Lecture 16 Flashcards
The blood, lymph, tissue fluid, and transcellular fluid are all examples of which of the following?
Fluid compartments
If the osmolarity of the tissue fluid rises, water moves ______ the cells.
out of
Which determines the direction and extent of osmosis between the intracellular and extracellular compartments?
Solute concentrations in the various compartments
Water output is primarily controlled through variations in which of the following?
Urine volume
Which best describes the role of the kidneys in maintaining water balance during dehydration?
The kidneys can slow down the rate of water and electrolyte loss through changes in urine volume and composition.
Match each fluid compartment with the percentage of the body water that it contains.
65% –> intracellular fluid
25% –> tissue (interstitial fluid)
8% –> blood plasma and lymph
2% –> transcellular fluid
How does water move from the digestive tract to the bloodstream?
Osmosis
During dehydration, urine volume decreases and more body water is retained. This is often due to increased reabsorption of which of the following?
Sodium
Water balance is most directly tied to which of the following?
Electrolyte balance
Which occurs when blood volume and pressure are too high?
Release of ADH is inhibited.
True or false: The only way to control water output significantly is through variations in urine volume.
True
In response to ADH release, collecting duct cells in the kidneys increase their expression of which of the following?
Aquaporins
True or false: During dehydration, the kidneys restore blood volume by the formation of metabolic water.
False
kidneys adjust the amount of sodium reabsorbed for excreted –> proportionate amount of water accompanies it
The blood, lymph, tissue fluid, and transcellular fluid are all examples of which of the following?
Fluid compartments
Hypovolemia and dehydration are both examples of fluid deficiency. How do they differ?
In dehydration water is lost, and in hypovolemia both water and electrolytes are lost.
Changes in urine volume are often linked to adjustments in which of the following?
Sodium reabsorption
True or false: In cases of volume depletion, total body water declines but fluid osmolarity is normal.
True
Choose all that inhibit ADH release.
- blood osmolarity is too high
- blood volume and pressure are too low
- blood volume and pressure are too high
- blood osmolarity is too low
Blood volume and pressure are too high. –> if you already have a lot of blood volume and pressure, don’t need to release ADH to reabsorb more water.
Blood osmolarity is too low. –> if you already have a low concentration of solutes and a high amount of water, don’t need to release ADH to reabsorb more water.
In response to ADH release, collecting duct cells in the kidneys increase their expression of proteins called ___. These proteins act as water channels and allow the kidneys to reabsorb more water and produce less urine.
aquaporins
Which may occur when proportionate amounts of water and sodium are lost without replacement, for example due to hemorrhage, chronic vomiting, or diarrhea?
Hypovolemia
Which best describes the role of the kidneys in maintaining water balance during dehydration?
The kidneys can slow down the rate of water and electrolyte loss through changes in urine volume and composition.
Which statement about dehydration is true?
Dehydration raises blood osmolarity.
Choose all that are types of fluid deficiency?
Dehydration
Volume depletion
Choose all that are possible effects of fluid deficiency.
- low blood osmolarity
- fluid retention
- circulatory shock
- neurological dysfunction
Circulatory shock –> low blood volume
Neurological dysfunction –> brain cells are dehydrated
Which term is another name for volume depletion? This occurs when proportionate amounts of both water and sodium are lost without replacement.
Hypovolemia
Which are types of fluid excess?
- hypotonic hydration
- circulatory shock
- volume excess
- hypovolemia
Hypotonic hydration
Volume excess
Which triggers the release of ADH?
Osmoreceptors detect the increase in osmotic pressure of body fluids and signal the posterior pituitary.
Which can result from aldosterone hypersecretion or renal failure?
Volume excess
Choose all the factors that can lead to volume depletion (hypovolemia).
- profuse sweating
- hemorrhage
- chronic vomiting
- diarrhea
Hemorrhage
Chronic vomiting
Diarrhea
Which term (also called water intoxication or positive water balance), refers to a condition in which more water than sodium is retained or ingested?
Hypotonic hydration
What happens to ECF osmolarity during dehydration?
It increases.
In which form of fluid imbalance is total body water reduced while osmolarity remains normal?
Hypovolemia (volume depletion)
Fluid deficiency can cause serious effects. For example, circulatory shock may be caused by which of the following?
Loss of blood volume
Choose all of the ions that are major cation electrolytes.
- sodium
- bicarbonate
- phosphate
- calcium
- chloride
Sodium
Calcium
Pulmonary and cerebral edema are among the most serious effects of which of the following?
Fluid excess
Which is the same in the ICF and in the blood plasma?
Osmolarity
If the body has retained too much sodium and water, but the ECF remains isotonic, the person has which of the following?
Volume excess
The most abundant solute particles are electrolytes, especially potassium in the intracellular fluid (ICF) and ___ in the extracellular fluid (ECF).
sodium
Which can cause hypotonic hydration?
ADH hypersecretion
Which is referred to as the “salt-retaining hormone” because it plays the primary role in adjusting sodium excretion?
Aldosterone
match each form of fluid imbalance to its description:
hypovolemia –> total body water is reduced; ECF remains isotonic
dehydration –> total body water is reduced; ECF becomes hypertonic
volume excess –> total body water is elevated; ECF remans isotonic
hypotonic hydration –> total body water is elevated; ECF becomes hypotonic
Aldosterone, antidiuretic hormone, and the natriuretic peptides help maintain concentrations which of the following?
Sodium
Sodium, potassium, calcium and hydrogen ions are examples of which of the following?
Cations
What are the primary effects of aldosterone on urine composition?
Decreases NaCl, increases K+, and decreases pH
Choose all the ways that blood plasma differs from the intracellular fluid.
- K+ concentration is lower in plasma
- plasma osmolarity is lower
- Na+ concentration is higher in plasma
- Ca2+ concentration Is higher in plasma
K+ concentration is lower in plasma.
Na+ concentration is higher in plasma.
Ca2+ concentration is higher in plasma.
Which has the largest effect on plasma sodium concentration?
ADH
Which ion is the principal cation of the ECF?
Sodium
Which inhibits Na+ and water reabsorption and lowers the blood pressure?
natriuretic peptides
Choose all that stimulate the secretion of aldosterone.
Hyponatremia – need more sodium
Hyperkalemia – too much calcium, need more sodium to balance it out
Hypotension – too little blood pressure, need more sodium –> more water –> increase BP
Choose all the statements that are true regarding potassium homeostasis.
- the more potassium there is in urine, the more sodium there is in the urine
- potassium homeostasis is closely linked to that of sodium
- aldosterone stimulates renal secretion of potassium
- ADH directly regulates potassium excretion
potassium homeostasis is closely linked to that of sodium
aldosterone stimulates renal secretion of potassium
The typical American diet contains 3 to 7 g of sodium per day. How much sodium per day does a typical adult need?
0.5 g
Which ions are the most abundant anions of the ECF and thus make a major contribution to its osmolarity?
Chloride
Choose all that are the primary effects of aldosterone.
- urine contains more K+
- urine has a lower pH
- urine contains less NaCl
- plasma sodium concentration increases
Urine contains more K+.
Urine has a lower pH.
Urine contains less NaCl.
Choose all that are affected by aldosterone.
- blood pressure
- blood sugar levels
- urine volume
- blood volume
Blood pressure
Urine volume
Blood volume
Which ion tends not to be independently regulated, but instead passively follows sodium as it is retained or excreted?
Chloride
The atrial natriuretic peptides inhibit the secretion of which two of the following?
- ACTH
- insulin
- renin
- ADH
Renin
ADH
Aldosterone stimulates which of the following?
- renal absorption of sodium
- renal secretion of sodium
- renal absorption of potassium
- renal secretion of potassium
Renal reabsorption of sodium
Renal secretion of potassium
What is the most abundant anion in the extracellular fluid?
Chloride
What are the primary effects of aldosterone on urine composition?
Decreases NaCl, increases K+, and decreases pH
Chloride homeostasis is achieved primarily as an effect of controlling the concentration of which other ion?
Sodium
Which ions are the most abundant anions of the ECF and thus make a major contribution to its osmolarity?
Chloride