Transport and Diffusion of Gases Flashcards
The standered unit of pressure is a pascal(Pa)
It’s often measured in Kilopascals(kPa)
At sea level air pressure is 101.3 kPa
Why are pressures important?
-Differences in pressure helps explain how O2 and CO2 diffuse into the lungs
-Gases will diffuse across a membrane from high to low pressure
-The greater the gradient, the faster the rate of diffusion
Oxygen Transport and Diffusion
- Once air draws into the lungs, the pressure of Oxygen in alveoli is greater than pressure of Oxyegn in the blood which forces oxygen into the blood.
Once in the bloodstream oxygen must be delivered to cells
-Pressure of blood in cells is higher than pressure of oxygen in cells. Oxygen is directed into the cells.
Circulatory system transports oxygen via
-Hemoglobin(98.5%)
-Dissolved in plasma(1.5%)
-Hemoglobin is a protein in red blood cells that bonds with oxygen and transports it around the body
-Hemoglobin increases bloodstream ability to carry oxygen significantly
Carbon dioxide transport and diffusion
Carbon dioxide must be removed from cells
-Pressure of CO2 in cells is more than CO2 in blood cells. Carbon will flow into the blood
Carbon dioxide must be exhaled
-Pressure of CO2 in blood at alveolus is more than CO2 in alveoli. Carbon will flow into the alveoli
Why does CO2 accumulate in cells?
-Due to cellular respiration and it diffuses into blood
* Dissolved in plasma(7%)
* Attaches to hemoglobin(20%)
* Reacts with water in plasma to form carbonic acid (73%) —> which dissociates into H+(acid) and HCO3
*Reforms CO2 at lungs to cross into alveolus
High altitude breathing
-Hypoxia: altitude sickness
-At high altitude
* O2 present in same proportion as lower altitudes
* Less total air
*Less oxygen available for breathing
How our body responses to meet oxygen needs
-Increased breathing rate
-Increased production of red blood cells using a substance called erythropoietin(EPO) made from the kidneys
-Short lived boost in physical endurance after return to normal altitude
Genetic adaptions of high altitude populations
-more alveoli
-more lung capillaries
ex: athletes train at high altitudes to improve performance
The control of breathing(Concentration of Carbon dioxide(main factor))
-Physical exertion results in increase rate of cellular respiration which produces CO2 which lowers the PH of blood
-Excess CO2 present in blood after gas exchange is carried to the medulla oblongata which sends signals to increase breathing rate and initiates contractions of the rib cage and diagram which increases the volume of inhalation
-Heart rate also increases to ensure O2 is delivered to the cells and CO2 is removed at a faster rate
The control of breathing(Concentration of oxygen(lesser factor))
-Chemoreceptors in the blood vessels detect if oxygen drops below a certain level and send a message to the medulla oblongata to increase breathing
-Stretch receptors in the alveoli detect deep inhalation and send a message to medulla oblongata to stop inhalation
