Transport of Blood Gases Flashcards
Oxygen and Haemoglobin
When oxygen combines with haemoglobin it forms oxy haemoglobin. Haemoglobin has a high affinity for oxygen. For exery one molecule of HB, 4 O molecules combine with it.
Oxygen and Myoglobin
Myoglobin is an iron based protein found in the muscles. This has a much gher affinity for Or than Hb. It acts as an oxygen store, by saturating t with open which has disassociated itself from haemoglobin.
Chain of events of 02 being taken up by Hb in the lungs and released to the muscle site
At lungs there is a high pO2 and a low pO2 in the blood
O2 diffuses the alveolar membrane into the bloodstream
O2 readily combines with haemoglobin until it almost fully saturated
Oxyhaemoglobin then travels to the muscles
At the muscles there is a low pO2 and high P02 in the blood
Oxygen in released by the haemoglobin(disassociates)
Can be used by the respiring muscles and tissues
Partial pressure
The pressure that is exerted by an individual gas when it exists with
a mixture of gases
Diffusion
The movement of respiratory gases from areas of higher partial pressure to areas of lower partial pressure
Diffusion of gases in the alveoli is facilitated by several structural features NAME 4
Respiratory memebrane is veery thin mreaning diffusion distance is very small
Numerous alveoli create a large surface area ober which diffusion can take place
Alveoli surrounded by a large capillary network which also provides a large surface area for gaseous exchange
Diameter of capillaries is slightly narroweer than the area of the red blood cell
Gaseous exchange at the tissue/muscle
This is also known as internal respiration. Like that of the gaseous exchange at the alveoli it occurs due to a partial pressure gradient between the capillaries and that of the muscle tissue.Therefore oxygen (02) must move along the concentration gradient. 02 will continue to travel across into the muscles until equilibrium is reached, Partial pressure of carbon dioxide (PCO2) is 45mmHg in the tissues and 40mmHg in the capillaries. Therefore CO2 moves out of the muscle and into the blood stream.
Factors that make gaseous exchange effective at the muscles and tissues
Diffusion gradient - o2 travels from the blood to muscle is relatively large
Myogloblobin has a higher affinity for o2 than haemogloblin
Diameter og capillaries is very narrow means in travels in single file maximising diffusion
Exclusive network of capillaries surrounding the tissues provides a large Surface area
Capilllary walls are all thivk meaning diffusion distance is very short
At rest oxygen diffuses into the __________where the Hb has a high affinity for oxygen and associates with it up to __% saturation. At the internal site, the capillary blood has a high partial pressure of o2 and the musclet issue a ___ ppo2. As gases move up and down a ________ gradient from an area of high to low pressure, the oxygen _______into the muscle tissue.
As Mo Farah begins to perform the 10000m race, the demand for oxygen increases and _____________ redirects the blood flow away from the organs to the working muscles. During exercise, there are increases in the temperature of blood and muscle tissue
The production on lactic acid
and production of CO2
Co2 is converted into _____acid and with lactic acid raises the acidity levels of the blood stream. This increases the disociation of 02 from Hb increasing the rate of diffusion. This is known as the Bohr effect.
During exercise, the muscles use greatedr volumes of oxygen drcreasing the ppo2 in the muscles tissue and increasing the diffusion gradient. The increased supply of oxygen to muscle cells and enables Mo Farah to exercise for longer at a higher intensity.
At rest oxygen diffuses into the bloodstream where the Hb has a high affinity for oxygen and associates with it up to 98% saturation. At the internal site, the capillary blood has a high partial pressure of o2 and the musclet issue a low ppo2. As gases move up and down a pressure gradient from an area of high to low pressure, the oxygen diffuses into the muscle tissue.
As Mo Farah begins to perform the 10000m race, the demand for oxygen increases and vascular shunt redirects the blood flow away from the organs to the working muscles. During exercise, there are increases in the temperature of blood and muscle tissue
The production on lactic acid
and production of CO2
Co2 is converted into carbonic acid and with lactic acid raises the acidity levels of the blood stream. This increases the disociation of 02 from Hb increasing the rate of diffusion. This is known as the Bohr effect.
During exercise, the muscles use greatedr volumes of oxygen drcreasing the ppo2 in the muscles tissue and increasing the diffusion gradient. The increased supply of oxygen to muscle cells and enables Mo Farah to exercise for longer at a higher intensity.
The oxy-haeomoglobin dissociation curve
This shows how saturated with oxygen the haemoglobin is; at any given po₂
The graph is S-shaped because when haemoglobin combines with the first oxygen molecule it changes shape in a way that makes it easier for other oxygen molecules to join. This means it has a step part in the middle, where it’s easier for oxygen to combine and shallow parts where it’s harder for oxygen to combine.
of you take a closer look at the graph, you will see that:
. At respiring muscles there is a very low po₂ which means the saturation of haemoglobin is also low. WHY? Because a large proportion has been released to the muscles for energy production
At the arteries/lungs where there is a high PO2 we find that the saturation of haemoglobin is almost 100%.
exercise and the Bohr shift
During exercise muscles require more oxygen, this means that oxygen will disassociate from haemoglobin more readily. This means that the curve shifts to the right, this is known as the BOHR EFFECT
Factors which affect the disassociation of oxygen
Carbon Dioxide - Higher the CO2, the less the affinity for O2 - the harder the tissue is working the more O2 is released
Blood Temp - Higher blood temp - the less the affinty for O2- because more O2 warmed up tissue
Blood pH - lower the pH - the less affinity for O2 - because more O2 to acidic sites working hard
