a&p 2 ch 26 review questions
What is the most important urinary buffer of H+?
The most important urinary buffer of H+ is the phosphate buffer system.
Estrogens are chemically similar to ____________ and enhance NaCl reabsorptionby the renal tubules.
aldosterone
One way the kidneys maintain HCO3- balance is by __________. reabsorbing CO2 generating Na+ ions generating new HCO3- reabsorbing H+
generating new HCO3-
All of the following would cause edema except __________. hypoproteinemia hypotension incompetent venous valves liver disease
hypotension
All of the following factors would stimulate the hypothalamic thirst center EXCEPT __________. decreased saliva production hypotonic extracellular fluid a decline in blood volume increased angiotensin II secretion
hypotonic extracellular fluid
Which condition would cause a drop in pH?
hypoventilation
The only organ(s) of the body that can remove excess nonvolatile fixed acids is/are the __________.
kidney
Potassium, magnesium, and phosphate ions are the predominant electrolytes in (a) plasma, (b) interstitial fluid, (c) intracellular fluid.
intracellular fluid
Most water is excreted via the __________.
kidneys
The largest percentage of body water is located in what compartment?
intracellular fluid
Name the body fluid compartments, noting their locations and the approximate fluid volume in each.
intracellular fluid compartment: fluid within a cell; 25 L extracellular fluid plasma: fluid in blood;3L interstitial fluid: fluid between cells: 12L
Pica, the desire to consume substances that are not normally considered food, such as chalk or clay, may be triggered by a deficiency of __________.
iron
Antidiuretic hormone (ADH) acts on the __________ to __________ water excretion.
kidneys; decrease
Diuresis peaks __________ after drinking water.
one hour
All of the following would occur if there was an increase in plasma osmolality except __________. production of large amounts of urine thirst concentrated urine release of ADH
production of large amounts of urine
Explain how the chemical buffer systems resist changes in pH.
they resists changes in pH by adding a strong acid or base -bind H+ when pH drops and releasing H+ when pH rises
Substance regulated by ADH's effects on the renal tubules.
water
For each of the following, state whether it might result in dehydration, hypotonic hydration, or edema (discussed in Chapter 19): (a) decreased synthesis of plasma proteins due to liver failure; (b) copious sweating; (c) using ecstasy (MDMA), which promotes ADH secretion.
(a) A decrease in plasma proteins causes edema. (b) Copious sweating causes dehydration. (c) Using ecstasy (together with drinking lots of fluids) could cause hypotonic hydration because ecstasy promotes ADH secretion, which interferes with the body's ability to get rid of extra water.
Describe the thirst mechanism, indicating how it is triggered and terminated.
-the thirst mechanisms is triggered by high ECF osmolality and low plasma volume -once you drink water and the mouth and throat moistens and the stomach and small intestine stretches the thirst center inhibits
For each of the following sets of blood values, name the acid-base imbalance (acidosis or alkalosis), determine its cause (metabolic or respiratory), decide whether the condition is being compensated, and cite at least one possible cause of the imbalance. Problem 1: pH 7.63; PCO2PCO2 19 mm Hg; HCO3− 19.5 mEq/L Problem 2: pH 7.22; PCO2PCO2 30 mm Hg; HCO3− 12.0 mEq/L
1. alkalosis; due to low CO2 which means it is respiratory alkalosis 2. acidosis; due to low HCO3-
Any arterial pH between __________ is considered physiological acidosis.
7.0 - 7.35
ADH, by itself, cannot reduce an increase in osmolality in body fluids. Why not? What other mechanism is required?
ADH cannot add water—it can only conserve what is already there. In order to reduce an increase in osmolality of body fluids, the thirst mechanism is required.
Define acidemia and alkalemia.
Acidemia is an arterial pH below 7.35 and alkalemia is a pH above 7.45.
What change in plasma is most important for triggering thirst? Where is that change sensed?
An increase in osmolality of the plasma is most important for triggering thirst. This change is sensed by osmoreceptors in the hypothalamus.
Explain why and how ECF osmolality is maintained.
ECF osmolality is maintained by the thirst mechanism. when it is high we drink more to dilute all the proteins... ADH also increases the absorption of water which lowers ECF
Explain how emphysema and congestive heart failure can lead to acid-base imbalance.
Emphysema impairs gas exchange or lung ventilation, leading to retention of carbon dioxide and respiratory acidosis. Congestive heart failure produces oxygenation problems as well as edema and causes metabolic acidosis due to an increase in lactic acid.
You eat salty pretzels without drinking. What happens to the volume of your extracellular fluid? Explain.
If you eat salty pretzels, your extracellular fluid volume will expand even if you don't ingest fluids. This is because water will flow by osmosis from the intracellular fluid to the extracellular fluid.
Renal tubule cells acidify the urine and parietal cells acidify the stomach contents (see Chapter 23, p. 891). In each case (a) which intracellular enzyme is key, and (b) blood concentration of which ion increases?
In both renal tubule cells and parietal cells, (a) the enzyme carbonic anhydrase is key, and (b) blood concentration of HCO3− increases.
Nathan has Addison's disease (insufficient aldosterone release). How does this affect his plasma Na+ and K+ levels? How does this affect his blood pressure? Explain
Insufficient aldosterone would cause Nathan's plasma Na+ to be decreased and his plasma K+ to be elevated. The decrease in plasma Na+ would cause a decrease in blood pressure, because plasma Na+ is directly related to blood volume, which is a major determinant of blood pressure.
Joanne, a diabetic patient, is at the emergency department with acidosis due to the production of ketone bodies (p. 632). Would you expect her ventilation to be increased or decreased? Why?
Joanne's ventilation would be increased. The acidosis caused by the accumulated ketone bodies will stimulate the peripheral chemoreceptors, and this will cause more CO2 to be "blown off" in an attempt to restore pH to normal.
Which two abnormalities in plasma are key features of an uncompensated metabolic alkalosis? An uncompensated respiratory acidosis?
Key features of an uncompensated metabolic alkalosis are an increase in blood pH and an increase in blood HCO3−. Key features of an uncompensated respiratory acidosis are a decrease in blood pH and an increase in blood PCO2.
The only cation exerting significant osmotic pressure in the ECF is __________.
Na+
What is the major cation in the ECF? In ICF? What are the intracellular anion counterparts of ECF's chloride ions?
Na+ is the major cation in the ECF and K+ is the major cation in the ICF. The intracellular counterparts to extracellular Cl− are HPO42− and protein anions.
Renal acid-base control mechanisms are coupled to __________.
Na+ transport
what is the major extracellular cation
Sodium (Na+)
How do the kidneys compensate for respiratory acidosis?
The kidneys compensate for respiratory acidosis by excreting more H+ and generating new HCO3− to buffer the acidosis
Which hormone is the major regulator of Ca2+ in the blood? What are the effects of hypercalcemia? Hypocalcemia?
The major regulator of calcium in the blood is parathyroid hormone. Hypercalcemia decreases excitability of neurons and muscle cells and may cause life-threatening cardiac arrhythmias. Hypocalcemia increases excitability and causes muscle tetany.
What are the body's three major chemical buffer systems? What is the most important buffer inside cells?
The three major chemical buffer systems of the body are the bicarbonate buffer system, the phosphate buffer system, and the protein buffer system. The most important intracellular buffer is the protein buffer system.
List the two mechanisms by which tubule and collecting duct cells generate new HCO3−.
The tubule and collecting duct cells generate new HCO3− either by excreting ammonium ions (NH4+) or by excreting buffered H+ ions.
Mr. Jessup, a 55-year-old man, is operated on for a cerebral tumor. About a month later, he appears at his physician's office complaining of excessive thirst. He claims to have been drinking about 20 liters of water daily for the past week and says he has been voiding nearly continuously. A urine sample is collected and its specific gravity is reported as 1.001. What is your diagnosis of Mr. Jessup's problem? What connection might exist between his previous surgery and his present problem?
This patient has diabetes insipidus caused by insufficient production of ADH by the hypothalamus. The operation for the removal of the cerebral tumor has damaged the hypothalamus or the hypothalamohypophyseal tract leading to the posterior pituitary. Because of the lack of ADH, the collecting tubules and possibly the convoluted part of the distal convoluted tubule are not absorbing water from the glomerular filtrate. The large volume of very dilute urine voided by this man and the intense thirst that he experiences are the result.
Which do you have more of, extracellular or intracellular fluid? Plasma or interstitial fluid?
You have more intracellular than extracellular fluid and more interstitial fluid than plasma.
Match the electrolyte balance term with its correct characteristic: Hyponatremia.
a condition that results from solute loss, water retention, or both
A major stimulus for the release of antidiuretic hormone is __________.
a rise in plasma osmolality
Explain the relationship of the following to renal secretion and excretion of hydrogen ions: (a) plasma carbon dioxide levels, (b) phosphate, and (c) sodium bicarbonate reabsorption.
a) higher the CO2 in peritubular capillaries the faster H+ will be secreted b) type A intercalated cells form H2CO3 and then secrete H+ to be combined with HPO42- to make H2PO4- which is then excreted in urine c) The rate of reabsorption of bicarbonate depends on the rate of secretion or excretion of H+ in the filtrate.
Which of the following tissues is the least hydrated?
adipose tissue
Estrogens are chemically similar to __________ and are therefore associated with water retention.
aldosterone
What happens when the concentration of Na+ decreases in the ascending limb of the nephron?
aldosterone levels increase
When the concentration of Na+ in the ECF decreases, __________.
aldosterone levels increase
Two ions produced during catabolism of glutamine.
ammonium ions bicarbonate
Two substances secreted into the proximal convoluted tubules in exchange for sodium ions.
ammonium ions hydrogen ions
Match the electrolyte balance term with the correct characteristic: Hyperkalemia.
an excess amount of potassium in the ECF
Which of the following factors will enhance ADH release? (a) increase in ECF volume, (b) decrease in ECF volume, (c) decrease in ECF osmolality, (d) increase in ECF osmolality.
an increase in EFC osmolality and a decrease in ECF volume
Which of the following individuals would have the most body water?
an infant
The most important buffer system of extracellular fluid, such as plasma, is the __________ buffer system.
bicarbonate
Part of an important chemical buffer system in plasma.
bicarbonate ? shouldnt it be protein buffer system
Two substances regulated by parathyroid hormone.
calcium phosphate
Which of the following is NOT a stimulus for the release of antidiuretic hormone? Reduced blood volume Increased ECF osmolality Decreased blood pressure Decreased Na+ concentration in plasma stimulation of the baroreceptors
decreased Na+ concentration in plasma
hen atrial natriuretic peptide is released by the heart because of increased blood pressure, it causes __________.
decreased sodium and water reabsorption
Identify the possible causes of hypernatremia
dehydration; uncommon in healthy individuals; may occur in infants or the confused aged or may result from excessive intravenous NaCl administration
Parathyroid hormone __________.
enhances release of calcium from bone
Sodium balance is regulated primarily by control of amount(s) (a) ingested, (b) excreted in urine, (c) lost in perspiration, (d) lost in feces.
excreted in urine
Parathyroid hormone (PTH) increases Ca2+ deposition in the bones. true or false
false
The most abundant cation in extracellular fluid is potassium. true false
false it is Na+
Most of the hydrogen ions in the body come from acidic substances in the foods we ingest. true or false
false most H+ are metabolic by products
Most fluid in the body is in the extracellular fluid (ECF) compartment. true false
false the intracellular compartment
Acidosis results in increasing levels of what ion?
hydrogen
The condition in which sodium levels are too low is referred to as __________.
hyponatremia
All of the following factors would stimulate the hypothalamic thirst center except __________. hypotonic extracellular fluid angiotensin II a decline in blood volume input from baroreceptors
hypotonic extracellular fluid
Which of the following is associated with a swelling of cells?
hypotonic hydration
Which of the following is associated with the swelling of cells?
hypotonic hydration
Describe the role of the respiratory system in controlling acid-base balance.
if CO2 rises respiratory rate and depth increases to rid of the acidic CO2 when blood pH rises respiratory rate drops and respiration becomes shallower which allows CO2 to accumulate
Body water content is greatest in (a) infants, (b) young adults, (c) elderly adults.
infants
water balance is regulated by control of amounts ....
ingested and excreted in urine
Water lost through expired air is referred to as __________.
insensible water loss
Edema is accumulation of fluid in the __________.
interstitial space
Edema is the accumulation of fluid in the __________.
interstitial space
Match the following electrolyte with its appropriate description and location: Potassium.
most abundant positive electrolyte in intracellular fluid
Which of the following is the most important process affected by calcium levels?
neuromuscular excitability
Mrs. Bush, a 70-year-old woman, is admitted to the hospital. Her history states that she has been suffering from diarrhea for three weeks. On admission, she complains of severe fatigue and muscle weakness. A blood chemistry study yields the following information: Na+ 142 mEq/L; K+ 1.5 mEq/L; Cl− 92 mEq/L; PCO2PCO2 32 mm Hg. Which electrolytes are within normal limits? Which are so abnormal that the patient has a medical emergency? Which of the following represents the greatest danger to Mrs. Bush? (a) a fall due to her muscular weakness, (b) edema, (c) cardiac arrhythmia and cardiac arrest.
normal sodium low potassium (hypolaemia) due to the diarrhea -this would lead to a medical emergency bc it can cause cardiac arrhythmia and cardiac arrest low chloride (hypochloremia)
What is the most abundant cation in intracellular fluid?
potassium
All of the following would occur if there were an increase in plasma osmolality EXCEPT __________. concentrated urine production of large amounts of urine thirst release of ADH
production of large amounts of urine
Which of the following would increase sodium excretion?
progesterone
Match the following condition with its possible cause and/or consequence: Hyponatremia.
promotes net osmosis into tissue cells, causing them to swell as they become abnormally hydrated
The most important buffer system in the intracellular fluid compartment (ICF) is the __________ buffer system.
protein
In an individual with metabolic acidosis, a clue that the respiratory system is compensating is provided by (a) high blood bicarbonate levels, (b) low blood bicarbonate levels, (c) rapid, deep breathing, (d) slow, shallow breathing.
rapid deep breathing
Someone who is suffocating would develop __________.
respiratory acidosis
Hyperventilation can lead to __________.
respiratory alkalosis
Electrolyte balance in the body usually refers to the balance of __________.
salts
Normal arterial blood pH is __________.
slightly alkaline
The most prevalent electrolyte in the extracellular fluid is __________.
sodium
two main substances regulated by the influence of aldoesterone on kidney tubules
sodium potassium
The most important factor that influences K+ secretion is __________.
the concentration of K+ in the ECF
Infants are more likely to experience problems regulating acid-base balance because of several factors, including __________.
the inefficiency of infant kidneys
Which of the following has the LEAST influence over the pH of blood plasma? the bicarbonate buffer system the phosphate buffer system respiratory rate the protein buffer system
the phosphate buffer system
During a routine medical checkup, Shelby, a 26-year-old physiotherapy student, is surprised to hear that her blood pressure is 180/110. She also has a rumbling systolic and diastolic abdominal bruit (murmur) that is loudest at the mid-epigastric area. Her physician suspects renal artery stenosis (narrowing). She orders an abdominal ultrasound and renal artery arteriography, which confirm that Shelby has a small right kidney and the distal part of her right renal artery is narrowed by more than 70%. Her physician prescribes diuretics and calcium channel blockers as temporary measures, and refers Shelby to a cardiovascular surgeon. Explain the connection between Shelby's renal artery stenosis and her hypertension. Why is her right kidney smaller than her left? What would you expect Shelby's blood levels of K+, Na+, aldosterone, angiotensin II, and renin to be?
the right kidney is smaller due to decreased blood flow from the narrowing of her right renal artery. The right kidney's reduced blood flow is decreasing the glomerular filtration rate of the kidney, which is responding by signaling to the body to increase blood pressure to increase blood flow to the kidney. You would expect to find her potassium levels low, and the levels of sodium, aldosterone, angiotensin II, and renin to all be high
Which of the following puts infants at increased risk for dehydration?
their inefficient kidneys
The major source of water loss from the body is __________.
urine
Match the electrolyte balance term with its correct characteristic: Hypocalcemia.
vitamin D deficiency can be a cause
Which statement about acids is true? Most acid is a result of ingestion with food. Our bodies have few ways to deal with excess amounts of acids. They have little physiological effect on chemical reactions in cells. When high in the body, they cause alkalosis. Weak acids only dissociate partially in solution.
weak acids only dissociate partially in solution
Explain why and how total body sodium content, ECF volume, and blood pressure are jointly regulated.
when there is more sodium ECF and blood pressure increase because water follows sodium
