Fluid, electrolyte, and Acid Base Homeostasis
What effect does an increase in antidiuretic hormone (ADH) have on the volume of extracellular fluid (ECF)?
ECF increases when antidiuretic hormone (ADH) is present.
Predict the effect of hypertonic fluid on a cell.
Hypertonic fluids cause water to move out of the cytosol and the cell shrinks.
Which of the following statements about ECF is correct?
It is made up of fluids such as plasma and interstitial fluid.
If the Pco2 in the plasma increases, what effect will this have on plasma pH?
The pH will decrease. (An increase in Pco2 is caused by hypoventilation and will result in acidosis.)
Select a statement that best describes an acid: -an acid is a chemical that accepts a hydrogen ion (H+) in a solution -An acid is a chemical that dissociates in water to release a hydrogen ion (H+) -An acid is a substance that generally has covalent bonds that do not dissociate into charged particles in water -An acid is a chemical that dissociates to release equal amounts of hydrogen ions (H+) and hydroxide ions (OH-)
an acid is a chemical that dissociates in water to release a hydrogen ion (H+)
Which hormone promotes the reabsorption of water from the kidneys back into the ECF by osmosis?
antidiuretic hormone (ADH)
The bicarbonate ion is an example of a(n) __________.
base (The bicarbonate ion is the most common BASE in the human body and is part of the major extracellular buffer system.)
What best describes hydrostatic pressure?
hydrostatic pressure is the force that fluid expert against the capillary wall.
The average young adult human male body contains about ________ liters of total body water.
42 liters
How much urine is lost through obligatory water loss each day?
500 ml
Select the blood pH that represents acidosis.
7.24
The normal range of blood pH is __________.
7.35 to 7.45
Why are chlorine ions important?
Chlorine ions are involved in the production of stomach acids.
Increased water volume causes the hydrostatic pressure in plasma to increase and the osmotic pressure to decrease; as a result, water will __________.
move from the ECF to the ICF (The ECF is now hypotonic to the ICF and water will move into cells)
Where are the majority of calcium ions stored in the body?
osseous tissue
What statement does NOT describe the methods by which chemical buffer systems operate to maintain pH?
All excess hydrogen ions are removed from the body in the urine.
Which of the following substances is the most acidic?
Gastric juice with a pH of 2 (The lower the pH, the more acidic the substance is.)
CO2 + H2O ↔ H2CO3 ↔ __________
H+ + HCO3- (The most important chemical buffer system in the blood is the carbonic acid-bicarbonate ion buffer system, which consists of the weak acid carbonic acid and its weak conjugate base, the bicarbonate ion. When carbonic acid dissociates, it yields a hydrogen ion and a bicarbonate ion.)
Calcium ion reabsorption in the kidneys is stimulated by the hormone __________.
PTH raises blood calcium levels by stimulating calcium ion reabsorption in the kidneys.
Determine the pH value that represents a basic, or alkaline, solution
Ph of 10
In what direction will water move when hypotonic fluids are present in the plasma?
Water is pulled from the interstitial fluid and plasma into the cell.
The hormone PTH causes __________.
a decrease in the reabsorption of phosphate ions
The primary role of the phosphate buffer system is to __________.
buffer intracellular fluid (ICF) (The phosphate buffer system consists of the weak acid dihydrogen phosphate and its conjugate base, hydrogen phosphate. It is an important buffer in the cytosol and in the filtrate within the kidney tubules.)
Substances that function to resist large swings in pH are called __________.
buffers (Buffers utilize weak acids and weak bases to minimize pH changes in the ECF and the ICF.)
Overhydration will cause __________.
cells gain water
Which of the following accounts for about 60% of our total body water?
cytosol
What triggers the release of parathyroid hormone (PTH)?
decreasing calcium ion concentration of the blood
Decreased volume and increased concentration of the extracellular fluid (ECF) is defined as:
dehydration
What is the most common cause for hypernatremia?
dehydration
Which of the following is an excess accumulation of interstitial fluid?
edema
Which of the following dissociates into ions when placed in water?
electrolyte
The human body stores more fluids in the extracellular compartment than in the intracellular compartment.
false
The osmotic pressure gradient, or the force of solutes in a solution, tends to push water away from the solution with the higher osmotic pressure, or the more concentrated solution, by osmosis.
false
When antidiuretic hormone (ADH) levels rise, less water is reabsorbed via the kidneys, the ECF volume decreases, and urine production increases.
false
The pH of the blood primarily depends upon a normal concentration of:
hydrogen ions
What part of the brain controls the thirst mechanism?
hypothalamus
Which of the following is a response mechanism for overhydration?
increased levels of ANP (The hormone ANP will cause decrease in ADH and water loss by the kidneys and therefore work to restore fluid homeostasis.)
Water loss from the body that we do not notice is known as:
insensible water loss.
Which ions are critical for the activation of some enzymes?
magnesium ions
What is a major function of potassium ions in the body?
repolarization of neurons and muscle cells after action potential
Hyperventilation causes __________, and hypoventilation causes __________.
respiratory alkalosis; respiratory acidosis (Hyperventilation can be caused by anxiety, whereas hypoventilation can be caused by COPD.)
Through what two systems is carbon dioxide eliminated from the body?
respiratory and urinary systems
An electrolyte is a __________.
substance that dissociates into ions when placed in water
Plasma has much higher protein content than interstitial fluid.
true
Which system is responsible for the most common route of water loss from the body?
urinary system
What is the main component of all body fluids?
water
