Theme 4 Part 3 Gas Exchange Flashcards
Why is gas exchanged needed
Needed for the Krebs cycle and oxidative phosphorylation (which consumes oxygen and makes co2)
Photosynthesis (which consumes co2 and makes oxygen)
Ph regulation (through co2 regulations which forms carbonic acid)
Red cells is
Blue cells is
Oxygenated
Deoxygenated blood
Where does co2 move
Where does oxygen move
Out of the cells and into the blood
Out of the blood and into the cells then back to heart
So oxygen and nuterients go to the cells
And co2 and waste goes into the blood
What are the broken down steps of respiration
- Ventilation by bulk flow
- Diffusion across the respiratory surface
- Circulation by bulk flow
- Diffusion between blood and cells
What happens in ventilation by bulk flow
Breathing to move oxygen into the lungs then co2 out
What happens in the smaller scale of Diffusion across the respiratory surface
Oxygen diffuses from the lung into the blood , the oxygenated blood goes back to the heart
Co2 goes out of blood into the lungs
This is when you breathe in
What happens in the smaller scale of circulation by bulk flow
The oxygenated blood and co2 is moving through the circulatory system through out the body
Also called perfusion (moving fluid throughout the body)
What happens in the smaller scale of diffusion between blood and cells
the oxygen in the blood now diffuses into the cells and
co2 diffuses out of the cells and into the blood
Now that blood goes back to the heart
How does drawing air into human lungs work
What about animals
By negative pressure breathing
Lowering diaphragm when breathing in causes inward bulk flow of air
They use positive pressure breathing
What is the respiratory medium
The gas exchange surface
Air/water
Body surface, lungs, gills, etc.
Diffusion of blood to cells and co2 to blood is
Slow
Gas exchange helps with…
The low diffusion rate of blood and co2 when breathing
It’s the diffusion between the environment (air/water) and the extracellular fluid in the body
Why are the lungs internalized
To prevent evaporative water loss during gas exchange
The surface area of the gas exchange surface is proportional to _____
What does this mean for large animals
The mass and metabolic rate of the organism
Smaller animals smaller gas exhance surface
Larger animals need specialized gas exchange structures to support their metabolic needs (lungs,gills,trachea)
not just the body surface would suffice since the area doesn’t increase
Animals with high metabolic rate have
Higher area of gas exchange surface
Opposite for animals with low metabolic rate
But for each as mass increases areas of gas exchange surface increases
How do fish extend the surface area of the gas exhange surface
By having gills that extend to pass flow
Have lamellae that extend outward like pages of a book and water passes over each sheet
This increases the SA that diffusion can happen against
How do terrestrial animals extend the surface area of the gas exhange surface
They have tracheoles (tube that let air pass through) which extend out to the surface of the body.
Then every cell is in contact with the tracheole
Bring external environment in
How do mammals extend the surface area of the gas exhange surface
They have internalized lungs that bring air go from large trachea
bringing air in then trachea splits into very small branches that lead to tiny thin alveoli (still in lungs) multiplied the SA since so many alveoli
What is ficks law of diffusion
Rate= D A (dC/dX)
D= diffusion coefficient
A= gas exchange area
Dc/dx= the partial pressure of oxygen being diffused/ the dstance (thickness)
If dx increases (alveoli get thicker) then diffusion rate decreases
What is the characteristic of the gas exhange structure
How does this relate to fick law
Has a large SA to support high rates of diffusion (ex alveoli increase A but reduce delta x)
It’s moist so that the gasses can dissolve through them
What does the heart do in terms on extracellular fluid
Has a series of vessels which transport the fluid around the body of the animal
What happens at the ECF cell interface for gas exchange
Diffusion occurs at the capillaries which are really small in diameter, thin, but high SA
So more area for exchange of oxygen and co2
How does air and elevation affect gas exchange
The partial pressure of oxygen changes with elevation
At low elevation the pressure of air is higher so partial pressure of oxygen is too
At higher elevation the pressure of air is lower so partial pressure of oxygen is too
What are partial pressure gradients
What happens if lower pressure
Diffusion is based on these
dC in ficks law
Gradient of what’s in the cell and what’s out the cell
Lower pressure, lower dC (partial pressure gradient. so diffusion rate decreases (numerator is smaller)
