1.
Most of the body water is in
Correct Answer
A. The intracellular fluid (ICF).
Explanation
The correct answer is the intracellular fluid (ICF). The majority of the body's water is found within the cells, making up the intracellular fluid. This fluid is essential for various cellular processes and helps maintain cell structure and function. The extracellular fluid, which includes tissue fluid, blood plasma, and lymph, makes up a smaller portion of the body's water content. However, the intracellular fluid is the primary location for water within the body.
2.
Osmosis from one fluid compartment to another is determind by
Correct Answer
B. The relative concentration of solutes in each compartment.
Explanation
The movement of osmosis from one fluid compartment to another is determined by the relative concentration of solutes in each compartment. Osmosis is the process of water moving across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. Therefore, the concentration gradient between the compartments drives the movement of water through osmosis. The temperature difference, relative volume, and relative size of the compartments do not directly affect osmosis. Blood pressure may indirectly influence osmosis by affecting the hydrostatic pressure, but it is not the primary determinant.
3.
In which of these compartments would fluid accumulate in edema?
Correct Answer
C. Tissue (interstitial) fluid
Explanation
Edema is the accumulation of excess fluid in the interstitial spaces, which are the spaces between cells in tissues. This excess fluid can cause swelling and can occur in various parts of the body. Therefore, the correct answer is tissue (interstitial) fluid.
4.
Most body water comes from _____, whereas most body water is lost via ___.
Correct Answer
D. Drinking; urine
Explanation
The majority of body water comes from drinking fluids, while most body water is lost through the process of urine excretion. Drinking fluids helps to replenish the body's water content, while urine excretion eliminates excess water and waste products from the body.
5.
Fluid intake is governed mainly by hypothalamic neurons called
Correct Answer
D. Osmoreceptors.
Explanation
Osmoreceptors are sensory neurons located in the hypothalamus that respond to changes in the osmotic pressure of the blood. When the osmotic pressure increases, indicating dehydration, the osmoreceptors stimulate the release of antidiuretic hormone (ADH) from the pituitary gland. ADH acts on the kidneys to reduce urine production and increase water reabsorption, leading to increased fluid intake. Therefore, osmoreceptors play a crucial role in regulating fluid intake by sensing changes in blood osmolarity and initiating appropriate responses to maintain fluid balance in the body.
6.
Antidiuretic hormone (ADH)
Correct Answer
B. Promotes water conservation.
Explanation
ADH, also known as vasopressin, plays a crucial role in regulating water balance in the body. It is released by the pituitary gland in response to low blood volume or high blood osmolality. One of its main functions is to promote water conservation by increasing the reabsorption of water in the kidneys, leading to decreased urine output and increased water retention. This helps to prevent dehydration and maintain proper fluid balance in the body. Therefore, the correct answer is "promotes water conservation."
7.
Water output is singnificantly controlled thorough variation in
Correct Answer
E. Urine volume
Explanation
The correct answer is urine volume because the output of water in the body is largely regulated through the variation in urine volume. When the body needs to conserve water, the urine volume decreases, leading to less water being excreted from the body. On the other hand, when the body needs to eliminate excess water, the urine volume increases, allowing for more water to be excreted. Therefore, the control of urine volume plays a significant role in regulating the water output in the body.
8.
When blood volume and pressure are too high
Correct Answer
A. ADH release is inhibited.
Explanation
When blood volume and pressure are too high, the release of ADH (antidiuretic hormone) is inhibited. ADH is responsible for regulating the amount of water reabsorbed by the renal tubules in the kidneys. When blood volume and pressure are high, it indicates that there is already enough fluid in the body, so the release of ADH is suppressed to prevent further water reabsorption. This helps to reduce blood volume and pressure, allowing the body to maintain a balance.
9.
Prolonged exposure to cold weather can lead to
Correct Answer
E. A negative water balance
Explanation
Prolonged exposure to cold weather can lead to a negative water balance. This is because cold temperatures can cause vasoconstriction, reducing blood flow to the extremities and increasing urine output. As a result, the body loses more water than it takes in, leading to dehydration and a negative water balance.
10.
Dehydration results in increased blood and ECF osmolarity. This makes osmoreceptors stimulate ____ secretion by the hypothalamus ____ in the DCT and CD.
Correct Answer
B. ADH; increasing water reabsorption
Explanation
Dehydration causes an increase in blood and extracellular fluid (ECF) osmolarity. This increase in osmolarity stimulates osmoreceptors in the hypothalamus to secrete antidiuretic hormone (ADH). ADH acts on the distal convoluted tubules (DCT) and collecting ducts (CD) of the kidneys, increasing water reabsorption. This helps to conserve water and prevent further dehydration.
11.
Hemorrhages
Correct Answer
A. Decrease body water but do not significantly affect osmolarity
Explanation
Hemorrhages result in a decrease in body water due to the loss of blood. However, they do not significantly affect osmolarity, which refers to the concentration of solutes in the body's fluids. This means that the loss of blood does not cause a significant change in the concentration of solutes in the body.
12.
Long-term inhibition of thirst is mostly associated with
Correct Answer
C. A drop in blo0d osmolarity
Explanation
Long-term inhibition of thirst is mostly associated with a drop in blood osmolarity. When blood osmolarity decreases, it indicates that the concentration of solutes in the blood is lower. This can occur when the body has enough water and does not need to activate the thirst mechanism. In this state, the body does not feel the need to drink water because it has already achieved a balance in fluid levels. Cooling of the mouth, distention of the stomach by ingested water, moistening of the mouth, and increased salivation may provide short-term relief or satisfaction, but they do not have a long-term inhibitory effect on thirst.
13.
This is the principal cation of the ECF.
Correct Answer
D. Na+
Explanation
Na+ is the correct answer because it is the principal cation of the extracellular fluid (ECF). The ECF refers to the fluid outside of the body's cells, including the fluid in the blood and the interstitial fluid. Sodium ions (Na+) play a crucial role in maintaining fluid balance, nerve function, and muscle contractions. They are also involved in the regulation of blood pressure and pH levels. Therefore, Na+ is the primary cation in the ECF.
14.
Aldosterone receptors are found on cells of
Correct Answer
E. DCT
Explanation
Aldosterone receptors are found on cells of the distal convoluted tubule (DCT). Aldosterone is a hormone produced by the adrenal cortex and acts on the DCT to increase sodium reabsorption and potassium secretion. This helps in regulating blood pressure and electrolyte balance. Therefore, the presence of aldosterone receptors on the DCT is necessary for the hormone to exert its effects.
15.
Aldosterone
Correct Answer
C. Increases Na+ reabsorption and K+ secretion.
Explanation
Aldosterone is a hormone produced by the adrenal glands that plays a role in regulating electrolyte balance in the body. It acts on the kidneys to increase the reabsorption of sodium ions (Na+) and the secretion of potassium ions (K+). This helps to increase the concentration of sodium in the blood and decrease the concentration of potassium. Therefore, the correct answer is that aldosterone increases Na+ reabsorption and K+ secretion.
16.
Hypernatremia is a plasma ___ concentration above normal.
Correct Answer
B. Na+
Explanation
Hypernatremia is a condition characterized by a higher than normal concentration of sodium ions (Na+) in the plasma. This imbalance can occur due to various reasons, such as excessive sodium intake, inadequate water intake, or impaired kidney function. When the sodium concentration in the blood is elevated, it can lead to symptoms like increased thirst, dry mouth, and altered mental status. Therefore, the correct answer is Na+.
17.
Hypernatremia tends to cause all of the following except
Correct Answer
E. A reduction in plasma volume
Explanation
Hypernatremia is a condition characterized by an elevated level of sodium in the blood. It occurs when there is an imbalance between water intake and excretion, leading to a relative deficiency of water in the body. This imbalance can cause various symptoms, including water retention, edema, hypertension, and interstitial fluid accumulation. However, hypernatremia does not typically result in a reduction in plasma volume. Instead, it often leads to an increase in plasma volume due to the movement of water from the intracellular space to the extracellular space.
18.
_____ is the most significant solute in determining the distribution of water among fluid compartments
Correct Answer
A. Na+
Explanation
Na+ is the most significant solute in determining the distribution of water among fluid compartments because it plays a crucial role in maintaining fluid balance and osmotic pressure. Na+ is the primary solute in extracellular fluid, and its concentration gradient across cell membranes helps regulate the movement of water into and out of cells. Changes in Na+ concentration can lead to shifts in fluid distribution and affect overall hydration status. Therefore, Na+ is a key factor in determining the distribution of water among different fluid compartments in the body.
19.
___ does not stimulate aldosterone secretion.
Correct Answer
D. High blood sodium concentration
Explanation
High blood sodium concentration does not stimulate aldosterone secretion. Aldosterone is a hormone produced by the adrenal glands that helps regulate sodium and potassium levels in the body. When blood sodium concentration is low, aldosterone is released to increase reabsorption of sodium in the kidneys, leading to increased water retention and increased blood volume. However, when blood sodium concentration is already high, there is no need for aldosterone to be secreted as the body does not need to retain more sodium.
20.
Women have a tendency to retain water during part of the menstrual cycle because estrogen mimics the action of
Correct Answer
B. Aldosterone
Explanation
During the menstrual cycle, women experience hormonal changes, including an increase in estrogen levels. Estrogen can mimic the action of aldosterone, a hormone that regulates the balance of water and electrolytes in the body. Aldosterone promotes the reabsorption of sodium and water in the kidneys, leading to water retention. Therefore, the increase in estrogen during the menstrual cycle can cause women to retain water, explaining why aldosterone is the correct answer.
21.
This is the most abundant cation of the ICF
Correct Answer
C. K+
Explanation
K+ is the most abundant cation in the intracellular fluid (ICF) because it plays a crucial role in maintaining the cell's resting membrane potential and regulating various cellular processes. It is involved in the transmission of nerve impulses, muscle contraction, and the balance of fluids and electrolytes within the cell. Additionally, K+ is actively pumped into the cell by the Na+/K+ ATPase pump, which helps maintain the concentration gradient necessary for these physiological functions. Therefore, K+ is the correct answer as it is the most abundant cation in the ICF.
22.
The total body water (TBW) content of a 70 kg young male is about
Correct Answer
C. 40 L.
Explanation
The total body water (TBW) content of a 70 kg young male is about 40 L. This is because the average TBW in adults is approximately 60% of their total body weight. Therefore, for a 70 kg individual, the TBW would be 70 kg x 0.6 = 42 L. However, it is important to note that this is an estimate and individual variations in body composition and hydration status can affect the actual TBW.
23.
This the gratest dererminant of intercellur volume
Correct Answer
A. K+
Explanation
The given options are various ions, including K+, Na+, Ca2+, Cl-, and PO43-. The question asks for the greatest determinant of intercellular volume. In this context, K+ (potassium) is known to be the major intracellular cation and plays a critical role in regulating cell volume. It is involved in maintaining osmotic balance and controlling cell membrane potential. Therefore, K+ is likely the correct answer as it has the most significant impact on intercellular volume.
24.
These scenarios are related with hyperkalemia except
Correct Answer
B. Resting membrane potential is more negative
Explanation
Hyperkalemia is a condition characterized by high levels of potassium in the blood. It can lead to various changes in cellular function. One of these changes is a shift in the resting membrane potential of cells towards a more positive value, rather than a more negative value. This means that the cells become less excitable, as it takes a stronger stimulus to depolarize the cell and initiate an action potential. Therefore, the statement "resting membrane potential is more negative" is not related to hyperkalemia.
25.
In state of hypokalemia
Correct Answer
E. Cells are hyperpolarized.
Explanation
In the state of hypokalemia, there is a decrease in the concentration of potassium in the extracellular fluid. This leads to a decrease in the resting membrane potential of cells, causing them to become hyperpolarized. Hyperpolarization means that the membrane potential becomes more negative than the normal resting potential, making the cells less excitable and more resistant to firing action potentials.
26.
Hypokalemia can result from all of the following except from
Correct Answer
D. Aldosterone hyposecretion
Explanation
Hypokalemia is a condition characterized by low levels of potassium in the blood. It can be caused by various factors such as chronic vomiting, diarrhea, heavy sweating, and excessive use of laxatives. However, aldosterone hyposecretion, which refers to a deficiency in the hormone aldosterone, is not a cause of hypokalemia. Aldosterone is responsible for regulating the balance of electrolytes, including potassium, in the body. Therefore, a decrease in aldosterone production would not directly result in hypokalemia.
27.
This the most abundant anion of the ECF
Correct Answer
E. Cl-
Explanation
The correct answer is Cl- because it is the most abundant anion in the extracellular fluid (ECF). The other options, such as HCO3-, PO43-, HPO42-, and H2PO4-, are not as abundant in the ECF as Cl-.
28.
Chloride homeostasis is achieved mainly as a result of ___ homeostasis
Correct Answer
D. Na+
Explanation
Chloride homeostasis is achieved mainly as a result of Na+ homeostasis. This is because sodium ions (Na+) play a crucial role in maintaining the balance of chloride ions (Cl-) in the body. Sodium and chloride ions are often found together in the extracellular fluid and are involved in various physiological processes, including fluid balance, nerve impulse transmission, and muscle contraction. The movement of sodium ions across cell membranes helps regulate the movement of chloride ions, ensuring their proper distribution and maintaining chloride homeostasis.
29.
The calcium of the body fluids does/is not
Correct Answer
B. A significant component of nucleic acids.
Explanation
Calcium is not a significant component of nucleic acids. Nucleic acids are made up of nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base. Calcium is not one of the components of nucleotides and therefore does not play a role in the structure or function of nucleic acids.
30.
Calcium concentration is regulated by
Correct Answer
A. Hormones
Explanation
Calcium concentration is regulated by hormones. Hormones play a crucial role in maintaining the balance of calcium in the body. They regulate calcium levels by influencing the absorption, storage, and release of calcium from bones, as well as its excretion through the kidneys. Hormones such as parathyroid hormone (PTH) and calcitonin help to increase or decrease calcium levels in response to the body's needs. PTH increases calcium levels by promoting its release from bones and enhancing its absorption from the intestines, while calcitonin decreases calcium levels by inhibiting its release from bones. Therefore, hormones are essential in regulating calcium concentration in the body.
31.
The inorganice phosphates (Pi) of the body fluids do/are not
Correct Answer
D. From crystals with calcium in the presence of calsequestrin
32.
Excretion of phosphate
Correct Answer
B. Increases free calcium ions in the ECF.
Explanation
Excretion of phosphate increases free calcium ions in the ECF. Phosphate and calcium ions have an inverse relationship in the body. When phosphate levels increase, calcium levels decrease, and vice versa. The excretion of phosphate leads to a decrease in phosphate levels, which in turn increases calcium levels. This occurs because phosphate and calcium ions compete for binding sites in the body, and when phosphate levels decrease, more binding sites become available for calcium ions, leading to an increase in free calcium ions in the extracellular fluid (ECF).
33.
___ represents the complete chemical equation for the bicarbonate buffer system
Correct Answer
A. CO2 + H2O H2CO3 HCO3- + H+
Explanation
The correct answer is CO2 + H2O H2CO3 HCO3- + H+. This equation represents the bicarbonate buffer system, which is an important physiological buffer system in the body. In this system, carbon dioxide (CO2) reacts with water (H2O) to form carbonic acid (H2CO3). Carbonic acid then dissociates into bicarbonate ions (HCO3-) and hydrogen ions (H+). This equation shows the reversible nature of the bicarbonate buffer system and how it helps to maintain the pH balance in the body.
34.
Tissue fluid normally has a pH of
Correct Answer
E. 7.35-7.45
Explanation
Tissue fluid normally has a pH range of 7.35-7.45. This pH range is slightly alkaline, which is important for maintaining the proper functioning of cells and enzymes in the body. The pH of tissue fluid is regulated by various mechanisms in the body, including the buffering capacity of bicarbonate ions in the blood. Any deviation from this pH range can disrupt cellular processes and lead to health problems.
35.
The major chemical buffers systems of the body are the ______ system.
Correct Answer
C. Bicarbonate, pHospHate, and protein
Explanation
The major chemical buffers systems of the body are bicarbonate, phosphate, and protein. These systems play a crucial role in maintaining the pH balance in the body by regulating the concentration of hydrogen ions. Bicarbonate acts as a buffer in the blood and extracellular fluid, phosphate buffers are found in intracellular fluid, and proteins act as buffers in both intracellular and extracellular fluids. Together, these systems help to prevent drastic changes in pH levels, ensuring the body's physiological processes can function properly.
36.
What protein(s) is/are the most important buffer(s) blood plasma?
Correct Answer
B. Albumim
Explanation
Albumin is the most important buffer in blood plasma because it helps maintain the pH balance of the blood. It acts as a buffer by accepting or donating hydrogen ions to maintain the blood's acidity level within a narrow range. This is crucial for proper functioning of enzymes and other biochemical processes in the body. Additionally, albumin also helps transport various substances such as hormones, fatty acids, and drugs in the blood.
37.
What protein(s) is/are the most important buffer(s) in erythrocytes?
Correct Answer
D. Hemoglobin
Explanation
Hemoglobin is the most important buffer in erythrocytes. It acts as a buffer by binding with hydrogen ions (H+) to maintain the pH balance in the blood. Hemoglobin's ability to bind and release oxygen also helps in regulating the acid-base balance. Additionally, hemoglobin can also bind with carbon dioxide (CO2) and transport it to the lungs for elimination, further contributing to its role as a buffer in erythrocytes.
38.
A weak base
Correct Answer
C. Binds little H+ and has weak effect on pH.
Explanation
A weak base binds little H+ and has a weak effect on pH because it does not readily accept protons (H+) from water molecules. This means that it does not significantly increase the concentration of H+ ions in the solution, resulting in only a small change in pH. Weak bases are typically not very reactive and do not completely dissociate in water, leading to a weak effect on pH.
39.
When the renal tubules secrete hydrogen ions into the tubular fluid, they ___ at the same time.
Correct Answer
E. Reabsorb sodium
Explanation
When the renal tubules secrete hydrogen ions into the tubular fluid, they reabsorb sodium at the same time. This is because the reabsorption of sodium helps to maintain the balance of electrolytes in the body and regulate blood pressure. The secretion of hydrogen ions is part of the process of maintaining the body's acid-base balance, and the reabsorption of sodium helps to counterbalance this secretion and prevent excessive loss of sodium from the body.
40.
The pH of the intracellular fluid buffered mainly by
Correct Answer
A. Proteins
Explanation
Proteins are the main buffers in intracellular fluid because they can accept or donate hydrogen ions, helping to maintain a stable pH. This is important for cellular processes as many enzymes and proteins function optimally within a specific pH range. The bicarbonate, phosphate, and carbonic acid systems also contribute to pH regulation, but proteins play a more significant role in buffering intracellular fluid. Ammonium ions are not typically involved in intracellular pH buffering.
41.
The bicarbonate buffer system would not work very well in the human body if not for the action of the respiratory system, which
Correct Answer
E. Expels CO2 produced by the buffer system
Explanation
The bicarbonate buffer system in the human body helps maintain the pH balance by regulating the levels of carbon dioxide (CO2) and bicarbonate ions (HCO3-). When CO2 is produced by the buffer system, it needs to be expelled from the body to prevent an increase in acidity. The respiratory system plays a crucial role in this process by expelling the excess CO2 through exhalation. Therefore, the correct answer is "expels CO2 produced by the buffer system."
42.
An antiport system on the basal side of renal tubule cells
Correct Answer
D. Exchanges K+ for Na+.
Explanation
The correct answer is "exchanges K+ for Na+." In the renal tubule cells, an antiport system facilitates the exchange of potassium ions (K+) for sodium ions (Na+). This helps maintain the balance of these ions in the body and is crucial for various physiological processes such as regulating blood pressure and fluid balance.
43.
Proteins can buffer a drop in pH by their _____ side groups and can buffer an increase in pH by their _____ side groups.
Correct Answer
C. -NH2; -COOH
Explanation
Proteins can buffer a drop in pH by their -NH2 (amino) side groups, which can accept protons (H+) and help maintain the pH level. On the other hand, proteins can buffer an increase in pH by their -COOH (carboxyl) side groups, which can donate protons (H+) and help lower the pH. Therefore, the correct answer is -NH2; -COOH.
44.
In a person with normal acid-base balance, there are no bicarbonate ions in urine because
Correct Answer
A. They are consumed by neutralizing H+.
Explanation
Bicarbonate ions (HCO3-) in the urine are not normally found because they are consumed by neutralizing H+ ions. This is because bicarbonate acts as a buffer in the body, helping to maintain the pH balance. When there is an excess of H+ ions, bicarbonate ions react with them to form carbonic acid (H2CO3), which can then be converted into water and carbon dioxide. This reaction helps to prevent the urine from becoming too acidic and maintains the acid-base balance in the body.
45.
In acidosis, the membrane potential of nerve cells is ___, which ___ the central nervous system.
Correct Answer
C. Hyperpolarized; depresses
Explanation
In acidosis, the membrane potential of nerve cells becomes hyperpolarized. This means that the inside of the cell becomes more negative compared to the outside. This hyperpolarization inhibits the central nervous system, leading to a decrease in nerve cell activity and ultimately depressing the central nervous system.
46.
In acidosis, the kidneys compensate by
Correct Answer
B. Secreting more ammonia
Explanation
In acidosis, the kidneys compensate by secreting more ammonia. Ammonia is a basic compound that can help neutralize the excess acid in the body. By increasing the secretion of ammonia, the kidneys can help balance the pH levels and maintain a more alkaline environment. This is an important mechanism to prevent the acidosis from worsening and to restore the body's acid-base balance.
47.
Breathing with the head inside a plastic bag can lead to
Correct Answer
E. Respiratory acidosis.
Explanation
Breathing with the head inside a plastic bag can lead to respiratory acidosis. When the head is inside a plastic bag, the person is inhaling the air that they have exhaled, leading to a buildup of carbon dioxide in the body. This excessive carbon dioxide causes the blood pH to decrease, resulting in respiratory acidosis.
48.
Excessive intake of antacids can lead to
Correct Answer
A. Metabolic alkalosis.
Explanation
Excessive intake of antacids can lead to metabolic alkalosis. Antacids work by neutralizing stomach acid, which can help relieve symptoms of indigestion or heartburn. However, if taken in excess, antacids can disrupt the balance of acids and bases in the body, leading to a condition called metabolic alkalosis. This occurs when there is an excess of bicarbonate ions in the blood, causing a shift towards alkalinity. Symptoms of metabolic alkalosis may include muscle twitching, hand tremors, and confusion. Treatment involves addressing the underlying cause and restoring the acid-base balance.
49.
Chronic vomiting can lead to
Correct Answer
B. Metabolic alkalosis
Explanation
Chronic vomiting can lead to metabolic alkalosis because when a person vomits frequently, they lose stomach acid, which is acidic. This loss of acid results in an imbalance in the body's pH levels, causing them to become more alkaline. This condition is known as metabolic alkalosis.
50.
Emphysema can lead to
Correct Answer
D. Respiratory acidosis
Explanation
Emphysema is a lung condition characterized by damage to the air sacs in the lungs, leading to reduced lung function. This damage can result in impaired gas exchange and the accumulation of carbon dioxide in the blood, leading to respiratory acidosis. In respiratory acidosis, the blood pH decreases due to an excess of carbon dioxide, causing symptoms such as shortness of breath, confusion, and fatigue. Therefore, it is logical to conclude that emphysema can lead to respiratory acidosis.