Body Fluid Compartments (Muster) - W1

Question 1

How much of our body is made up of water?

Answer 1

60%

Question 2

Defined as the total free solute per Kg of solvent

Answer 2

OsmolaLITY

Question 3

Defined as the total free solute per liter of solvent

Answer 3

OsmolaRITY

Question 4

Where is plasma found and what are its components?

Answer 4

• Intravascular space (inside the blood vessel)
• Huge amount of negative charge - comes from albumin
• total solute = 300
• Sodium = 140
• Choridie = 105
• HCO3 = 26
• Urea = 6
• Weak organic acid = 6
• glucose =5
• K+ =4
• Ca++ = 4
• Mg+ = 1
• H2PO4 = 1
• Albumin =1

Question 5

How do we calculate the anion gap and what is responsible for it?

Answer 5

• Albumin generates anion gap
• Na+ - (Cl + HCO3+)
  
  • a wide differenence in the gap indicates disease

Question 6

What is interstitial fluid and what separates it from plasma?

Answer 6

• IF = plasma without albumin
• capillary wall separates the two

Question 7

What are the forces at play between the IF and plasma?

Answer 7

• Cl- wants to flow across into plasma, water would follow
• Albumin generates oncotic pressure and acts as a draw.
• Pressure inside capillary favors FILTRATION.
• Oncotic pressure favors REABSOPRTION.
• Pressure in IF favors REABSORPTION.
• Oncotic pressure in IF favors FILTRATION.

Question 8

What are the components of intracellular fluid?

Answer 8

• More K+ = 140
• PO4- = 4
• Cl - = 20
• Protein = lots
• Na+ = 10
• Mg+ = 10
• SO4- = 20
• Total = 240

Question 9

What are the forces acting on the intracellular and interstitial fluid and what separates them?

Answer 9

• separated by cell membrane ​
• sodium wants to flow INTO CELL, K+ wants to flow out. Water would flow in and lead to bursting.
  
  • prevent with Na/K ATPase to maintain gradient.

Question 10

Any solution that has ~300mOsmos

Answer 10

Isosmotic

Question 11

Any solution that WILL NOT change the VOLUME of a cell.

Answer 11

isoTONIC

Question 12

Decribe how water is distributed in the body between the compartments.

Answer 12

• Total body water = 60%
  
  • intracellular = 2/3
  • extracellular = 1/3
    
    • ​interstitial = 3/4
    • plasma = 1/4

Question 13

Explain what happens with the EC compartements when you water to a patient?

Answer 13

• Volume - INCREASES in both IC and EC
• EC Na+ decreases.
• IC K+ decreases.

Question 14

Explain what happens with body compartments when you give NS?

Answer 14

• ONLY goes into EC compartment
• Volume = INCREASED IN EC
• NA REMAINS SAME. = ISOTONIC

Question 15

Explain what happens with compartments when you give pure salt:

Answer 15

• only goes into EC compartment
• Na+ INCREASES in EC
• water moves from IC to EC
• DECREASED cell volume
• INCREASED EC volume

Question 16

What is volume depletion?

Answer 16

• Extracellular volume loss from ANY CAUSE - most often loss of salt and water. ​

Question 17

What is dehydration?

Answer 17

• presence of hypernatremia (increased osmolality) due to pure water loss

Question 18

If you drink IL of water, how will it distribute?

Answer 18

• 2/3 IC = 666
• 1/3 EC = 333
  
  • 3/4 interstiial = 250
  • 1/4 plasma = 83

Question 19

What will happen if you infuse normal saline?

Answer 19

• Increased PRESSURE in the plasma
• decreased oncotic pressure in plasma
• will flow into interstital but be STUCK THERE
• Overall
  
  • 750mL to interstitial
  • 250mL to plasma
  • no change in overall osmolality.

Question 20

What situations call for NS?

Answer 20

• DKA - diabetic ketoacidosis
  
  • volume depleted - water follows glucose into urine
  • may be hypotensive and tachycardic
• Sepsis

Question 21

In what situations would you give 1/2NS and how does it affect the cell?

Answer 21

• Distribution
  
  • NS goes extracellular
  • water goes everywhere
• Known as a maintenance fluid
• Situations
  
  • Sweat loses - water, Na, Cl- is lost
  • Hospitalization - patients are often sweating and have fever + water loss w/higher RR

Question 22

What situations would you give 1L of D5W and how does it distribute?

Answer 22

• distributes everywhere
  
  • ​glucose gets removed completely - sol’n is isosmotic in bag but hypotonic in vivo.
• Situations
  
  • Diabetes insipidus - pee lots of water
  • Severe hypoglycemia