Mcp Lect 01-02 - Homeostasis And Body Fluid Compartments

Front 1

Mole

Back 1

Gram molecular weight of a compound

6.02 x 10^23 molecules

Front 2

Molarity

Back 2

Moles of a substance per liter of solution

Front 3

Molality

Back 3

Moles of a substance per kilogram of solvent

Front 4

Equivalent =

Back 4

=Number of moles of an ionized substance*charge
=Gram molecular weight/charge

The number of equivalents of Ca++ is 2x the number of moles.
or
1mEq Ca++= 40mg/2

Front 5

1 Eq =

Back 5

Gram molecular weight of an electrolyte divided by its charge

Eg. 1mEq Na = 23 mg/1
1 mEq Ca++ = 40 mg/2

Front 6

Milligrams percent (mg%)=

Back 6

Number of milligrams of a substance / 100 ml of solution

Front 7

1 Osmole (Osm)=

Back 7

One gram mole of non-diffusible and non-ionizable substance

Eg. 1 mole of glucose = 1 Osm; 1 moles of NaCl = 2 Osm

Front 8

Osmolarity=

Back 8

Osmols of a substance per liter of solution

Front 9

Osmolality=

Back 9

Osmoles of a substance per kilogram of solvent

Front 10

Osmotic pressure =

Back 10

Measured as the hydrostatic pressure applied to a solution separated from pure solvent by a selectively permeable barrier (permeable only to solvent) which will prevent the movement of solvent into the solution

pi = oicRT
pi=osmotic pressure
o=reflection coefficient (0=permeable 1=impermeable) = 1-(Psolute/Pwater)
c=concentration
R=gas constant
T= temperature in Kelvin

Front 11

Intracellular fluid

Back 11

Fluid contained within the cells of the body

Front 12

Extracellular fluid

Back 12

Fluid external to the cells of the body

Front 13

Interstitial fluid

Back 13

Extracellular fluid outside the vascular compartment of the body

Front 14

Plasma

Back 14

Fluid compartment of the blood

Front 15

Serum

Back 15

Plasma without clotting factors

Front 16

Plasma membrane

Back 16

The unique lipid bilayer structure separating intra-and extracellular fluid compartments

Front 17

Effective osmotic pressure

Back 17

Part of the total osmotic pressure of a solution which governs the tendency of its solvent to pass through a semipermeable membrane

Front 18

Oncotic pressure

Back 18

-The osmotic pressure due to colloids
-A form of osmotic pressure exerted by proteins in blood plasma that usually tends to pull water into the circulatory system.

Front 19

Tonicity

Back 19

The effective osmotic pressure

Front 20

Diffusion

Back 20

The random movement of molecules resulting from the inherent kinetic energy of the same molecules

Front 21

Bulk flow

Back 21

The movement or flow of solutions resulting from the application of an external force (ie. hydrostatic pressure)

Front 22

What percentage of body weight is water?

Back 22

Approx. 60%, roughly 40 L in a 70 kg person

-As you age, this percentage decreases
-Percentage also decreases in obese individuals:
INCREASE in adipose = DECREASE in WATER

Front 23

What are the important body fluid compartments? Roughly what % of the total volume does each constitute?

Back 23

1. Intracellular fluid compartment (2/3 total body water)
2. Extracellular fluid compartment (1/3 total body water)
3. Interstitial compartment (3/4 ECV)
4. Plasma (1/4 ECV)
5. Red cell

Front 24

Milieu interio

Back 24

Internal environment around cells that allows for homeostasis and
function

Front 25

Homeostasis

Back 25

The process by which the body maintains constancy in internal function in the face of changes in the external environment

Front 26

Concentration

Back 26

The quantity (mass) of the substance (solute) which is dissolved in a volume of fluid (solvent)

Front 27

To accurately measure the volume of a particular compartment you must know:

Back 27

1. The quantity of your indicator or dye to be injected into the compartment
2. The indicator stays within the compartment to be measured
3. The indicator disperses throughout the compartment

Front 28

Measurement of Plasma Volume:

Back 28

1. Evans blue dye
2. Radioiodinated albumin

*needs to bind to protein or be big enough to stay in the plasma and not cross the capillaries

Front 29

Measurement of Extracellular Fluid Volume:

Back 29

1. Radioisotopes of selected ions (sodium, chloride, sulfate thiocyanate)
2. Nonmetabolizable saccharides (inulin, mannitol, raffinose)
3. Radioactive iothalamate (125i-iothalamate)

Front 30

Measurement of Total Body Water:

Back 30

1. Tritiated water (3h-H2O)
2. Deuterium oxide (D2O)

Front 31

Measurement of Intracellular Fluid Volume:

Back 31

Needs to be calculated:
Total body water - extracellular fluid volume

Front 32

Measurement of Interstitial Fluid Volume:

Back 32

Needs to be calculated:
Extracellular fluid volume - plasma volume

Front 33

Measurement of Blood Volume:

Back 33

A. Radiolabeled red blood cells with chromium51

B. Can also be calculated:
1. Hematocrit: Fraction of RBC/BV (usually expressed as a percent)
2. BV = plasma volume / 1 - Hematocrit fraction

Front 34

Hematocrit

Back 34

Fraction of RBC/BV (usually expressed as a percent)

Front 35

Porous Membrane

Back 35

o Lets solute and water through
o Membrane in name only

Front 36

Ideal semipermeable membrane

Back 36

o Only lets solvent through, not solute
o Biological membranes are not ideal

Front 37

Semipermeable (selectively permeable) membrane

Back 37

o Biological membranes are selectively semipermeable
o They let some things through but not others

Front 38

Osmosis

Back 38

o The tendency of a fluid, usually water, to pass through a semipermeable membrane into a solution where the solvent concentration is higher, thus equalizing the concentrations of materials on either side of the membrane.
o “Water goes where salt is”

Front 39

Hydrostatic Pressure

Back 39

o The pressure exerted by a fluid at equilibrium due to the force of gravity

Front 40

Hypo-osmotic solution

Back 40

o Containing a lower concentration of osmotically active components than a standard solution

Front 41

Hyper-osmotic solution

Back 41

o Containing a higher concentration of osmotically active components than a standard solution

Front 42

Iso-osmotic solution

Back 42

o Having the same osmotic pressure

Front 43

List the Starling forces governing fluid movement across capillaries.

Back 43

Capillary pressure (Pc)
interstitial fluid pressure (Pif)
plasma colloid osmotic pressure (πp)
interstitial fluid colloid osmotic pressure (πif)

Hydrostatic: Pc, Pi
Oncotic: Pic, Pii
Typically: Pc > Pi --> fluid out ; Pic > Pii --> fluid reabsorption

Front 44

What is the osmolality of the extracellular and intracellular compartments under steady state conditions?

Back 44

~300 mOsmoles/L

Front 45

What happens if you put a cell in a hypertonic solution?

Back 45

Cell shrinks

Front 46

What happens if you put a cell in a hypotonic solution?

Back 46

Cell swells
(like a hippo!)

Front 47

Jv=

Back 47

Jv=flux
Jv=kf*[(HPc-HPi)-(PiC-PiI)]

where

kf=surface area and hydraulic permeability
Hpc= Hydostatic Capillary Pressure
HPi = Hydrostatic Interstitial Pressure
PiP= Plasma colloid osmotic pressure
PiI=Interstitil colloid osmotic pressure