lecture 19: c02 transport in blood Flashcards
As O2 is used for cellular metabolism what is formed
•
CO2 is formed
explain diffusion of CO2 from peripheral tissues to caps to alveoli
- As O2 is used for cellular metabolism, CO2 is formed
- intracellular PCO2 ¢ pressure gradient between cells and interstitial fluid ¢ CO2 diffusion from cells into interstitial fluid
- interstitial fluid PCO2 ¢ pressure gradient between
interstitial fluid and tissue capillaries ¢ diffusion of CO2 into capillaries - CO2 is then carried by the blood to the lungs
- PCO2 is higher in pulmonary capillaries than in alveoli (pressure gradient) CO2 diffuses from capillaries into alveoli where it gets expired
as intracellular PCO2 increase during to 02 being used for cellular metabolism, what is the pressure relationship and what does that means
increase PCO2
=pressure gradient b/w cells and interstitial fluid
=co2 diffusion from cells to interstitial fluid
as interstitial fluid PCO2 increases what is the pressure relationship between interstitial fluid and capillaries and what does that mean
interstitial fluid PCO2
pressure gradient between interstitial fluid and tissue capillaries
diffusion of CO2 into capillaries
true or false: PCO2 is higher in pulmonary capillaries than in alveoli?
true
since PCO2 is higher in pulmonary capillaries than in alveoli, what is the movement of CO2
PCO2 is higher in pulmonary capillaries than in alveoli
(pressure gradient) CO2 diffuses from capillaries into
alveoli where it gets expired
in each point of the gas transport chain, co2 moves diffuses in THE SAME direction or OPPOSITE direction as o2
opposite
besides the direction of diffusion between o2 and co2, what is the main difference in terms of diffusion
c02 can diffuse 24x faster than 02
what diffused faster : c02 or o2
co2
pressure gradients required to cause CO2
diffusion is much LOWER or HIGHER than the gradients required for O2 diffusion
lower
are pressure gradients required to cause CO2
diffusion or o2 diffusion higher in 02 or co2
02
explain how co2 can move from inside a tissue cell to the tissue interstitial fluid even if there is only a difference in partial pressures of 1 mmHg
c02 has a much higher solubility which means it is easier to push CO2 through the membrane which means you need a much lower partial pressure/pressure gradient to move CO2
what is the effect of blood flow on c02 pressure in interstitial fluid
if there is decreased blood flow
=decrease co2 transport away from tissue
=increased pCO2
what is the affect of tissue metabolic rate on c02 pressure in interstitial fluid
increased tissue metabolic rate
=more c02 production
-increased PCO2
what are the 3 forms of co2 transport in the blood
dissolved in plasma in the form of bicarbonate ion
bound with hb and plasma proteins in RBC
true or false; CO2 Dissolved in plasma Accounts for a MAJOR part of total CO2 transported by blood to lungs
false, only minor part of transport
how is the main way carbon dioxide is transported
in the form of bicarbonate ion
explain how co2 is transported in the form of bicarbonate ion
CO2 reacts with H2O (catalyzed by carbonic anhydrase) to form H2CO3 (carbonic acid) _ H2CO3 then dissociates into HCO3- (bicarbonate) and H+
true or false: you can only have oxygen on the hemoglobin molecule
false, you can also have c02
explain co2 transport by HB and plasma proteins
CO2 reacts with amine radicals of Hb molecules to form
carbaminohemoglobin (CO2Hgb)
the partial pressure of co2 is determined by what
the amount of co2 dissolved in plasma
combination of co2 and hb is loose and reversible or non reversible
reversible
what is the bond of co2 on hb determined by
Bond depends on PCO2, so CO2 is easily released into
alveoli since PACO2 is lower than in pulmonary capillaries
is more co2 transported on Hb or plasma proteins and why
Small amount of CO2 also reacts with plasma proteins
● Much less significant form of transport than bound to Hb
because the quantity of these proteins in blood is ¼ that of Hb
what is the Quantity of CO2 that can be carried from tissues to the lung via carbamino combination with Hb and plasma proteins:
– ~30% of total quantity of CO2 transported @ 15 ml/100 ml blood
what is the Haldane affect
The Haldane effect describes the shift in the CO2 dissociation curve caused by the oxygenation of Hb
=binding between hemo and c02 is affected by o2 pressure
As blood passes through the lungs, PO2 increases and O2
binds with Hb Hb becomes a stronger acid
● The increased acidity due to O2 binding to Hb causes the
following two effects:
what are the 2 effects?
CO2 attached to Hb (carbaminohemoglobin) is displaced, and free
CO2 diffuses through the pulmonary capillary membrane into alveoli
– Also promotes H+ dissociation from Hb = excess H+ binds with
the bicarbonate ion HCO3- to form carbonic acid H2CO3
= H2CO3 dissociates into H2O and CO2
= CO2 is released from the blood into
alveoli and, finally, into the air
ADD SLIDES 14-17
what does RER reflect
– Reflects % aerobic vs. % anaerobic metabolism
– Also reflects % substrate utilization
what is the RER equation
R=rate of c02 output/rate of o2 uptake
RER=VCO2/VO2
RER= (V-A)CO2 diff/(A-V)O2 difference
EXCHANGE OF GASES BETWEEN THE AIR AND BLOOD IS __________________ AND THE EXCHANGE OF GASES BETWEEN BLOOD AND TISSUE FLUID IS _____________
external respiration ; internal respiration
IDENTIFY THE FUNCTION OF THE MUCOUS MEMBRANE LINING RESPIRATORY AIRWAYS
CLEAN, WARM AND MOISTEN AIR
THE SEROUS MEMBRANE ADHERING TO THE SURFACE OF THE LUNGS IS THE ______ AND THE SEROUS MEMBRANE THAT LINE STHE THORACIC CAVITY IS THGE __________
VISCERAL PLEURA ; PARIETAL PLEURA
DURING INSPIRATION, AIR FLOWS INTO THE LUNGS BECAUSE ATMOSPHERIC PRESSURE IS
GREATER THAN INTRAPULMONARY PRESSURE
IN ORDER TO SING OR BLOW OUT BIRTHDAY CANDLES, CONTRACTION OF THE _________ MUSCLES ARE NEEDED.
INTERNAL INTERCOSTALS
A DECREASE IN pH or ________ can occur when one ________
acidosis; hypoventilates
which of the following statements is/are true?
a. according to fick’s law of diffusion, an increase in the surface area for gas exchange would increase the rate of pulmonary diffusive O2 flux.
b. an increase in physiologic deadspace would increase alveolar ventilation by increasing dead space ventilation when breathing at any given respiratory rate.
c. according to fick’s law of diffusion, an increase in the thickness of the alveolar pulmonary capillary membrane would decrease the rate if pulmonary diffusive O2 flux.
d Both A and C are true
E a,b,c are all true
D. Both A and C are true.
