Respiratory L15 Flashcards
what are the 2 functions of the conducting zone?
a. Transports air to the lungs
b. Warms, humidifies, filters, and cleans the air
1) Mucus traps small particles, and cilia move it
away from the lungs.
c. Voice production in the larynx as air passes
over the vocal folds
- Mucus secreted by cells of the conducting zone traps
small particles. - Mucus moves along by cilia that beat in a coordinated
fashion (mucociliary escalator) to the pharynx, where it
can be cleared by swallowing or expectorating. This
process is called mucociliary clearance. - In cystic fibrosis the mucociliary escalator fails to
function properly. This is because this abnormal mucus
is too thick for the cilia to properly clear. - Cigarette smoking also damages cilia and reduces
mucociliary clearance.
what are the 3 types of pressure?
a. Atmospheric pressure: pressure of air
outside the body
b. Intrapulmonary or intra-alveolar pressure:
pressure in the lungs
c. Intrapleural pressure: pressure within the
intrapleural space (between parietal and
visceral pleura); contains a thin layer of fluid
to serve as a lubricant
during inspiration(inhaling), Intrapulmonary
pressure is ________ than atomospheric pressure,
Expiration (exhalation): Intrapulmonary
pressure is___________ than atmospheric pressure.
lower
-3mmHg
greater
+3mmHg
3 physical properties of lungs
Compliance, elasticity, and surface tension
Lung compliance(stretching) is reduced by
actors that produce a resistance to
distention such as the infiltration of connective
tissue proteins in pulmonary fibrosis
Surface Tension: Fluid is absorbed by active transport of___ and secreted by active transport of ___
Na
Cl
Surfactant secreted by
type 2 alveolar cells
what is this pulmonary function test
Subject breathes into and out
of a device that records volume and
frequency of air movement on a
spirogram.
a. Measures lung volumes and capacities
b. Can diagnose restrictive and disruptive lung
disorders
Pulmonary Function Tests
Spirometry:
during exercise, which increases first? rate or depth?
depth
then rate
Alveolar vs pulmonary Ventilation
Pulmonary ventilation is the volume of air entering into the lungs in unit time whereas alveolar ventilation is the volume of air entering into the alveoli at the same time
Alveolar Ventilation
– Volume of air exchanged between the atmosphere
and the alveoli per minute
– Less than pulmonary ventilation due to anatomic
dead space
* Volume of air in conducting airways that is useless for
exchange
* Averages about 150 mL in adults
* Alveolar ventilation =
(tidal volume –dead space) × respiratory rate
Dalton’s Law
a. The total pressure of a gas mixture is equal to the sum
of the pressures of each gas in it.
b. Partial pressure: the pressure of an individual gas; can
be measured by multiplying the % of that gas by the
total pressure
1) O2 makes up 21% of the atmosphere, so partial pressure of
O2 = 760 x 20% = 159 mmHg.
Dalton’s Law-in a mixture of non-reacting gases, the total pressure
exerted is equal to the sum of the partial pressures of the individual gases
Total pressure
Nitrogen makes up 78% of the atmosphere, O2
21%, and CO2 <1%.
Pdry = PN2 + PO2 + PCO2 = 760 mmHg
When air gets to our lungs, it is humid, so the
calculation changes to:
Pwet = PN2 + PO2 + PCO2 + PH2O= 760 mmHg
Calculation of PO2
a. Addition of water vapor also takes away from the total
atmospheric pressure when calculating partial
pressure O2.
1) Pressure of water at 37°C is a constant 47 mmHg.
2) Partial pressure O2 at sea level:
.21(760 − 47) = 150 mmHg
Result of Gas Exchange
a. In the alveoli, the percentage of oxygen decreases
and CO2 increases, changing the partial pressure of
each.
Henry’s Law
The amount of gas that can dissolve in liquid
depends on:
1) Solubility of the gas in the liquid (constant)
2) Temperature of the fluid (more gas can dissolve in cold
liquid); doesn’t change for blood
3) Partial pressure of the gases, the determining factor
Significance of Blood PO2 and PCO2
Measurements
- Only measures oxygen dissolved in the blood
plasma. It will not measure oxygen bound to
hemoglobin in red blood cells. - It does provide a good measurement of lung
function. - When lungs are functioning properly, PO2 of
systemic arterial blood is only 5mm Hg less
than PO2 of alveolar air
a. At normal PO2 of about 100mm Hg, hemoglobin is
almost completely filled with O2
b. Oxyhemoglobin saturated of 97%
c. Adding more O2 will not significantly change
the amount of O2 in RBCs, but can increase the
amount of dissolved oxygen
d. Since O2 must dissolve in the plasma before it
can be delivered to tissues, the rate of O2
diffusion would increase
4. Blood gas measurement of venous blood is
not very useful
________made in the kidneys
stimulates hemoglobin/RBC production in
red bone marrow when O2 levels are low.
EPO
Loading and Unloading hemoglobin
direction of reaction depends on:
Loading: when hemoglobin binds to oxygen in the
lungs
Unloading: when oxyhemoglobin drops off oxygen
in the tissues
deoxyhemoglobin + O2 ⟷oxyhemoglobin
Direction of reaction depends on PO2 of the
environment and affinity for O2.
1) High PO2 favors loading.
2) Strong bond favors loading and inhibits unloading
________ and _______ change the affinity of
hemoglobin for O2.
a. This ensures that muscles get more O2 when
exercising.
- Affinity _________ at lower pH and
________ at higher pH = Bohr effect.
a. More unloading occurs at lower pH.
b. Increased metabolism = more CO2 = lower pH
c. More O2 unloading
d. Curve shifts to the right
pH and temperature
decreases
increases
Hemoglobin affinity for O2 is ____________ at
increased temperatures.
a. This further enhances the amount of O2
unloaded to muscles during exercise.
b. Curve shifts to the right
decreased
RBCs obtain energy from the anaerobic
metabolism of______ (has no nucleus or
mitochondria)
a. During this process, 2,3 diphosphoglyceric acid
(2,3-DPG) is made.
b. Inhibited by oxyhemoglobin
c. 2,3-DPG is produced if a person is anemic or at
high altitude.
d. This increases oxygen unloading.
e. Shifts the oxyhemoglobin dissociation curve to
the right
glucose
Carbon dioxide is carried in the blood in
three forms:
a. Dissolved in plasma (more soluble than O2)
b. As carbaminohemoglobin attached to an
amino acid in hemoglobin
c. As bicarbonate ions (accounts for the
majority of transport)
____________is the enzyme that
catalyzes the reaction to form carbonic acid
at high PCO
carbonic anhydrase
The exchange of
bicarbonate out of and
Cl− into RBCs is called
the chloride shift
(Once bicarbonate ion is
formed in the RBC, it
diffuses into the plasma
H+ in RBCs attach to
hemoglobin and attract
Cl−.)
Bohr Effect
a. Bonding of H+ to hemoglobin lowers the
affinity for O2 and helps with unloading.
b. This allows more H+ to bind, which helps the
blood carry more carbon dioxide.
Reverse Chloride Shift
- In pulmonary capillaries, increased PO2
favors the production of oxyhemoglobin. - This makes H+ dissociate from hemoglobin
and recombine with bicarbonate to form
carbonic acid:
H+ + HCO3− →H2CO3 - Chloride ion diffuses out of the RBC as
bicarbonate ion enters. - In low PCO2, carbonic anhydrase converts
carbonic acid back into CO2 + H2O:
H2CO3 →CO2 + H2O - CO2 is exhaled.
volatile acids example:
non-volatile acids examples:
carbonic acid (can be converted into a gas and exhaled)
lactic, fatty, ketones) are
buffered by bicarbonate; can not be regulated
by breathing, but rather the kidneys
Acidosis: 2 types
Acidosis: when blood pH falls below 7.35
1) Respiratory acidosis: caused by hypoventilation;
rise of CO2 which increases H+ (lowers pH)
2) Metabolic acidosis: caused by excessive
production of acids or loss of bicarbonate
(diarrhea)
