Ch. 24: Acid/Base Balance
physiological
A ______ buffer is a system (for example the respiratory or urinary system) that stabilizes pH by controlling the body's output of acids, bases, or CO2.
respiratory acidosis
A blood pH of 7.2 caused by inadequate pulmonary ventilation would be classified as...
Resists changes in pH
A buffer can be generally defined as a mechanism that does which of the following?
hyponatremia
A deficiency of sodium ions in the blood is called ____.
75, 45
A newborn baby's weight is as much as __% water, whereas obese and elderly people's weight is as little as __% water.
balance
A person is in a state of fluid ______ when daily gains and losses are equal.
acidosis
A tissue fluid pH below 7.35 is defined as a state of ______.
Weak
An acid such as carbonic acid (H2CO3-) that ionizes only slightly and keeps most hydrogen in a chemically bound form that does not affect pH, is classified as which type of acid?
Strong
An acid such as hydrochloric acid (HCl) that ionizes freely, gives up most of its hydrogen ions, and can markedly lower the pH of a solution is known as what type of acid?
hyperkalemia
An excessive concentration of potassium ions in the blood is called ____.
fluid sequestration
Any abnormal accumulation of fluid in a particular place in the body is called ____.
chemical
Any substance that binds H+ and removes it from solution as its concentration begins to rise, or releases H+ into solution as its concentration falls is classified as a ______ buffer. Examples include proteins, bicarbonate, and phosphate.
Weak base
As compared to hydroxide (OH-), bicarbonate (HCO3-) binds a relatively small amount of the available H+ and therefore has less of an effect on pH. Because of this, bicarbonate is classified as which of the following?
8%
Blood plasma and lymph fluid holds what percentage of body water?
extracellular
Blood plasma is a type of ______ fluid.
Acts as second messenger and activates exocytosis during neurotransmission Acts as a factor for blood clotting Participates in muscle contraction Participates in bone and tooth development
Calcium does which of the following?
dehydrating
Cold weather has a ______ effect on the human body.
Pulmonary ventilation rate increases.
Describe respiratory compensation in response to acidosis.
Pulmonary ventilation rate decreases.
Describe respiratory compensation in response to alkalosis.
No Reason: Respiratory loss increases in cold weather because cold air is drier and absorbs more body water.
Does respiratory loss decrease in cold weather?
Weak acid
H2CO3 ionizes only slightly and keeps most of its hydrogen in a chemically bound form that does not affect pH. Because of this it is classified as which of the following?
Strong acid
HCl ionizes freely, gives up most of its hydrogen ions, and can markedly lower the pH of a solution. Because of this it is classified as which of the following?
Reduced pulmonary ventilation allows CO2 to accumulate, lowering the pH back to normal.
How can the respiratory system compensate for a drop in blood H+ concentrations?
Strong base
Hydroxide (OH-) has a great tendency to bind H+ and raise the pH. It is therefore classified as which of the following?
acidosis
Hyperchloremia is most likely to result in...
natriuretic peptide
Hypertension is likely to increase the secretion of...
ADH hypersecretion
Hypotonic hydration can result from ____.
In dehydration water is lost, and in hypovolemia both water and electrolytes are lost.
Hypovolemia and dehydration are both examples of fluid deficiency. How do they differ?
normal
In cases of volume depletion, total body water declines but fluid osmolarity is ______.
Hypotonic hydration (positive water balance, water intoxication)
In which form of fluid imbalance is total body water elevated while osmolarity is reduced?
Dehydration (negative water balance)
In which form of fluid imbalance is total body water reduced and osmolarity elevated?
acidosis
Increased excretion of ammonium chloride in the urine most likely indicates...
65%
Intracellular fluid (ICF) holds what percentage of body water?
intracellular
Most of the water (65%) is found in the __________ compartment.
Bicarbonate, phosphate, and protein
Name the three important chemical buffer systems in the body.
urinary
Of the two major physiological buffer systems, the respiratory system can restore the pH quickly, whereas the ______ system can take several hours to days to restore the pH.
GTP ATP Nucleic acids cAMP Phospholipids
Phosphate is a necessary component of which of the following?
Nucleic acids GTP Phospholipids cAMP ATP
Phosphate is a necessary component of which of the following?
Perspiration Respiratory loss
Prolonged, heavy work increases which of the following? Select all that apply.
pH
Slight deviations from the body's normal ____ range can shut down metabolic pathways as well as alter the structure and function of other macromolecules. Buffer systems help to avoid this.
Cations
Sodium, potassium, calcium and hydrogen ions are examples of which of the following?
hypocalcemia
Tetanus is most likely to result from...
Respiratory
The addition of CO2 to the body fluids raises H+ concentration and lowers pH, while the removal of CO2 has the opposite effect. This is the basis for the strong buffering capacity of which system?
Fluid compartments
The blood, lymph, tissue fluid, and transcellular fluid are all examples of which of the following?
the intracellular fluid
The greatest percentage of the body's water is in...
sodium
The most abundant cation in the ECF is ___.
protein
The most effective buffer in the intracellular fluid is...
water
The only way to control ____ output significantly is through variations in urine volume.
Hydrogen
The pH of a solution is determined solely by the concentration of which ion?
potassium
The principal determinant of intracellular osmolarity and cellular volume is ____.
Cold or hot weather Diabetes mellitus Profuse sweating Overuse of diuretics
The simplest cause of dehydration is a lack of drinking water. Which of the following can also cause dehydration?
cutaneous transpiration
The skin loses water by two processes, sweating and ______.
potassium and magnesium
The two most abundant cations in the ICF are ___ and ____.
Around 55 - 60% of total body weight
The water content (as a percentage of total body weight) of a 70 kg young male is which of the following?
25%
Tissue (interstitial) fluid holds what percentage of body water?
Hypotonic hydration
Total body water is elevated; ECF becomes hypotonic.
Volume excess
Total body water is elevated; ECF remains isotonic.
Dehydration
Total body water is reduced; ECF becomes hypertonic.
Hypovolemia
Total body water is reduced; ECF remains isotonic.
2%
Transcellular fluid
tubular reabsorption of sodium
Tubular secretion of hydrogen is directly linked to...
Urine volume
Water output is primarily controlled through variations in which of the following?
metabolic water
Water produced by the body's chemical reactions is called ____.
2500
We typically gain and lose about ______ mL of fluids a day.
It participates in muscle and nerve depolarization. It is involved in generating body heat via the Na-K pump. It participates in cotransport of glucose, K+ and Ca+.
What are the important functions of sodium?
The protein buffer system The phosphate buffer system The bicarbonate buffer system
What are the major chemical buffer systems of the body? Select three options from the list below.
It increases.
What happens to ECF osmolarity during dehydration?
Chloride
What is the most abundant anion in the extracellular fluid?
7.35 - 7.45
What is the normal pH range of tissue fluid?
Hyponatremia Hyperkalemia Hypotension
What stimulates the secretion of aldosterone? Select all that apply.
Hypothalamus
Where are osmoreceptors found?
Reduced blood pressure Increased blood osmolarity Reduced salivation
Which are effects of dehydration?
It can be generated by the hydrolysis of ATP. It exists in fluids as an equilibrium mixture of phosphate, monohydrogen phosphate, and dihydrogen phosphate. It is a component of nucleic acids, phospholipids, ATP, GTP, and cAMP.
Which are true regarding phosphate?
It is a component of nucleic acids, phospholipids, ATP, GTP, and cAMP. It exist in fluids as an equilibrium mixture of phosphate, monohydrogen phosphate and dihydrogen phosphate. It can be generated by the hydrolysis of ATP.
Which are true regarding phosphate?
It is effective in correcting for PCO2 imbalances. It corrects the pH of body fluids by expelling or retaining CO2.
Which are true regarding respiratory compensation?
Dehydration Volume depletion
Which are types of fluid deficiency?
Hypothalamic neurons that respond to increased solute concentration in the extracellular fluid
Which best defines osmoreceptors?
It increases the number of Na+-K+ pumps in the nephron.
Which best describes how aldosterone acts as the "salt retaining hormone"?
Potassium
Which ion is the greatest determinant of intracellular osmolarity and cell volume?
Potassium
Which ion is the most abundant cation of the ICF?
Sodium
Which ion is the most significant solute in determining total body water and the distribution of water among fluid compartments?
Sodium & Calcium
Which ions are major cation electrolytes?
Calcium
Which is a cation that lends strength to the skeleton, activates muscle contraction, serves as a second messenger for some hormones and neurotransmitters, and is an essential factor in blood clotting?
Aldosterone
Which is referred to as the "salt-retaining hormone" because it plays the primary role in adjusting sodium excretion?
A base that binds only some of the available H+ and has relatively small effect on pH
Which is the best definition of a weak base?
pH
Which property of a solution is determined by the concentration of hydrogen ions?
Intracellular fluid
Which represents the largest fluid compartment in the body?
Dehydration raises blood osmolarity.
Which statement about dehydration is true?
Urinary system
Which system buffers the greatest quantity of acid or base but requires several hours to days to exert an effect?
Hypovolemia
Which term is another name for volume depletion? This occurs when proportionate amounts of both water and sodium are lost without replacement.
Chemical buffer
Which term refers to a compound that helps maintain a stable pH by binding protons if H+ concentration begins to rise, and releasing them into solution if H+ concentration falls?
Alkalosis
Which term refers to a tissue fluid pH above 7.45?
Metabolic water
Which term refers to water that is produced as a by-product of dehydration synthesis reactions and aerobic respiration?
preformed water
Which term refers to water that is taken into the body in food and drink?
Urinary system Respiratory system
Which two organ systems form physiological buffers that help stabilize pH by controlling the body's output of acids, bases, or CO2?
Chemical
Which type of buffer is defined as a substance that binds H+ and removes it from solution as its concentration begins to rise, or releases H+ into solution as its concentration falls?
7.4
Which would be considered a normal pH value for arterial blood?
The have higher metabolic rates and produce toxic metabolites faster.
Why are infants more vulnerable to dehydration than adults?
Slight deviations from normal pH can shut down metabolic pathways. The structure and function of macromolecules are pH dependent.
Why is it important to maintain the pH of blood and tissue fluids within normal limits?
antidiuretic hormone
____ increases water reabsorption without increasing sodium reabsorption.
