Clin Med Pulmonary exam 1 Flashcards
Where does the O2 ultimately go?
Mitochondria (ATP)
Where does gas exchange occur?
Alveolia and capillary
3 Factors that affect gas exchange
Surface area
respiratory membrane
blood supply (amount)
Trace the airway tree all the way to capillary
Oral cavity Oropharnyx larnyx trachea carina primary secondary tertiary smaller bronchioles bronchioles terminal bronchioles respiratory bronchioles Alveolar sacs Alveoli
WHere do the respiratory bronchiles start?
when you start to see alveoli
What about alveoli make it goor for gas exchange
good blod supply
thin membrane
How do bronchioles shange their radius?
they use smooth muscle
At what size do the bronchioles start?
1mm
what are the 2 functional zones of ventilation?
respiratory
conducting
How many total generations of ther ventilatory functional zones are there?
23 brnaches
16 in the conducting
7 in the respiratory
Describe conducting zone
Anatomical dead space (150ml)
16 branches
upper zone
conducts air to the respiratory zone
Describe respiratory zone
Respiration through bronchioles and alveoli
350ml normal value of participating air space
7 branches
this is where gas exchange occurs
Describe dead space
where no respiration occurs
150ml normal value
normal tidal volume
500ml
What secretes mucous in lungs?
goblet cells
WHat are cilia extensions of?
plasma membrane
Describe mucous elevator
cilia brings mucous and particles up airway to oral cavity where they are swalloed
similar to mexican wave
Is there mucous and cilia in respiratory zone
no, only in the conducting zone
Macrophages are in respiratory zone
What is used to help keep respiratory zone clean
macrophages
Where is cartilage distribution in airway?
Cartilage gets less and less as you go down the conducting zone
none in respiratory zone
Cartilage is C shaped
Where is the smooth muscle distribution in the airway?
none at the top
lots in the bronchioles
What does smooth muscle do in the airway
Bronchoconstriction
bronchodilation
Where is there no goble cells, mucous, cilia, cartilage
Respiratory zone
What are muscles for inspiration
Diaphram
sternocleidomastoid
scalenes
external intercostal
Is inspiration active or passive?
active
Is expiration active or passive
passive (unless forced)
Describe expiration at rest
normal
passive
no energy expended
diaphragm relaxes recoil of lungs (which have elastic properties)
Describe forced expiration
Cough, sneeze, balloon Abdominal muscles rectus abdominus external obliques internal intercostals
Describe the rib movement on respiration
Like a bucket handle
on inspiration they go up and out
on exhalation they go down and in
Describe pressure gradient fro inspiration vs expiration
Gas moves from high pressure to low pressure
How do we change pressure in the lungs
we change the volume which changes the pressure
how does pressure change on inspiration
the volume increases and the pressure drops which allows air to flow in
How does pressure change on expiration
teh volume decreases, the pressure then increases which expels air
What is the complete process for inspiration
the inspiratory muscle contract the diaphragm decends the rib cage rises THoracic cavity volume increases the lungs are stretched the intrapulmonary volume increases the intrpulmonary pressure decreases Air then flows into the lungs down the pressure gradient The air continnues until pressure equalizes at 0 atm
What is the complete process for expiration
inspiratory muscles relax diaphragm rises rib cage descends thoracic cavity volume decreases intrpulmonary pressure increases air flows out of lungs down pressure gradient until 0 ATM
WHat shape is the diaphragm
concave when relaxed
flattens out when it contracts
What do muscles do on inspiration
diaphragm moves inferiorly and flattens out
intercostals increase latteraly
sternocleidomastoid and scalene help superiorly
what is the P in PO2and PCO2
partial pressure
What is the total pressure at sea level
760mmhg
what is percentage of oxygen on earth regardless of altitude
21% o2
79% nitrogen
1% everything else
What is PO2 when inhaled
160mmhg
What is PO2 in alveoli
104mmhg
what is PO2 in arterial blood?
95mmhg
What is the PO2 in the tissues/capillary
40mmhg
WHat happens when the arterial blood at 95mmhg reaches the capillaries at 40mmhg?
the O2 in the blood will go down the pressure gradient and into the tissue
What is the PO2 of the venous blood
40mmhg
Trace PO2 pressure through circulation
inhaled 160mmhg lungs 104 arterials 95 capillaries 40 venous 40 lungs 104
What happens to the deoxgenated blood when it gets back to the lungs in regards to pressure
the O2 inhaled at 160mmhg travels down the pressure gradient and oxygenates the blood returning to the lungs at 40mmg to restart the cycle.
What is the nitrogen air percentage inhaled and exhaled
79% for both, doesn’t change
What is O2 percentage in haled and exhaled
21% inhaled
15-18% back out
the more intense the exercise, the less the %
What is the CO2 percentage inhaled and exhaled
0.04% inhaled
3-5% back out
HIgher instenisty activity, higher percentage
What is H2O percentage in haled and exhaled
.46% in
.46% out
No change
WHat is co2 pressure in arterials
40%
What is CO2 pressure in capillaries
46%
Why don’t we need as much of a pressure gradient for CO2
it is more soluble
How does CO2 get back into blood i the tissue
travels down pressure gradient 46% in tissue 40% in blood travels through venous system and exhaled
What prevents natrual airway collapse
the intrapleural sac
a negative pressure between the two pleurae
suction force
causes chest wall and lung to move together
with a pneumothroax, what does the loss of negative pressure allow?
it allows the recoil of the lungs to happen and the lungs collapse
lung pulls away from chest wall
lung becomes inefficeint due to loss of surface area
What does the alveolar cycle mimic?
the lung cycle
inhalation and exhalation
Trace alveolar cycle
Inspiratory muscles contract thoracic cavity expands pleural pressure becomes more negative transpulmonary pressure increases lungs inflate alveolar pressure becomes subatmospheric air flows into the lungs until alveolar pressure equals atmospheric pressure
What does spirometry measure
lung volume
On a PFT report, what does a downward deflection represent?
expiration
On a PFT report, what does a upward deflection represent?
Inspiration
PFT Inspiration categories
IRV Inspiratory reserve volume 3.1 liters
PFT expiratory categories
ERV expiratory reserve volume 1.2 liters
RV Residual volume 1.2 liters
FRC functional residual capacity 2.4 liters
PFT Both inspiratory and expiratory categories
VT tidal volume (500ml)
IC inspiratory capacity 3.6 liters
VC Vital capacity 4.8 Liters
TLC total lung capacity 6 liters
What is FVC?
Forced vital capacity
maximum amount of air forcibly exhaled at a maximum inhalation
4.8L
What is FEV1/FVC
Forced expired volume / forced vital capacity ratio
Percentage of FVC exhaled in 1 sec
80% is normal
What is FEV1
forced expiratory volume
Maximum volume of air forcibly exhaled in 1 second
4.0L
What is TLC
Total lung capacity The volume of air in the lungs at the end of maximum inspiration Everything on graph combined IRV+VT+ERV+RV=TLC 6L
WHat is VC
Vital capacity
Maximum volume of air that can be exhaled
IRV+VT+ERV=VC
4.8L
WHat is IC
Inspiratory capacity
Maximum amount of air inhaled at end of normal inspiration
VT+IRV=IC
3.6L
What is VT
Tidal volume
Volume of air inhaled and exhaled with each normal breath
500ml
What is FRC
Funtional residual capacity Volume of air remaining in lungs at the end of normal tidal volume ERV+RV=FRC 2.4L (Expiration)
WHat is RV
Residual Volume
Volume of air remaining in lungs after maximum exhalation
1.2L
(Exhalation)
What is ERV
Expiratory reserve volume
Maximum volume of air exhaled at end of tidal volume
1.2L
(exhalation)
What is IRV
Inspiratory reserv volume
Maximum volume of air inhaled at the end of normal inspiration
1.2L
(Inspiration)
Wha tis normal percentage for FEV1/FVC ratio
80%
WHat is normal FEF
25-75
In obstructive disorder what does FEV1/FVC ratio do
decrease
In obstructive disorder what does FVC do
Decrease or could be normal
In obstructive disorder what does FEV1 do
Decrease
In restrictive disorder what does FEV1/FVC do
Normal or increases
In restrictive disorder what does FEV1 do
decrease
In restrictive disorder what does FVC do
decrease
Examples of obstructive disorders
Emphysema
Chronic bronchitis
bronchiectasis
asthma
Examples of restrictive disorders
intersitual lung disease idiopathic pulmonary fibrosis pneumoconiosis sarcoidosis chestwall neurmuscular disease
Why dont lung disease spread to the other lung typically
lungs are seperatate and comparmentalized
Describe the restrictive disorder
Reduced expansion of lung parenchyma accompanied by decreased lung total capcacity
Describe obstructive disorder
Limitation of airflow due to partial or compele obstruction
WHat is minute ventilation
tidal volume times respiration rate ve=vt x f example 500 x 12 = 6000 not really important compared to alveolar ventilation
What is alveolar ventilation
subtract the dead space from the tidal volume then multiply times respiration rate example 500-150 =350 350 x 12 = 4200
How is alveolar vetilation calculated
by measuing a persons expired CO2
What happens to CO2 in hypoventilation?
retain more CO2
more CO2 in blood
What happens to CO2 in hyperventilation?
Blow off more CO2
Blood becomes more basic
What is hypernea
INcreased breathing and metaboic rate due to exercise
what is the relationship between PAco2 and alveolar ventilation
they are inversely related
What does lung compliance measure
distensibilty
Will it be harder or easier to breath if lung compliance is low
harder
it will be more difficult to inhale due to a stiffer lung
Will it be harder or easier to breath if lung compliance is high
it will be easier
less work to inflate the lung
how does gravity affect the alveoli in the lung
The weight of the lung compress the alveoli in the base of the lung
contrast the alveoli in the base of the lung verse the apex
at the base, they are small alveolus that can expand greatly and have high comliance
at the apex, alveolus are larger, respiration is poorer, they change very little in size and the compliance is low
WHat does surfactant do?
lowrs the surface tension and stabalizes alveoli at low lung volumes
it is like dish soap
reduces the tendency of alveoli to stick together
keeps alveoli from collapsing
What cells secrete surfactant
Type 2 endothelial cells
What kind of cells are type 1 endothelial cells
simple squamous
How does alveolar surface tension affect lung compliance
Increased surfactant = increased compliance
less surfactant = less compliance
increased comliance = increased volume at a givn pressure
Is ther more surfactnat in smaller or larger alveoli
Smaller alveoli have more surfactant
larger alveoli have less surfactant
this negates any pressure gradient and keeps the alveoli from collapsing
What are the cells of the alveoli
simple squamous epithlial
1 layer
flat squashed cells
Are the majority of the alveoulus type 1 or type 2 cells
type 1 cells make up majority
Are alveoli seperate or connected
they are all connected via pores
Why do alveoli have macrophages
they have no cilia or mucous
Select the correct statement about the physical factors influencing pulmonary ventilation.
A. A decrease in compliance causes an increase in ventilation.
B. B. A lung that is less elastic will require less muscle action to perform adequate ventilation.
C. C. As alveolar surface tension increases, additional muscle action will be required.
D. D. Surfactant helps increase alveolar surface tension
C. C. As alveolar surface tension increases, additional muscle action will be required.
Which of the following would best characterize pulmonary function in a patient with asthma?
A. Maximal expiratory airflow is increased from normal.
B. B. Residual volume is decreased from normal.
C. C. Forced vital capacity is increased from normal.
D. D. Resistance to airflow is increased from normal.
E. E. The FEV1/FVC ratio is increased.
D. D. Resistance to airflow is increased from normal.
An individual has an alveolar ventilation of 6,000 mL/minute, a tidal volume of 600 mL, and a breathing rate of 12 breaths/minute. What is this individual’s anatomic dead space? A. 100 mL B. B. 120 mL C. C.150 mL D. D. 200 mL
A. 100 mL
6000 = (600 - X)12 solve for X 6000 /12 = 500 500 = 600 - X 500 – 600 = -100 -100 = -X X= 100
pressure at sea level vs alitutde
Sea level 760mmhg = PO2 = 160
Mt everest 253 mmhg = PO2 = 53
FIO2
21% O2
Whenis partial presure of O2 highest?
when it leaves the lungs
When is Partial pressure of CO2 highest
when it enters the lungs
How are distance and diffusion related
distance reduces efficiency of diffusion
What is lung diffusion capacity
the ability of the lungs to transfer gases
How does diffusion relate to hematocrit and blood volume
If you decrease hematocrit you will decrease diffusion capacity
if you decrease blood volume, you will decrease diffusion capacity
low cardiac output, anemia, blood loss
How much O2 does arterial blood carry?
20ml of O2 per Deciliter
What is O2 bound hemoglobin called
oxyhemoglobin
What is no O2 bound to hemoglobin called
deoxyhemoglobin
What is CO2 bound hemoglobin called
carboxyhemoglobin
How is oxgen transported % wise
- 5 % is bound in hemoglobin
1. 5% dissolved in plasam
WHere does the O2 bind to hemoglobin
it binds to the iron that is in the Heme
Where does the CO2 bind in hemoglobin
it binds to the globin
What happens as more and more O2 binds to Hemoglobin
it causes more and more CO2 unbinding
What happens as more and more CO2 binds to hemoglobin
it causes more and more O2 to unbind
What is the plateua phas ein the oxyhemoglobin dissociation curve
Loading phase (lungs) where there is a high affinity for hemoglobin in the lungs
What is the steep phase of the hemoglobin dissociation curve
unloading phase (tissues / capillaries) Low affnity for hemoglobin in tissues
What causes sigmoidal shape in hemoglobin dissociation curve graph
The cooperative binding
What does a right shift on the graph represent
increases oxygen unloading
What does a left shift on the graph represent
increased oxygen loading
What is p50 for hemoglobin
the 50% saturation rate of hemoglobin
What are factors that can cause right shift on the hemoglobin dissocation graph (increased unloading)
INcreased Temperature INcreased CO2 INcreased H+ INcreased BPG increased workload
How is most of the CO2 in the blood transported
in the plasma as bicarbonate
60-70%
30% is bound to hemglobin as carbamino
10% is dissolved in the plasma
What is carbonic anhydrase reaction
CO2 + H2O ←CA→ H2CO3 ↔ H+ + HCO3- CO2 combines with H2O and using carbonic anhydrase makes carbonic acid Carbonic acid then dissociates into H+ and bicarbonate Occurs in the Red blood cells This equation occurs in the tissues/capillaries the reverse occurs in thelungs
What happens to the charge when HCO3- leaves the red blood cell
a Cl- ion enters to balance the charge
Known as chloride shift
What is chloride shift
when a HCO3 leaves a red blood cell and a cl- enters in order to balance the charge
where does this equation occur?
CO2 + H2O ←CA→ H2CO3 ↔ H+ + HCO3-
in the tissue/capillaries
Forward in lungs,
backwards in tissues
the reverse equation occurs in the lungs
Where does this equation occur?
H+ + HCO3- ↔ H2CO3 ←CA→ H2O + CO2
In the lungs
Forward in lungs,
backwards in tissues
the reverse occurs in the tissus/capillaries
What is reverse chloride shift
the HCO3 enters the red blood cell while a cl ion leaves
Which of the following increases oxygen unloading from hemoglobin?
A. increased carbon dioxide in the tissue
B. increased oxygen levels in the tissue
C. increased blood pH
D. decreased metabolism
E. decreased temperature
A. increased carbon dioxide in the tissue
Which of the following will most likely lead to decreased oxygen exchange at the respiratory membrane in a healthy individual?
A. Increased cardiac output, low atmospheric PO2
B. Increased pulmonary capillary recruitment, exercise
C. Decreased O2 diffusion distance in the alveolar–capillary membrane
D. Decreased alveolar PO2
D. Decreased alveolar PO2
If alveolar ventilation is held constant, which of the following predicted changes in alveolar oxygen and carbon dioxide tensions would occur when metabolic rate is increased? PACO2 PAO2 A Increases Increases B Increases Decreases C Increases No change D Decreases Decreases
B Increases Decreases
What is the differnec betweent he bronchiole circulation and the pulmonary circulation
they are seperate
Bronchial circulation is to nourish the conducting airways
Pulmonary circulation is gas exchange
What is the primary function of bronchiole circulation
to nourish conducting zone
What is the primary function of pulmonary circultion
Primary is gas exchange Secondary are flitering (thrombi) Metabolic organ (ACE) Blood source (10% volume)
What are secondary functions of pumonary circulation
Primary is gas exchange Secondary are flitering (thrombi) Metabolic organ (ACE) Blood source (10% volume)
as cardiac output decreases, what happens to resistance in the vascular system
it is inverse
it increases
as cardiac output increases, what happens to resistance in the vascular system
it is inverse
it decreases
is the pulomnary circuit high pressure or low pressure
unlike systemic circuit
the pulmonary ciruit is low pressure
is pulmonary circuit normally dialated or constricted
Pulmonary circuit is normally dialated
systemic circuit is normally constricted
which side has greater cardic output, the left or the right
Neither, they are equal
Pressures differ
volumes are the same
What can increase capillary recruitment in the lungs
increased cardiac output
How does pulmonary circulation help decrease resistance when arterial pressure rises
Capillary recruitment Capillary distention Due to more capillaries capillaries in parallel more distented capillaries
What does capillary recruitment do in the lungs
when cardiac output increases, capillary recruitment can effect a marked decrease in pulmonary vascular resistance Due to more capillaries capillaries in parallel more distented capillaries helps decrease pulmonary edema
What does capillary distetion do in lungs?
increases capillary surface area
increase gas exchange
helps decrease pulmonary edema
When does pulmonary vascular resistance increase?
At hig and low lung volumes At low volumes extra alveolar compress at high lung volumes alveolar vessles compress
What are factors that can effect fluid exchange in the capillaries
alveolar surface tension which enhances filtration
Alveolar pressure which opposes filtration
Which enhances filtration?
Alveolar surface tension
or
Alveolar pressure
Alveolar surface tension
Which opposes filtration?
Alveolar surface tension
or
Alveolar pressure
Alveolar pressure
WHat helps to keep the alveoli dry and avoid edema
a low pulmonary capillary hydrostatic pressure
what is the most frequent cause of pulmonary edema
increased capillary hydrostatic pressure
this is due to abnormally high pulmonary venous pressure
what is the second major cause of pulmonary edema
First is increased capillary hydorstatic pressure
second is noncardiogenic and is due to increasd alveolar tension
How is blood flow distributed in the lungs
Blood flow is more copius at the base and dimishes towards the apex
How many zones are there for blood flow in the lungs
3 zones zone 1 is at top (apex) no perfusion, no gas exchange Zone 2 is in middle a little, but not a lot of gas exchange Zone 3 is at base Largest rate of blood flow Best gas exchange occurs here
How does gravity affect the the perfusion, and ventilation ratio in the lung
In the apex, there is hig ventilation but poor perfusion
this gives a high number for ratio
in the base there is low ventilation but good perfusion
gives a low number for ratio
What does low oxygen tension in the lungs cause
pulmonary vasoconstriction
what does regional hypoxia in the lungs cause
regional vasoconstriction which isolates poorly ventilated areas
What dos general hypoxia cause in the lungs
General hypoxia causes vasoconstriction thoughout the lungs,
in other vessels outsod eof the lungs, hypoxia causes vasodialation
WHen you have hypoxia why do the lungs vasoconstrict
This increases resistance and pilmonary artery pressure
When do the lungs change ventilation to match changes in perfusion
decreased blood flow and less co2 in the Alveoli is the stimulus for the bronchioles to constrict.
this reduces the air flow so tht it matches the blood flow
When do the lungs change perfusion to match changes in ventilation
decreased airflow which reduces PO2 in blood vessels which causes vasoconstriction
this results in decreased bloodflow to match the decreased air flow
What happens to ventilation perfusion ratio if there is an airway Obstruction
In normal airway, airway is open, capillaries are open, there is good gas exchange, minimal shunting of air or blood (wasted air/blood)
In obstruction
this causes low ventilation / perfusoin ratio
we are underventilated compared to ou blood flow
increases wasted blood (shunting)
increases venous admixture
What happens to ventilation perfusion ratio if there is an capillary obstruction
In normal airway, airway is open, capillaries are open, there is good gas exchange, minimal shunting of air or blood (wasted air/blood)
This will cause a high ventilation / perfusion ratio
over ventilated compared to blood flow
this will increase wasted air (psyiological dead space)
Which of the following would be predicted to occur in a healthy individual, who has a 50% increase in his cardiac output?
Pulm Blood Flow Cap Recruitt PulmVasc Resist A Increases Increases Decreases B Increases Increases Increases C Increases No Change Decreases D No change Increases No change
A Increases Increases Decreases
Which of the following best characterizes alveoli that are well ventilated but are poorly perfused?
A. They are most likely to occur with a partially plugged airway.
B. They are most likely to occur at the base of the lung.
C. PO2 is high in these alveoli, while PCO2 is low.
D. PO2 is low in these alveoli, while PCO2 is high.
E. Both PO2 and PCO2 are normal.
C. PO2 is high in these alveoli, while PCO2 is low.
Most of the oxygen in the pulmonary capillaries is delivered to the heart from the base rather than from the apex of the lungs. This is primarily due to the fact that
A. the high V/Q ratio occurs at the base of the lungs.
B. the base of the lungs receives more ventilation than the apex.
C. the base of the lungs has a higher blood flow than the apex.
D. more shunted blood occurs at the lung apex.
E. the PO2 is lower in capillary blood leaving the lung apex than at the base.
C. the base of the lungs has a higher blood flow than the apex.
WHere are the respiratory centers?
The medulla and the Pons
What are the two respiratory cneters in the medulla
DRG and VRG
DRG or dorsal respiratory group
is in nucleus of the tractus solitirus
primarily for inspiration
VRG or ventilatory respiratory group
is in the nucleus ambiguos and nucleus retroambiguos
it has both inspiratory and expiraotry neurons
VRG expiration is active, unlike normal expiration which is passive
VRG is larger
WHat is the DRG
DRG or dorsal respiratory group
is in nucleus of the tractus solitirus
primarily for inspiration
What is VRG
VRG or ventilatory respiratory group
is in the nucleus ambiguos and nucleus retroambiguos
it has both inspiratory and expiraotry neurons
VRG expiration is active, unlike normal expiration which is passive
VRG is larger
Describe role of phrenic nerve
Somatic nerve in charge of respiration
Controls diaphragm
c3,4,5, keep the diaphragm alive
WHat are the two types of chemo receptors
central and peripheral
THese are not sensitive to changes in O2
dont detect O2 changes until around 40mmhg
Very sensitive to CO2
Describe peripheral chemoreceptors
Carotid sinus
aortic arch
Receptors for CO2, H+ and O2
Describe Central chemoreceptors
IN lungs
Receptors for CO2 mainly
but also H+
What are the three types of receptors in the lungs
Chemoreceptors
mechanoreceptors
muscle propioceptors
What do muscle proprioceptors do in the lung
They are used for the feed forward mechanism
Describe the mechanoreceptors in the lung
Stretch receptors
J receptors (juxtaposed)
activated by engourgment of pulmonary capillaries
Irritant receptors
Typically stimulate respiratory cneter but can
depress it
Where does voluntary control of respiration come from
cerebrum
hold breath
breath faster or slower
How is everything relayed to the respiratory centers in pons and medulla
signals are relayed to spinal motor nerves ie the phrenic nerve then they are relayed to diaphragm intercostals acessory muscles muscles of respiration
describe neural reflexes in the control of breathing
as CO2 goes up, minute vetilation goes up
(linear relationship, straight line)
CO2 is powerful stimulus for ventilation
O2 is not the same, it needs to drop a really long ways to have any changes in ventilation
(to around 40mmhg)
Central and peripheral chemoreceptors detect the changes
they respond to changes in arterial blood gases
and
H+ ion concentrations
Talk about the blood brain barriers role in ventilation
The BBB is impermeable to H+ and HCO3
It is permeable to CO2
this can cause rapid changes in acid base status
The more CO2, the more ventilation
CO2 in relation to ventilation
the more CO2 the more ventilation
The increase in ventilation from moderate exercise in a healthy individual is caused by:
A. an increase in lactic acid production.
B. an increase in arterial PCO2.
C. a decrease in arterial PO2.
D. a decrease in the pH of brain extracellular fluid.
E. an increase in limb joint and muscle receptor excitation.
E. an increase in limb joint and muscle receptor excitation.
A patient suddenly has a decrease in her arteriolar PO2. Which of the following statements best describe the ventilatory response to the decreased arteriolar PO2?
A. The response is mediated by both peripheral and central O2 chemoreceptors.
B. The response is mediated by peripheral O2 chemoreceptors.
C. The response is mediated by O2-sensitive chemoreceptors in skeletal muscle.
D. The response is mediated by O2-sensitive chemoreceptors in the alveolar capillary membrane.
B. The response is mediated by peripheral O2 chemoreceptors.
A newborn inhales and stimulates the stretch receptors in the airway smooth muscle.
This will:
A. inhibit inspiration and stimulate expiration.
B. stimulate depth of breathing and oxygen uptake in the lung. C. inhibit depth of breathing and stimulate shallow breathing.
D. stimulate depth and rate of breathing.
A. inhibit inspiration and stimulate expiration.
A 50-year-old man with a persistent cough and difficulty breathing is referred
by his family physician for pulmonary function tests. The test results show
that the forced vital capacity (FVC), forced expired volume in 1 s (FEV1), and
functional residual capacity (PRC) are all significantly below normal. Which
of the following diagnosis is consistent with these pulmonary function test
results?
A. Asthma
B. Chronic bronchitis
C. Emphysema
D. Pulmonary fibrosis
D. Pulmonary fibrosis
- A 19-year-old man is taken to the emergency department after being stabbed
in the right side of the chest. ‘Ihe entry of air through the wound resulted in a
pneumothorax on the right side of his chest What difference between the right
and left sides of the chest would be apparent on a plain chest x-ray?
A. ‘Ihe lung volume on the right would be larger
B. The position of the diaphragm on the right would be higher
C. The thoracic volume on the right would be larger
D. There would be no dllferences in thoracic geometry
C. The thoracic volume on the right would be larger
A 28-year-old man is involved in a high-speed motor vehicle accident in which
he suifers multiple rib fractures. On arrival at the emergency department. he
is conscious but in severe pain. His respiratory rate is 34 breaths/min, and his
breathing is labored. His blood pressure is 110/95 mm Hg, and his pulse is 140
beats/min. His arterial Po2 is 50 mm Hg, and he is unresponsive to supplemental 0 1
• His arterial Pco2 is 28 mm Hg. What is the most likely cause of this
patient’s hypoxemia?
A. Alveolar hypoventilation B. High ventilation/perfusion (V / Q) ratio C. Increased dead space ventilation D. Intrapulmonary shunt E. Low V/Q ratio
D. Intrapulmonary shunt
A 16-year-old girl is found unconscious in the street. She has no visible injuries
but is cold and is taking shallow breaths at a rate of 6-8 per minute. An arterial blood gas analysis recorded in the emergency department shows that her
Po2 is 55 mm Hg and her Pco2 is 75 mm Hg. What is the most likely cause of
hypoxemia in this patient?
A. Alveolar hypoventilation B. High ventilation/perfusion (V / Q ) ratio C. Increased dead space ventilation D. Intrapulmonary shunt E. Low V/ Q ratio
A. Alveolar hypoventilation
A 62-year-old man with a history of COPD is admitted to the hospital due to
acute deterioration in lung function as a result of a viral chest infection. An
anal}’5is of arterial blood gases shows that his Po2 is 60 mm Hg and his Pco1 is
70 mm Hg. His exhaled minute ventilation rate is two times higher than that of
a normal individual of the same age and body size. He has hypercapnea. despite
having an increased exhaled minute ventilation rate because his
A. alveolar ventilation is increased B. dead space ventilation is increased C. VT is increased D. ventilation/perfusion (V / Q) ratio is decreased E. intrapulmonary shunt is increased
B. dead space ventilation is increased
A 40-year-old woman presented with dyspnea, hematuria, and right flank pain.
CT scans revealed a renal tumor, with an extensive venous thrombus that hadnvaded the inferior vena cava. Fragments of the thrombus had entered the
lungs and were blocking several major branches of the pulmonary arteries.
Aasuming that there was no change in VT or respiratory rate, what effect would
these pulmonary emboli have on arterial blood gases within the first few minutes of their occurrence?
A. Decreased Pco2 and decreased Po2 B. Decreased Pco2 and increased Po2 C. Increased Pco2 and decreased Po2 D. Increased Pco2 and increased Po2 E. No change in Pco2 or Po2
C. Increased Pco2 and decreased Po2
A 9-ycar-old boy decided to find out for how long he could continue to breathe
into and out of a paper bag. After approximately 2 minutes, his friends noticed
that he was breathing very rapidly so they forced him to stop the experbnent.
What change in arterial blood gas composition was the most potent stimulus
for this boy’s hyperventilation?
A. Dcacased Pco2 B. Decreased Po2 C. Decreased pH D. Increased Pco2 E. Increased Po2 F. lncrcaacd pH
D. Increased Pco2
A 54-ycar-old woman with advanced emphysema due to many years of cigarette smoking is admitted to the hospital because of severe peripheral edema
and shortness of breath. On physical examination, there is jugular venous distension and a widely split second heart sound with a loud pulmonic sound. A
differential diagnosis of right heart failure and pulmonary hyperte1U1ion is confirmed by cardiac cathetmzation. The results of her arterial blood gas analpiis
show Po2 = 55 mm Hg, Pco2 = 75 mm Hg, and pH = 7.30. What is the most
lilccly cause of pulmonary hypertension in this patient?
A. Decreased alveolar Po2 B. Decreased lung compliance C. Decreased parasympathetic neural tone D. Increased alveolar Pco2 E. Increased thoracic volume F. Increased sympathetic neural tone
A. Decreased alveolar Po2
A group of medical students is experimenting with a peak flow meter in the
respiratory phy&iology laboratory. Two students decide to compete to see which
of them can blow the hardest into the device. Which of the following mwcles is
most effective at producing a maximal expiratory effort such as this?
A. Diaphragm B. External intercostal muscles C. Internal intercostal muscles D. Rectus abdominus E. Sternocleidomastoid
D. Rectus abdominus
A 22-year-old man was involved in a :6.ght in which he received a severe blow
to the head. On arrival at the emergency department. he was unconscious and
initially received assisted ventilation via a manual bag-valve device. An analysis
of his arterial blood gases shows:
Po2 =45mmHg
Pco2 = 80 mm Hg
pH=7.05
HC0,-=27 mM
In what form was most col being transported in his arterial blood?
A. Bicarbonate ions
B. Carbaminohemoglobin comp
A. Bicarbonate ions
A 67-year-old woman involved in a motor vehicle accident lost 1 L of blood
became of an open fracture of her left femur. Paramedics were able to prevent
further bleeding. What changes to her intracellular fluid (ICF) and extracellular
fluid (ECF) volumes would be observed 15 minutes after this blood loss?
A. ECF volume smaller; ICP volume unchanged
B. ECF volume smaller; ICF volume smaller
C. ECF volume unchanged; ICF volume unchanged
D. ECF volume unchanged; ICF volume smaller
A. ECF volume smaller; ICP volume unchanged
1he following pressure measurements were obtained from within the glomerulus of an experimental animal:
Glomerular capillary hydrostatic pressure = 50 mm Hg
Glomerular capillary oncotic pressure = 26 mm Hg
Bowman’s space hydrostatic pressure = 8 mm Hg
Bowman’s space oncotic pressure = 0 mm Hg
Calculate the glomerular net ultrafiltration pressure (positive pressure favors
filtration; negative pressure opposes filtration).
A. +16mmHg B. +68mmHg C. + 84mmHg D. Omm.Hg E. -16mmHg F. -68mmHg G. -84mmHg
A. +16mmHg
A novel drug aimed at treating heart failure was tested in experimental animals.
The drug was rejected for testing in humans because it caused an unacceptable
decrease in the glome.rular filtration rate (GFR). Further analysis showed that
the drug caused no change in mean arterial blood pressure but renal blood 1low
(RBF) wu increased. The filtration fraction wu decreased. What mechanism is
most likely to explain the observed decrease in GFR?
A. Afferent arteriole constriction
B. Afferent arteriole dilation
C. Efferent arteriole constriction
D. Efferent arteriole dilation
D. Efferent arteriole dilation
A healthy 25-year-old woman was a subject in an approved research study. Her
average urinary urea excretion rate was 12 mglmin, measured over a 24-hour
period. Her average plasma urea concentration during the same period was
0.25 mg/mL. What is her calculated urea clearance?
A. 0.25 mL/min
B. 3mUmin
C. 48mUmin
D. 288 mLlmin
C. 48mUmin
A 54-year-old woman received. a life-saving kidney transplant 6 months ago
and had been well until the p8$1 few days. She now reports severe fatigue and
dizziness upon standing. Urinalysis is positive for glucose, and there is excessive excretion of HC03 - and phosphate. In which segment of the nephron is
function most likely to be abnormal?
A. Proximal tubule
B. Loop of Henle
C. Distal tubule
D. Collecting duct
A. Proximal tubule
A resident in internal medicine was called to the hospital room of an 85-yearold patient in the middle of night. The man was sitting up in bed coughing. and
was severely short of breath. Crackles heard in both lungs suggested pulmonary
ed.ema. Which diuretic is most appropriate for this patient?
A. Carbonic anhydrase inhibitor
B. Loop diuretic
C. Thiazide diuretic
D. Potassium-sparing diuretic
B. Loop diuretic
