L03a: Body Fluids

Question 1

What are the 4 ways out excreting water

Answer 1

Lungs
Skin
Urine
Faeces

Question 2

What are the compartments of water

Answer 2

Plasma water 
Intracellular 
Interstitial 
Transcellular 
Fat

Question 3

What site is the extracellular fluid found

Answer 3

Plasma water
Intersitial
Fat

Question 4

How does water move from the plasma water

Answer 4

1) ingested into the plasma
2) passes to intersitial space
3) can cross to intracellular compartment
4) then to transcellular if possible

Question 5

Where is most of the water found

Answer 5

Intracellular compartment

Question 6

What is the total body fluid of an average 70kg person

Answer 6

42 litres

Question 7

List the largest to smallest water depending on its compoartmwern

Answer 7

Intracellular
Interstitial
Plasma
Transcellular

Question 8

What are the examples of transcellular compartments

Answer 8

Peritoneal space
CSF
Pleural cavity
Synovial fluid

Question 9

How to we measure body fluid

Answer 9

Volume of distribution

Question 10

How do we carry out volume of distribution

Answer 10

Inject a known amount of drug

Then measure its concentration in plasma

Question 11

What is the volume of distribution equation

Answer 11

VD= known amount injected/ concentration in plasma

Question 12

What happens to the volume of distribution if the concentration of a drug is higher outside the plasma

Answer 12

Volume of distribution is higher

Question 13

How to we measure total body water

Answer 13

We used labelled water 
Inject a volume volume 
Allow it to equilibrate 
Take a blood sample
Measure normal water to labelled water ratio

Question 14

What does blood contain

Answer 14

Plasma: the fluid component of blood
Haematocrit: cells in the blood

Question 15

What are substances are in body fluids

Answer 15

Sodium 
Potassium 
Calcium 
Chloride
Bicarbonate 
Glucose

Question 16

Which ion is the highest intracellular

Answer 16

Potassium

Question 17

Which ion is the highest extracellular

Answer 17

Sodium

Chloride

Question 18

What happens to half of the calcium when it is the circulation

Answer 18

Binds to albumin

Question 19

How do we measure the free calcium (the half of the calcium not bound to albumin)

Answer 19

Calculate a corrected calcium concentration

Question 20

What is an osmole

Answer 20

The number of molecules that a compound dissociated into when in dissolved solution

Question 21

What is unit of osmole represented as

Answer 21

Osm or osmol

Question 22

If there is 100 millimol of sodium chloride what would its miliosmole be in solution

Answer 22

200 mOsm

Question 23

Why is the mili osmole of sodium chloride not 100 but 200

Answer 23

Because sodium chloride which is one molecule dissociates into 2 molecules of na+ and cl- so there is 200 mOsm of sodium chloride in solution

Question 24

What is the mili osmole of 4 mmol of glucose in solution

Answer 24

4mosm because glucose does not dissociate in solution

Question 25

What is the definition of osmolality

Answer 25

The number of osmoles per unit mass of solvent

Question 26

What is the unit of osmolality

Answer 26

Osm per kg

Question 27

What is osmolarity

Answer 27

The number of osmoles per unit volume of solution

Question 28

What is the unit of osmolarity

Answer 28

Osm per litre

Question 29

What is osmotic pressure

Answer 29

The pressure that occurs between 2 solutions with different molecules = osmotic pressure

Question 30

What happens to water when there is a compartment with high solutes

Answer 30

Water moves to that compartment by osmotic pressure

Question 31

What does it mean if 2 solutions are isosmotic

Answer 31

They share the same osmolality

Question 32

What does it mean if a solution is isotonic

Answer 32

There will not be a net fluid movement usually in RBC

Question 33

What is oncotic pressure

Answer 33

The pressure generated by proteins that draws water

Question 34

What is the hydrostatic pressure

Answer 34

The pressure generated by the heart

Question 35

What does osmotic pressure cause

Answer 35

Draws water towards it

Question 36

What is the emergency treatment for intracrainal haemorrhage

Answer 36

Inject mannitol

Question 37

How does mannitol draw water from the intracellular and transcellular space to reduce intracrainal pressure

Answer 37

Mannitol in the plasma increases osmolality and osmotic pressure Water is drawn into the plasma from the intracellular and transcellular space