Renal System by Archer

What percentage of body fluid is found within cells, constituting the intracellular fluid (ICF)?

• 25%

• 50%

• 60%

• 66%

Answer explanation

✓ The ICF contains the majority of the body's fluid, which is critical for cellular processes.

✓ The remaining 34% of body fluid is in the extracellular compartment, including plasma and interstitial fluid.

✓ Fluid balance between compartments is regulated by osmosis and blood pressure.

✓ Proper ICF volume is essential for maintaining cell shape and function.

✓ Electrolytes in the ICF, such as potassium and phosphate, play vital roles in cellular activities. 

Which electrolyte imbalance is likely to occur with prolonged vomiting?

• • Hyperkalemia

• • Hypokalemia

• • Hypercalcemia

• • Hypocalcemia

Answer explanation

✓ Vomiting leads to the loss of gastric contents, which are rich in potassium.

✓ This loss can result in decreased potassium levels in the blood.

✓ Hypokalemia can cause muscle weakness, cramping, and cardiac arrhythmias.

✓ Potassium supplementation or dietary adjustments may be needed to correct hypokalemia.

✓ Monitoring and managing electrolyte balance are crucial in patients with prolonged vomiting. 

What percentage of the filtrate produced by the glomeruli is typically reabsorbed by the renal tubules?

• • 10%

• • 30%

• • 50%

• • 99%

Answer explanation

Approximately 99% of the filtrate produced by the glomeruli is reabsorbed by the renal tubules. This high reabsorption rate ensures that essential nutrients, electrolytes, and water are retained in the body while waste products and excess substances are excreted in the urine.

Which hormone decreases sodium reabsorption to help lower blood pressure?

• Aldosterone

• Antidiuretic hormone (ADH)

• Atrial natriuretic peptide (ANP)

• Renin

Answer explanation

✓ ANP is released by the atria of the heart in response to increased blood volume and pressure.

✓ It promotes sodium excretion by the kidneys, leading to increased urine output.

✓ This reduction in sodium and water reabsorption lowers blood volume and pressure.

✓ ANP opposes the actions of the renin-angiotensin-aldosterone system, maintaining fluid balance.

✓ Conditions that cause elevated blood volume, such as heart failure, can trigger ANP release. 

Which fluid compartment contains the largest proportion of body water?

• • Extracellular fluid (ECF)

• • Plasma

• • Interstitial fluid

• • Intracellular fluid (ICF)

Answer explanation

The intracellular fluid (ICF) compartment contains the largest proportion of body water, accounting for about two-thirds of the total body water. This compartment includes all the fluid within cells, which is essential for various cellular functions and processes.

✓ The ICF includes all the fluid within cells, accounting for about 40% of body weight.

✓ Maintaining fluid balance within the ICF is crucial for cellular function and homeostasis.

✓ The ECF, including plasma and interstitial fluid, makes up the remaining one-third of body water.

✓ Proper fluid distribution between compartments is essential for nutrient transport and waste removal.

✓ Disruptions in fluid balance can lead to conditions such as dehydration or edema. 

Which of the following electrolytes is most critical for nerve impulse transmission and muscle contraction?

• • Sodium

• • Calcium

• • Magnesium

• • Chloride

Answer explanation

✓ Sodium ions are essential for generating and propagating action potentials in neurons and muscle cells.

✓ The sodium-potassium pump maintains the resting membrane potential by actively transporting sodium out of cells and potassium into cells.

✓ Proper sodium levels are necessary for muscle contractions and normal neurological function.

✓ Imbalances in sodium can lead to conditions such as hypernatremia or hyponatremia, affecting neurological and muscular systems.

✓ Monitoring and managing sodium levels are vital in clinical practice, especially in patients with electrolyte disturbances.