Unit 5 Respiration Flashcards
What is the functions of respiration
- gas exchange
- control of pH
- olfactory receptors
- filtration of air
- regulation of heat + H20
- Sound production
Aerobic metabolism
02 + glucose -> co2 and energy
diffusion
- high to low concentration
- passive
- sufficient for organism
Graham’s Law
diffusion rate is inversly porportional to the square root of Molecular weight
-o2 and co2 diffuse at similar rates
Fick’s Law
rate of diffusion = change in P * A * D / change in X
p= gas gradient, partial pressure between two compartments
a= surface area for gas exchange
D= diffusion coefficient (depends on the MW and permeability of the barrier
change in X = the distance the gas must travel
Gas Laws
PV= nRK
Dalton’s Law of Partial Pressure
- the partial pressure of a substance in independent of the gases around it
- total pressure = sum of all the partial pressures
Bunsen Solubility coeffieceint
- varies with gas, temperature, and liquid
- O2 solubility decreased with increasing temp and ionic strength
Air
- gases are more soluble
- energy must be expended on ventilation
- in and out ventilation
- ventilation is keyed to CO2
H20
- gases are less soluable
- CO2 is more soluable than O2
- CO2 diffusion is more effective than O2
- Easy CO2 diffusion
- Flow through ventilation
- Ventilation is keyed to O2
H20 vs Air (O2 solubility, density, viscosity, heat capacity)
O2 1/30 in h20 : 1 Air
density 800 H20 : 1 Air
Viscosity 50 H20 : 1 Air
Heat Capacity 3000: 1 Air
Nature of the respiratory epithelial
- large SA an small distance
- lung SA = 50 -100 m2 , Body SA = 2 m2
4 Steps of Gas transfer
- Ventilation/ Breathing movement
- Diffusion of gases across the respiratory epithelium
- Bulk transfer/ transport of gases in the blood
- Diffusion of gases between blood and cells
Henry’s Law
quantity of dissolved gas (Q)=alpha * P
alpha= solubility coefficient
P= partial pressure
Respiratory Pigments
- enhances bloods capability to carry 02
- vertebrates = hemoglobin and myoglobin
- other respiratory pigments = hemocyanin, hemerythrin, chlrocurin
- antarctic fish lack respiratory pigments - instead they increase blood volume and cardiac output
P50
pO2 when Hb is 50% saturated - high P50 = low O2 affinity
Bohr effect
- reduced O2 affinity resuting from decrease pH and/or increased CO2
- Bohr coefficient change in log P50/ change in pH
- tissues - increased CO2= right shift = more O2 unloaded
- lungs - increased CO2 = left shift = increase CO2 loading
temperature effect on Oxygen and CO2 levels
- increased temp= right shift = more O2 unloaded
- ectotherms = increased temp = increased metabolic rate but decreased O2 loading and solubility
Organic Phosphates
increased organoposphates = right shift
decreased organophosphates = left shift
mammals = 2,3 diphosphoglycerates (DPG) increases with decreased O2
Developmental hemoglobin
-fetal hemoglobin has a left shift - higher O2 affinity
Sickle Cell Anemia
Affects the beta-chain of human hemoglobin and causes bemoglobin polymer formation (distorts erythrocytes)
Three forms of Carbon Dioxide transport in the Blood
- physical transport - molecular CO2
- Carbamino CO2: protien-NH2 + CO2 into H+ + protein-NCOO-
only beta-globin chains in fish and amphibians have terminal -NH2 avialable - HCO- ions
Transfer of Gases at tissues
CO2 enters / leaves blood as molecular CO2
carbonic anhydrase: Catalyzes CO2 conversion to HCO3- within blood cells
chloride shift; RBC permeable to HCO3- and Cl- via Band III protien
Lamprey and hagfish transfer of gases in tissues
lack band III: CO2 transport primarily as HCO3- in rbc
Transfer of gases at tissues
Haldane effect: deoxy-Hb has a higher affinity for H+
than oxy-Hb
i. Deoxygenated blood has a higher CO2 content (at a given PCO2) than
oxygenated blood
ii. Oxygenation of Hb releases H+ (lowers pH of cell interior in lungs to
balance CO2 decrease )
iii. Deoxygenation of Hb bin
Cutaneous blood vessels
absorb O2 by diffusion across the skin
Max arterial p O2
Problems with Cutaneous Respiration
- limited SA - limits size and metabolism
- vulnerable to abrasion and dessicaiton
lung development
-develops as the diverticula of the gur
lung complexity and oxygen uptake
-complexity varies from amphibians- reptiles-mammals - Critical factor is the surface area
Oxygen uptake is highter per unit body weight in small mammals and children
Respiratory and non-respiratory regions
trachea, bronchus and bronchiole, alveolus, alveolar sac
Mammalian Model of gas exchange
ciculated, pool-type gas exchange mechanism
PaO2
Lung anatomy: Birds
small compact lung with thin-walled air sacs, Lung volume ~50% of mammalian; respiratory vol. 3X mammalian
- small diffusion distance (o.1 um)
- little change in lung volume
- unidirectional
- air sacs are like bellows
- volume changes by movement of sternum and ribs
- 2 respiratory cycles
Avian Model of Gas exchange
- air flow= posterior to anterior
- cross current arrangement pa02 > peO2
- high altitude tolerance
Lung anatomy: Reptiles
- thoracic cage: ribs, no diaphragm
- passive exhalation
- turtles/ tortoises: ribs fused to rigid shell- Outward movement of limbs, ventral shell
Lung Anatomy: Frogs
Air through the nares into the buccal cavity through the glottis to the lungs
-raising and lowering the buccal floor: multiple inhalations possible, incomplete exhalations (reduce CO2 oscillations?)
Pulmonary Circulation
- divided systems: equal cardiac output, lowwer pressure in pulmonary than systemic
- control mechanisms: local decrease in PO2 or pH causes vasoconstriction, only minor response to neural control or drugs
Pulmonary Circulation Distribution
flow rate parameters: Pa (arteriol), Pv (venous), PA (alveolar)
-variation in vertical lung
Breathing Jargon
look at these terms
Human Pulmonary Values
Anatomical dead space ~150 ml
Tidal volume (VolT): ~500 ml (10% lung vol)
Alveolar ventilation volume (VolA)~350 ml
Residual volume ~2000 ml
Breathing rate (BR) 10-15 X/min
Sufactans
mammals, birds, reptiles, and amphibians
-surfactans can be lipoprotein complexes, lower surface tension, reduced breathing effort, prevent alveolar collapse, reduce breathing effort, prevent alveolar collapse
head and water loss in the lungs
inspired air- warmed and humidified in lungs
- nasal passages control heat and water loss
- water condenses in nose during exhalation
Poikilotherms and head +water loss
-less O2 required, less ventilation, less water and heat loss
Gills
evagination- intenal or extenal- extensive folding
high ventilation rate in comparison with air
Gills- flow of Air
- bills between buccal and opercular chambers
- buccal and opercular pumps
- unidirectional and nearly continuous water flow
- ram ventilation
Gill anatomy for Teleosts
- 4 gill arches/side
- 2 rows of filaments/arch
- many lamellae/ filament
- covered by mucous layer
gill anatomy- lamellae
- sieve
- highly collagenous
- respiratory surface
- blood flow opposite water flow
Lamellar structure;
- 2 epithelial sheets
- pillar cells
- sheet flow
diffusion barrier
-mucous layer, respiratory epithelium, blood (5 um)
Concurrent vs. counter-current exchange
review graphs on slides
Ventilation to perfusion rations
Va (rate of ventilation) / Q (rate of perfusion
Neural Regulation of Respiration
2 aspects: pattern, rhythm
