Definitions Flashcards
What are the 4 stages of anaesthesia?
1) analgesia- decreased small and pain sensation. can also be associated with auditory or visual hallucinations.
2) Excitement- most reflexes still present but swallowing is not. associated with pupil dilation, increased autonomic activity, eye movements, irregular breathing and vomiting.
3) surgical anaesthesia- broken up into 4 planes on increasing depth with the aim generally to be in plane 2/3 for most surgery.
4) medullary paralysis- this is the toxic stage indicative of an impending overdose.
What is vapour pressure?
Vapour pressure is the pressure exerted by a vapour above the surface of a liquid.
What is saturation vapour pressure?
Saturation vapour pressure is the pressure exerted by a vapour in equilibrium with liquid of the same substance. It is influenced by the colligative properties of the liquid (eg. solute concentration) and the temperature.
aka
“The pressure exerted by a pure substance (at a given temperature) in a system containing only the vapour and condensed phase (liquid or solid) of the substance.”
What is boiling point temperature?
The boiling point temperature is the temperature at which vapour pressure equals atmospheric pressure. A lower atmospheric pressure will result in a lower boiling point temperature
What is critical temperature?
Critical temperature is the temperature above which you cannot liquefy a given gas by increasing its pressure
A substance is a gas when it is above its critical temperature, and a vapour when it remains in gaseous phase below its critical temperature.
(think gas is a state of matter, while vapour co exists with a solid or liquid)
What is Critical pressure?
Critical pressure is the minimum pressure which would suffice to liquefy a substance at its critical temperature.
what is the critical point (re: gaseous forms)
Critical point is the point of minimum pressure and maximum temperature at which both a gaseous and a liquid phase of a given compound can coexist.
What is the specific critical volume?
Specific critical volume is the volume of space occupied by 1kg of a gas at its critical point
What is the latent heat of vapourisation?
The latent heat of vapourisation is the energy in the form of heat required to convert a substance from liquid to vapour at a given temperature. Latent heat of vapourisation decreases as ambient temperature increases, and is reduced to zero at the critical temperature of that substance.
Specific latent heat is defined as the heat required to convert 1 kilogram of a substance from one phase to another at a given temperature (SI unit of specific latent heat Jkg-1).
What is the absolute humidity?
The absolute humidity is the mass of water vapour present in a given volume of air.
What is relative humidity?
Relative humidity is the percentage ratio of the mass of water vapour in a given volume of air to the mass required to saturate that given volume of air at the same temperature.
This is the conventional measurement of humidity, as in when you refer to it being 40% humid, that is relative humidity.
What are the colligative properties of a substance?
All fluid properties related to freezing or boiling are colligative properties.
these include;
Vapour pressure
Boiling point
Freezing point
Osmotic pressure
What is the distinction between a gas and a vapour?
The word “vapour” is used to describe an evaporated substance which is below its critical temperature; i.e. its a gas which still has the option of becoming a liquid if the pressure rises. In contrast, the word “gas” is specifically used to describe a substance which is above its critical temperature, i.e. no matter what the pressure does it will never liquify. Thus, all water in the troposphere of the earth is by this definition a vapour, as the critical temperature for it is approximately 354°C.
A “gas” and a “vapour” state of any substance may have essentially identical physicochemical properties.
So strictly speaking the word ‘gas’ applies to a substance above its critical temperature while ‘vapour’ is the word used for a substance below its critical temperature.
What is the specific critical volume?
The volume of space occupied by 1kg of a gas at its critical point is generally referred to as the specific critical volume.
what is the hamburger effect?
chloride shift into cells via Cl-/HCO3- antiporters, in pulmonary capillaries this is reverse with HCO3- being pumped into cells so more CO2 can be created by the reaction with carbonic anhydrase.
