respiration 5 Flashcards
lung compliance and elastance
- compliance is how easily the lungs stretch during inhalation
- elastance is ease of returning to shape on exhalation
surfactants
- surface tension in alveolar fluid lowers compliance
- reduces surface tension by disrupting cohesive forces between water molecules
resistance increases/decreases with…
increases with length and viscosity
descreases with radius
airway resistance and diameter
as diameter increases, resistance decreases, and vice versa
- higher resistance requires more work/energy
- diameter is affect by nervous system , hormones, and paracrine messengers
bronchoconstriction
caused by parasympathetic nerve stimulation and histamine
bronchodilation
caused by sympathetic nerve stim, epinephrine, high CO2, and corticosteroids
dead space
air that does not participate in gas exchange
anatomical: volume of trachea and bronchi
alveolar: volume of alveoli that is not perfused
tidal volume
volume of air moved in one normal ventilatory cycle
alveolar ventilation
volume of air that enters alveoli with each resp cycle
aka VA=VT-VD
inspired reserve volume (IRV)
max inspiration beyond normal tidal volume
inspiratory capacity (IC)
VT plus IRV
expired reserve volume (ERV)
max expiration beyond normal tidal volume
vital capacity VC
VT+IRV+ERV
residual volume RV
never expired or measured
total lung capacity TLC
Vt+IRV+ERV+RV or VC+RV
ventilation-perfusion matching
efficient gas exchange at resp surface requires match of vent and blood flow, at a ratio of Va/Q; alveolar ventilation vs rate of flow
-arterioles dilate or constrict to distribute blood to well ventilated alveoli
O2 transport, Metalloproteins
- respiratory pigments used to increase oxygen carrying capacity by up to 50x
- proteins contain metal ions which reversibly bind to oxygen
- at tissue surface low PO2 in blood causes release of O2 down its gradient
metalloproteins
3 types: hemoglobins, hemocyanins, and hemerythrins
hemoglobins
- globin protein bound to heme molecule that contains iron
- usually within blood cells
- appear red when oxygenated
- myoglobin is type of hemoglobin found in muscles
- found in vertebrates, nematodes, crustaceans, and insects
hemocyanins
- found in arthropods and molluscs
- contain COPPER, not heme
- dissolved in hemolymph and appears blue when oxygenated
hemerythrins
found in brachiopods and some annelids
- contains iron directly bound to protein, no heme involved
- ususaly inside coleomic cells or muscle cells
- appears violet-pink when oxygented
oxygen loading
amount of oxygen stored on hemoglobin determind via:
- amount of pressure oxygen can bring to bear on the system/how much O2 is being loaded=PO22 of the plasma
- the affinity/ability of the carrier (hemoglobin) to carry O2=Hb=oxygen affinity of hemoglobin
oxygen loading and PO2 of envrionment/plasma
high PO2 favours loading, low favours unloading
oxygen loading and Hb affinity
high affinity favours loading, low affinity favours unloading
hyperbolic oxygen equilibrium graphs
found in myoglobin because each oxygen binds independently
sigmoidal oxygen equil graphs
sigmoidal because of cooperativity; hemoglobin has a higher affinity for oxygen since more oxygen bind to its heme
factors that affect hb affinity
pH, pCO2, aka the bohr and root effects
-temperature effect and organic modulators
bohr effect
higher pH, fewer H+, minimal CO2, and O2 its taken up more easily at resp surface
- low pH lots of H+ and CO2 allows O2 more easily released at tissues
- bohr effect is a decreased affinity due to increased CO2
root effect
increased H+/decreased pH decreases affinity
temperature shift
higher temp indicates more active tissues, thus O2 affinity must decrease to move more O2 to tissues
organic modulators
act as allosteric regulators, they affect the function of a protein by binding to the non-active sties
-can be activators or inhibitors
-important in control loops
ie 2,3-DPG in mammals and reptiles lowers Hb affinity
