Physiology 1

Question 1

Tracer for TBW

Answer 1

3H20

Question 2

Tracer for ECF

Answer 2

Inulin

Question 3

Tracer for plasma

Answer 3

Labelled albumin

Question 4

V=D/C

Answer 4

Volume (litres) = Dose/Sample concentration

Question 5

How do you measure water imbalance?

Answer 5

Changes in body fluid osmolarity

Question 6

Sodium greatest concenctration ICF or ECF?

Answer 6

ECF
-lots of chlorine in ECF as well
(potassium in ICF)

Question 7

Fluid shift?

Answer 7

Movement of water between the ICF and ECF in response to an osmotic gradient

Question 8

Gain and loss of NaCl and change in volumes of ECF and ICF

Answer 8

ECF NaCl gain:
ECF ↑ ICF↓
ECF NaCl loss:
ECF ↓ ICF ↑

Question 9

What happens with gain or loss of isotonic fluid?

Answer 9

e.g. 0.9% NaCl solution
= no change in fluid osmolarity
Change in ECF only

Question 10

Primary anion of the ECF?

Answer 10

Chlorine

Question 11

Primary cation of the ECF?

Answer 11

Sodium

cation = positive

Question 12

When does electrolyte balance occur?

Answer 12

When rates of gain = rates of loss (lol)

Question 13

> 90% of the osmotic concentration of the ECF results from the presence of …?

Answer 13

sodium salts

Question 14

What can happen if concentration of K+ falls?

Answer 14

Muscle weakness –> paralysis

Cardiac irregularities –> cardiac arrest

Question 15

Plays a key role in establishing membrane potentials?

Answer 15

K+

Question 16

Salt imbalance is manifested as changes in …?

Answer 16

Salt imbalance is manifested as changes in extracellular fluid volume
(remember water was measured as changes in osmolarity)

Question 17

ICF percentage of TBW?

Answer 17

67%

Question 18

ECF percentage of TBW?

Answer 18

33%

plasma makes 20% of this, Interstitial fluid makes 80% of this

Question 19

Main ions in the ECF?

Answer 19

Na+, Cl-, HCO3

Question 20

Main ions in the ICF?

Answer 20

K+, Mg2+

Question 21

Which ion is mainly present in the ECF and is therefore a major determinant of ECF volume?

Answer 21

Na+

Question 22

You need to control this ion to prevent muscle weakness (–> paralysis) and cardiac irregularities (–> cardiac arrest)

Answer 22

K+

Question 23

Regulation of what is important for the long-term regulation of blood pressure?

Answer 23

Extracellular fluid volume

Question 24

Total body water of male?

Answer 24

60% of body weight

Question 25

Total body water of female?

Answer 25

50% of body weight