Unit 3 Flashcards
(26 cards)
Bulk flow
- 2 steps
1. Ventilation - movement of medium (air/water) over respiratory surface (lung/gill)
2. Circulation
-movement of body fluids containing dissolved gases
Single celled organisms/ simple multicellular animals
- exchange compounds with environment through diffusion
Eukaryotic organisms
- require O2 for ATP production
- rely on a combination of diffusion and bulk flow for gas exchange
Goal of gas transport
- deliver oxygen to mitochondria
- bulk flow maximizes gradients
— diffusion works better when you have a big gradient
Active ventilation
- animals create ventilatory currents that flow across gas exchange surface
- use suction or positive pressure
— expends metabolic energy
Passive ventilation
- environmental air or water currents induce flow to and from the gas exchange membrane
- no use of metabolic energy
Ram ventilation
- species ventilate by swimming
Gas exchange organs in aquatic animals
- bony fish pump water against gills
- fish have unidirectional respiration and countercurrent blood flow
Land animals can achieve higher O2 uptake retakes
- O2 content of air is much faster than water
— O2 diffuses 8000 times faster than water
— air is less dense and viscous (requires less energy to pump)
Tidal ventilation
-mammals increase lung volume by actively expanding thoracic cavity to draw O2 rich air into lungs
- O2 poor air is expelled from lungs using passive elastic recoil (exhalation)
Alveoli
- sacs that are blind ended (never fully empty)
- amount of O2 and Co2 in alveoli different from environment
- surrounded by capillaries
- surfactants reduce surface tension in (allow for easier inflation of lungs)
Stale air
- upon inspiration, fresh air pushes stale air deeper into lungs
- at end of resting inhalation, 12% in airways is fresh, 8k% is left over from previous breaths
Birds (unidirectional ventilation)
- First inhalation draws O2 rich air into posterior air sacs
- First exhalation moves fresh air into lung
- Second inhalation moves stale O2 poor air from lungs using passive into anterior air sacs
- Second exhalation moves air out of anterior air sacs
Open circulatory systems
- lymph flow through a vessel and empties into an open body cavity to supply the tissues with nutrients and is returned to circulation
Closed circulatory system
- blood flows through connected blood vessels by muscular heart(s)
- blood flows through vessels to supply tissues with nutrients
Chemoreceptors
- we have chemoreceptors in our brain stem that detect Co2 and H+
— if Co2 is too high, chemoreceptors in brain stem stimulate respiratory muscles
Three components of circulatory systems
- Fluid that circulates through the system
- System of tubes, channels, or spaces
- Pump or propulsive structures
Vertebrate blood
- hematocrit (%)
— fraction of blood made up by red blood cells, plasma, and white blood cells
— affects resistance
Carotid and aortic bodies
- detect O2 and H+
Hemoglobin
- globular protein with 4 subunits
— each subunit surrounds a heme group containing iron
— each heme group brings to one O2 group
Transportation differs between O2 and CO2
- O2 diffuses into blood, then Red blood cells, and binds reversibly to heme group for transport
- CO2 carried in plasma as bicarbonate and H+
Fish circulation
- deO2 blood enter atrium from main vein and then the ventricle
- de O2 blood is pumped from ventricle into main artery
Blood flow of 4 chamber heart
- De O2 blood enter right atrium (from inferior and superior vena cava)
- De O2 blood passes through right valve (and Enters right ventricle)
- De O2 blood pumped into pulmonary arteries (to the lungs)
- 02 blood returns from lungs to left atrium
- O2 blood enters left ventricle (through left valve)
- O2 blood pumped through aortic valve into systematic circulation
Pulmonary and systemic circuits
-allows for
— increase supply of O2 blood to tissues (pumped at high pressure)
— increased uptake of O2 at gas exchange surface (due to lower pressure, and more time for extraction)
