A & P 2 lecture exam fluid balance

What percentage of the human body is water?

~60%

Where is most body water located?

In the intracellular fluid (ICF)

What are the two components of extracellular fluid?

Plasma and interstitial fluid.

What happens to cells if ECF becomes hypertonic?

Cells will lose water and shrink.

What happens if ECF becomes hypotonic?

Cells will gain water and swell.

What is the major cation in ECF?

Sodium (Na+).

What is the major cation in ICF?

Potassium (K+).

Why is potassium imbalance dangerous?

It can affect heart rhythm.

What is the main function of calcium in the body?

Muscle contraction and nerve signaling.

What happens if calcium levels drop too low?

Muscle spasms, numbness, and cardiac arrhythmias.

What happens if calcium levels raise too high?

It can lead to muscle weakness, confusion, and cardiac arrest.

What does ADH do for fluid balance?

Helps regulate fluid balance by increasing water reabsorption in the kidneys, reducing urine output.

What triggers ADH release?

Dehydration, high blood osmolality, or low blood volume.

What is the function of aldosterone in fluid balance?

Promotes sodium reabsorption in the kidneys, which helps to retain water and increase blood volume, thus regulating fluid balance.

What is the function of ANP in fluid balance?

Decreases blood volume and pressure by promoting sodium and water excretion in the kidneys, thus helping to regulate fluid balance.

How does the body maintain balance between ICF and ECF?

The regulation of osmotic gradients, primarily via the movement of water and electrolytes across cell membranes, facilitated by mechanisms such as osmosis and active transport.

What happens during dehydration?

The body loses water, leading to increased osmolarity of extracellular fluid, which triggers hormonal responses such as the release of aldosterone and ADH to conserve water and restore fluid balance.

What happens during overhydration?

The body retains excessive water, resulting in decreased osmolarity of extracellular fluid, which can lead to hyponatremia and may require mechanisms to excrete excess fluid.

What is edema?

Accumulation of excess fluid in the interstitial spaces, which can occur due to various factors such as increased capillary permeability, reduced osmotic pressure, or obstruction of lymphatic drainage.

What can cause edema?

Heart failure, kidney disease, liver dysfunction, inflammation, and venous insufficiency, leading to fluid accumulation in tissues.

How is sodium balance primarily regulated?

The kidneys through mechanisms such as renin-angiotensin-aldosterone system (RAAS), and adjustments in sodium reabsorption in the nephron.

How is potassium balance regulated?

The kidneys, which control its excretion and reabsorption in the nephron, often influenced by factors such as aldosterone and dietary intake.

Why are electrolyte imbalances dangerous?

They can disrupt normal cellular functions, cause muscle weakness, affect heart rhythm, and lead to severe neurological disturbances.

What is the normal blood pH range?

~7.35-7.45

What is acidosis?

A pH below 7.35.

What is alkalosis?

A pH above 7.45.

How do lungs help regulate the pH?

By controlling CO2 levels.

What happens if CO2 increases?

It leads to a decrease in pH, causing acidosis.

How do kidneys help regulate pH?

They excrete bicarbonate or hydrogen ions.

What is the most important buffer system in blood?

The bicarbonate buffer system, which maintains pH by exchanging bicarbonate and carbonic acid.

Where is the phosphate buffer system most important?

In the intracellular fluid and in the kidney tubules.

Where are protein buffers important?

Both ICF and ECF.

What causes respiratory acidosis?

Buildup of carbon dioxide due to inadequate respiration, leading to increased levels of carbonic acid in the blood.

What causes respiratory alkalosis?

A decrease in carbon dioxide levels due to hyperventilation, resulting in decreased carbonic acid in the blood.

What causes metabolic acidosis?

Accumulation of acid or loss of bicarbonate, often due to conditions like renal failure or diabetic ketoacidosis.

What causes metabolic alkalosis?

Excessive bicarbonate or loss of acid, often due to vomiting or diuretics.

How does the body compensate for respiratory acidosis?

Renal retention of bicarbonate and increased excretion of hydrogen ions to restore pH balance.

How does the body compensate for respiratory alkalosis?

Renal excretion of bicarbonate and decreased excretion of hydrogen ions to restore pH balance.

How does the body compensate for metabolic acidosis?

Increased respiratory rate to eliminate carbon dioxide and renal excretion of hydrogen ions while retaining bicarbonate to restore pH balance.

How does the body compensate for metabolic alkalosis?

Renal retention of bicarbonate and increased excretion of hydrogen ions to restore pH balance.

What is the major anion in the ECF?

Chloride (Cl⁻), which plays a critical role in maintaining osmotic pressure and fluid balance.

What is the major anion in the ICF?

Phosphate (HPO4²⁻), essential for cellular function and energy metabolism.

Why are electrolyte distributions important?

They influence fluid balance, nerve conduction, muscle contraction, and overall cellular function.

What are the major solid components of the body?

Proteins, lipids, and minerals.

Which solid component is most abundant?

Proteins.

Why are minerals important?

Various bodily functions, including bone formation, enzyme activity, nerve conduction, and maintaining fluid balance within cells and tissues.

What are the major sources of body water?

Ingestion of liquids, food moisture, and metabolic water produced during cellular respiration.

What are the major routes of water loss?

Urination, perspiration, respiration, and feces.

What happens to water loss during exercise?

Water loss during exercise can occur through increased perspiration and respiration, leading to dehydration if not replenished.

What is the role of sodium?

To regulate ECF volume and blood pressure.

What is the role of potassium?

To control cardiac and muscle function.

What is the role of calcium?

To facilitate muscle contraction, neurotransmitter release, and blood coagulati

What is the role of magnesium?

To aid in enzymatic reactions and muscle function.

What is the role of phosphorus?

To help with energy production, bone health, and cellular function.

What is the role of chloride?

To maintain fluid balance, electrolyte status, and stomach acid production.

What is acid?

A substance that donates protons (H+) in a solution, leading to a decrease in pH. Acids play a crucial role in various biochemical processes.

What is base?

A substance that accepts protons (H+) in a solution, leading to an increase in pH. Bases are essential in maintaining pH balance and various biochemical reactions.

What is salt?

A compound formed from the reaction of an acid and a base, consisting of cations and anions that can help to maintain fluid and electrolyte balance in the body.

What are the three classes of acids in the body?

Volatile, fixed (organic), and inorganic.

What is a volatile acid?

Carbonic acid.

What are fixed acids?

Lactic acid and keto acids. Comes from metabolism.

What are inorganic acids?

Acids that dissociate in water to produce hydrogen ions and include hydrochloric acid and sulfuric acid.

How does the carbonic acid-bicarbonate buffer work?

It maintains pH by converting carbonic acid ($H<em>2CO</em>3$) to bicarbonate ions ($HCO_3^-$) and vice versa, depending on the concentration of hydrogen ions in the solution.

What happens in the carbonic acid-bicarbonate buffer if H+ increases?

The buffer system shifts to convert bicarbonate ions ($HCO<em>3^-$) into carbonic acid ($H</em>2CO_3$), which helps to lower the concentration of hydrogen ions, thus stabilizing the pH.

What organs systems control the carbonate acid-bicarbonate buffer?

The respiratory and renal systems regulate the bicarbonate concentration and carbonic acid levels, helping maintain acid-base balance in the body.

How do protein buffers work?

By binding to hydrogen ions ($H^+$) through amino acid side chains, allowing them to either release or accept $H^+$ ions, thus helping to maintain a stable pH in the body.

Where are protein buffers most important?

In the blood plasma and intracellular fluids, where they help regulate pH levels by interacting with hydrogen ions.

How do phosphate buffers work?

By accepting or donating hydrogen ions ($H^+$) through their dihydrogen phosphate and hydrogen phosphate forms, crucial for stabilizing pH in intracellular fluids and renal tubules.

Where is phosphate buffer most important?

In intracellular fluids and renal tubules, where it plays a key role in maintaining pH balance.

How does aging affect fluid balance?

Aging can lead to decreased total body water, reduced renal function, and altered thirst mechanisms, making the elderly more susceptible to dehydration and electrolyte imbalances.

How does aging affect kidney function?

Aging often results in a decline in renal blood flow, glomerular filtration rate, and tubule function, which can impair the kidneys' ability to regulate fluid and electrolyte balance.

How does aging affect electrolyte balance?

Aging can disrupt the balance of electrolytes due to decreased renal function, affecting sodium and potassium homeostasis. This may lead to conditions like hyponatremia or hyperkalemia, increasing the risk of complications.

How does aging affect acid-base balance?

Aging can lead to a decreased ability to regulate acid-base balance due to reduced renal function and metabolic changes, potentially resulting in conditions such as metabolic acidosis or alkalosis.