oxygenation is the answer i found somewhere else
Deoxygenated blood is not collected anywhere. Blood is a constantly moving stream - it never stops, as the question implies. The oxygen poor blood goes to the lungs, where it turns oxygenated as it takes up oxygen.
Oxygen diffuses into cells from the bloodstream due to a concentration gradient, where oxygen is higher in the blood compared to inside the cells. This diffusion occurs passively, moving from an area of higher concentration (blood) to an area of lower concentration (cells), to meet the cell's energy demands for cellular respiration.
alveoli in the lungs, where it passes through the thin walls of the capillaries surrounding the alveoli to enter the bloodstream. This process is driven by a concentration gradient, with oxygen moving from an area of high concentration in the alveoli to an area of lower concentration in the blood.
Oxygen enters the blood stream through the air sacs in you lungs.
Pizza
Oxygen diffuses from an alveolus to the blood around it because of the concentration gradient between the high oxygen concentration in the alveolus and the lower oxygen concentration in the blood. This process allows oxygen to move from the lungs into the bloodstream for transport to the body's cells.
In air breathing animals, oxygen enters the blood stream through the alveoli, tiny sacs in the lungs. In water breathing animals oxygen enters the blood stream through the gills.
The umbilical vein carries oxygen-rich blood from the placenta to the fetus, making it the fetal blood vessel with the highest oxygen concentration.
dosent
when you inhale air into your lungs the concentration of oxygen in the blood can be no greater than that in the air.As the blood reaching the lungs is lower in oxygen there is transfer from the air to the blood stream until the concentrations stabilise.However there is no active transfer.Therefore there will always be Oxygen in exhaled air even if the initial oxygen concentration in the blood is zero as the air oxygen and the blood oxygen will reach a steady state equilibrium
The oxygen in each breath is circuited to the lungs where the alveoli absorb the oxygen and passed to the blood cells. The blood cells enter the heart where the oxygenated blood is circulated where needed.