A&P 26: Fluid, Electrolyte, & Acid-Base Balance

Question 1

Fluid compartments

Answer 1

water occupies 2 main ___ ______ within the body

Question 2

Intracellular fluid compartment (ICF)

Answer 2

almost 2/3 by volume of the water in the body is in this compartment

Question 3

Extracellular fluid compartment (ECF)

Answer 3

1/3 of the water in the body is in this compartment

Question 4

Plasma

Answer 4

fluid portion of the blood

Question 5

Interstitial Fluid (IF)

Answer 5

fluid in the microscopic spaces between tissue cells

Question 6

Nonelectrolytes

Answer 6

substances that have bonds (usually covalent) that prevent them from dissociating in solution

Question 7

Electrolytes

Answer 7

chemical compounds that do dissociate into ions in water

Question 8

Milliequivalents per liter (mEq/L)

Answer 8

measure of the electrical charges in 1 L of solution

Question 9

Metabolic water (water of oxidation)

Answer 9

body water produced by cellular metabolism

Question 10

Insensible water loss

Answer 10

water that vaporizes out of the lungs in expired air or that diffuses directly through the skin

Question 11

Thirst mechanism

Answer 11

driving force for water intake

Question 12

Obligatory water losses

Answer 12

output of certain amounts of water is unavoidable; helps to explain why we can’t survive for long without drinking

Question 13

Sensible water loss

Answer 13

minimum daily water loss of 500mL in urine

Question 14

Dehydration

Answer 14

fluid loss, either the loss of water or the loss of water and solutes together

Question 15

Hypotonic hydration

Answer 15

cellular overhydration

Question 16

Hyponatremia

Answer 16

hallmark of hypotonic hydration; low ECF Na+ concentration; promotes net osmosis into tissue cells, causing them to swell as they become abnormally hydrated

Question 17

Edema

Answer 17

atypical accumulation of fluid in the interstitial space, leading to tissue (but not cell) swelling

Question 18

Hypoproteinemia

Answer 18

condition of unusually low levels of plasma proteins; results in tissue edema because protein-deficient plasma has abnormally low colloid osmotic pressure

Question 19

Electrolyte balance

Answer 19

salt balance in the body

Question 20

Aldosterone

Answer 20

hormone that “has the most to say” about renal regulation of sodium ions

Question 21

Atrial natriuretic peptide (ANP)

Answer 21

reduces blood pressure and blood volume by inhibiting nearly all events that promote vasoconstriction and Na+ and water retention

Question 22

Estrogens

Answer 22

chemically similar to aldosterone; like aldosterone, enhance NaCl reabsorption by the renal tubules; female sex hormone; responsible for water retention when its levels rise during the menstrual cycle and the edema during pregnancy

Question 23

Progesterone

Answer 23

decreases Na+ reabsorption by blocking the effect aldosterone has on the renal tubules; diuretic-like effect; promotes Na+ and water loss

Question 24

Glucocorticoids

Answer 24

cortisol and hydrocortisol; enhance tubular reabsorption of Na+ ; promote an increase glomerular filtration rate that may mask their effect on the tubules

Question 25

Parathyroid hormone (PTH)

Answer 25

ECF calcium ion levels are closely regulated by this hormone

Question 26

Acid-base balance

Answer 26

nearly all biochemical reactions are influenced by the pH of their fluid environment; closely regulated

Question 27

Alkalosis

Answer 27

whenever the pH of arterial blood rises above 7.45; AKA alkalemia

Question 28

Acidosis

Answer 28

a drop in arterial pH below 7.35 results in this condition; AKA acidemia

Question 29

Chemical buffer

Answer 29

system of 1 or more compounds that resists changes in pH when a strong acid or base is added; binds to H+ when pH drops and releases them when pH rises

Question 30

Bicarbonate buffer system

Answer 30

mixture of carbonic acid and its salt, sodium bicarbonate, in the same solution; buffers the ICF, but is the ONLY important ECF buffer

Question 31

Alkaline reserve

Answer 31

if enough acid enters the blood so that all available HCO3- ions, referred to as __ ___, are tied up, the buffer system becomes ineffective and blood pH changes

Question 32

Phosphate buffer system

Answer 32

operation of this system is nearly identical to that of the bicarbonate buffer; components = sodium salts of dihydrogen phosphate and monohydrogen phosphate

Question 33

Protein buffer system

Answer 33

proteins in plasma and in cells are the body’s __ ___ ___; 3/4 of all the buffering power of body fluid resides and cells & most of this reflects the powerful buffering activity of intracellular proteins

Question 34

Amphoteric molecules

Answer 34

molecules that can function reversibly as either an acid or base depending on the pH of its environment

Question 35

Volatile acid

Answer 35

an acid that can be eliminated by the lungs; carbonic acid is converted to CO2, which diffuses into the alveoli

Question 36

Nonvolatile (fixed) acids

Answer 36

acid generated by cellular metabolism that must be eliminated by the kidneys

Question 37

Respiratory acidosis

Answer 37

common cause of acid-base imbalance; most often occurs when a person breathes shallowly or when gas exchange is hampered by diseases such as pneumonia, cystic fibrosis, or emphysema

Question 38

Respiratory alkalosis

Answer 38

results when CO2 is eliminated from the body faster than it is produced; AKA hyperventilation; results in the blood becoming more alkaline; often due to stress or pain

Question 39

Metabolic acidosis

Answer 39

2nd most common cause of acid-base imbalance; recognized by low blood pH and HCO3- levels; typical causes = ingesting too much alcohol (metabolized to acetic acid), excessive loss of HCO3- (persistent diarrhea), accumulation of lactic acid during exercise or shock, ketosis in diabetic crisis/starvation, kidney failure (infrequent)

Question 40

Metabolic alkalosis

Answer 40

indicated by rising blood pH and HCO3- levels; much less common than its opposite; typical causes = vomiting the acidic contents of the stomach (or loss of those secretions through GI suctioning), intake of excess base (too many antacids)

Question 41

Respiratory and renal compensations

Answer 41

the respiratory system attempts to compensate for metabolic acid-based imbalances, and the kidneys (though much slower) work to correct imbalances caused by respiratory disease; recognized by resulting changes in plasma Pco2 and bicarbonate ion concentrations