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APK2105C Ch 17
N/A
105
Physiology
Undergraduate 2
12/11/2012

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Term
Oxygen is in higher concentration in the ______ and diffuses in the ______
Definition
Alveoli
Blood
Term
Carbon dioxide is in higher concentration in the ______ and diffuses in the ______
Definition
Blood
Alveoli
Term
Respiratory Quotient (RQ) =
Definition
VCO2/VO2
At rest, cells use 250 mL o2/min
At rest, cells generate 200 mL/ Co2 min
Resting RQ= 200/250= 0.8
Term
A high lipid diet results in
Definition
low RQ (0.7) because O2 is consumed independent of carbon dioxide production during lipid catabolism
Term
The pressure exerted by each individual gas is called _______
Definition
Partial pressure
Term
Partial pressure is determined by which 2 factors
Definition
1) Fractional concentration of gas in that mixture (Quanity relative to total quanity)
2) Total pressure exerted by the gas mixture
Term
Total Barometric Pressure (P)
Definition
PO2 + PN2 + PCO2
Term
Oxygen
Definition
20.93%
Term
Nitrogen
Definition
79.04%
Term
Carbon Dioxide
Definition
0.03%
Term
As air moves through the conduction zone what is it humidified too?
Definition
100% saturation
Term
Does Total Barometric Pressure (P) decrease or increase with 100% Humidity?
Definition
Decrease
Term
CO2 is 20X (more/less) soluble than water
Definition
more
Term
At equilibrium, partial pressure of gas in liquid equals the partial pressure of the gas in air, but this does not mean ___________
Definition
that the concentrations of the gas are in equal form
Term
Henry's Law
Definition
When temperature is constant, the concentration of gases in a liquid is proportional to its partial pressure
c = kP
Term
According to Henry's law, as P increase, c _______
Definition
increases
Term
What happens to scuba divers with "the bends"?
Definition
If a diver surfaces too quickly, nitrogen gas bubbles form in the blood as the pressure decreases (also called decompression sickness)
These bubbles lodge in the joints, vessels and nervous system
Term
How do alveolar gas pressures differ from Patm?
Definition
1) Exchange of gases occur continually between alveolar air and capillary blood
2) Upon inspiration, fresh atmospheric air mixes with air rich in CO2 and relatively poor O2 in the dead space (of conducting zone)
3) Air in alveoli is saturated with water vapor
Term
What 2 partial pressures are the same in the partial pressures of O2 and Co2 in atmospheric air, alveolar air and various sites in the body?
Definition
Systemic Veins and Cells
Term
Mixed venous blood is important because
Definition
all tissues use different amount of O2 and CO2 (although it is the same in right atrium)
Term
Why is diffusion rate (of O2 and CO2) rapid?
Definition
thinness of respiratory membrane
Term
Why is the speed of gas exchange important?
Definition
Provides a safety margin so that gases can still equilibrate between capillary blood and alveolar air even if blood is flowing at a rate up to 3 times faster (example: exercise)
Term
Pulmonary Edema causes: (increase/decrease) distance between alveoli and capillaries, which (increases/decreases) thickness of the diffusion barrier between air and blood, which (increases/decrease) rate of diffusion of gases, which (increases/decreases)exchange of gases, resulting in (higher/lower) PO2 and (higher/lower) PCO2
Definition
Increases
Increases
Decreases
Decreases
Lower
Higher
Term
When O2 and CO2 diffuse down their partial pressure gradient, O2 moves from ____ to ____ while CO2 moves from ____ to _____
Definition
Blood; Tissue
Tissue; blood
Term
Venous blood coming from the capillaries will have a (higher/lower) PO2 and a (higher/lower) PCO2, than venous blood coming from capillaries supplying less active tissue.
Definition
Lower
Higher
Term
Factors that affect Alveolar Partial Pressures
Definition
1) PO2 and PCO2 of inspired air
2) Minute alveolar ventilation (volume of fresh air reaching the alveoli each minute)
3) rates at which respiring tissues consume O2 and produce CO2
Term
Hypoxia
Definition
deficiency of O2 in the tissues
Term
Hypoxemia
Definition
deficiency of O2 in the blood
Term
Hypocapnia
Definition
deficiency of CO2 in the blood
Term
Pulmonary Edema
Definition
accumulation of excess fluid in the lungs
Term
Most important feature of the transportation of O2
Definition
Reversible
Tight enough so that it can pick up large quanities of O2 in the lungs, but not not so tight that it can't release the oxygen into respiring tissues later
Term
When hemoglobin in 100% saturated
Definition
1 gram of hemoglobin carries 1.34 mL of O2 (so 200 mL of oxygen in every liter)
Term
Oxyhemoglobin Dissociation Curve
Definition
Percent of saturation increases as PO2 increases, but binding isn't linear! S-shaped because the ability of hemoglobin to bind depends on the amount of oxygen already bound
Term
Partial Pressure: Atmospheric Air
Definition
O2 = 160 mmHg
CO2 = 0.3 mmHg
Term
Partial Pressure: Alveolar air
Definition
O2 = 100 mmHg
CO2 = 40 mmHg
Term
Partial Pressure: Pulmonary viens
Definition
O2 = 100 mmHg
CO2 = 40 mmHg
Term
Partial Pressure: Systemic Arteries
Definition
O2 = 100 mmHg
CO2 = 40 mmHg
Term
Partial Pressure: Cells
Definition
O2 = <40 mmHg
CO2 = >46 mmHg
Term
Partial Pressure: Systemic Veins
Definition
O2 = 40 mmHg
CO2 = 46 mmHg
Term
Partial Pressure: Pulmonary Arteries
Definition
O2 = 40 mmHg
CO2 = 46 mmHg
Term
Low affinity for O2
Definition
(doesn't happen in blood), very little oxyhemoglobin
Term
Steeper Curve
Definition
At Po2 between 20-40, affinity for O2 increases as more O2 binds with Hb
(Hemoglobin taking in more O2)
Term
Flattened curve
Definition
Above PO2 of ~60, less available binding sites as Hb approaches saturation
Term
Carbon Monoxide
Definition
Binds to hemoglobin more readily than oxygen, prevents oxygen from binding, decreases oxygen carrying capacity
Term
What lead to decreased affinity and promote O2 off-loading?
Definition
1) Increased Temp
2) Decreased pH
3) Increased CO2
Term
Transportation of CO2 in the Blood
Definition
1) 5% dissolved in plasm
2) 10% CO2 Hb-bound
3) 85% HCO3
Term
Systemic tissues: PO2 (increases/decreases) and PCO2 (increases/decreases)= CO2 ______ and PCO2 _______
Definition
Decreases
Increases
Loading
Unloading

Opposite: in lungs
Term
Carbonic Anhydrase
Definition
catalyzes the reversible reaction that converts carbon dioxide and water to carbonic acid (h2CO3)
Term
(Acid Base Balance) An (increase/decrease) in PCO2, causes an (Increase/decrease) in the acidity of blood, which (increases/decrease) hydrogen ion concentration
Definition
Increase FOR ALLL OF DEEEMMM
Term
Haldane effect
Definition
Carbon dioxide content of blood falls as the PO2 rises
Term
O2 (release/loading) at tissues promotes CO2 (release/loading)
Definition
Release
Loading
(opposite in alveoli)
Term
Bohr effect
Definition
When oxygen binds to hemoglobin, certain amino acids in the protein release hydrogen ions (Increase in pH/Decrease in hydrogen ions or vice versa is the effect)
Term
Carbamino Effect
Definition
Carbon dioxide is bound to hemoglobin, it changes hemoglobin's conformation and decreases it's affinity for oxygen (PCO2)
Term
Decrease in PO2, direct effects is increase O2 (unloading/loading), it's Haldane effect is increased CO2 (unloading/loading) and it's carbamino effect is (Increased/Decreased) Hemoglobin's affinity for O2
Definition
unloading
loading
Decreased
Term
Increase in PCO2, direct effects is increased CO2 (loading/unloading), if there is an increase in Hydrogen ions, pH (decreases/increases) (Bohr Effect), it's carbamino effect is (decreased/increased) Hemoglobin's affinity for O2
Definition
Loading
Decreased
Decreased
Term
The body maintains normal partial pressured of O2 and CO2
Definition
through changing Ve (Vt x RR) by ventilation
Term
What innervates the diaphragm?
Definition
Phrenic Nerve
Term
Respiratory Control Centers are located
Definition
Medulla and Pons
Term
Medulla
Definition
-Ventral respiratory group (2 expiratory/ 1 inspiratory)
-Dorsal Respiratory group (primarily inspiratory)
-Groups of inspiratory and expiratory neurons and expiration
Term
Pons
Definition
-Pontine respiratory group
-Neurons involved in inspiratory and expiration
Term
Central Pattern Generator
Definition
Location unknown, but helps with collaboration and redundancy (also with Pons and Medulla) for a 'back up' system that will help protect the body
Term
Chemoreceptors
Definition
detect changes in partial pressures of O2 and CO2 and relay this information to the respiratory control center
-Increased PO2 & Decreased PCO2 = increased Ventilation
Term
Peripheral Chemoreceptors
Definition
Carotid bodies near carotid sinus
-In direct contact with arterial blood and communicate with afferent neurons projecting medullary respiratory control
-Respond to changes in PO2, PCO2, or pH
Term
Central Chemoreceptors
Definition
Medulla oblongata
-respond directly to changes in hydrogen ion concentration in the cerebrospinal fluid surrounding the area, also affected indirectly by PCO2
(But not PO2)
Term
Decreased PO2 (< 60 mmHg), which activates (peripheral/central) chemoreceptors that detect and respond by (increasing/decreasing) ventilation
Definition
Peripheral
Increasing
Term
Increased PCO2, with Increased H+ ions, which is an (increase/decrease) in pH, which activates (peripheral/central) chemoreceptors, which (increase/decrease) ventilation
Definition
decrease
peripheral
increase
Term
Increased PCO2 (in Cerebrospinal fluid), which decrease ph (so theres an increase/decrease in H+), and (peripheral/central) chemoreceptors detect and respond, by (increase/decrease) ventilation
Definition
increase
central
increase
Term
It is ideal for blood flow (Q) to match
Definition
Ventilation (Va)
Term
Hypoventilation = (increase/decrease) in PCO2, (increase/decrease) in H+, (increase/decrease) in PO2 = chemoreceptors detect and respond = (increase/decrease) ventilation
Definition
Increase
increase
decrease
increase
Term
______ of lung is over perfused relative to ventilation
Definition
Base
Term
As long as we have _____ Va/Q ration, our body will be okay
Definition
0.5 (but 1 is ideal)
Term
Factors that affect ventilation-perfusion inequalities
Definition
Disease, damages to pulmonary capillaries, gravity, blood flow, exercise
Term
Obstruction of airway
Definition
Va Decreases, no change in Q (Va/Q ratio decrease)
Term
Obstruction of blood vessel
Definition
Va no change, decrease in Q (Va/Q ratio increases)
Term
O2 predominantly acts on ____________
Definition
pulmonary arteriolar smooth muscle
Term
CO2 predominantly acts on _____________
Definition
bronchiolar smooth muscle
Term
In the lungs, O2 and CO2 have (similar/opposite) effects on pulmonary arterioles compared to systemic arterioles
Definition
opposite
Term
Increase in PCO2 and Decrease in PO2 = (increase/decrease) in contractile activity of smooth muscle in bronchioles, which equals Bronchodilation= (decreased/increase) resistance of respiratory tract which equals increase in ventilation
Definition
decrease
decrease
Term
Increase in PCO2 and Decrease in PO2 = (increase/decrease) in contractile activity of smooth muscle in pulmonary arteries, which equals vasoconstriction = (decrease/increase) resistance in pulmonary circuit which equals decreased perfusion
Definition
increase
increase
Term
Normal pH is
Definition
7.38-7.42
Term
Acidemia
Definition
blood pH <7.35
Term
Alkalemia
Definition
blood pH is >7.45
Term
Respiratory System Buffers
Definition
Hemoglobin and Bicarbonate
Term
Hemoglobin formula
Definition
Hb x O2 ---> O2 + Hb
hB + (H+) ---> HbH
Term
Bicarbonate Ion Formula
Definition
CO2 + H2O ---> H2CO3 ---> HCO3- + (H+)
(H+) + Hb --> HbH
Term
At high altitudes, Patm is
Definition
Decreased
Term
Acute exposure to High Altitude
Definition
Hypozemia ===> hypoxia
Increase in ventilation ---> alkalemia (pH>7.45)--> increase in Hb-O2 affinity (less off-loading in tissues, more O2 loading at the lungs)
Term
Chronic Exposure
Definition
Kidneys start helping out
Kidneys excrete bicarbonate and secrete erythropoietin = more Hb --> polycythemia
Term
How much oxygen is contained in a liter of blood? Does it all directly contribute to blood PO2?
Definition
~ 200mL O2/L
~ 3mL dissolved in plasma (DIRECT contributor to blood PO2)
~ 197 oxyhemoglobin (indirectly contributor to blood PO2)
Term
Alveolar PO2 value?
Alveolar PCO2 value?
Definition
100 mmHg
40 mmHg
Term
Resting venous blood is __% saturated
Definition
75
Term
1g of hemoglobin carries how much oxygen at 100% saturation?
How mch Hb is in the blood?
Definition
1.34mL/g
150g/L
Term
Oxyhemoglobin dissociation curve describes the relationship between ______ and ________
Definition
PO2
hemoglobin saturation
Term
Where is PCO2 46 and PO2 40?
Definition
systemic veins, pulmonary arteries, and cells (tissues)
Term
Where is PO2 100 and PCO2 40?
Definition
systemic arteries, pulmonary veins, alveolar air
Term
What does carbonic acid (H2CO3) dissociate into?

What happens to these products?
Definition
hydrogen ion (H+) and bicarbonate (HCO3-)

bicarbonate leaves the RBC, bringing chloride in

H+ binds with hemoglobin, decreasing Hb affinity for O2
Term
An increase in CO2 would cause (increase/decrease) in H+
Definition
increase
Term
The body maintains normal partial pressures of O2 and CO2 by changing
Definition
Minute ventilation
Term
Central chemoreceptors are located in the _________ and respond to changes in ________.
Definition
dorsal medulla
PCO2 (NOT PO2)!!
Term
Base of lung is (over/under) perfused relative to ventilation
Definition
over
VA/Q ratio <1
Term
CO2 acts predominantly on (pulmonary arteriolar/bronchiolar) smooth muscle
Definition
bronchiolar
Term
O2 acts predominantly on (pulmonary arteriolar/bronchiolar) smooth muscle
Definition
pulmonary arteriolar
Term
Increased PO2 would (dilate/constrict) pulmonary arterioles
Definition
dilate
Term
Increased CO2 would (dilate/constrict) bronchiolar smooth muscles
Definition
dilate
Term
Decrease in PO2
(increase/decrease) O2 unloading
(increase/decrease) CO2 loading
Definition
Decrease in PO2
increase O2 unloading
increase CO2 loading
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