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ANATOMY & PHYSIOLOGY II
Lecture #16: Fluid and Electrolyte Balance
To Do: Tell if each of these is part of or refers to the intracellular (I) or the extracellular fluid compartment E).
Lymph
Cytoplasm
Plasma
Interstitial fluid
Contains most of the body’s water
Fluid located between tissue cells
Transports substances in body
Provides medium for chemical reactions to occur
Answer the following:
If you urinate more than you drink, you are in: a) positive water balance; b) negative water balance
Obligatory water loss is: a) the amount of water we lose after vigorous exercise as sweat;
b) loss that results in a negative water balance; c) the minimum amount of water lost each day.
Other than urine, most water is lost through the: a) skin; b) lungs; c) sweat; d) feces.
To Do: For each of the following statements, decide which direction fluid would tend to
move. Use these choices: B = into the blood
I = into the interstitial fluid C =
into the cells
Lower than normal sodium levels.
Low blood pressure.
Higher than normal sodium levels.
Lower than normal levels of plasma proteins.
High blood pressure.
Higher than normal levels of plasma proteins.
To Do: Mark whether each of these occurs when the plasma is too dilute (D) or too concentrated (C).
Osmoreceptors in hypothalamus are stimulated.
Vagus nerve causes feelings of thirst.
Osmoreceptors in hypothalamus are inhibited.
Feelings of thirst decrease.
ADH secretion decreases.
Water output decreases (more reabsorption)
ADH secretion increases.
Water output increases (less reabsorption)
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To Do: Indicate whether each of the following would occur when fluid volume is too high (H) or too low (L).
Hypovolemic shock
Decreased angiotensin II levels
High blood pressure
Increased aldosterone secretion
Decreased renin secretion
Decreased aldosterone secretion
Increased renin secretion
Increased reabsorption of sodium
Increased angiotensin II levels
Decreased reabsorption of sodium
If ADH is present, what effect will the absorbed fluid have on plasma concentration?
a) it will make it more dilute
b) it will make it more concentrated
c) it will not change it
REVIEW OF FLUID BALANCE – Answer the following questions:
Fluid balance means that: a) the total volume of fluid is normal; b) the distribution of fluid in the various
compartments is normal; c) both a and b
To maintain fluid balance, output must input. a) be greater than; b) equal; c) be less than
Movement between the plasma and interstitial fluid is controlled by: a) osmotic pressure
b) hydrostatic pressure; c) both a and b
Movement between interstitial fluid and intracellular fluid is controlled by: a) osmotic pressure
b) hydrostatic pressure; c) both a and b
The hormone that maintains the correct fluid volume is: a) aldosterone; b) ADH; c) angiotensin
The hormone that maintains the correct fluid concentration is: a) aldosterone; b) ADH; c) angiotensin
Eating salty potato chips without a drink would stimulate release of: a) aldosterone; b) ADH
Dehydration due to evaporation of water vapor from the lungs would stimulate release of:
a) aldosterone; b) ADH
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To Do: Complete the following:
Write the symbols for Na+, K+, Cl-, HPO4-2, Ca+2, and Mg+2 either inside or outside the cell to show where most is found.
Which two fluid compartments are most similar in terns of the amounts of electrolytes found there?
a) extracellular and intracellular b) interstitial and intracellular
c) plasma and interstitial
Edema could be caused by: a) lots of salt; b) too much potassium; c) too little sodium
True or False: A change in the amount of fluid in a compartment could cause an electrolyte imbalance.
Match the electrolytes with the statements below. Choices: Na+, K+, Cl-, 4HPO -2, Ca+2, and Mg+2.
Forms bones & teeth, needed for blood clotting
Helps maintain blood pressure
Maintains electrical potential of cells
Forms gastric acid, helps transport O2 and CO2
To Do: Match the statements with the imbalance they apply to. (Letters match the
sections above)
b. Simple water depletion
c. Salt depletion
d. Salt poisoning
e. Abnormal sodium retention
Taking a salt tablet without drinking sufficient water.
Dehydration resulting from loss of water vapor through the lungs.
The kidneys reabsorb too much salt and water due to high levels of aldosterone.
A person with diarrhea drinks plenty of water, but doesn’t eat anything.
Too little fluid is in the cells and too much is in the plasma and interstitial fluid; the fluid throughout the
body has too much salt.
The cells remain normal and the fluid concentration is fine, but there is too much fluid in the plasma and
interstitial compartment.
Fluid throughout the body is too dilute; the cells have too much water while the plasma and interstitial
fluid have too little.
Both the cells and the plasma and interstitial fluid have too little fluid; all the body’s fluids are too
concentrated.
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Lecture #16: Fluid and Electrolyte Balance – Answer Key
Page 2 - Tell if each of these is part of or refers to the intracellular (I) or the extracellular fluid compartment E).
E
Lymph
I
E
I
Cytoplasm
E
Plasma
E
Interstitial fluid
Contains most of the body’s water
E
Fluid located between tissue cells
Transports substances in body
I
Provides medium for chemical reactions to occur
Answer the following:
B If you urinate more than you drink, you are in: a) positive water balance; b) negative water balance
C Obligatory water loss is: a) the amount of water we lose after vigorous exercise as sweat;
b) loss that results in a negative water balance; c) the minimum amount of water lost each day.
B Other than urine, most water is lost through the: a) skin; b) lungs; c) sweat; d) feces.
Page 3 - For each of the following statements, decide which direction fluid would tend to move. Use these choices:
B = into the blood
I = into the interstitial fluid
C Lower than normal sodium levels.
I
Higher than normal sodium levels.
I
High blood pressure.
B
C = into the cells
Low blood pressure.
I
Lower than normal levels of plasma proteins.
B
Higher than normal levels of plasma proteins.
Page 4 - Mark whether each of these occurs when the plasma is too dilute (D) or too concentrated (C).
C Osmoreceptors in hypothalamus are stimulated.
C
Vagus nerve causes feelings of thirst.
D Osmoreceptors in hypothalamus are inhibited.
D
Feelings of thirst decrease.
D ADH secretion decreases.
C
Water output decreases (more reabsorption)
C ADH secretion increases.
D
Water output increases (less reabsorption)
Page 5 - Indicate whether each of the following would occur when fluid volume is too high (H) or too low (L).
L
Hypovolemic shock
H Decreased angiotensin II levels
H High blood pressure
L
Increased aldosterone secretion
H Decreased renin secretion
H Decreased aldosterone secretion
L
Increased renin secretion
L
L
Increased angiotensin II levels
H Decreased reabsorption of sodium
Increased reabsorption of sodium
C If ADH is present, what effect will the absorbed fluid have on plasma concentration?
a) it will make it more dilute
b) it will make it more concentrated
c) it will not change it
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Page 6 - REVIEW OF FLUID BALANCE – Answer the following questions:
C Fluid balance means that: a) the total volume of fluid is normal; b) the distribution of fluid in the various
compartments is normal; c) both a and b
B To maintain fluid balance, output must input. a) be greater than; b) equal; c) be less than
C Movement between the plasma and interstitial fluid is controlled by: a) osmotic pressure
b) hydrostatic pressure; c) both a and b
A Movement between interstitial fluid and intracellular fluid is controlled by: a) osmotic pressure
b) hydrostatic pressure; c) both a and b
A The hormone that maintains the correct fluid volume is: a) aldosterone; b) ADH; c) angiotensin
B The hormone that maintains the correct fluid concentration is: a) aldosterone; b) ADH; c) angiotensin
B Eating salty potato chips without a drink would stimulate release of: a) aldosterone; b) ADH
B Dehydration due to evaporation of water vapor from the lungs would stimulate release of:
a) aldosterone; b) ADH
A Drinking a liter of water without eating food would cause more secretion of: a) aldosterone; b) ADH
Page 9 - Complete the following:
Write the symbols for Na+, K+, Cl-, HPO4-2, Ca+2, and Mg+2 either inside or outside the cell to show where most is found.
Na+
Cl -
Ca+2
K+ HPO4-2
Mg+2
C Which two fluid compartments are most similar in terns of the amounts of electrolytes found there?
a) extracellular and intracellular b) interstitial and intracellular
c) plasma and interstitial
A Edema could be caused by: a) lots of salt; b) too much potassium; c) too little sodium
T
True or False: A change in the amount of fluid in a compartment could cause an electrolyte imbalance.
Match the electrolytes with the statements below. Choices: Na+, K+, Cl-, 4HPO -2, Ca+2, and Mg+2.
Ca+2 Forms bones & teeth, needed for blood clotting
K+ Maintains electrical potential of cells
Mg+2
Na+
Helps maintain blood pressure
Cl-
Forms gastric acid, helps transport O2 and CO2
HPO4-2 Part of ATP, forms a buffer system for pH
Depressing ion found in chlorophyll
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Page 11 - Match the statements with the imbalance they apply to. (Letters match the sections above)
b. Simple water depletion
c. Salt depletion
d. Salt poisoning
e. Abnormal sodium retention
D
Taking a salt tablet without drinking sufficient water.
B
Dehydration resulting from loss of water vapor through the lungs.
E
The kidneys reabsorb too much salt and water due to high levels of aldosterone.
C
A person with diarrhea drinks plenty of water, but doesn’t eat anything.
D
Too little fluid is in the cells and too much is in the plasma and interstitial fluid; the fluid throughout the
body has too much salt.
E
The cells remain normal and the fluid concentration is fine, but there is too much fluid in the plasma and
interstitial compartment.
C
Fluid throughout the body is too dilute; the cells have too much water while the plasma and interstitial
fluid have too little.
B
Both the cells and the plasma and interstitial fluid have too little fluid; all the body’s fluids are too
concentrated.
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