Fluid compartments Flashcards
(88 cards)
1
Q
how much percent of our body is water
A
60%
2
Q
how is water divided in ECF and ICF
A
ECF is 1/3
ICF is 2/3
3
Q
the plasma is considered ECF or ICF
A
ECF
4
Q
What is in the “third space” when there is excess fluid
A
water from epithelial secretions, synovial and CSF
5
Q
what percent of ECF is plasma
A
1/4
6
Q
how many liters are in the Arterial effective circulating volume
A
.7 liters
7
Q
What is the effective circulating volume independent of
A
extracell volume, plasma volume and CO
8
Q
What is Vd of a drug
A
the colume of body fluid in which the total dose is distributed at same concentration of plasma
9
Q
if the Vd is 45
A
45 all body tissues, even bone and spinal fluid
10
Q
how does daily total intake and output of fluid compare
A
in the end equal each other.
11
Q
Compare Na, K, Ca, Mg and HCO3 and HPO4 in ICF vs ECF
A
ECF has higher Na and Cl and HCO3-
ICF has higher K, Mg and HPO4
12
Q
How is the osmolarity in ECF vs ICF
A
the same osmolarity
13
Q
where are there higher non-electrolyte protein levels
A
ICF, intravascular compartments
14
Q
do the proteins change osmolarity? oncotic pressure?
A
changes oncotic pressure
does not change osmolarity because the large proteins are impermeable
15
Q
majority of the non-electrolytes in the plasma are what 2 compounds
A
phospholipids and cholesterol
16
Q
how do we measure total body water and plasma volume directly, clinically
A
dilution of injected radioactive substances or dyes
17
Q
how is ICF fluid calculated
A
TBW-ECF
18
Q
how is interstitial volume calculated
A
ECF- plasma volume
19
Q
how can total blood volume be calculated
A
need to know plasma volume and Hct
TBV= plasma volume/1-Hct
20
Q
how can you estimate plasma osmolality by [Na]
A
2X plasma [Na]
21
Q
What is the donnan effect
A
Na K concentrations are higher in vascular spaces due to the negative charges of proteins
22
Q
what besides [Na] is important in plasma osmolality
A
glucose/18 and urea/2.8
23
Q
What keeps the Na concentration what it is
A
Na-K ATPase pump
24
Q
what ion is the key regulater of intracellular osmolality
A
presence of K
25
fluid distribution between ECF and ICF depends on what
osmotic effects of Na and Cl
26
What is the capillary cell membrane between ECT and capillary permeable to
small ions
27
what is the fluid distribution dependent on between capillary and interstitial fluid
starling forces
28
What scenarios clinically result from fluid/solute loss
Bruns, Hemorrhage, vomiting/diarrhea, dehydration
29
what do you target during intravenous replacement fluids when oral rehydration is not suitable
target the volume-depleted comparment
30
what is in crystalloid fluids
contain varying concentrations of electrolytes and can stay in ECF or be widely distributed depending on composition
31
what are types of crystalloid fluids
normal saline, lactated Ringer's solutions
32
what is in colloid fluids
large proteins and molecules that stay in vascular space
33
why do we give colloid fluids
to pull volume out of cells
34
a isosmotic solution means what
solutions that have the same osmolarity as the ECF
| does not change osmolarity, increases volume only
35
a hyperosmotic solution means what
solutions have an osmolarity greater than that of the ECF
36
What will happen in the addition of a hyper osmotic solution
when added to the ECF, osmolarity increases and causes water to move from cells to ECF to increase volume
37
a hyposmotic solution means what
solutions having an osmolarity less than that of ECF
38
what happens in the addition of a hyposmotic solution
decreases the osmolarity and water moves into the cells
| Increases both ECF and ICF
39
What does tonicity of a solution depend on
the concentration of impermeant solutes in ECF vs ICF
40
how does cell volume change when in an hypotonic solution? hypertonic? isotonic?
in hypotonic the cell V increases
in hypertonic the cell V decreases
isotonic- the cell V does not change
41
What factors affect osmolarity and V of ECF and ICF
water ingestion, dehydration, intravenous infusions, diarrhea or vomiting, sweating, diuresis, disease
42
what factor affects distribution of fluid between ECF and ICF compartments
```
ion distribution Na
ATPase actvity(keeps Na low and K high intracell)
```
43
what factos affect distribution of ECF between plasma and interstitial comparments
balance of hydrostatic vs oncotic pressure
| intravascular pressure in capillaries vs plasma protein and solute concentration
44
palpable swelling is from what
expansion of interstitial fluid volume
45
renal retention of dietary Na and water how does ECF change
increases
46
At what levels is edema apparent
2.5-3 L aboe normal plasma volume of 3L
47
what usually causes edema
compensatory renal retention of Na and water to maintain plasma volume
48
what clinical situations result in edema
primary renal disease like glomerulonephritis and nephrotic syndrome
49
what causes non-pitting edema
swollen cells due to increased ICF volume
50
how is edema usually treated
diuretics
51
how is osmotic pressure determined
by the number of solutes in a solution, not size or mass or chemical nature
52
what is the difference between osmolarity and osmolality
osmolarity is the number of solutes per L of solvent
| osmolality is the number of solute per 1 kg of solvent
53
What factor is osmolality independent of
temperature
54
if you placed a RBC in a solution of urea what would happen
the RBC would burst because urea is hypotonic
55
would urea be condisered and effective or ineffective osmole when talking about RBC membrane
ineeffective because it cannot exert an osmotic pressure since it can cross the membrane
56
What is oncotic P
osmotic P generated by large molecules (proteins) in solution
57
what is specific gravity
the total solute concentration in a solution
58
What do we measure clinically to assess the concentrating ability or the urine
the specific gravity
59
What makes of ECF
1/4 plasma
| 3/4 interstitial fluid from bone, dense CT and CSF
60
Ascites is an example of what fluid utilization
"third space"
61
how is urea measure in plasma
as the nitrogen in the urea molecule. BUN
62
does hydrostatic pressure cause a gradeint across ECF and ICF? osmotic pressure?
hydrostatic pressure does not
| osmotic pressure does
63
what does the capillary filtration coefficient reflect of capillary wall? Kf
the movement of fluid and SA available for filtration
64
Precapillary sphincters control what
hydrostatic P in an individual capillary and number of perfused capillaries in tissue
65
What is used clinically to decrease a cerebral edema
mannitol because it does not cross blood brain barrier and sucks water out, effective osmole
66
if you need to increase a patients vascular volume what do you infuse
5% albumin because albumin does not cross barrier
67
how do you expans a patients ECF
isotonic NaCl solution
68
what are the neural and hormonal effector mechanisms to changes in volume and osmolarity of blood
neural is sympathetic discharge
| hormonal is ADH and aldosterone secretion
69
where are the osmoreceptors of the body located
anterior hypothalamus near supraoptic nuclei
70
what do osmoreceptors not respond to
hypertonic solutions of urea or glucose
71
where are the volume receptors of the body located
right atrium
72
an increase in blood volume has what effect
stimulate volume receptors that inhibit vasomotor area and suppress sympathetic discharge
also inhibit thirst and ADH secretion
73
which type of receptor in the body is more sensitive. osmo or volume?
which has greater effects?
osmoreceptors more senstiive
| volume receptors have stronger effects
74
Where is ADH released and what is its role
posterior pituitary gland to promote water reabsorption from collecting duct to make isotonic or hypertonic
75
What stimulates the release of aldosterone
circulating ANG II from SANS activity
rise in plasma [K]
fall in plasma [Na]
76
What is the effect of aldosterone
reabsorption of Na from distal convoluted tubule
77
What stimulates thirst? inhibits?
stimulated by osmoReceptor impulses and ANG II
| inhibited by volume receptor stimulation
78
What are the two major responses to hypovolemia
salt cravings and sympathetic discharge to retain Na and H2O
79
What are the consequences to a lot of drinking plain water
increase ICF and ECF volumes with slightly lower osmolarity
80
What is the response to drinking mass amounts of plain water
excretion of hypotonic urine. however Na always gets out so long term leads to Na depletion
81
what is the consequence of drinking excess salt, hypertonic saline
plasma volume and osmolarity increase. the plasma colloid pressure decreases. so water moves out of capillaries increasing ECF volume and osmolarity. this extracts fluid from ICF (shrinking cells)
82
what is the corrective response to intake of hypertonic saline
water retention because increase of plasma osmolarity. plasma volume overload overrides this osmolarity tonicity.
suppress thirst and ADH, excretion large volumes hypotonic urine..exacerbating osmolarity
Natriuretic hormone that promotes Na excretion
83
sweating is creating what type of tonicity
loss of hypotonic fluids
84
diarrhea, intestinal obstruction, ascites, burns, hemorrhage is creating what type of tonicity
loss of isotonic fluids
85
what is the consequence of profuse sweating or diarrhea or hemorrhage
ECF V decreases(plasma is ok because proteins retain fluid)
ECF osmolarity increases(unless loss isotonic)
Rise in ECF osmolarity draws water from cells, Shrunk cells--> painful cramps
86
what is the corrective response to losing hypotonic solution
stimulation of osmoR because plasma osmolarity increased, redicution of the plasma volume inhibits volume R.
need to re-correct with isotonic or hypotonic SALT solutions
87
Na restricted diet or loss of hypertonic fluid from vomititng causes what
decrease in ECF osmolarity, water moves into cells
ECF V dec, ICF V increases- cell swell
thirst center swells and interprets as excess water so inhibits thirst
88
what is the corrective response to loss of hypertonic solution
thirst is absent, which is good so cells don't burst
intense Na craving to draw water out from ICF back into ECF
as cells lose water thirst is restored and fluid intake corrects the rest
