Heat, Cold Flashcards
In medicine
What is the matter?
Matter is composed of molecules that are in
motion.
How the molecular in gas or liquid move?
In a gas or liquid the molecules move
about, hitting one another or the walls of the
container, even in a solid the molecules have
some motion about the sites that they occupy
within the crystal structure
What mean the molecules move ?
that they have kinetic
energy.
What kinetic energy is related ?
kinetic energy is related with temperature.
The average kinetic energy of the molecules
directly proportional to the temp. T or F
( T ) because directly
What can you do to order to increase the temp. of a gas?
necessary to increase the average kinetic
energy of its molecules by putting the gas in
contact with a flame.
What can cause energy transferred from the flame to the gas ?
causing the temp. rise is called heat .
Are the temperature measure directly is easy or difficult?
is difficult to measure directly.
How measure the temperature indirectly?
measure it indirectly by measuring one of physical properties that change with temp.
What the most common way to measure temp?
is
with
a glass fever thermometer
containing
mercury or alcohol.
What the factors that increase the visibility of the capillary in thermometer?
1-the glass case acts as magnifying glass.
2- an opaque white backing is used to
increase the visibility.
What can do to avoid liquid to return when the temp.
falls in thermometer?
The capillary of a fever thermometer has a
restriction just above the bulb so that after
the liquid is forced into the stem by
expansion.
Where is usually the temperature taken ?
underneath the
tongue or
in the rectum
thermometer is …..than the body, it
lowers the temp of the surrounding ……. .
- Colder
2. tissues first
it takes one hour before the temp. of
the tissues rises to the original value.(T ,F)
(F) several minutes
The total heat transferred of conductive method will depend upon :
` 1-the area of contact.
` 2- the temp. difference between two objects.
` 3- the time of contact.
` 4- the thermal conductivity of the materials.
What the conductive method depend of?
is based on the
physical fact that if two objects at different
temp. are placed in contact, heat will transfer
by conduction from the warmer object to the
cooler one.
Difficulty to preserve organs in blood sand method?
1-the large physical dimensions limit the
cooling rate .
` 2- adding & removing protective agents is
difficult.
What mean the blood sand method?
blood is sprayed onto a liquid nitrogen
surface & freezes into small droplets. The
droplets are about the size of grains of sand
– hence the name “blood – sand”.
` the droplets are collected & then stored in
special containers, usually at the temp. of
liquid nitrogen.
What mean the thin – walled containers ?
This method is constricted so that the blood
volume between the walls is small.
` After it is filled with blood it is quickly
inserted into a liquid nitrogen bath.
` The frozen blood can be stored at the temp.
of liquid nitrogen (- 196˚C).
Low Temperature of Liquid air(liquid nitrogen )
` liquid helium ?
- ( -196˚ C)
2. ( -269 ˚C)
the study
of low- temp. effects in biology & medicine is
called:
cryobiology
What mean the Cryogenic?
is the science & technology of
producing & using very low temp.
How are the Cryogenic method used in medicine?
` 1-Low temp. have been used for long –term
preservation of blood , sperm, bone marrow,
& tissues.
` 2-using cryogenic methods to cool the body
into a state of “ suspended animation “ so
that it can pass time without aging.
3-preserve at a low temp. people with fatal
diseases with the hope that in the future they
could be revived & their diseases cured.
` 4-moderate cooling is used in conjunction
with surgery
