Chapter 1/2/3 (Gas Exchange and Gas Transport) Flashcards
Describe the difference between adaptation, acclimatization, and acclimation.
- adaptation: genetic modifications in response to change in external environment, long term
- acclimatization: behavioural modifications in response to change in external environment, short term
- acclimation: behavioural change that occurs in a controlled environment
Fick’s first and second laws
- Fick’s first law: solute moves from high to low concentration
- Fick’s second law: amount that diffuses is proportional to surface area and inversely proportional to diffusion distance
external respiration
exchange of oxygen and carbon dioxide between external environment and internal animal
ventilation vs perfusion
- ventilation: movement of respiratory medium across respiratory surface (oxygen to respiratory tissue)
- perfusion: delivery of oxygen to tissues by blood (blood that reaches alveoli via capillaries)
internal respiration (mitochondrial respiration)
use of oxygen to make energy
Henry’s law
amount of gas dissolved in liquid depends on partial pressure of gas and solubility of liquid
Graham’s law
- diffusion rate is proportional to solubility but inversely proportional to root of molecular weight
- increased solubility increases diffusion rate
- increased molecular weight decreases diffusion rate
Boyle’s law
gases move from high to low pressure
nondirectional ventilation
- medium flows past respiratory surface in an unpredictable pattern
- e.g. sponges
tidal ventilation
- medium flows in and out of respiratory chamber (back and forth)
unidirectional ventilation
- medium enters respiratory chamber one way and exits through another
- flow is in a single direction across respiratory surface
(can be concurrent, countercurrent or crosscurrent)
concurrent vs. countercurrent vs. crosscurrent flow
- concurrent flow: same direction
- countercurrent flow: opposite directions
- crosscurrent flow: at an angle
Explain the buccal-occular pump used by teleost fish.
- mouth opens; buccal cavity expanded; opercular valve closed; opercular cavity expands
- mouth closed; buccal cavity compressed; opercular valve closed; opercular cavity expanded
- mouth closed; buccal cavity compressed; opercular valve open; opercular cavity compressing
- mouth open; buccal cavity expands; opercular valve open; opercular cavity compressed (some backflow)
[flow is unidirectional; negative pressure created inside buccal cavity]
Explain the ventilatory cycle in air-breathing fish.
- mouth opens; buccal cavity expands; air enters buccal cavity
- mouth closes; buccal cavity compresses; air enters anterior chamber
- mouth closed; anterior chamber closed; posterior chamber contracts and used air is exhaled from posterior chamber, exiting via operculum
- mouth closed; anterior chamber opens and contracts; fresh air flows into posterior chamber; gas exchange occurs
Explain the ventilatory cycle in a frog.
- air enters pocket of buccal cavity through open nares
- glottis opens; elastic recoil of lungs and compression of chest wall reduces lung volume; air forced out through nares
- nares close; buccal cavity floor rises and air is pushed into lungs
- glottis closes; gas exchange occurs in the lungs
book lungs
- found in chelicerates (tarantula)
- thin plates called lamellae
- oxygen from air diffuses across lamellae into hemolymph
- spiracles are openings in the shell/cuticle that lead to tracheal system
muscles used to change thoracic cavity volume and operate suction pumps in lizards vs. chelonians (turtles) vs. crocodilians
- lizards: intercostal muscles
- chelonians: abdominal muscles
- crocodilians: diaphragm
Explain the ventilatory cycle in birds.
- chest expands; first inhalation brings fresh air into posterior air sacs
- chest compresses; first exhalation pushes fresh air from posterior air sacs to lungs
- chest expands; second inhalation pushes stale air from lungs to anterior air sacs
- chest compresses; second exhalation pushes stale air from anterior air sacs out
Define the different patterns of ventilation: eupnea, apnea, hypernea, tachypnea, dyspnea, hyperventilation and hypoventilation
- eupnea: normal breathing
- apnea: no breathing
- hypernea: increased ventilation frequency or volume (increase in metabolism/exercise)
- tachypnea: increase ventilation frequency/rate with decrease in ventilatory volume (panting)
- dyspnea: difficult, laboured and uncomfortable
- hyperventilation: increased ventilation in excess of metabolic needs
- hypoventilation: decreased ventilation
respiratory pigment
- metalloproteins that circulate in bodily fluids and undergo reversible chemical combination with oxygen
- respiratory pigments in RBCs is hemoglobin
oxyhemoglobin vs deoxyhemoglobin vs carbaminohemoglobin
- oxyhemoglobin: heme bound to O2
- deoxyhemoglobin: heme not bound to O2 (after O2 dissociates)
- carbaminohemoglobin: when CO2 binds to globin
methemoglobin reductase
- converts ferric (Fe3+) back to normal ferrous (Fe2+) in order to bind to more O2
Why is the shape of the O2/Hb saturation curve a sigmoid shape?
cooperative binding: binding of O2 facilitates binding of more O2
effect of pH on Hb-O2 affinity (Bohr effect and Root effect)
- decrease pH = increase PCO2 = decrease Hb-O2 affinity = curve shifts right
- Bohr effect: looks at only Hb-O2 relationship; no change in saturation
- Root effect: decrease pH causes Bohr effect AND decreases O2 carrying capacity of Hb (more exaggerated shift)
effect of organic modulators (2,3-DPG) on Hb-O2 affinity
- increased 2,3-DPG decreases Hb-O2 affinity to increase O2 delivery
- increased organic modulators = increased metabolic rate so higher oxygen demand
effect of temperature on Hb-O2 affinity
- higher temp = higher metabolic rate = higher oxygen demand
- Hb-O2 affinity decreases to increase O2 delivery
Haldane effect
- relationship between CO2 and Hb (with effect of O2)
- CO2 saturation in deoxygenation blood higher than oxygenated blood
carbonic anhydrase
catalyzes conversion of CO2 + H2O to H2CO3
