Ch. 13 Part 1 (Book) Flashcards
there is a lot of free O2 in the air, but in water…
only a small amount is dissolved
a lot of CO2 is dissolved though
2 ways O2 is transferred btw atmosphere and water
turbulence
diffusion
does the solubility of O2 in water decrease as temp and salinity increase?
yes
O2 is added to water as __________ is carried out by aquatic plants and algae
photosynthesis
how are O2 and CO2 transferred across the body surface
by diffusion
high surface area to volume ratio and low distrance traveled is good
respiratory epithelium
specialized respiratory surface made of thin cells
_________ systems have evolved to transfer O2 and CO2 via blood flowing betwen the respiratory epithelium and tissues
circulatory
how does the circulatory system work in relation to gas exchange
blood passes through a capillary network in a thin film beneath the gas-exchange surface
minimizes distance gases have to diffuse through
maximizes surface area
4 basic steps of gas exchange
beathing - supplies the lungs/gills
diffusion of O2/CO2 across respiratory epithelium
bulk transport of gases by blood
diffusion of O2/CO2 across capillary walls in tissue
hemoglobin
respiratory pigment that binds O2
increases carrying capacity of blood
antarctic icefish
has no respiratory pigment and low O2 content
compensates with a high blood volume and cardiac output
structure of hemoglobin
4 iron-containing heme groups
globin tetrametic protein
2 aB dimers
positive cooperativity in hemoglobin
binding of 1 O2 makes binding of other O2s easier
O2 bound = oxyhemoglobin
O2 unbound = deoxyhemoglobin
myoglobin
respiratory pigment in muscle
high O2 affinity = not good at releasing –> hyperbolic curve
is affinity of hemoglobin for carbon monoxide higher than affinity for O2?
yes, 200x higher
carboxyhemoglobin
features of hemoglobin O2 transport in blood
at low pO2, low O2 is bound to hemoglobin
at high pO2, a lot of O2 is bound to hemoglobin
sigmoidal curve from pos. cooperativity
high pO2 in lungs = a lot of bound O2 –> low pO2 in muscle = release of O2 into muscle
sickle cell anemia
sickle shaped RBC can’t pass through capillaries
impaired O2 delivery
malaria resistance
Bohr effect
low blood pH makes hemoglobin O2 affinity lower
release more O2 into tissues
what other states lower hemoglobin O2 affinity
high temp
high CO2
hemoglobin binding DPG
at high altitude what happens to O2 in the air
there is less O2 –> low blood O2 levels
what does a low blood O2 level stimulate in humans
more breathing
higher DPG levels
do hemoglobins change during development?
yes, fetal hb binds O2 more tightly to facilitate transfer of O2 from mother to fetus
has gamma chains instead of beta chains
CO2 diffuses into the _______ from the ________
blood, tissues
from the blood, CO2 _______ across the respiratory surface and is…
diffuses, deposited into the environment
CO2 + H2O –>
CO2+ H2O –> H2CO3 –> H+ + HCO3- –> CO32- + H+
CO2 to carbonic acid to bicarbonate to carbonate ions
CO2 + OH- –>
CO2 + OH- –> HCO3-
__________ is the predominant form of CO2 in the blood at normal pH
bicarbonate
carbamino compounds
protein-NH2 + CO2 –> H+ + protein-NHCOO-
does CO2 enter and leave the blood as CO2 or HCO3-
CO2 b/c it diffuses through membranes much faster than HCO3- ions
carbonic anhydrase
enzyme that catalyzes CO2 + OH- –> HCO3-
most CO2 entering and leaving the plasma….
done by RBC b/c they have carbonic anhydrase
chloride shift
when HCO3- ions leave RBC, Cl- ions enter the RBC via band III protein to maintain ion balance
Haldane effect
deoxygenation of Hb in tissues reduces pH as Co2 enters the blood
where is carbonic anhydrase in the lungs
in the endothelial cell membranes
so HCO3- can be converted to CO2 fast as blood perfuses the lung capillaries
