Chr. 27 - Fluid, Electrolyte, and Acid-Base Homeostasis Flashcards

1
Q

[27.1] What is a body fluid?

A

A substance produced by the body consisting of water and dissolved solutes.

Two main types: intracellular fluid and extracellular fluid.

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2
Q

[27.1] What is intracellular fluid?

A

Fluid with the cell.

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3
Q

[27.1] What is extracellular fluid?

A

Fluid existing outside cells.

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4
Q

[27.1] What is interstitial fluid?

A

Extracellular fluid existing in the microscopic spaces between tissue cells. 80% of extracellular fluid.

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5
Q

[27.1] What is blood plasma?

A

Extracellular fluid composing the liquid portion of blood. 20% of extracellular fluid.

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6
Q

[27.1] What is fluid balance?

A

The required amount of water and solutes correctly proportioned among the various compartments.

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7
Q

[27.1] What is the largest signle component of the body?

A

Water, 45-75% of total mass.

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8
Q

[27.1] What is an electrolyte?

A

Inorganic compounds that dissociate into ions when dissolved. Affects fluid balance through osmosis.

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9
Q

[27.1] What is metabolic water?

A

Water produced in the body when electrons are accepted by oxygen during aerobic respiration. 200mL/day

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10
Q

[27.1] What is the thirst center?

A

An area of the hypothalamus governing the urge to drink.

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11
Q

[27.1] What is dehydration?

A

A decrease in water volume and increase in osmolarity of body fluids.

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12
Q

[27.1] What are osmoreceptors?

A

Receptors in the hypothalamus that detect increased blood osmolarity and stimulate the thirst center.

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13
Q

[27.1] What receptors stimulate the thirst center?

A

Water BANS:
1. Baroreceptors in blood vessels
2. Angiotensin II
3. Neurons within the mouth detecting dryness.
4. Stretch receptors in the atria

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14
Q

[27.1] How does elimination of excess body water occur?

A

Mainly by control of urine output.

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15
Q

[27.1] What is the main factor of urine output determining body fluid volume?

A

Urinary salt loss.

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16
Q

[27.1] What is the main hormone regulating water loss?

A

Antidiuretic hormone.

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17
Q

[27.1] Which other hormones play a role in fluid balance?

A

Aldosterone and atrial natriuretic peptide.

18
Q

[27.1] How does aldosterone play a role in fluid balance?

A

Promotes reabsorption of sodium in the distal convoluted tubule and collecting ducts. Water follows the sodium, increasing blood volume.

19
Q

[27.1] How does atrial natriuretic peptide play a role in fluid balance?

A

Promotes natriuresis, elevated excretion of sodium into urine leading to increase water loss.

20
Q

[27.1] What is hypertonicity of extracellular fluid?

A

When solutes occur in greater concentration within extracellular fluid, drawing out fluid from within cells and causing them to shrink.

21
Q

[27.1] What is hypotonicity of extracellular fluid?

A

When solutes within a cell occur at greater concentration than extracellular fluid, leading to movement of water into cells and causing swelling.

22
Q

[27.1] What is water intoxication?

A

A state in which excessive body water causes cells to swell dangerously, occurs when water intake occurs faster than kidneys can excrete it.

23
Q

[27.2] List the four general functions of ions within the body.

A
  1. Control osmosis of water between compartments
  2. Maintain acid-base balance
  3. Carry electrical current
  4. Serve as cofactors for enzymes.
24
Q

[27.2] What is milliequivalents per liter (mEq/liter)?

A

The unit of measurement expressing the concentration of ions. Typically 1mmol/liter for ions with a single charge, and 2mmol/liter for ions with two charges, positive or negative.

25
Q

[27.2] What is an equivalent?

A

A positive or negative charge equal to the charge of one mole of hydrogen; 1g of hydrogen.

26
Q

[27.2] What is a milliequivalent?

A

One one-thousandth of an equivalent.

27
Q

[27.2] What is the most abundant ion in extracellular fluid?

A

Sodium, most abundant ion, and most abundant positive ion.

136 - 148 mEq/liter in blood plasma.

28
Q

[27.2] What is hyponatremia?

A

Blood plasma concentration of sodium below 135 mEq

29
Q

[27.2] What is hypernatremia?

A

Blood plasma concentration of sodium above 148 mEq

30
Q

[27.2] What is the most abundant negative ion in extracellular fluid?

A

Chloride.

95 - 105 mEq in blood plasma.

31
Q

[27.2] What is the most abundant cation in intracellular fluid?

A

Potassium

3.5 - 5 mEq in blood plasma.

32
Q

[27.2] Why does the mEq/liter of bicarbonate fluxuate?

A

As blood absorbs carbon dioxide from cellular metabolic waste, it combines with water in the blood plasma to form bicarbonate.

22 - 26 mEq in arterial blood plasma
23 - 27 mEq in venous blood plasma

33
Q

[27.2] What is the most abundant mineral in the body?

A

Calcium.

4.5 - 5.5 mEq in blood plasma.

34
Q

[27.2] Describe the presence of phosphate in the body.

A

Occurs as calcium phosphate salts in bones and teeth, as phosphate ions ((H2PO4)-, (HPO4)2-, and (PO4)3-) acting as intracellular anions and a buffer for hydrogen ions.

1.7 - 2.6 mEq in blood plasma.

35
Q

[27.2] What hormones regulate calcium and phosphate levels?

A

Parathyroid hormone and calcitriol.

36
Q

[27.2] Describe the presence of magnesium in the body.

A

Occurs as magnesium salts forming bone, as well as intracellular cations. Also acts as a cofactor for enzymes.

1.3 - 2.1 mEq in blood plasma.

37
Q

[27.3] List the major mechanisms for removal of hydrogen ions from body fluids.

A
  1. Buffer systems
  2. Exhalation of carbon dioxide
  3. Kidney excretion of hydrogen
38
Q

[27.3] What is a buffer system?

A

A mechanism composed of a weak acid and a weak base, typically a salt formed from the acid. Prevents rapid, drastic changes of pH by converting strong acids and bases to weaker ones.

39
Q

[27.3] Describe the protein buffer system.

A

A prolific buffer system between intracellular fluid and blood plasma utilizing the carboxyl and amino groups of amino acids, as well as side chains of 7/20 amino acids. Able to buffer acids and bases.

40
Q

[27.3] Describe the carbonic acid - bicarbonate buffer system.

A

A buffer system utilizing bicarbonate as a weak base and carbonic acid as a weak acid. Carbonic acid provides flexibility, removing excess hydrogen and dissociating into water and carbon dioxide, or release hydrogen ions and forming bicarbonate.

41
Q

[27.3]

A