Introductory Weeks Flashcards
How many millilitres (ml) in 1 litre (L)?
1000 ml
What is a decilitre (dl)?
1/10 of a litre
= 100 ml
What is a millilitre (ml)?
1/1,000 of a litre
= 1 ml
How much is a microlitre (µl)?
1/1,000,000 of a litre (1 µl)
What is 1 ml equivalent to in ‘real life’ measurements?
20 drops of water
1/5 of a teaspoon
How much is 5 ml in a teaspoon?
It is a full teaspoon
How many grams (g) in a kilogram (kg)?
1000 g
What is 1 gram (gm)?
1/1,000 of a kilogram
What is 1 milligram (mg)?
1/1,000 of a gram
1/1,000,000 of a kilogram
What is 1 microgram (µg)?
1/1,000,000 of a gram
1/1,000,000,000 of a kilogram!
In the case of water, what does 1L equal in weight?
1 L = 1 Kg
What are we measuring if we say we have 1 L of water?
Volume
What are we measuring if we say we have 1 g of water?
Weight (mass)
Order these from smallest to largest:
decilitre (dl), litre (L), microlitre (µl), millilitre (ml)
Microlitre = 1/1,000,000 of a litre (1 µl) Millilitre = 1/1,000 of a litre (1 ml) Decilitre = 1/10 of a litre (100 ml = 1 dl) Litre = 1 L (1000 ml = 1 L)
Order these from largest to smallest:
gram (g), kilogram (kg), microgram (µg), milligram (mg)
Kilogram = 1000 g (1000g = 1 kg) Gram = 1/1,000 of a kilogram (1 g) Milligram = 1/1,000,000 of a kilogram (1 mg) Microgram = 1/1,000,000,000 of a kilogram (1 µg)
If 1 L = 1 kg, then how much does 1 ml equal?
1 g
What is the weight of the average adult male?
70 kg
How much of the total body weight is made up of water, and therefore how many litres will that be equivalent to?
~ 60%
70 kg X 0.6 = 42 kg
= 42 L
How is the total body water distributed to the intracellular and extracellular compartments, and what volumes do these equal to?
Of the 42 litres total body water:
1/3 is extracellular, which is 14 L
(42 L X (1/3) = 14 L)
2/3 is intracellular, which is 28 L
(42 L X (2/3) = 28 L)
(remember, 1 before 2, e before i)
How is the extracellular water distributed?
~ 14 L extracellular water distributed into
11 L interstitial water
5 L circulating blood volume
How much water is circulating blood volume in an average 70 kg male?
5 L
How much of the circulating blood volume is plasma, and how much is red blood cells?
3 L = plasma
2 L = red blood cells
(to create 5 L circulating blood volume)
What is haematocrit?
The proportion, by volume, of blood that consists of red blood cells
What is required to collect blood for centrifugation?
10 ml (venous) blood in a test tube with one drop of EDTA (an anticoagulant).
How does blood appear after centrifugation (sedimentation)?
A light (yellow) LIQUID layer appears on top - this is the PLASMA
Below that is a THIN LAYER/BUFFY COAT, which is made up of WHITE CELLS & PLATELETS (appears ‘white’)
At the bottom are the RED CELLS (appears red, or ‘dark’ red)
How much of centrifuged blood is plasma, and how much is red cells?
60% plasma
40% red cells
(Which corresponds to 3 L plasma and 2 L red cells in 5 L circulating blood volume)
What is the haematocrit levels for males following UHL guidelines?
40% - 54%
What is the haematocrit levels for females following UHL guidelines?
37%-47%
What is the normal haematocrit level (important!)?
2 litres in 5 litres, aka 40%
What is the average resting heart rate?
70 beats per minute (bpm)
What is the average stroke volume of the left ventricle, at rest?
70 ml/beat
What is cardiac output?
Heart Rate x Stroke Volume
beats/min x L/beat = L/min
What is the average resting cardiac output?
Cardiac Output (CO) = Heart Rate (HR) x Stroke Volume (SV)
At rest:
Heart Rate = 70 bpm
Stroke Volume = 70 ml/beat
So …
CO = 70 beats/min x 70 ml/beat
CO = 4900 ml/min
This rounds up to 5 L/min (learn!)
NB: CO will vary in individuals depending on many factors
How many times does the total blood volume circulate per minute?
Once
Normal circulating blood volume = 5 L
Normal cardiac output = 5 L
So the total blood volume circulates once per minute
Why might different sources on body fluid volumes be confusing?
The numbers are based on the AVERAGE 70kg individual - but as we know, humans tend to vary widely in real life!
