Upgrade to remove ads
Only $35.99/year

Respiratory Part 2

Terms in this set (48)

partial pressures definition
the individual pressure exerted independently by a particular gas within a mixture of gases
gas exchange caused by
partial pressure gradients
gas exchange involves
simple passive diffusion of O2 and CO2 DOWN its gradient
partial pressure =
(total pressure) x (% gas in mixture)
partial pressure gradients for gas exchange at TISSUES favor
passive movement of O2 OUT of blood and INTO cells for metabolic needs
gas exchange in systemic capillaries O2 and CO2 exchange
passively, down their gradients
In systemic capillaries O2 has ____ partial pressure compared to
high; cells

-because cells using O2 up
In systemic capillaries CO2 has ____ partial pressure compared to
low; cells

because CO2 created via metabolism
after equilibrium blood leaving the systemic capillaries is ____ in O2, ____ CO2, and returns to _____
low; high; right side of the heart to lungs
rate of gas exchange inversely proportional to
thickness of barrier separating air and blood
rate of gas exchange directly proportional to (2)
1. surface area
2. diffusion coefficient for a gas
CO2 coefficient is
20x greater than O2s resulting in equal gas exchange despite pressure gradient differences


-co2 has more of a driving force of O2 even though there is less present in the body
CO2 method of transport in blood (3)
1. physically dissolved
2. bound to hemoglobin
3. as bicarbonate
oxygen transport
Hb + O2 --> HbO2
When PO2 in blood increases the reaction is driven to the ___
right
Hb + O2 --> HbO2

-increase in %HB saturation
when blood PO2 decreases the reaction is driven to the ____
left
Hb + O2 --> HbO2

O2 released from HB = less % Hb saturation
in pulmonary capillaries Hb is almost
fully saturated

(plateau)
in systemic capillaries Hb
unloading increases in response to a small local decline in blood PO2

(steep portion of curve)
how does increased metabolism affect the Hb saturation curve?
shifts curve to right BECAUSE of enhancing oxygen release
main factor determining % of Hb saturation
PO2
there is a net diffusion of
O2 from the alveoli to the blood
-this occurs until Hb is fully saturated
At tissues Hb rapidly
unloads O2 into the plasam for diffusion to tissue cells
factors that increase Hb dissociation from O2 (4)
1.CO2
2. decrease in pH (acidic H+)
3.increase temp
4. 2-3PG

*all components of exercise
*referred to as shifting curve to the right
The Bohr effect
the influence of CO2 and acid on the release of O2
CO2 and H+ combine ____ with Hb
reversibly

combine at sites other than O2 binding sites
-changes the structure of Hb that reduces affinity for O2
Most CO2 is transported as
bicarbonate ion (HCO3-)
CO2 combines with H2O to form ____ facilitated by _____
carbonic acid; carbonic anhydrase
bicarbonate reaction
CO2 + H2O <-> H2CO3 <-> H+ + HCO3-
bicarbonate reaction favored at the
tissue cells
reverse of bicarbonate reaction occurs in
lungs

-bicarb ions forming free molecules of CO2
_____ and ____ accumulate in RBCs
HCO3- and H+
HCO3- diffuses ____ cell and Cl- diffuses _____ cell
out of; into

chloride shift
Haldane effect
unloading of O2 facilitates Hb pickup of CO2 and H+
Bicarbonate moves by ______ down its gradient out the RBC into the _____
facilitated diffusion; plasma
Increased ventilation results in (3)
1. CO2 exhalation
2. reduces PO2
3. reduces H+

increases pH
decreased ventilation results in (3)
1. build up of CO2
2. increases PO2
3. increases H+ ions (ph decrease)
hypercapnia
excessive carbon dioxide in the blood

-hypoventilation
hypocapnia
low PCO2 in blood

hyperventilation
resting expiration is
passive
apneustic center
prolongs inspiration
pneumotaxic center
limits inspiration
pneumotaxic enter sends impulses to
dorsal respiratory group that help SWITCH off inspiratory neurons

allows for expiration to occur naturally
pneumotaxic center dominates over
apneustic center
apneustic center prevents
inspiratory neurons from being SWITCHED OFF
-extra boost to inspiratory drive
peripheral chemoreceptors stimulated when O2 falls below
60 mmHg
PCO2 arterial change directly related to
ventilation
H+ stimulates
central chemoreceptors
elevated Co2 -> increase in
ECF H+ -> activates central chemoreceptors -> increase in ventilation
Students also viewed