11B H2O/electrolyte & Fluid Physiology Flashcards Preview

AS - N927 Chem/Physics > 11B H2O/electrolyte & Fluid Physiology > Flashcards

Flashcards in 11B H2O/electrolyte & Fluid Physiology Deck (33)
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1
Q

Homeostasis

A

Given physiologic function or variable remains w/in predictable range (time averaged mean) over time
When ↑↓ disturbed, restored to baseline

2
Q

Hydrostatic Pressure

A

Pressure exerted by any fluid at equilibrium d/t gravitational force

3
Q

Concentration

A

Amount solute (particles) per unit solvent volume

= Amount solute / Volume solvent

4
Q

Ion

A

Atom or group of atoms w/ an electrical charge +/-
Cation (+)
Anion (-)

5
Q

Octet Theory

A
All elements need 8e¯ in outer orbit 
Stable & unreactive 
Elements w/ 4e¯ share (Amphoteric)
< 4e¯ tend to lose
> 4e¯ tend to gain
6
Q

Valence e¯

A

electrons in an atom outermost energy level (shell)
NOT the same as valency
Chloride 7 valence e¯

7
Q

Valence Osmosis

A

Atom combining power
Absolute number electrons gained, lost, or borrowed in order to fill outermost energy level
Chloride 1 valency

8
Q

Equivalents

A

Represents electroneutrality (balanced +/-) in solutions
Electroneutrality maintained in plasma & ISF
Total # ionic charges in solution (ion moles) and considers each ion valence (charge)
1 Mole Cl¯ = 1Eq
1 Mole Ca2+ = 2Eq

9
Q

mEq

A

Electrolyte chemical activity
1/1,000
NaCl = mEq +/-

10
Q

mg/dL → mEq/L

A
mg/dL = (mEq/L x Atomic weight) / (10 x valence)
mEq/L = (mg/dL x 10 x valence) / Atomic weight
11
Q

Conversions mEq/Moles/mg

A
222mg CaCl2 in 1L fluid
GMW = 111g/Mol = 111mg/mMol
222mg/(111mg/mMol) = 2 mMol in 1L
2mMol/L = 2mM
2mM CaCl2 → 2mM Ca2+ + 4mM Cl¯
Ca2+ 2mMol x valency 2 = 4mEq/L cation
Cl¯ 4mMol x valency 1 = 4mEq/L anion
Electroneutrality maintained when salt dissolves
12
Q

Osmosis

A

Net water diffusion across membrane

H2O movement across selectively permeable membrane

13
Q

Osmotic Pressure

A

Pressure that must be applied to solution to prevent net flow water into (osmosis)
Number particle correlates to osmotic pressure
Large (glucose) and small (Na+) particles exert the same osmotic pressure
Smaller mass = higher velocity
K = (mv^2) / 2
Directly r/t solute concentration (osmolality)
H2O moves from high to low osmolality areas
Indirect measure H2O & solute concentration
↑ osmotic pressure → ↑ solute concentration ↓ H2O

14
Q

Osmol

A

Amount per unit volume
Expresses solute concentration
1 mole (GMW) of solute particles dissolved in solution
Osmoles refers to osmotically active particles in solution

1 Mole / 1L = 1 Molar = 1M
1 osmol / 1L = 1 osmMolar = 1 osmM

1 Osmole = 1 Mole solute particles = 1,000 mOsm
Total number particles in solution measured in osmoles

15
Q

OsmolaRity

A

Chemistry term
Osmotic concentration of solution
Osmoles of solute per liter of solution
Unable to measure actual L fluid in body - estimate
Molar solution # moles of solute per liter of solution
Osmoles/L solution
Directly proportional to osmotic pressure

16
Q

OsmolaLity

A

Physiological term - most correct clinically
Body weight in Kg (measurable)
Osmotic concentration of solution
Osmoles of solute per Kg of solution
Molal solution # moles of solute per Kg of solution
Osmoles/Kg solution

17
Q

Total Body Water

A
60%
70Kg x 0.6 = 42L
Extracellular
- Plasma (3L)
- Interstitial (11L)
Intracellular 28L
18
Q

Sodium

A
Na+ 
1° extracellular cation
Accurately reflects osmolality
H2O moves out
↑ osmolality
↑ Na+ concentration
19
Q

Potassium

A

K+

1° intracellular cation

20
Q

The Donnan Equilibrium

A

Negatively charged non-diffusible protein molecules (Albumin) on one membrane side leads to an excess diffusible cations and deficit diffusible anions on same side
Proteins are multi-valent (many negatively charged areas) therefore attract multiple cations

21
Q

Van Hoff’s Law

A
π = CRT
Osmotic pressure in mmHg π 
C = solute in osmoles/L
R = Ideal gas constant 62.36
T = temperature in °Kelvin

1 mOsm = 19.3mmHg

22
Q

Calculate Osmotic Pressure

A
0.9% NaCl = 0.9g/100ml = 9g/L
NaCl GMW = 23 +35.5 = 58.5g/mole
(9g/L) / (58.5g/mole) = 0.154moles/L
154mMoles/L
Na+Cl¯ dissociates in solution to Na+ and Cl¯ ions
1 Mole NaCl = 2osmoles
154mMoles/L x 2 = 308mOsm/L = Isotonic
23
Q

Adult Osmolality

A

285-295mOsm/Kg

24
Q

Pediatric Osmolality

A

275-290mOsm/Kg

25
Q

Isotonic

A

No net movement

26
Q

Hypertonic

A

400mOsm

Water moves out into solution → cells shrink

27
Q

Hypotonic

A

200mOsm

Water moves into cells → cells swell

28
Q

Colloid Osmotic Pressure

A

Oncotic pressure
Donnan equilibrium effect results in colloid osmotic pressure in the plasma
Increases effect by 50% as compared to proteins alone

29
Q

Isotonic Crystalloid

A
NS or LR
Stays in extracellular fluid - plasma &amp; ISF
20% (3/14) left in plasma
No impact on intracellular
Exception - dehydrated cell
30
Q

Hypotonic Crystalloid

A

D5W
Dextrose used in metabolism leaving hypotonic H2O
7% (1/14) left in plasma
Equilibrates across all three compartments

31
Q

Isotonic Colloid

A

5% Albumin
All volume remains in plasma 100%
Unable to cross endothelium ჻ confined to plasma
Donnan effect to pull additional fluid into vasculature

32
Q

Hypertonic Crystalloid

A

3% saline
Equilibrates across extracellular compartments - plasma & ISF
Pulls fluid from intracellular to extracellular

33
Q

Plasma Volume Expansion

A

How much fluid stays in the plasma?
PV expansion = PV / Vd
↑ Vd ↓ plasma volume expansion