gas exchange/respiration Flashcards
what are the general steps for gas exchange?
1) ventilation
2) diffusion at respiratory surface
3) circulation of blood
4) diffusion at tissues
5) cellular respiration
what two respiratory options do fish have and what are their features?
open ventilation: moving water through gills by opening + closing mouth and operculum
ram ventilation: moving water through gills by swimming fast
what is the structure of a fish gill?
hundreds of gill filaments each comprised of lamellae
what two things do countercurrent exchange accomplish in a fish?
- establishes a partial pressure gradient between blood and water in the lamellae
- establishes a partial pressure difference from the beginning to end of respiration system
what happens to the diaphragm during inhalation and exhalation?
inhalation: diaphragm drops, negative pressure is established, volume increases as air enters
exhalation: diaphragm relaxes, volume decreases and pushes air out
what part of the brain regulates breathing?
medullary respiratory system (medulla)
what reaction happens when exercising?
- CO2 reacts with water and cerebrospinal fluid to form carbonic acid
- carbonic acid dissociates into protons and bicarbonate
- pH drops and neurons signal medulla to increase respiration for more oxygen
what does blood do?
- transports O2/CO2
- transports nutrients from digestive system to cells
- moves waste to kidneys and liver
- delivers hormones to targets
- delivers immune cells
- distributes heat
what is the structure of a red blood cell?
- one hemoglobin per cell
- four iron molecules on each hemoglobin
- can bind to 4 O2 molecules total
define cooperative binding
binding of one oxygen to hemoglobin causes a conformation change that triggers binding of subsequent oxygens
what is the bohr shift?
tendency for hemoglobin to release O2 when:
1) Pco2 is high
2) pH is low
3) temperatues are high
4) tissues are under oxygen stress
explain the blood relationship between a fetus and its mother
- O2 affinity in fetus blood»_space; O2 affinity in mother’s blood
- O2 moved from mother to fetus
what is the role of carbonic anhydrase in the bloodstream?
- catalyzes conversion of CO2 and water to carbonic acid
- causes bohr shift (causes hemoglobin to drop O2)
- lowers O2 affinity, favouring movement from tissues to bloodstream
how is CO2 respirated from the blood?
- Pco2 drops
- bicarbonate turns to carbonic acid
- CO2 diffuses from blood into alveoli out to lungs
what feature does an open circulation system have?
- pumps blood out into body cavity coming into direction contact with tissues
- decreases D (thickness for diffusion)