Chapter 26 Practice Questions

Most water is excreted via the __________. kidneys intestines skin lungs

a

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 sodium water calcium

a

Which statement about acids is true? Weak acids only dissociate partially in solution. They have little physiological effect on chemical reactions in cells. When high in the body, they cause alkalosis. Our bodies have few ways to deal with excess amounts of acids. Most acid is a result of ingestion with food.

a Strong acids dissociate fully, and weak acids dissociate incompletely.

The largest percentage of body water is located in what compartment? intracellular fluid extracellular fluid blood plasma interstitial fluid

a The largest percentage of body water is located in the intracellular fluid.

The most important buffer system of extracellular fluid, such as plasma, is the __________ buffer system. phosphate bicarbonate hemoglobin protein

b

Edema is the accumulation of fluid in the __________. plasma interstitial space intracellular space organelles

b

One way the kidneys maintain HCO3- balance is by __________. reabsorbing CO2 generating new HCO3- reabsorbing H+ generating Na+ ions

b

Renal acid-base control mechanisms are coupled to __________. plasma protein levels Na+ transport ADH secretion water intake

b

All of the following factors would stimulate the hypothalamic thirst center EXCEPT __________. a decline in blood volume hypotonic extracellular fluid increased angiotensin II secretion decreased saliva production

b Angiotensin II would stimulate the hypothalamic thirst center.

Antidiuretic hormone (ADH) acts on the __________ to __________ water excretion. kidneys; increase kidneys; decrease intestines; decrease intestines; increase

b Antidiuretic hormone (ADH) acts on the kidneys to decrease water excretion. When ADH levels are high, most or all of the filtered water is reabsorbed and a small amount of concentrated urine is excreted. When ADH levels are low, less water is reabsorbed and dilute urine is excreted.

the condition in which sodium levels are too low is referred to as __________. Cushing's syndrome hyponatremia hypokalemia aldosteronism hypernatremia

b Hypo- means low, and natrium is Latin for sodium.

Water lost through expired air is referred to as __________. water intake insensible water loss water of oxidation metabolic water

b Metabolic water is the water gained through cellular metabolism.

What is the most abundant cation in intracellular fluid? calcium potassium magnesium sodium bicarbonate

b While sodium is abundant in the interstitial fluid, the sodium-potassium pump keeps intracellular sodium levels relatively low.

Hyperventilation can lead to __________. respiratory acidosis respiratory alkalosis metabolic alkalosis metabolic acidosis

b decreased CO2 levels will increase blood pH. If one hyperventilates, the levels of CO2 drop to below normal levels and can cause respiratory alkalosis. Increased CO2 will lower blood pH. In response to high CO2 levels, the rate of and depth of breathing will increase in an effort to vent off excess CO2. If one is unable to breathe, CO2 levels increase, leading to respiratory acidosis.

Any arterial pH between __________ is considered physiological acidosis. 6.5 and 7.0 6.5 and 7.35 7.0 and 7.35 7.35 and 7.45

c

Diuresis peaks __________ after drinking water. ten minutes half an hour one hour three hours

c

Electrolyte balance in the body usually refers to the balance of __________. carbohydrates lipids salts proteins

c

The most important factor that influences K+ secretion is __________. the level of aldosterone in the plasma water balance in the body the concentration of K+ in the ECF the concentration of Na+ in blood plasma

c

Which of the following is NOT an electrolyte? sodium chloride glucose potassium

c

Which of the following puts infants at increased risk for dehydration? their high residual lung volume their low metabolic rate their inefficient kidneys their low surface area to volume ratio

c

Acidosis results in increasing levels of what ion? chloride calcium hydrogen phosphorus sodium

c Acidosis refers to high H+ concentration.

Which of the following is associated with a swelling of cells? edema dehydration hypotonic hydration hypoproteinemia

c Hypotonic hydration causes hyponatremia (low concentration of Na+ in the extracellular fluid), leading to cell swelling. Edema (tissue swelling) is an atypical accumulation of fluid in the interstitial space, leading to tissue (not cell) swelling. Edema can be caused by any event that increases fluid loss from the blood to the tissues, or that prevents effective return of fluid from the interstitial space to the bloodstream.

Normal arterial blood pH is __________. neutral slightly acidic slightly alkaline highly acidic strongly alkaline

c Normal arterial blood pH is 7.4, which is slightly alkaline.

Parathyroid hormone __________. activates osteoblasts is released when aldosterone levels climb enhances release of calcium from bone results in a lower blood calcium level targets the thyroid gland

c PTH activates osteoclasts, which break down the bone matrix, releasing calcium.

Which of the following would increase sodium excretion? aldosterone glucocorticoids progesterone estrogens

c Reabsorption of sodium does not exhibit a transport maximum. In healthy individuals, nearly all sodium in the renal filtrate is reabsorbed in the proximal convoluted tubules of the kidneys. Atrial natriuretic peptide (ANP) and progesterone increase Na+ excretion. Progesterone appears to decrease NaCl reabsorption by blocking the effect aldosterone has on the renal tubules. Aldosterone is the key regulator of sodium reabsorption in the kidney. It encourages Na+ reabsorption. Estrogens, like aldosterone, encourage Na+ reabsorption. Glucocorticoids enhance tubular reabsorption of sodium.

Which of the following has the LEAST influence over the pH of blood plasma? respiratory rate the protein buffer system the phosphate buffer system the bicarbonate buffer system

c The bicarbonate buffer system is the primary buffer system for the ECF. Because the phosphate buffer system is present in low concentrations in the ECF (approximately one-sixth that of the bicarbonate buffer system), it is relatively unimportant for buffering blood plasma. However, it is a very effective buffer in urine and in ICF, where phosphate concentrations are usually higher.

The only organ(s) of the body that can remove excess nonvolatile fixed acids is/are the __________. lungs spleen kidney liver sweat glands

c The only organ of the body that can remove excess nonvolatile fixed acids is the kidney. Fixed acids are also called metabolic acids.

Estrogens are chemically similar to __________ and are therefore associated with water retention. rennin ANP ADH aldosterone

d

The most prevalent electrolyte in the extracellular fluid is __________. calcium potassium phosphate sodium chloride magnesium

d

Which of the following tissues is the least hydrated? nervous tissue muscle tissue bone adipose tissue

d

When atrial natriuretic peptide is released by the heart because of increased blood pressure, it causes __________. vasoconstriction increased antidiuretic-hormone secretion increased renin secretion decreased sodium and water reabsorption

d ANP reduces blood pressure and blood volume by inhibiting nearly all events that promote vasoconstriction, sodium retention, and water retention.

Which of the following individuals would have the most body water? an older obese person a healthy young male a healthy young female an infant

d An infant's body is 73% or more water.

Which condition would cause a drop in pH? hypernatremia hypokalemia hyperventilation hypoventilation

d Hypoventilation causes a drop in pH. Breathing slowly increases PCO2.

All of the following would occur if there were an increase in plasma osmolality EXCEPT __________. release of ADH concentrated urine thirst production of large amounts of urine

d If the plasma osmolality were to increase, the urine would be concentrated.

Infants are more likely to experience problems regulating acid-base balance because of several factors, including __________. low rate of insensible water loss from skin high residual volume of infant lungs lower amount of fluid intake and output in infants the inefficiency of infant kidneys decreased surface area relative to body volume

d The kidneys are immature at birth; they are approximately half as proficient at concentrating urine as mature kidneys. Infant kidneys are also inefficient in ridding the body of acids.

Someone who is suffocating would develop __________. respiratory alkalosis metabolic alkalosis metabolic acidosis respiratory acidosis

d The most common cause of acid-base imbalance is respiratory acidosis, a result of elevated blood levels of CO2 due to shallow breathing, suffocation, or lung diseases that impede O2 and CO2 exchange.

The major source of water loss from the body is __________. feces insensible respiratory loss insensible skin loss urine sweat

d Urine accounts for roughly 60% of the body's water loss.

A major stimulus for the release of antidiuretic hormone is __________. an increase in potassium levels in the ICF stimulation of the baroreceptors inhibition of the osmoreceptors an increase in ECF water concentration a rise in plasma osmolality

e A major stimulus for the release of antidiuretic hormone is a rise in plasma osmolality. ADH results in increased water reabsorption.

The most important buffer system in the intracellular fluid compartment (ICF) is the __________ buffer system. phosphate sulfate bicarbonate chloride protein

e Most of the buffering power of body fluids resides in cells, and most of this reflects the buffering activity of intracellular proteins.

The only cation exerting significant osmotic pressure in the ECF is __________. Ca2+ Mg2+ Fe2+ K+ Na+

e Na+ is the only cation exerting significant osmotic pressure in the ECF.

When the concentration of Na+ in the ECF decreases, __________. more ADH is released osmoreceptors are stimulated ANP levels increase a person experiences increased thirst aldosterone levels increase

e When the concentration of Na+ in the ECF decreases, there is an increase in the level of aldosterone, which causes facultative Na+ reabsorption.

Most fluid in the body is in the extracellular fluid (ECF) compartment. True False

false

The most abundant cation in extracellular fluid is potassium. True False

false

parathyroid hormone (PTH) increases Ca2+ deposition in the bones. True False

false

Most of the hydrogen ions in the body come from acidic substances in the foods we ingest. True False

false Small amounts of acids enter the body via ingested foods. However, most H+ ions originate as metabolic by-products or end products. For example, the breakdown of phosphorus-containing proteins, the anaerobic breakdown of glucose, fat metabolism, and the loading and transport of CO2 in the blood all serve as sources of hydrogen ions in the body.

mastering a&p labeling question Label the parts associated with aldosterone release mechanisms and consequences. increased K+ concentration in the ECF kidney tubules increased K+ secretion increased Na+ reabsorption homeostatic plasma levels of Na+ and K+

increased K+ concentration in the ECF & the renin-angiotensin mechanism stimulates the adrenal cortex which releases aldosterone which targets the kidney tubules which increases K+ secretion and increases Na+ re absorption which restores homeostatic plasma levels