Fluid, electrolyte, + acid base

• What are the fluid components of the human body?

  Intracellular fluid (ICF) and extracellular fluid (ECF)

  
• What is the function of intracellular fluid (ICF)?

  It provides a stable environment for cellular processes and maintains cell structure.

  
• What percentage of the body's total water content is made up by intracellular fluid (ICF)?

  About 60%

  
• What is extracellular fluid (ECF) and what percentage of total body water does it account for?

  Fluid outside the cells, accounting for 40% of total body water.
• What are the subcategories of extracellular fluid (ECF)?

  • Interstitial fluid (IF): Fluid between cells for nutrient and waste exchange.
  • Blood plasma: Fluid in blood vessels carrying electrolytes, proteins, nutrients, and wastes.
  • Minor ECF compartments: Includes cerebrospinal fluid, lymph, synovial fluid, etc.

  
• What are the two primary forces that drive fluid movement between compartments?

  Hydrostatic pressure and colloid osmotic pressure.
• What is hydrostatic pressure?

  The force exerted by a fluid against a wall, such as blood against capillary walls.
• What causes hydrostatic pressure in blood vessels?

  It results from blood pressure in the vessels pushing fluid out of the capillaries.

  
• What is colloid osmotic pressure?

  The opposing force to hydrostatic pressure, primarily produced by circulating albumin.
• How does colloid osmotic pressure affect fluid movement?

  It attracts water back into the capillaries from the interstitial fluid.

  
• What determines the net filtration pressure?

  The balance between hydrostatic and colloid osmotic pressures.
• What occurs at the arterial end of the capillary?

  Net filtration occurs, allowing nutrients and oxygen to reach tissues.

  
• What happens at the venous end of the capillary?

  Net reabsorption occurs, drawing fluid back into the capillaries.

  
• What is the effect of positive net filtration pressure?

  Fluid moves out of the capillaries into the surrounding interstitial fluid.

  
• What is the effect of negative net filtration pressure?

  Fluid is pulled into the capillaries from the cells and interstitial fluid.

  
• What is the role of antidiuretic hormone (ADH) in fluid homeostasis?

  ADH increases water reabsorption in the kidneys and causes vasoconstriction.

  
• What triggers the release of ADH?

  High blood osmolality or low blood volume.
• How does ADH affect urine output?

  It reduces urine output by increasing water reabsorption.
• What is the thirst mechanism?

  It is triggered by the hypothalamus when the body is dehydrated to encourage water intake.

  
• What does osmolality refer to?

  The concentration of solutes in a solution, mainly salts like sodium and chloride.
• What happens during high osmolarity?

  Water moves out of the cells into the extracellular fluid to equalize solute concentrations.
• What occurs during low osmolarity?

  Water moves into the cells from the extracellular fluid to balance concentrations.
• What are osmoreceptors?

  Specialized cells in the hypothalamus that detect changes in blood osmolality.
• What happens when blood osmolality increases?

  Osmoreceptors trigger thirst and stimulate the release of ADH to conserve water.

  
• What happens during sweating?

  The body loses water and electrolytes, mainly sodium and chloride.
• How does osmosis affect fluid balance during dehydration?

  Water moves out of cells into the extracellular fluid to balance concentrations.
• What are the symptoms of dehydration?

  Dry skin, reduced urine output, and fatigue.
• What happens during rehydration?

  Water first enters the extracellular fluid before moving into the intracellular fluid.
• How does osmosis restore hydration levels in cells?

  Water moves from the extracellular fluid into the intracellular fluid until equilibrium is reached.
• What are the six important electrolytes and their functions in the human body?

  1. Sodium (Na+): Regulates fluid balance, nerve transmission, and muscle contractions.
  2. Potassium (K+): Maintains cell membrane potential and regulates fluid balance inside cells.
  3. Chloride (Cl-): Maintains osmotic pressure and balances charge across cell membranes.
  4. Bicarbonate (HCO3-): Acts as a buffer to regulate blood pH.
  5. Calcium (Ca2+): Vital for bone strength, muscle contraction, and blood clotting.
  6. Phosphate (PO4 3-): Part of ATP and nucleotides; acts as a buffer in the ICF.
• What is acidosis?

  A condition where blood pH falls below 7.35 due to respiratory or metabolic causes.
• What are the compensation mechanisms for acidosis?

  Increased breathing rate and renal excretion of hydrogen ions.

  
• What is alkalosis?

  A condition where blood pH rises above 7.45 due to loss of acids or gain in bases.
• What are the compensation mechanisms for alkalosis?

  Decreased breathing rate and renal excretion of bicarbonate.

  
• How does respiration affect pH?

  CO₂ forms carbonic acid in the blood, impacting pH levels.
• What happens during hyperventilation?

  It increases CO₂ exhalation, reducing carbonic acid and increasing pH.
• What happens during hypoventilation?

  It retains CO₂, raising carbonic acid and lowering pH.
• How does the renal system affect pH?

  The kidneys excrete excess hydrogen ions and reabsorb bicarbonate to buffer blood pH.
• What is the long-term regulation of pH by the kidneys?

  The kidneys provide a sustained response to pH imbalances, adjusting acid-base balance.
• Extracellular fluid (ECF) is the fluid outside the cells, including interstitial fluid, plasma, lymph, and transcellular fluid.