Oxygen Transport Anatomy and Physiology Flashcards
Why is oxygen necessary for cells?
To fuel and enable cells to stay alive and carry out their activities.
What is the route of oxygen into the cells?
- ) Oxygen uptake through ventilation into lungs
- ) Oxygen diffusion into blood capillaries from the alveoli in lungs
- ) Oxygen transportation on Hemoglobin in the RBCs into cellular tissue all over the body
TRUE OR FALSE. Oxygen molecules change from their state as a gas freely circulating in the air, into a solution in the plasma within the capillaries of the alveoli.
True.
What are capillaries?
They are the smallest blood vessels in the body. They connect arteries to veins. Their primary function is to exchange materials between the blood and the tissue cells. They carry o2 and nutrients to cells.
Red cells take up oxygen where?
From the blood. 98% of the oxygen diffused into the blood is taken up by passing red cells. The remaining 2% remain unattached.
What is the special oxygen-binding protein that Red cells carry?
Hemoglobin.
- Each molecule of Hgb contains Heme (an iron-containing pigment).
Bright red Hgb = saturated with O2 (OXYHEMOGLOBIN)
Blue Hgb = un-oxygenated (DEOXYHEMOGLOBIN)
When does hemoglobin give up its oxygen?
As red blood cells travel through capillaries to tissues where there is a low content (partial pressure) of oxygen.
What does partial pressure represent?
The level of dissolved oxygen in plasma.
As oxygen is released and is again carried in solution, the partial pressure of o2 in the capillaries becomes _____
Greater than the partial pressure of oxygen in the surrounding tissues
–> this causes oxygen to move out of the capillaries into the tissues to finally reach the cells.
OXYGEN FROM ALVEOLI –> BLOOD CAPILLARIES –> TISSUES
What does the Oxygen Dissociation Curve demonstrate?
What does its shape mean?
The relationship between oxygen carried by Hemoglobin, the o2 saturation, and the partial pressure of o2 in the arterial blood.
– the affinity (attraction of hub to o2 molecules)
–> remember, o2 NEEDS to be released from hemoglobin for it to be useful in the body and participate in cellular metabolism.
The sharp upstroke and the flat plateau illustrate how oxygen is released to the tissues.
It’s shape means that –> even when the level of dissolved o2 in the plasma is lower than normal, the o2 saturation (o2 bound to hub) will remain high.
ex: Although the partial pressure of o2 in the blood returning from the lungs and being pumped out by arteries may be reduced to only 50% or the normal value, (say due to lung disease or high altitude), hemoglobin will still be 85% saturated with oxygen.
What 2 forms is oxygen transported in the blood?
Plasma and bound to hemoglobin
What % of o2 is dissolved in plasma?
What % of o2 is attached to hemoglobin?
3% –> reflected In the PaO2 level measured in the ABG
97%–> reflected in the SaO2
Describe the steps in the pathway of Oxygen Transport
- ) Inspired O2 in Alveoli crosses through the AC membrane and dissolves in plasma
- ) Oxygen in the plasma is picked up and bound to Hgb and transported throughout the body
- ) O2 is released from Hgb and again dissolves in plasma
- ) Once in dissolved form, o2 is able to diffuse into the cells.
What happens when there is not enough Hemoglobin in the body?
Hgb would need to travel more distance to deliver a higher amount of o2.
The hemoglobin that is available would need to make a higher amount of “trips” back and forth to transport O2. Heart rate is raised due to compensation, so the lower than normal amount of hemoglobin can still effectively deliver oxygen to the cells.
When the affinity of Hgb molecules is increased, Hgb binds to o2 more readily but is _____ to release it
slower
