A&P 2 fluid electrolyte and acid-base balance study guide

Intracellular fluid (ICF)

Fluid within cells, accounting for about 2/3 of total body water.

Extracellular fluid (ECF)

Fluid outside cells, including interstitial fluid and blood plasma, making up about 1/3 of total body water.

Major electrolytes in the body

Sodium (Na+), potassium (K+), chloride (Cl-), bicarbonate (HCO3-), calcium (Ca2+).

Role of sodium (Na+)

Primary extracellular cation; regulates fluid balance, nerve impulses, and muscle contractions.

True or False: Potassium (K+) is primarily found in extracellular fluid.

False. Potassium is the main intracellular cation, crucial for cellular function.

Osmosis

Movement of water across a semipermeable membrane from low solute concentration to high solute concentration.

Hydration status assessment

Evaluated through urine color, skin turgor, and thirst perception.

Hypotonic solution effect

Cells swell as water moves in due to lower solute concentration outside.

Fluid balance mechanisms

- Thirst mechanism - Hormonal regulation (ADH, aldosterone) - Renal function

Electrolyte balance regulation

Maintained by kidneys through filtration, reabsorption, and secretion processes.

Causes of dehydration

Inadequate fluid intake, excessive loss (sweating, vomiting), or certain medical conditions.

Fill in the blank: The main hormone regulating water reabsorption is _____.

Antidiuretic hormone (ADH).

Chloride (Cl-) function

Helps maintain osmotic pressure and acid-base balance; often follows Na+.

Acid-base balance and electrolytes

Electrolytes like bicarbonate (HCO3-) play crucial roles in buffering pH changes.

Normal serum sodium levels

Typically range from 135 to 145 mEq/L; critical for overall homeostasis.

True or False: Calcium (Ca2+) is mainly involved in muscle contraction.

True. Calcium ions are essential for muscle contraction and neurotransmitter release.

Acid-Base Homeostasis

The maintenance of stable pH levels in the body fluids, crucial for physiological functions.

What role do buffers play in acid-base balance?

Buffers resist changes in pH by binding to or releasing hydrogen ions (H+).

True or False: The lungs are involved in acid-base regulation.

True - The lungs regulate CO2 levels, affecting blood pH through the bicarbonate buffer system.

Fill in the blank: CO2 + H2O ↔ H2CO3 ↔ HCO3- + H+

This equation represents the bicarbonate buffer system's role in regulating pH.

Respiratory compensation

The adjustment of breathing rate to control CO2 levels and thus alter blood pH.

What is metabolic acidosis?

A condition where the body produces excessive acid or the kidneys lose too much bicarbonate.

Compare metabolic acidosis and respiratory acidosis.

Metabolic acidosis is due to metabolic factors; respiratory acidosis is due to impaired CO2 removal.

Acidosis effects on the body

- Depression of the central nervous system - Reduced cardiac output - Increased heart rate

What is the Henderson-Hasselbalch equation?

A formula used to calculate pH based on the concentration of carbonic acid and bicarbonate: $\displaystyle pH = pK_a + log\left(\\frac{[HCO_3^-]}{[H_2CO_3]}\right)$.

Kidneys in acid-base balance

The kidneys excrete hydrogen ions (H+) and reabsorb bicarbonate (HCO3-) to regulate pH.

Cause → Effect: Increased CO2 levels

Cause: Hypoventilation → Effect: Decreased blood pH (acidosis).

What is respiratory alkalosis?

A condition caused by low CO2 levels due to excessive ventilation, leading to increased pH.

True or False: Bicarbonate is a strong acid.

False - Bicarbonate is a weak base, important for neutralizing excess acids in the body.

Renal compensation

The kidneys adjust bicarbonate and hydrogen ion levels to combat acidosis or alkalosis.

What are the primary buffers in the blood?

- Bicarbonate - Phosphate - Proteins

Acidosis and potassium relationship

Acidosis often leads to hyperkalemia as H+ ions enter cells and K+ ions exit.

Dehydration

A condition resulting from excessive loss of body fluids. Symptoms may include dry mouth, fatigue, and decreased urine output.

Hyponatremia

An electrolyte imbalance with low sodium levels in the blood. Causes include excess fluid intake, certain medications, and adrenal insufficiency.

Hyperkalemia

An elevated level of potassium in the blood. This can lead to cardiac arrhythmias and muscle weakness.

Acidosis vs. Alkalosis

Acidosis is an increase in acidity, while alkalosis is an increase in alkalinity. Both can disrupt cellular functions.

Clinical dehydration signs

- Thirst - Dry skin - Rapid heartbeat - Low blood pressure

True or False: Edema indicates fluid overload.

True. Edema is the accumulation of excess fluid in tissues, often due to heart failure or kidney issues.

Causes of metabolic acidosis

- Diarrhea - Diabetic ketoacidosis - Renal failure

Hypokalemia

Low potassium levels that can cause muscle cramps, weakness, and arrhythmias. May result from diuretics or inadequate dietary intake.

Fluid overload

An excess of body fluid leading to symptoms like hypertension and shortness of breath. Common in heart failure patients.

How does respiratory failure affect acid-base balance?

It can lead to respiratory acidosis due to CO2 retention, disrupting the body's pH balance.

Fill in the blank: Hypernatremia is often caused by _____.

dehydration or excessive salt intake.

Signs of hypocalcemia

- Muscle cramps - Numbness - Tetany - Seizures

Renal failure and electrolyte balance

Renal failure affects the kidneys' ability to excrete electrolytes, leading to imbalances like hyperkalemia and hyperphosphatemia.

Causes of respiratory alkalosis

- Hyperventilation - Anxiety - High altitude exposure

True or False: Potassium is crucial for cardiac function.

True. Proper potassium levels are vital for maintaining normal heart rhythm and function.

What is the effect of vomiting on electrolyte balance?

Vomiting can lead to loss of hydrochloric acid, causing metabolic alkalosis and hypochloremia.