respiratory system gas transport Flashcards
in oxygen transport, what % is bound to-
hemoglobin:
dissolved in plasma:
does oxygen have high or low solubility compared to CO2
98.5
1.5
low
how many mL of oxygen is transported in arterial blood per L
200 mL
hemoglobin-
what are the proteins on hemoglobin called and how many are there
each globin has a heme group, binds one O2 to an ____ atom
what is an O2 bound to hemoglobin
what is hemoglobin with no O2 where the Hb serves as a buffer for H+
globins; 4
iron
oxyhemoglobin
deoxyhemoglobin
how many O2s can one hemoglobin carry
what is the saturation of Hb with 4 O2s per Hb
what about with 2 O2s
4
100%
50%
oxyhemoglobins disassociation curve:
why is it S shaped
what are the percentages
oxygen increases as PO2 increases until max capacity, and after that it levels off with about 22% till 100% saturation
what are the 3 ways that carbon dioxide is transported (with %s)
gas dissolved in plasma - 5%
carbonic acid - 90%
carbamino (carbaminohemoglobin) - 5%
how does the carbonic acid reaction occur within blood plasma
how does it occur in red blood cells
what causes this change is rates?
slowly
quickly
enzyme catalyses the reaction (carbonic anhydrase)
are the relative amounts of CO2 exchanged from the blood to the alveolar air different from the relative amounts transported in blood
yes
blood ___ ___ the dissolved CO2 gas and CO2 from the ____ ____ more easily than CO2 from bicarbonate carbonic acid
gives up
carbamino compounds
most exchanged CO2 comes from carbonic acid, but it is not the full % present in the blood. How much is present in the blood from this method of exchange?
70%
does more exchanged CO2 come from carb amino compounds than is in blood?
what is the % associated with this
yes
23
is there more gaseous CO2 delivered to the alveoli than is present in blood?
what is the % associated with this
yes
7%
for alveolar (external respiration):
what is the PO2
what is the PCO2
104 mm Hg
40 mm Hg
for systemic (internal) respiration, what is the
PO2
PCO2
40 mm Hg
46 mm Hg
for the antiport on hemoglobin:
what is going in
what is coming out
Cl -
HCO3 - (bicarbonate)
when CO2 is diffused into a blood cell, what happens to the H (after the RBC undergoes a reaction and H is a product)
it gets used as a reactant for O2 to be diffused from the RBC to tissues
what is in between the capillary blood and alveolar air (that gas molecules have to cross)
respiratory membrane
what is the abbreviation for hemoglobin
what is the abbreviation for deoxyhemohlobin
Hb
HHb
what does hemoglobin adjust to when unloading O2
metabolic needs
what are the 4 factors of the rate of oxygen unloading to need
ambient PO2
ambient pH
temperature
bisphosphoglycerate
does active tissue have high or low PO2
what happens during activity
low
O2 released from Hb
what is the ambient pH affecting O2 unload called
does active tissue have high or low amounts of CO2 (is this acid or base)
does the Bohr effect raise or lower the pH of blood (describing the relationship)
what does it promote
Bohr affect
high; acid (lowers pH)
lowers
O2 unloading
what happens when blood pH is lower than 7.35
what happens when blood pH is high than 7.45
acidosis
alkalosis
the lower the pH, Hb’s affinity for O2 ____, which causes _____
decreases
offloading
does high or low temperature promote O2 unloading
high
what happens when bisphorsphoglycerate (BPG) binds to Hb
this is released when:
body temp is ____
when 4 hormones are released
O2 is unloaded
high
thyroxine, growth hormone, testosterone, epinephrine
as body temp increases, Hb’s affinity for oxygen _______, and it promotes _____
decreases
unloading
what types of altitudes promote O2 unloading
high
a left shift is associated with:
a right shift is associated with:
(in regards to hemoglobin and O2 offloading)
lower offloading
higher offloading
what is the nemonic for oxygen offloading
ACE BATS RIGHT HANDED
Acid
pCo2
Exercise
Bpg
Altitude
Temp
what is the ideal:
blood pH
PCO2
PO2
7.35-7.45
40
95
where do brainstem respiratory centers receive input from that monitor composition of CSF and blood
central and peripheral chemoreceptors
what its the most potent stimulus for breathing
what is the second most potent
pH
Co2
pulmonary ventilation is adjusted to maintain _____ of the brain
pH
central chemoreceptors in what part of the brain produce about 75% of the range in respiration induced by a pH shift
what forms when CO2 crosses BBB and reacts with water in CSF
what strongly stimulates central chemoreceptors since CSF foist contain much buffer
medulla
carbonic acid
H+ from the carbonic acid
what ions stimulate peripheral chemoreceptors
what % of the respiratory response to pH are these receptors responsible for
hydrogen
25%
what is PCO2 during hypocapnia
it is the most common cause of ______
less than 37
alkalosis
what is the PCO2 for hypercapnia
most common cause of _____
greater than 43
acidosis
what is a corrective homeostatic response to acidosis
hyperventilation
what is a corrective homeostatic response to alkalosis
hypoventilation
PO2 usually has little effect on respiration at ____ elevations except for:
-if arterial PO2 is less than ___. heavy breathing is stimulated.
what sense that?
-respiration is driven more by low PO2 than by ___
what is this called?
can occur in what 2 diseases
what elevation
low
chromic hypoxemia
60
carotid bodies
pH
hypoxic drive
emphysema, pneumonia
high elevations
where does the brain signal to in addition to skeletal muscles during exercise
why do they increase pulmonary ventilation before exercising the muscles
respiratory centers
anticipation
what type of receptors does exercise stimulate in muscles and joints
when this happens, where are excitatory signals sent to
breathing is increased ____ to the demand or need for more O2
increase in pulmonary ventilation keep levels ____ during exercise
propioreceptors
respiratory center in brain stem
prior
normal
what is the deficiency of oxygen or the inability to use oxygen
it is a _____ of respiratory diseases
hypoxia
consequence
what is a state of low arterial PO2
what is this usually due to
hypoxemia hypoxia
inadequate pulmonary gas exchange
what is the inadequate circulation of blood
what is this due to
ischemic hypoxia
congestive heart failure
what is the inability of blood to carry adequate oxygen
anemia hypoxia
what is when metabolic poisons prevent O2 use in tissue
histotoxic hypoxia
what is hypoxia often marked by
blueness of skin
what happens when pure O2 is breathed at 2.5 atm or greater
what does this generate (2)
what does it destroy
what does it damage
oxygen toxicity
free radicals and hydrogen peroxide
enzymes
nervous tissue
