Respiratory Systems Flashcards
(13 cards)
How do fish ventilate their gills?
Using buccal pumping (mouth movement) or ram ventilation (swimming with mouth open) to pass water over the gills.
What is countercurrent exchange in fish?
Blood flows opposite to water across the gills, maximizing oxygen uptake.
How do mammals ventilate their lungs?
With negative pressure breathing — diaphragm and rib muscles expand the chest, drawing air in (tidal ventilation).
What is tidal ventilation?
Air moves in and out of the lungs via the same pathway during inhalation and exhalation (as in mammals).
How do birds ventilate their lungs?
Air flows unidirectionally through lungs, powered by air sacs acting like bellows.
What is crosscurrent exchange in birds?
Blood flows perpendicularly to air flow, optimizing oxygen uptake during flight.
What factors affect gas exchange at capillaries?
Partial pressure gradients, membrane thickness, surface area, and gas solubility.
How is oxygen transported in the blood?
Mostly bound to hemoglobin; a small amount is dissolved in plasma.
How is carbon dioxide transported in the blood?
As bicarbonate (HCO3-), bound to hemoglobin, and dissolved in plasma.
What shifts the oxygen-hemoglobin dissociation curve right?
Increased CO2, acidity (low pH), temperature, or 2,3-BPG — all promote oxygen unloading.
What are the two types of respiratory chemoreceptors?
Peripheral chemoreceptors (in carotid and aortic bodies) detect O₂, CO₂, and pH;
Central chemoreceptors (in medulla) respond mainly to CO₂/pH in cerebrospinal fluid.
What role do chemoreceptors play in breathing regulation?
Peripheral chemoreceptors (in carotid/aortic bodies) sense O2; central chemoreceptors (in brain) sense CO2/pH to adjust ventilation.
What happens when CO₂ levels rise?
Ventilation increases to expel CO₂ and restore blood pH.
