Lecture 14 Body Fluids and Compartments and Urinary System Overview Flashcards Preview

Whitney - Physiology Test 2 > Lecture 14 Body Fluids and Compartments and Urinary System Overview > Flashcards

Flashcards in Lecture 14 Body Fluids and Compartments and Urinary System Overview Deck (34)
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1

Osmolarity

mOsm (milliosmoles)/L = concentration of particles per liter of solution

2

Osmolality

mOsm/kg = concentration of particles per kg of solvent (water in biological systems)

3

Effective Osmole

Refers to solute that does not easily cross a membrane
It is an effective osmole because it creates an osmotic force for water.

4

______ are effective osmoles for the vascular compartment

Proteins

5

Daily intake of water through ingestion (fluids or foods)

2100 ml/day

6

Daily intake of water through metabolism

200 ml/day

7

Total daily intake of water

2300 ml/day

8

Daily loss of water through insensible evaporation

350 ml/day through skin
350 ml/day via lungs
3-5 Liters/day for severe burns

9

Daily loss of water through sweat

100 ml/day
5000 ml/day during exercise

10

Daily loss of water through feces

100 ml/day

11

Daily loss of water through urine

1400 ml/day
500 ml/day during exercise

12

Total daily loss of water

2300 ml/day

13

Osmolar Gap

Helps to narrow the differential diagnosis
Difference between the measured osmolality and the estimated osmolality

14

Common things that can elevate the osmolar gap:

Ethanol
Methanol
Ethylene glycol
Acetone
Mannitol

15

Ionic composition of plasma and interstitial fluid is similar because:

they are separated by a highly permeable capillary membranes

16

Why is there a higher concentration of proteins in the plasma?

Because capillaries have a low permeability to plasma proteins

17

Intracellular fluid composition:

Small amounts of sodium and chloride ions
Almost no calcium ions
Large amounts of potassium and phosphate ions
Moderate amounts of magnesium and sulphate ions

18

Indicator-Dilution Principle

Applies to measurement of fluid volumes in body fluid compartments

19

Requirements for an indicator:

Disperses evenly throughout compartment
Disperses only in compartment being measured
Not metabolized or excreted
Not toxic

20

Relative amounts of extracellular fluids in interstitial spaces and plasma are determined primarily by:

Balance of hydrostatic and colloid forces across capillary membranes

21

Distribution of fluid between intracellular and extracellular compartments is determined mostly by:

osmotic effects primarily of sodium and chloride

22

Units of concentration in body fluids are typically expressed in terms of:

Milliosmoles (mOsm)

23

For each mOsm concentration gradient of an impermeant solute, about _____ mmHg osmotic pressure is exerted across the cell membrane.

19.3

24

Calculating Potential Osmotic Pressure of a Solution

Slide 21

25

About 80% of the total osmolarity of the interstitial fluid and plasma is due to:

Sodium and chloride ions

26

For intracellular fluid, about half the osmolarity is due to:

Potassium ions

27

Addition of isotonic saline to extracellular fluid compartment:

Extracellular osmolarity does not change
Extracellular volume increases

28

Addition of a hypertonic saline to extracellular fluid compartment:

Intracellular volume decreases
Extracellular volume increases
Osmolarity in both compartments increases

29

Addition of hypotonic saline to extracellular fluid compartment:

Volume of both compartments increases
Osmolarity in both compartments decreases

30

A solution of impermeant solutes having an osmolarity of 282 mOsm/L is isotonic --> ?

Water cannot enter or leave the cell