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55 Cards in this Set
- Front
- Back
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Electrolytes that release hydrogen ions are called _____.
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acids
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An ___ is any atom that is missing electrons or has gained electrons.
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ion
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Substances that readily combine with hydrogen ions are called ____.
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bases
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The pH of body fluids must be regulated around ____ + - 0.02 in order to maintain homeostasis.
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7.40
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The concentration of the _________ ion influences the rates of chemical reactions, the shape and function of enzymes as well as other cellular proteins, and the integrity of the cell itself.
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hydrogen
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An ____ is defined as a molecule that can liberate hydrogen ions and thus can raise the hydrogen ion concentration of an aqueous solution above that of pure water.
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acid
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A _____ is a molecule that is capable of combining with hydrogen ions and therefore lowers the hydrogen ion concentration of the solution.
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base
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Acids that tend to give up hydrogen ions (ionize) more completely are termed ______ acids. Lactic acid is an example of this.
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strong
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At normal pH, lactic acid tends to liberate almost all of its hydrogen ions and therefore _______ the hydrogen ion concentration of the body.
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elevates
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Bases that ionize completely are defined as _____ bases. The bicarbonate ion is an example.
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strong
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Bicarbonate ions are found in relatively large concentrations in the blood and are capable of combining with hydrogen ions to form a weak acid called _______ acid.
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carbonic
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The __ of a solution is defined as the negative logarithm of the hydrogen ion concentration.
___ = -log[H+] |
pH
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As the hydrogen ion concentration increases, pH declines and the acidity of the blood increases, resulting in a condition termed _______.
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acidosis
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As the hydrogen ion concentration decreases, pH increases and the solution become more basic. This condition is termed _________.
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alkalosis
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The body is more tolerant to (alkalosis/acidosis) than it is to (alkalosis/acidosis).
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acidosis
alkalosis |
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The major threat to the pH of body fluids is acids formed in metabolic processes. These metabolic processes can be divided into three groups:
a. Volatile ____ b. Fixed _____ c. Organic _____ |
acids
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An example of a volatile acid is ______ _______, an end product in the oxidation of carbohydrates, fats, and proteins and can be regarded as an acid by virtue of its ability to react with water to form carbonic acid. Because it is a gas and can be eliminated by the lungs, it is often referred to as a volatile acid. Increased "volatile load" on body during exercise
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carbon dioxide
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Examples of fixed acids are _______ acid and ________ acid. Sulfuric acid is a product of the oxidation of certain amino acids, while phosphoric acid is formed in the metabolism of various phospholipids and nucleic acids. Both of these are nonvolatile so are referred to as fixed acids. Not greatly influenced by acute exercise.
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sulfuric
phosphoric |
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An example of an organic acid is ______ acid. This formed in the metabolism of carbohydrates and fats. Under normal resting conditions, it is further metabolized to CO2 and therefore does not greatly influence the pH of body fluids. During periods of intense physical efforts, contracting skeletal muscles can produce large amounts of ______ acid, resulting in acidosis.
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lactic
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The hydrogen ions released by lactic acid can exert a powerful effect on other molecules due to their small size and positive charge. Hydrogen ions exert their influence by attaching to molecules and thus altering their original ____ and _____, which may alter the normal function of the enzyme and therefore influence metabolism in an important way.
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size
shape |
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An increase in the hydrogen ion concentration reduces the muscle cell's ability to produce ___ by inhibiting enzymes involved in both anaerobic and aerobic production of ATP.
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ATP
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Hydrogen ions compete with ______ ions for binding sites on troponin, thereby hindering the contractile process.
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calcium
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A ______ resists pH change by removing hydrogen ions when the hydrogen ion concentration increases and releasing hydrogen ions when the hydrogen ion concentration falls.
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buffer
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Buffers often consist of a ____ acid and its associated base (called a conjugate base).
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weak
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The first line of defense in protecting against pH change during exercise is in the cell itself. The most common intracellular buffers are ______ and _________ groups.
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proteins
phosphate |
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Intracellular ___________ has been shown to be a useful buffer at the onset of exercise.
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phosphocreatine
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The blood contains three principal buffer systems and act as buffers in the extracellular compartment:
a. _______ b. _________ c. _________ |
proteins
hemoglobin bicarbonate |
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________ is a particularly important protein buffer and is a major blood buffer during resting conditions and has approximately six times the buffering capacity of plasma proteins due to its high concentrations.
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hemoglobin
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True/False Deoxygenated hemoglobin is a better buffer than oxygenated hemoglobin because it is better able to bind to hydrogen ions formed when CO2 enters the blood from tissues.
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True
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The ________ buffer system is probably the most important buffer system in the body and is described by the equation pH = pKa + log (HCO3/H2CO3)
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bicarbonate
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Respiratory control of acid-base balance involves the regulation of blood PCO2. An increase in blood PCO2 ______ pH, whereas a decrease in blood PCO2 _______ pH.
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decreases
increases |
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The principle means by which the kidneys regulate hydrogen ion concentration is by increasing or decreasing the __________ concentration.
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bicarbonate
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When the hydrogen ion concentration increases in body fluids, the kidney responds by a _________ in excretion of bicarbonate.
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reduction
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The kidney mechanism involved in regulating the bicarbonate concentration is located in a portion of the kidney called the ______, and acts through a series of complicated reactions and active transport across the tubular wall.
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tubules
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During the final stages of an incremental exercise test or during near-maximal exercise of short duration, there is a ______ in both muscle and blood pH primarily due to the increase in the production of lactic acid.
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decrease
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Muscle pH is always 0.4 to 0.6 (lower/higher) than blood pH because muscle lactic acid concentration is higher than that of blood and muscle buffering capacity is lower than that of blood.
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lower
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The amount of lactic acid produced during exercise is dependent on
a. the exercise _______ b. the amount of muscle _____ involved c.the _________ of the work |
intensity
mass duration |
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Intracellular proteins are the buffer system within the _______ itself. Because the muscle's buffering capability is limited, extracellular fluid must possess a means of buffering hydrogen ions as well. Blood bicarbonate.
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muscle
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As blood lactic acid concentration increases, blood bicarbonate ________ proportionally.
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decreases
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The overall process of respiratory assistance in buffering lactic acid during exercise is referred to as ____________ _____________ for metabolic acidosis.
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respiratory compensation
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Acidosis is defined as
a. a blood pH below 7.4 b. a blood pH greater than 7.4 c. a blood pH of 7.4 d. a condition of low H+ concentration in the blood. |
a. a blood pH below 7.4
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Exercise results in the production of large amounts of lactic acid which
a. is produced by contracting skeletal muscle b. ionizes and releases hydrogen ions c. contributes to lower muscle and blood pH d. all of the above are true |
d. all of the above are true
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The most important intracellular buffers are
a. proteins b. phosphate groups c. muscle bicarbonate d. hemoglobin |
a. proteins
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Muscle pH is always ________ blood pH?
a. higher than b. the same as c. lower than |
c. lower than
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Ingestion of bicarbonate has been shown to
a. improve performance in some types of exercise b. improve performance in all types of exercise c. have no effect on performance |
a. improve performance in some types of exercise
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The kidney is not an important regulator of the acid-base balance during exercise because
a. it can only decrease the rate of bicarbonate excretion b. it can only increase the rate of bicarbonate excretion c. it responds too slowly to be of major benefit d. it is not capable of regulating hydrogen ion concentration |
c. it responds to slowly to be of major benefit
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The amount of lactic acid produced during exercise is dependent upon
a. the exercise intensity b. the muscle mass involved c. the duration of exercise d. all of the above |
d. all of the above
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Intracellular proteins are responsible for approximately
a. 60% of the cell's buffering capacity b. 20 to 30% of the cell's buffering capacity c. 10 to 20% of the cell's buffering capacity d. none of the above |
a. 60% of the cell's buffering capacity
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The most important extracellular buffer is/are
a. blood proteins b. hemoglobin c. phosphate groups d. bicarbonate |
d. bicarbonate
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Respiratory compensation for metabolic alkalosis refers to
a. the increase in the lactic acid production b. the increase in ventilation resulting in a decrease in PCO2 c. the decrease in ventilation resulting in a decrease in PCO2 d. the decrease in ventilation resulting in a increase in PCO2 |
b. the increase in ventilation resulting in a decrease in PCO2
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High intensity exercise can cause blood pH to decline to a value of _______ within a few minutes.
a. 6.0 b. 7.0 c. 7.4 d. 7.6 |
b. 7.0
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The pH of a solution can be calculated using the formula
a. pH = –log10[H+]. b. pH = pKa + log10 (HCO3– / H2CO3) c. both of these equations d. neither of these equations |
c. both of these equations
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True/False Buffers protect against pH change by releasing hydrogen ions.
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False
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Sulfuric acid can be produced during exercise
a. as a result of carbohydrate metabolism b. from the buffering of H+ by HCO3- c. from the metabolism of certain amino acids d. none of the above are true |
c. from the metabolism of certain amino acids
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True/False Exercise lasting <45 seconds results in the production of significant amounts of hydrogen ions.
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False
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