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volume. Acid-Base Balance (page 205)
1. Blood is continuously circulating and carrying with it
the products of metabolic activity (which are generally
acidic and could potentially alter pH considerably
if the blood were not buffered). The efficiency (and
continuation) of metabolic processes depends on
blood pH staying within the narrow range required by
the enzymes catalyzing metabolic processes. 2. Metabolic acidosis is caused by increased production
of H+ by the body or the inability of the body to form
bicarbonate (HCO3–) in the kidney. Causes can be
varied by include diarrhea (loss of HCO3–), renal
failure, starvation, and poisoning. 3. (a) Chemical buffers in the blood tie up excess H+
or bases temporarily. The bicarbonate ion and its
acid (carbonic acid) are in a dynamic equilibrium
to mop up excess H+ and OH–. The system
is supported by the charged groups on blood
proteins, which act as H+ acceptors or donors.
(b) If a base is added to the system, the OH– is
neutralized to a weak base (HCO3–) 4. (a) The respiratory response to excess H+ is an
increase in the rate and depth of breathing.
(b) The excess H+ comes from the dissociation of
carbonic acid (H2CO3), which arises as a result of
carbon dioxide combining with water.
(c) Respiratory acidosis is the result of decreased
ventilation of the pulmonary alveoli. This can arise
as a result of airway obstruction (e.g. asthma),
depression of the respiratory center (e.g. as a
result of trauma), certain diseases (e.g. muscular
dystrophy), and obesity. 5. It is only through the renal system that excess acids
and bases can be permanently eliminated from
the body; the main ways this is achieved is through
excretion of hydrogen ions and reabsorption of
hydroxide ions (since most metabolic wastes are
acidic). Alcohol inhibits ADH release causing greater urine
output, resulting in dehydration and thirst. 3. 4. Active transport of sodium and chloride in the nephron
is used to establish and maintain the salt gradient
through the kidney that is essential to...
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- Winter '13