L2 BODY FLUID COMPARTMENTS

Question 1

What are the body fluid compartments?

What structure separates these compartments?

Answer 1

1. Intra-cellular fluid (ICF)
2. Extra-cellular fluid (ECF)

Cell membrane separates them.

Question 2

What are the components of the extracellular fluid ?

What structure separates the components?

Answer 2

1. Interstitial fluid
2. Plasma fluid
   3.Transcellular fluid (<1%)
   Capillary wall separates them.

Question 3

Where is transcellular fluid found?

Answer 3

This compartment includes fluid in the synovial, peritoneal, pericardial, and intraocular spaces, as well as the cerebrospinal fluid.

Question 4

Percentage of total body weight in Extracellular fluid?

Answer 4

20%

Question 5

What fraction of total body water is Extracellular fluid?

Answer 5

1/3

Question 6

Percentage of total body weight in Intracellular fluid?

Answer 6

40%

Question 7

Fraction of total body water in Intracellular fluid?

Answer 7

2/3

Question 8

Fraction of ECF is interstitial fluid?

Answer 8

3/4

Question 9

What fraction of ECF is plasma fluid?

Answer 9

1/4

Question 10

What is the name of the principle used to measure fluid compartments?

Answer 10

Indicator Dilution Principle

Question 11

The measurement of fluid compartments utilizes what formula?

Answer 11

𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 =

Amount (Mass) / 𝑉𝑜𝑙𝑢𝑚𝑒 of Distribution

Question 12

Describe the principle used to measure fluid compartments?

Answer 12

It requires the introduction of a substance, of known conc. & amount (mass) into a particular compartment, allowing it to disperse evenly throughout the compartment’s fluid, and then analysing the extent to which the substance becomes diluted so as to calculate the volume of the other fluid compartment.

Total mass of a substance after dispersion in the fluid compartment will be the same as the total mass injected into the compartment.

Question 13

Desirable characteristics of a substance used to measure fluid compartments?
(5)

Answer 13

1. Measurable
2. Remains in compartment (loss & metabolized)
3. Evenly distributed within the compartment
4. Does not alter water distribution
5. Non-toxic

Question 14

What substances can be used in the calculation of Total Body Water?

Answer 14

Deuterated water (D2O), tritiated water (THO), and 
antipyrine

Question 15

What substances can be used in the calculation of Extracellular Fluid Volume (ECFV)?

Answer 15

Labeled inulin, sucrose and mannitol

Question 16

What substances can be used in the calculation of Plasma Volume (PV)?

Answer 16

Radiolabeled albumin or Evans Blue Dye (which binds to albumin)

Question 17

Formula to calculate Intracellular Fluid Volume (ICFV)?

Answer 17

Total body water – Extra cellular fluid volume

Question 18

Formula to calculate Interstitial Fluid Volume (ISFV)?

Answer 18

Extracellular volume – Plasma volume

Question 19

What are Starling’s forces?

Answer 19

Starling’s forces are the forces that act upon the fluid in the capillaries.

Question 20

What are the components of extracellular fluid?

Answer 20

the major cation of the ECF is Na+

the major anions are Cl- and HCO3-

Question 21

What are the components of intracellular fluid?

Answer 21

The major cation of ICF is K+

the major anions are phosphates, organic anions
and negatively charged proteins.

Question 22

What is Capillary hydrostatic pressure (Pc)?

Answer 22

Force that pushes fluid out of capillaries

Question 23

What is Osmotic force due to interstitial fluid protein concentration (πif)?
(interstitial oncotic pressure)

Answer 23

Force that draws fluid out of capillary and into interstitial

Question 24

What is Interstitial fluid hydrostatic pressure (Pif)?

Answer 24

Force that pushes fluid into capillary

Question 25

What is Osmotic force due to plasma protein concentration (πp)? (capillary oncotic pressure)

Answer 25

Force that pulls fluid into capillary

Question 26

What is hydrostatic pressure?

Answer 26

Force generated by pressure of fluid on capillary walls either by blood plasma or interstitial fluid. Generated by pumping action of heart Promotes ultrafiltration from capillary

Question 27

What is oncotic pressure?

Answer 27

Derived from non-diffusible proteins

Question 28

What are three causes of odema?

Answer 28

Hydrostatic pressure changes Oncotic pressure changes Capillary membrane changes

Question 29

What do hydrostatic pressure changes result in?

Answer 29

Increased arterial pressure venous blockage/stasis lymph node enlargement lymphatic blockage, e.g. filariasis

Question 30

What do oncotic pressure changes result in?

Answer 30

plasma protein changes nephritis malnutrition (kwashiokor) hepatic damage

Question 31

What do capillary membrane changes result in?

Answer 31

Histamine increases permeability of membrane, more fluid leaving capillary and going into interstitial

Question 32

What is Water Steady State?

Answer 32

The amount of water coming into the body each day must equal the amount of water eliminated from the body over the same period of time.

Question 33

What are sources of water?

Answer 33

Water Drinking Water contained in Food Metabolism = CO2 and H2O

Question 34

What are the means by which water is lost?

Answer 34

``` Urinary loss/ Fecal loss. Insensible H2O loss. Evaporation from the respiratory tract and the skin surface Sweat Losses ```

Question 35

Symptoms of Mild Dehydration | <5% BW

Answer 35

``` Thirst Loss of Appetite Dry Skin Skin Flushing Dark Colored Urine Dry Mouth Fatigue or Weakness Chills Head Rushes ```

Question 36

Symptoms of Moderate or Severe Dehydration

Answer 36

``` Increased heart rate Increased respiration Decreased sweating Decreased urination Increased body temperature Extreme fatigue Muscle cramps Headaches Nausea Tingling of the limbs ```

Question 37

What are Darrow-Yannet Diagrams used for?

Answer 37

Used to give a simple assessment of volume and osmolality status of body. How the volume of fluid in the ECF and ICF are affected in various situations

Question 38

Steps to using Darrow-Yannet Diagram

Answer 38

1. Determine the change in ECF volume 2. Determine the change in ECF osmolarity 3. Consider the shift in water across the cell membrane via osmosis 4. Determine the change in ICF volume

Question 39

Describe Iso-osmotic dehydration in terms of Darrow-Yannet Diagram

Answer 39

Loss of equal amount of water and solutes. This results in a decreases of volume in ECF & No change in osmolarity or ICF volume.

Question 40

Describe Iso-osmotic over hydration in terms of Darrow-Yannet Diagram

Answer 40

Gain of equal amount of water and solutes. This results in an increase of volume in ECF & No change in osmolarity or ICF volume.

Question 41

Describe Hyper-osmotic dehydration in terms of Darrow-Yannet Diagram Loss of hypotonic

Answer 41

Loss of more water than solute. This results in an decrease of volume in ECF & osmolarity increases and ICF volume decreases.

Question 42

Describe hypo-osmotic overhydration in terms of Darrow-Yannet Diagram Gain of hypotonic fluid

Answer 42

Gain of more water than solute. This results in an increase of volume in ECF & osmolarity decreases and ICF volume increases.

Question 43

Describe hypo-osmotic dehydration in terms of Darrow-Yannet Diagram Loss of hypertonic fluid

Answer 43

Loss of more solute than water. This results in a decrease of volume in ECF. Osmolarity decreases and ICF volume increases.

Question 44

Describe hyper-osmotic overhydration in terms of Darrow-Yannet Diagram Gain of hypertonic

Answer 44

Gain more solute than water. This results in an increase of volume in ECF. Osmolarity increases and ICF volume decreases.