Laws

Dalton’s Law

Dalton’s law apply specifically to atmospheric gases.  Mr. Dalton, excuse me, Dr. Dalton established the concept of partial pressures for a gas of combined gases.  The atmosphere is a gas of combined gases.  There is oxygen, carbon dioxide, nitrogen gas, and other gases in the atmosphere.  Each gas has its own pressureThe force exerted by gases in the respiratory system, affecting airflow and gas exchange., which we would call a partial pressureThe pressure exerted by a single gas in a mixture; drives diffusion in respiration..  If we simply add up those pressures, we get the total pressure of the atmosphere. 

Henry’s Law

Henry’s lawStates that the amount of gas dissolved in a liquid is proportional to its partial pressure and solu is something you have experienced if you have ever had a soda.  Mr. Henry, excuse me, Dr. Henry also dabbled in partial pressures as Dr. Dalton did.  Dr. Henry said that the concentration of a gas in a fluid is equivalent to the gases partial pressure in air.  Huh?  What he meant is this:

Carbon dioxide gas is forced into a soda under pressurized conditions.  You open the soda and almost immediately, carbon dioxide rushes out of the soda.  Over the next hour, if you don’t cap that soda bottle, the carbon dioxide will continue to diffuse out. This will happen until the partial pressure of carbon dioxide in the air equals its concentration in the soda.  Your soda has been made a homogenous mixture with the air.

Boyle’s Law

You can only manipulate volume.

We have probably already talked about Boyle’s Law without pinpointing its name.  This is the concept that volume and pressure are inversely related.  One goes up, the other goes down and vice versa.  I have a picture here of someone squeezing a lime onto what looks like a really nice bowl of vegetables.  As this person squeezes the lime, the pressure in the lime increases, pushing out the juice.  The lime also gets smaller in volumes as this person squeezes it.  This is Boyle’s lawStates that at constant temperature, the pressure of a gas is inversely proportional to its volume (. 

Take a deepAway from the surface of the body. breath, just one so you don’t pass out.  As you took this breath, your diaphragm contracted, moving downward and your external intercostalsElevator Between ribs; lifts rib cage during breathing in. contracted, moving your rib cage outward.  You increased the volume of your chest.  Therefore, the pressure inside your alveoliMicroscopic air sacs in the lungs where gas exchange occurs between air and blood. decreased.  Actually, it decreased below atmospheric pressure, creating a gradient along which air can flow.  Do it again.  Deep breath, increase volume, decrease pressure, air flows in.  OK.  Now do the opposite.  Defate your lungs in exhalation, making them smaller and pushing air out. 

Charles’s Law

Dr. Charles’s lawStates that gas volume is directly proportional to temperature at constant pressure (warmer air expa is simple to remember, but I think sometimes students get Charles’s Law and Boyle’s Law mixed up.  Charles’s law says that temperature and volume rise together.  Both Boyle’s law and Charles’s Law have volume in them, but one relates to pressure and the other to temperature.  Here is a really simple example of Charles’s Law:

You inhale 500 mL of air

It gets warmed to your body temperature by the  conducting system

It expands to 536 mL by the time it gets to respiratory membrane