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86 Cards in this Set

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-Single squamous epithelium that forms the alveolar wall.
-Surrounded by pulmonary capillaries.
-Forms extremely thin barrier gas exchange between air and blood. “blood-air  barrier”
Type I Alveolar Cells
-secretes pulmonary surfactant
-Prevent fluid buildup
Type II Alveolar Cells
Phospholipoprotein complex that
facilitates lung expansion
pulmonary surfactant
During intrauterine life, by the __________, development of lungs and their different parts (ie bronchi and even alveoli), has taken place but not type 2 cells
7th month
Treatment for <7month premature birth?
-Incubation and O2 therapy
-Injection of cortisol to develop surfactant
In dry inspired air, PO2=?
PCO2=?

In blood (Pulmonary a.) PO2=40 mmHg, PCO2=46 mmHg
In blood (Pulmonary v.) PO2=100 mmHg, PCO2=4o mmHg
PO2=160 mm Hg,

PCO2=0 mm Hg
In humidified tracheal air at 37C (H2O):
PO2=?
PCO2=?
PO2=150 mmHg,

PCO2=0 mmHg
Partial pressures of O2 and CO2 in inspired air, alveolar air:
PAO2=?
PACO2=?
(A=Alveolar)
PAO2=100 mmHg
PACO2=40 mmHg
(A=Alveolar)
For gases, the rate of transfer by diffusion is _________ to the driving force, a diffusion coefficient, and the surface area available for diffusion, it is ________ to the thickness of membrane barrier.
-directly proportional

-inversely proportional
DL can be measured with _______ because its transfer across the alveolar/pulmonary capillary barrier is limited exclusive by the diffusion process.
carbon monoxide (CO)
in emphysema, DL deceases because ?
destruction of alveoli results in a decreased surface area for gas exchange.
In fibrosis or pulmonary edema, DL decreases because
the diffusion distance (membrane thickness or interstitial volume) increases.
In anemia, DL decreases because
the amount of hemoglobin in red blood cells is reduced (recall that DL includes the protein-binding component of O2 exchange).
During exercise, DL increases because
additional capillaries are perfused with blood, which increases the surface area for gas exchange.
DL only increases during?
exercise
for a perfusion-limited process, diffusion of the gas can be increased only if ?
blood flow increases.
Anatomic dead space
.
-is the volume of the conducting airways.
-is normally approximately 150ml
anatomic dead space locations
Nasal cavity, trachea, primary, secondary, tertiary bronchi
the volume of the lungs that does not participate in gas exchange
-physiologic dead space

-is approximately equal to the anatomic dead space in normal lungs.
volume of air that can be expired in the first second of a forced maximal expiration
FEV1
FEV1 is normally _____ of the forced vital capacity, which is expressed as
80%
In obstructive lung disease, such as asthma, FEV1 is ?
both FEV and FVC are reduced but FEV1 is reduced more than FVC so that FEV1/FVC is decreased.
In restrictive lung disease, such as fibrosis, FEV1 is?
both FEV1 and FVC are reduced but FEV is decreased LESS than FVC so FEV/FVC increases.
Innervation of diaphragm is by _______. The origin is _______
-phrenic nerve

-C3-C4-C5
External intercostals are used for ____________

Internal intercostals are used for_________
-inspiration

-expiration
Large alveoli have ______ collapsing pressures and are ______ to keep open.
-low

-easy
Small alveoli have ______ collapsing pressures and are _______ to keep open.
-high

-more difficult
In the absence of surfactant, the small alveoli have a tendency to collapse known as?
atelectasis
Surfactant is synthesized by type II alveolar cells and consists primarily of ?
the phospholipid dipalmitoryl phosphatidylcholine (DPPC)
______________ can occur in premature infants because of the lack of surfactant. The infant exhibits atelectasis (lung collapse), difficulty reinflating the lungs (as a result of decreased compliance), and hypoxemia because of the V/Q defect
Neonatal respiratory distress syndrome
The major site of airway resistance is the __________.
medium-sized bronchi
The smallest airways would seem to offer the highest resistance, but they don’t because of ________
their parallel arrangement.
sympathetic agonists like ________ dilate the airways via beta receptors, increase the radius, and decrease the resistance to airflow
isoproterenol

albuterol
During a deep-sea dive, both air density and resistance to airflow are ________.

How fixed?
-increased

- Breathing a low-density gas, such as helium, reduces the resistance to airflow.
At rest intrapleural pressure is
negative
During ispiration intrapleural pressure
becomes more negative
During expiration intrapleural pressure
returns to its resting value during a normal (passive) expiration.
In asthma in children, the most common triggers are
viral illnesses such as those that cause the common cold
In asthma air that should have been expired is not, leading to air trapping and _______ functional residual capacity (FRC)
increased functional residual capacity (FRC)
the total amount of air that you can forcibly blow out after full inspiration, measured in liters
FVC
have mild hypoxemia and, because they maintain alveolar ventilation, normocapnia (normal Pco2).
Pink puffers (primarily emphysema)
have serve hypoxemia with cyanosis and because they do not maintain alveolar ventilation, hypercapnia (increased Pco2). They have right ventricular failure and systemic edema.
Blue bloaters (primarily bronchitis)
FRC?
Functional Residual Capacity is the volume of air present in the lungs at the end of passive expiration
Fibrosis is a restrictive disease with decreased lung compliance in which ________ is impaired.
inspiration
Fibrosis effect on FEV1/FVC?
Both values are decreased but FEV1 is decreased less so FEV/FVC can be INCREASED or normal
Of the gases found in inspired air, ______ is the only one that is carried only in dissolved form, and it is never bound or chemically modified.
nitrogen (N2)
Example of chemically modified gas?
is the conversion of CO2 to bicarbonate (HCO3-) in red blood cells by action of carbonic anhydrase
_______ percent of CO2 is converted to bicarb?
90%
Hemoglobin: Each subunit contains a hem moiety, which is
iron –containing porphyrin
The iron in hemoglobin is in the _______ state
ferrous state (Fe2+)
Fetal hemoglobin, the beta chains are replaced by _______; thus fetal hemoglobin is called _______
gama chains

alpha2 gama2
The O2 affinity of fetal hemoglobin is ______ than the O2 affinity of adult hemoglobin because ?
-higher

-2,3-diphosphoglycerate (DPG) binds less avidly
consequence of fetal hemoglobins affinity?
Because the O2 affinity of fetal hemoglobin is higher than the O2 affinity of adult hemoglobin, O2 movement from mother to fetus is facilitated
Effect of 2,3 BPG?
2,3-BPG is present in human red blood cells (RBC; erythrocyte) at approximately 5 mmol/L. It binds with greater affinity to deoxygenated hemoglobin (e.g. when the red cell is near respiring tissue) than it does to oxygenated hemoglobin (e.g. in the lungs). thus enhancing the ability of RBCs to release oxygen near tissues that need it most
Hemoglobin-O2 dissociation curve
sigmoid
significance of sigmoid Hemoglobin-O2 dissociation curve
The sigmoid shape of the curve is the result of a change in the affinity of hemoglobin as each successive O2 molecule binds to a heme site. -Binding of the first O2 molecule increases the affinity for the second O2 molecule, and so forth.
What portion of the sigmoid curve represents oxygen off-loading at the lung?
This change in affinity facilitates the loading of O2 in the lungs (flat portion of the curve) and the unloading of O2 at the tissues.
Shifts in curve to the right occur when ?

Caused by?
-occur when there is decreased affinity for O2

-Increased CO2/decreased pH
-increased temp
-increased DPG
Shifts in curve to the left occur when ?

Caused by?
-occurs when there is increased affinity for O2

-decreased CO2/increased pH
-decreased temp
decreased BPG
The curve is notably shifted in
fetal hgb
In the TISSUES: HCO3- leaves the RBCs in exchange for _______ known as the_______ and is transported to the lungs in the plasma. HCO3- is the major form in which CO2 is transported to the lungs.
CL-

chloride shift
In the Lungs what happends to HCO3-?
HCO3 enters the RBCs in exchange for Cl-. HCO3 recombines with H+ to form H2CO3, which decomposes into CO2 and H2O. Thus, CO2, originally generated in the tissues, is expired
-Pulmoary pressure and resistance are _______ than cardiace pressure/resistance.

-Pulmonary arterial pressure?
-lower

-15 mmHg
cardiac output of the right ventricle is _______ CO of the left ventricle
equal to
Zone-1 pressures?
Alveolar pressure > arterial pressure > venous pressure
Zone-2 pressures?
Arterial pressure > alveolar pressure > venous pressure
Zone-3 pressures?
Arterial pressure> venous pressure > alveolar pressure
In the lungs, hypoxia causes __________.

-This response is the opposite of that in other organs, where hypoxia causes _______
-lung hypoxia causes vasconstriction

-vasodilatation
Importance of vasoconstriction in hypoxic areas of lungs?
Physiologically, this effect is important because local vasoconstriction redirects blood away from poorly ventilated, hypoxic regions of the lung and toward well-ventilated regions.
Central chemoreceptors are in the ________
medulla
Peripheral chemoreceptors are in the ?
carotid and aortic bodies
chemoreceptors detect
a. Decreases in arterial Po2
b. Increases in arterial Pco2
c. Increases in arterial H+
Other type of receptors for control of breathing
1. Lung stretch receptors
2. Irritant receptors
3. J (juxtacapillary) receptors
4. Joint and muscle receptors
Medullary respiratory center -is located in the __________
-reticular formation

-vagus and glossopharyngeal nerves.
The vagus nerve relays information from __________ and __________. The glossopharyngeal nerve relays information from ___________.
-peripheral chemoreceptors and mechanoreceptors in the lung

-peripheral chemoreceptors
Output from the dorsal respiratory group travels, via the ________, to the _______
phrenic nerve to the diaphragm
Ventral respiratory group is primarily responsible for ________
expiration.
Is the ventral respiratory group active during normal breathing?
no
Apneustic center is located in the ______.
lower pons
Apneustic center stimulates ?
inspiration, producing a deep and prolonged inspiratory gasp (apneusis
Pneumotaxic center is located in the _________.
-upper pons
Pneumotaxic center function?
inhibits inspiration and, therefore, regulates inspiratory volume and respiratory rate.
CO2 flows from the vessel into the alveolus on the ______ side of the capilary.
arterial
HCO3- leaves the RBCs in exchange for CL- (chloride shift) and is transported to the lungs in the _________
plasma
In the lungs, _______ enters the RBCs in exchange for_______. HCO3 recombines with H+ to form H2CO3, which decomposes into CO2 and H2O. Thus, CO2, originally generated in the tissues, is expired.
-HCO3 enters the RBCs in exchange for Cl-
In the lungs after HCO3 enters the RBCs in exchange for Cl- then HCO3 ?
HCO3 recombines with H+ to form H2CO3, which decomposes into CO2 and H2O. Thus, CO2, originally generated in the tissues, is expired.