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170 Cards in this Set
- Front
- Back
Knowledge of respiratory physiology is important for what?
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Proper diagnosis and treatment of pulmonary disease
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What is the main function of the respiratory system?
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To exchange gases in order to maintain pH, arterial oxygen, and CO2
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Each lung is ____ shaped & covered with a ______
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Cone shaped; with a visceral pleura
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Which lung is larger and why?
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The right lung because the left is smaller to make room for the heart
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How many lobes does the right lung have?
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3: upper, middle, lower
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How many lobes does the left lung have?
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2: upper, lower
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All lobes of the lungs are subdivided into what segments?
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Broncho-pulmonary segments
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The lungs are innervated by which systems?
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BOTH sympathetic & parasympathetic
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Sympathetic stimulation to the lungs causes what?
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Bronchodilation with vasoconstriction (so tubes in airway open up but blood supply is less)
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Parasympathetic stimulation to the lungs causes what?
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Bronchoconstriction with vasodilation (so tubes in airway close but blood supply increases)
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As inspired air flows through the nose to the alveoli, the forward velocity is ______, which allows for diffusion through the alveoli into the pulmonary _________.
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Slowed; Capillaries
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What are the functions of the nose?
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1. Filter air
2. Humidify air 3. Cool/warm the air to body temp |
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What is the function of the pharynx?
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Serves as a conduit for air to travel by
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What is the function of the larynx?
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The epiglottis acts as a valve preventing food from entering the trachea
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Voluntary control of breathing is important durning verbal communication where does it originate from?
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the cortex
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Where does the main control of respiratory centers arise from?
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chemoreceptors
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is Co2 regulated more tightly or o2
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Co2
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Where are central chemoreceptors located and what do they monitor?
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medulla, measure co2 levels of arterial blood and the CSF
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What equation shows the regulation of co2
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CO2 + H20 ⇒ H2CO3 ⇒ H+ + HCO3 -
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h+ ions stimulate the central chemoreceptors which stimulate what?
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medullary centers
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A rise in paco2 does what to alveolar ventilation?
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increases it which restors paco2 to normal levels
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where are peripheral chemoreceptors located
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carotid and aortic bodies
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peripheral chemoreceptors are stimulated by:
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1. low arterial oxygen tension
2. high co2 tension (body is most sensitive to this) 3. acidocis |
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When the brainstem centers have been depressed by narcotics or anoxia what can maintain breathing?
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carotid bodies
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What is hering-bruer reflex (inflation reflex)?
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It is the longest lung reflex. stimulated by lung inflation during inspiration. the reflex is inhibition of deep inspiration
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Who does the hering-bruer reflex occur in?
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newborns or patients under anesthesia
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Where do the results if a sneeze stimulus occur
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upper airways
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what stimulates the sneeze or cough reflex?
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stimulation of irritant receptors by particles, gases, or excessive amounts of sticky mucus
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where do the results of a cough if stimulus occurs
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lower airways
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What does peripheral pain receptor stimulation result in?
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hyperventilation, tachycardia, and rise in bp
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What does visceral pain receptor stimulation result in?
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inhibition of breathing, bradycardia. and fall in bp
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during light sleep breathing is dominated by what control
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chemical
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During what stage of sleep does sleep apnea occur?
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REM
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When sleep apnea occurs what is stimulated by deranged blood gases because of obstruction of airways?
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peripheral chemoreceptors
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What is the normal range of ph
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7.35-7.45
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what is acidemia
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ph below 7.35
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what is alkalemia
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ph above 7.45
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Significant changes in ph can result in what?
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coma or convulsions
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What are 3 buffer systems for the blood?
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1. hemoglobin and protiens bin with H+
2. Respiratory system: regulates paco2 3. Renal system: bicarbonate |
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What is normal paco2
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35-45 mm Hg
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how does hyperventilation control ph in blood?
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decreases the paco2 levels which decreases h+ which moves ph higher
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how does hypoventilation control ph in blood?
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increase the paco2 levels which increases h+ which move ph lower
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Where is bicarbonate produced?
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kidneys
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decreased pao2 results in what?
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hypoxemia (decreased oxygenation of blood)
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assesment of arterial blood gases provides information about what?
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oxygenation, ventilation, and acid-base balance
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when pa02 is adequate is oxygenation adequate?
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yes
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what is oxygenation?
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binding of oxygen on hemoglobin
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what are the signs of hypoxemia
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1. pallor
2. cyanosis 3. skin coolness 4. unexplained behavioral change |
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What is the body's response to hypoxemia? and is it effective?
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increased total ventilation. and may not be effective due to increased consumption of respiratory muslces
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What is the structure lined with ciliated epithelium which carries debris toward the pharynx?
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Trachea
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How many horseshoe shaped cartilaginous rings form the trachea?
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16 to 20
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Which cartilaginous ring of the trachea is the most cephalic?
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Cricoid ring
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What do the cartilaginous rings protect the trachea from during forced inspiration and expiration?
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compression/collapse
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What does the trachea branch into?
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left and right main bronchi
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Which main bronchus branches at a more acute angle? (Left or Right)
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Left
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Which main bronchus is longer? (Left or right)
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Left
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Which main bronchus is more in line with the trachea? (Left or right)
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Right
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Which lung is predisposed to aspiration of material due to the alignment of the bronchus?
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Right
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What structure is defined as:
Small envaginations of the respiratory bronchioles, alveolar ducts, and alveolar sacs? |
Alveoli
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What are the thin walls of the alveoli suited for?
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gas exchange
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Which alveolar wall cells are large, flat, and comprise most of the internal alveolar surface?
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Type 1 cells
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Which alveolar wall cells are less numerous, ovoid in shape, and synthesize surfactant?
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Type 2 cells
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Ventilation is the process of ________ and ________
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inspiration, expiration
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Ventilation maintains optimal levels of _______ and _______
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oxygen, carbon dioxide
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Define Minute ventilation (Ve)
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Volume of air expired each minute
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A x B = Ve
What x What = Minute Ventilation? |
Tidal Volume x Frequency
Vt x f |
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Tidal volume (Vt) is the sum of what two variables?
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Volume of alveolar gas (Va)
Dead Air (Vd) |
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Does hyperventilation increase or decrease carbon dioxide levels?
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decrease (hypocapnia)
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Does hypoventilation increase or decrease carbon dioxide levels?
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incresse (hypercapnia)
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Is oxygen tension of alveolar air increased or decreased by hyperventilation?
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increased
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What lung volume is defined as:
The volume of gas inspired or expired during each respiratory cycle? |
Tidal Volume (Vt)
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What lung volume is defined as:
The maximum volume of gas that can be inspired from the peak of a tidal volume? |
Inspiratory reserve volume
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What lung volume is defined as:
The maximum volume of gas that can be expired from a normal tidal expiration |
Expiratory reserve volume
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What lung volume is defined as:
The volume of gas remaining after greatest expiration? |
Residual volume
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What lung capacity is defined as:
the amount of gas in the respiratory system after a maximal inspiration? |
Total lung capacity (TLC)
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What lung capacity is defined as:
The maximum volume of gas that can be expelled from the lungs after a maximal inspiration? |
Vital capacity (VC)
VC = IRV + TV + ERV |
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What lung capacity is defined as:
The maximum volume of gas that can be inspired from the resting end expiration level? |
Inspiratory Capacity (IC)
IC = TV + IRV |
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What lung capacity is defined as:
The volume of gas in the lungs when the respiratory system is at rest; volume in the lung at the end of a normal expiration? |
Functional residual capacity (FRC)
FRC = ERV + RV |
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On what 2 factors does FRC depend?
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Inward elastic recoil of the lung
Outward elastic recoil of the chest wall |
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What respiratory volume does Dead Space define?
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Volume that does not participate in gas exchange
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Which dead space is the volume of gas that is contained in the conducting airways?
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Anatomic dead space
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Which dead space is the volume of gas in wasted ventilation?
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Alveolar dead space
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What is physiologic dead space?
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The total volume of air NOT involved in gas exchange
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In normal individuals, are physiologic and anatomic dead space equal or unequal?
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equal
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In diseased individuals, what does physiological dead space equal?
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anatomic dead space + alveolar dead space
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True or False:
Inspired air is uniformly distributed throughout the lungs |
FALSE
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True or False:
Lungs are different in size which allows for unequal distribution |
TRUE
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In what position(s) does apical ventilation exceed basilar ventilation?
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Sitting or Standing
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In the supine position, which portion of the lung is better ventilated? (Anterior or Posterior)
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Posterior
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True or False:
During heavy breathing all areas of the lungs tend to be well ventilated |
TRUE
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During shallow breathing, what happens to some airways?
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They become closed
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What factors aside from position and depth of breath may cause limited ventilation? (4)
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Respiratory muscle weakness
Regional airway obstruction Abnormal lung/chest wall compliance Disease |
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What is spirometry used to measure?
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Lung volumes
Specific ventilatory capacities |
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Which specific lung volumes can spirometry measure?
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tidal volume
inspiratory reserve volume expiratory reserve volume |
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Which capacity can measure ventilatory capacity?
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Forced Vital Capacity
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To measure Maximum Voluntary Ventilation, how long must the patient breathe as rapidly and deeply as possible?
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15 seconds
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What does Maximum Voluntary Ventilation assess?
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Respiratory muscle endurance
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What is the FEV1?
(Forced Expiratory Volume at 1 second) |
The volume of gas forcibly expired in 1 second after maximal inspiration
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What information regarding the lungs does FEV1 give us?
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Information about airway resistance and elastic recoil
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By measuring what can we commonly determine alveolar ventilation?
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CO2 elimination by the lungs
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With restrictive diseases, what happens to total lung capacity and forced vital capacity? (Increase or decrease)
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Decrease
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With restrictive diseases, does the FEV1/FVC ratio increase or decrease?
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Increases
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With obstructive diseases, does the FEV1/FVC ratio increase or decrease?
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Decreases
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With obstructive diseases, does total lung capacity and functional residual capacity increase or decrease?
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increase
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In breathing, what must respiratory muscle forces overcome?
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elastic recoil of the lungs and thorax
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During breathing there is a frictional ________ to air flow
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resistance
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During inspiration, which tissues stretch?
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lungs and thorax
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During inspiration, is the pressure inside the chest negative or positive?
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negative
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During inspiration, do muscles contract to raise or lower the diaphragm?
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lower
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What is defined as:
The ratio of change in lung volume to change in distending pressure? |
Lung compliance
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With decreasing lung compliance, are lungs more or less stiff?
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Stiffer
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Does pulmonary fibrosis increase or decrease lung compliance?
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decrease
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What substance is increasingly present in lung tissue with pulmonary fibrosis?
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collagen
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What substance is decreased in the lung tissue with emphysema?
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elastin
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With emphysema, is lung compliance increased or decreased?
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increased
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What is the main purpose of surfactant?
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lower surface tension inside the alveoli
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What is atelactasis?
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lung collapse
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What two conditions may result from a delay in surfactant production?
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low lung compliance
atelactasis |
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Is the chest wall elastic or inelastic?
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elastic
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Which tissues contribute to the elasticity of chest wall compliance?
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Ribcage
Diaphragm |
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In which 3 disorders is chest wall compliance decreased?
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Scoliosis
Skeletal muscle disorders Abdominal disorders |
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From where does oxygen enter blood?
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Alveolar air
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From where does CO2 enter alveolar air?
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The blood
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How many alveoli do we have?
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Several hundred million
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What determines the amount of O2 and CO2 that is exchanged?
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Metabolic activity of tissues
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During strenuous exercise, how much greater may oxygen uptake be as compared to resting levels?
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10 times
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What is the respiratory quotient?
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CO2 output/O2 uptake
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The respiratory quotient is usually what at rest?
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0.8
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What is a synonym for partial pressure?
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concentration
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True or False:
The amount of pressure which a gas exerts is proportional to the amount of gas in the mixture |
TRUE
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What are the 4 factors determining the rate of diffusion of a gas? (Fick's Law)
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Surface area available for gas exchange
Thickness of the tissue Partial pressure gradient across the tissue Diffusing constant for the gas |
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What happens to alveolar walls with Emphysema?
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They may be destroyed or blocked by an emobolus
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What happens to alveolar walls with pulmonary fibrosis?
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They may be thickened
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The partial pressure gradient of oxygen is ____ times greater than carbon dioxide
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15
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Carbon dioxide is _____ times more soluble than oxygen
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20
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Which gas diffuses more easily - CO2 or O2?
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CO2
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What are other factors influencing oxygen diffusion? (3)
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Reduction in volume of blood flowing through capillaries
Reduction in red blood cell mass Presence of abnormal hemoglobin molecules |
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By what pathway is oxygen transported to the tissue capillaries?
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Blood
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What is oxygen used for once it reaches target cells via the capillaries?
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ATP production
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What is the result of ATP production? (Aside from ATP)
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CO2
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How much of all O2 is transported as oxyhemoglobin?
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99%
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How many molecules of O2 can combine with 1 molecule of hemoglobin?
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4
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What determines the volume of oxygen that can combine with hemoglobin?
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Partial pressure of dissolved O2
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Is the oxyhemoglobin dissociation curve negatively or positively correlated?
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positively
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What is the usual level of O2 saturation in hemoglobin?
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97%
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At what range of O2 partial pressures is hemoglobin saturation 100%?
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250 - 350 mmHg
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How much of hemoglobin's O2 content is unloaded in the capillaries?
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25%
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During exercise, which way does the oxyhemoglobin dissociation curve shift?
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Right
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Pulmonary circulation carries the output of the _____ heart through the lungs to the _____ heart
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right, left
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Where is re-oxygenated blood deposited in the heart?
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Left atrium
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Sympathetic stimulation results in minor pulmonary vessel _________
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constriction
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Humoral substances such as histamine can cause significant ________
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vasoconstriction
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Ideal gas exchange involves:
equal volumes of air coming into the _______ coming in contact with equal volumes of _____ flowing through alveolar capillaries. |
alveoli, blood
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What is the relationship between Alveolar ventilation (Va) and Pulmonary blood flow (Q)?
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Ventilation/Perfusion ratio
Va/Q Ideally = 1 |
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What is normal alveolar ventilation?
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4 L/min
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What is normal cardiac output?
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5 L/min
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What is normal ventilation/perfusion ratio?
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0.8
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On what two factors does lung ventilation depend?
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Compliance
Openness |
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In COPD, the reduced ventilation to large areas of the lungs due to blockage by secretions results in what Va/Q ratios?
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Low
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On what does the blood flow to lungs depend?
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Patency of blood vessels
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In standing, gas exchange is ___ times greater and blood flow is ____ times greater at the base than at the apex of the lung
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3, 10
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In an upright person, is blood flow greater or lesser than ventilation at the apex?
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less
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By what systems is the rate and depth of respiration controlled?
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Automatic & Voluntary
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Where does the automatic system originate?
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Brainstem
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Where does the voluntary system originate?
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Cerebral cortex
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Do chemoreceptors more tightly control CO2 or O2?
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CO2
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In which areas do central chemoreceptors in the medulla monitor CO2 levels?
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Arterial blood
CSF |
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What does a rise in Pa CO2 signal an increase in?
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Alveolar ventilation
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Where are peripheral chemoreceptors found?
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carotid & aortic bodies
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What 3 factors stimulate peripheral chemoreceptors?
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Low arterial oxygen tensions
High arterial CO2 tension Acidosis |