Respiratory system 1-6 Flashcards
What is the purpose of the respiratory system?
Ensure all tissues receive the oxygen they need and disposes of the CO2 they produce.
How is pressure generated by gases?
By collision of molecules with the walls - more frequent and harder collisions, higher pressure
What is Boyles law?
the product of the pressure and volume for a gas is a constant for a fixed amount of gas at a fixed temperature.
PV = constant
What is Charles law?
if a given quantity of gas is held at a constant pressure, its volume is directly proportional to the absolute temperature. (Kelvin)
What is the universal gas law?
PV=RT
Allows calculation of how volume will change as pressure and temperature changes
How do gases behave when mixed with other gases?
Behave independently so each gas exerts a partial pressure
How do you calculate the partial pressure of each gas in a mixture?
The same fraction of the total pressure as the volume fraction of the gas in the mixture
What happens when gas comes in contact with water?
Water molecules evaporate and gas molecules dissolve.
What effect does evaporated water mixing with a gas have?
Exerts vapour pressure
How is the saturated vapour pressure achieved?
When molecules leave and enter water at the same rate.
What does the saturated vapour pressure depend on?
Temperature
What is the pressure of a gas in a liquid referred to as?
Tension - at equilibrium tension is the same as the partial pressure of gas in gas mixture
What does the tension of a gas in a liquid indicate?
How readily the gas will leave the liquid NOT how much gas is in the liquid
What does solubility determine?
The amount of gas which enters the liquid to establish a particular tension
content = solubility x tension
How does reactions of a gas with a component of liquid affect tension?
Reaction must complete before tension can be established
reacted gas + dissolved gas = content
How much oxygen must the blood pick up per minute at rest?
12 mmol
Explain how the lungs and blood are able to supply enough oxygen to the body.
300 million alveoli each surrounded by a capillary
Describe the differences between bronchi and bronchioles.
Bronchi have cartilage in walls and less smooth muscle
Describe the resistance and pressure of the pulmonary circulation
Low resistance and pressure.
Receives entire cardiac output
Why is it important that very little tissue fluid is formed by the pulmonary circulation?
Would fill space between alveoli and capillaries affecting gas exchange
How is air drawn into the lungs?
By increased volume of terminal and respiratory bronchioles as lungs expand in inspiration. Each breath draws a tidal volume into and out of the lungs
What effects ventilation?
Tidal volume and respiratory rate
Where does the nasal cavity lie?
Extends from the nostrils to posterior nares
What divides the nasal cavity?
septum - medial wall of each nasal cavity. Made of cartilage and bone