmonary emphysema, the obstruction increases airway resistance which increases what? |
|
Definition
|
|
Term
| Which chronic pulmonary emphysema, expiration is particularly difficult why? |
|
Definition
| Because compression of the alveoli and bronchioles (for normal expiration) further compresses the already obstructed airways, further increasing resistance. |
|
|
Term
| With chronic pulmonary emphysema, the destruction of the alveolar walls decrease diffusion capacity of the lung which reduces the ability to do what? |
|
Definition
|
|
Term
| With chronic pulmonary emphysema obstruction can be worse in some parts of the lungs than others. This can lead to what? |
|
Definition
| Very abnormal Va/Q ratios in some parts, including both physiologic shunts and dead space |
|
|
Term
| With chronic pulmonary emphysema, loss of alveolar walls decreases number of pulmonary capillaries which increases pulmonary vascular resistance which results in pulmonary hypertension which can overload which side of the heart? |
|
Definition
|
|
Term
| An inflammatory condition of the lung in which som or all of the alveoli are filled with fluid and blood cells. |
|
Definition
|
|
Term
| Often begins with an infection of the alveoli = inflammation of the membrane becoming more porous = leakage of fluids from capillaries into alveoli |
|
Definition
|
|
Term
| With pneumonia, gas exchange functions decline in different stages of the disease. Early on, the disease might be localized nly to a portion of the entire lung. Perfusion is ___, but ventilation is __ with results in a decreased Va/Q ratio. This will lead to hypoxia (low blood O2) and hypercapnia (high blood CO2) |
|
Definition
|
|
Term
| Collapse of the alveoli, Can occur in localized areas or the entire lung. |
|
Definition
|
|
Term
| Namee 2 most common causes of atelectasis |
|
Definition
Airway obstruction
Lack of surfactant |
|
|
Term
| Can result from blockage of many small bronchi with mucus or obstruction of a major bronchus (tumor, mucus plug, etc) |
|
Definition
|
|
Term
| With airway obstruction, the entrapped air is absorbed within minutes to hours which creates a very negative pressure within the alveoli and pulls fluid out of the capillaries and into the alveli. This occludes the alveoli and almost always increases resistance to blood flow through the vessels of the __ lung. |
|
Definition
|
|
Term
| With airway obstruction, the overall Va/Q ratio is only moderately compromised because of what 2 reasons? |
|
Definition
| Function lung and rerouting of blood |
|
|
Term
| Occurs in respiratory distress syndrome; quantity of secreted surfactant is greatly reduced and that leads to surface tension of alveolar fluids which gives them a tendency to collapse. |
|
Definition
|
|
Term
| Characterized by the spastic contraction of smooth muscle in the bronchioles, which partially obstructs the bronchioles |
|
Definition
|
|
Term
| What is the usual cause of asthma? |
|
Definition
| Contractile hypersensitivity in response to foreign substances in the air |
|
|
Term
| With asthma, combined molecular effects produce localized edema in the walls of the small bronchioles, secretion of thick mucus, spasm of the muscle results in increased what? |
|
Definition
|
|
Term
| With asthma, expiration is more difficult because of the added compression of bronchioles during expiration. Clinical measurements include reduced __ and __ |
|
Definition
|
|
Term
| During an asthma attack, there is reduced FRC and reduced RV. Why? |
|
Definition
|
|
Term
| People with asthma have a difficult time expiring air, what is the adaptive change that occurs over time? |
|
Definition
| Barrel chest to increase the volumes of RV and FRC |
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