Water, Electrolytes & Acid/Base Balance S.G #3

What is the average percentage of water in each of the fluid compartments of the body?

Intracellular fluid (ICF) is approximately 65%, extracellular fluid (ECF) is about 35% with interstitial fluid making up 25% and blood plasma around 8%.

How do electrolytes affect water distribution and total water content?

Electrolytes create osmotic gradients that draw water into specific compartments, influencing overall water distribution in the body.

What are the ways in which water is gained and lost by the body?

Water is gained through ingestion (liquids and food) and metabolic water, and lost through urine, sweat, respiration, and feces.

What is metabolic water?

Water produced internally as a byproduct of metabolic reactions.

How does dehydration affect the body?

Dehydration decreases blood volume, increases osmolarity, impairs cellular functions, and leads to dry skin, reduced urine output, and possible organ failure.

What hormones are involved in regulating thirst?

ADH (antidiuretic hormone), angiotensin II, and aldosterone.

What are the short-term and long-term satiation mechanisms for thirst?

Short-term mechanisms include the cooling and moistening of the mouth and stomach distension; long-term mechanisms involve the body's hormonal responses to hydration levels.

How do kidneys regulate urine volume?

Kidneys regulate urine volume by adjusting the reabsorption of water and electrolytes based on hormone signals.

What are aquaporins?

Aquaporins are water channels in cell membranes that facilitate water transport.

What is the difference between volume depletion and dehydration?

Volume depletion is the loss of water and solutes; dehydration is the loss of water only. Causes of volume depletion can include bleeding, excessive sweating, and certain medications, while dehydration is often caused by inadequate fluid intake or excessive fluid loss.

Why are infants particularly vulnerable to dehydration?

Infants are more vulnerable due to their higher metabolic rate, greater body surface-to-volume ratio, and immature kidneys.

What are some effects of fluid deficiency in the body?

Effects include decreased blood volume, impaired cellular function, risk of shock, and organ damage.

What is the difference between volume excess and hypotonic hydration?

Volume excess has normal osmolarity, while hypotonic hydration has excess water that dilutes electrolytes. Causes of volume excess can include excessive fluid intake and kidney failure, while hypotonic hydration often results from excessive water intake.

What is fluid sequestration and give examples?

Fluid sequestration is the abnormal accumulation of fluid in compartments, such as edema (swelling) and ascites (fluid in the abdominal cavity).

Name the major cations and anions in the body fluids.

Cations: Sodium (Na⁺), potassium (K⁺), calcium (Ca²⁺), and magnesium (Mg²⁺); Anions: Chloride (Cl⁻), bicarbonate (HCO₃⁻), and phosphate (PO₄³⁻).

What are the functions of sodium in the body?

Sodium maintains osmolarity, supports nerve impulses, and facilitates muscle contraction.

How is sodium homeostasis maintained?

Sodium homeostasis is regulated by aldosterone, ADH, and ANP, which adjust renal reabsorption or excretion.

What are hypernatremia and hyponatremia?

Hypernatremia is excess sodium leading to dehydration symptoms; hyponatremia is low sodium causing neurological issues.

What are the main functions of potassium in the body?

Potassium is crucial for nerve function, muscle contraction, and protein synthesis.

How does aldosterone affect potassium levels?

Aldosterone promotes potassium excretion to maintain balance.

What are hyperkalemia and hypokalemia?

Hyperkalemia is high potassium causing cardiac arrhythmias; hypokalemia is low potassium leading to muscle weakness.

What is the role of chloride in the body?

Chloride maintains osmotic pressure, acid-base balance, and is involved in stomach acid production.

How is chloride homeostasis maintained?

Chloride follows sodium and is regulated through renal mechanisms.

What are hyperchloremia and hypochloremia?

Hyperchloremia is high chloride causing acidosis; hypochloremia is low chloride leading to alkalosis.

What are the functions of calcium in the body?

Calcium is involved in bone structure, blood clotting, muscle contraction, and nerve signaling.

Which hormones regulate calcium homeostasis?

Calcium homeostasis is regulated by parathyroid hormone (PTH), calcitonin, and vitamin D.

What are hypercalcemia and hypocalcemia?

Hypercalcemia can cause muscle weakness and kidney stones; hypocalcemia can result in muscle spasms and cardiac issues.

What is the primary function of phosphate in the body?

Phosphate is key for bone structure, ATP formation, and buffering systems.

How is phosphate homeostasis regulated?

Phosphate homeostasis is regulated by PTH, which increases renal excretion and reabsorption.

What is the normal pH range for extracellular fluid (ECF)?

The normal pH range for ECF is 7.35–7.45.

What defines acids and bases in terms of pH?

Acids donate H⁺ ions and lower pH; bases accept H⁺ ions and raise pH.

What is a buffer?

A buffer is a system that resists changes in pH by neutralizing added acids or bases.

What are physiological and chemical buffers?

Physiological buffers include the respiratory and renal systems; chemical buffers include bicarbonate, phosphate, and protein buffers.

What are the functions of bicarbonate, phosphate, and protein buffers?

Bicarbonate is the primary ECF buffer; phosphate is important in ICF and renal tubules; protein is a major buffer in cells and plasma.

How does the respiratory system help regulate pH?

The respiratory system regulates pH by removing CO₂, which lowers acidity and provides a rapid response to pH changes.

How does the urinary system control pH?

The urinary system controls pH by excreting H⁺ or retaining bicarbonate to balance pH; this method is slower but very effective.

What is acidosis and its effects?

Acidosis is low pH (<7.35) that depresses CNS function, increasing the risk of coma.

What is alkalosis and its effects?

Alkalosis is high pH (>7.45) that can overexcite nerves, leading to muscle