Chapter 42.7 Flashcards
what does the metabolic demands of many organisms require
that the blood transort large quantities of O2 and CO2
Blood arriving in the lungs has a…
low partial pressure of O2 and a high partial pressure of CO2 relative to air in the alveoli
what happens in the alveoli
O2 diffuses into the blood and CO2 diffuses into the air
what happens in tissue capillaries
partial pressure gradients favor diffusion of O2 into the interstitial fluids and CO2 into the blood
respiratory pigments
proteins that transport oxygen
what do respiratory pigments greatly increase
the amount of oxygen that blood can carry
What do arthropods and many molluscs have
hemocyanin with copper as the oxygen-binding component
What do most vertebrates and some invertebrates use
hemoglobin
what is hemoglobin contained within in vertebrates
erythrocytes
What can a single hemoglobin molecule carry
for molecules of O2 (one molecule for each iron-containing heme group)
What does the hemoglobin dissociation curve show?
that a small change in the partial pressure of oxygen can result in a large change in delivery of O2
What does CO2 produced during cellular respiration lower and decrease
blood pH; the affinity of hemoglobin for O2
What is the lowering of blood pH and decrease of the affinity of hemoglobin for O2 called
the Bohr shift
What does hemoglobin play a minor role in
the transport of CO2 and assistance in buffering the blood
What percent of CO2 from respiring cells diffuses into the blood and is transported in blood plasma
7%
what happens to the remainder of the CO2
it diffuses into erythrocytes and reacts with water to form H2CO3
H2CO3
dissociates into H+ and bicarbonate ions (HCO2-)
What occurs in the lungs
the relative partial pressures of CO2 favor the net diffusion of CO2 out of the blood
What adaptations do diving mammals have
evolutionary adaptations that allow them to perform extraordinary feats
What is the blood to body volume ratio of diving mammals
high
What do deep-diving air breathers stockpile and deplete slowly
O2
what can diving mammals store and where
oxygen; muscles in myoglobin proteins
How else do diving mammals conserve oxygen
- changing their buoyancy to glide passively
- decreasing blood supply to muscles
- deriving ATP in muscles from fermentation once oxygen is depleted
