10.3 Transport and diffusion of gasses Flashcards
Control of breathing
When we inhale, the brain sends signals to contract the diaphragm and the external intercostal muscles
Once fully expanded, signals are sent back to the brain to stop the contraction, allowing us to exhale
Pressure
Pressure varies with height
We are found at sea level where pressure is 101.3kpa
Air pressure
As mentioned, air is composed of many different gasses
Therefor, the 101.3kpa is based upon the pressure of each gas added together
Pressure drops with high altitudes
Blood and oxygen
The oxygen leaves the alveoli and enters two portions of the blood to be circulated through the body
Red blood cells carry 98.5% of oxygen
Plasma carries 1.5% of oxygen
In red blood cells, a protein containing iron called hemoglobin binds with molecules of oxygen to form oxyhemoglobin
This gives blood the bright red color
When there is no oxygen in the blood, its dark red not blue
Hemoglobin carries about 2 ml of oxygen for every 100 ml of blood
Blood and carbon dioxide
Just like oxygen diffuses in, carbon dioxide diffuses out
CO2 can be transported in 3 different ways
1. 7% remind in plasma in the blood
2. 20% attaches to hemoglobin to be excreted, called carbaminohemoglobin
3. 73% reacts with water to make carbonic acid, which quickly separates into H+ and HCO3-
This can causes plasma to be acidic and dangerous
Hemoglobin saves the day
As hemoglobin releases oxygen molecules to tissue cells it attaches to H+, removing this dangerous ion from reaching too high a concentration
Hemoglobin and H+ bond with bicarbonate to reform CO2 and H2O, eventually allowing the CO2 to be expelled
EPO
EPO of “Erythropoietin” is a hormone that stimulates the production of red blood cells
The more red blood cells we have, the more hemoglobin is present, the more oxygen can be absorbed and delivered by blood
We can force stimulation at high altitudes for athletes
At high elevations there is low oxygen which triggers your body to release EPO
