Fluid and Electrolytes Lecture Outline

These flashcards cover key concepts related to fluid and electrolyte balance, hormones, acid-base balance, and their physiological importance.

Fluid balance

The state when fluid intake equals fluid output in the body.

Electrolyte balance

The process of constantly regulating electrolyte levels in the body.

Intracellular fluid (ICF)

Fluid located within cells, making up about two-thirds of total body fluid.

Extracellular fluid (ECF)

Fluid outside of cells, including interstitial fluid and blood plasma.

Interstitial fluid

Fluid that surrounds cells in the body, composing two-thirds of extracellular fluid.

Blood plasma

The fluid component of blood that contains proteins and is separated from interstitial fluid.

Fluid sequestration

Abnormal distribution of body fluids leading to accumulation in specific areas.

Osmolarity

The concentration of solutes in body fluids, affecting water movement.

Dehydration

A state resulting from excessive water loss, where fluid loss exceeds solute loss.

Hypotonic hydration

Condition of water intoxication where fluid moves into cells causing swelling.

Sensible water loss

Measurable loss of water from the body, such as through urine and feces.

Insensible water loss

Unmeasured loss of water, such as through skin and respiration.

Obligatory water loss

Water loss that occurs regardless of hydration status.

Facultative water loss

Controlled water loss that varies depending on hydration levels.

Na+ (Sodium ion)

The principal cation in extracellular fluid, critical for fluid balance.

K+ (Potassium ion)

The primary cation in intracellular fluid, essential for neuromuscular function.

Cl- (Chloride ion)

The most abundant anion in extracellular fluid, associated with sodium.

Ca2+ (Calcium ion)

An essential mineral found in bones, also involved in muscle contraction and neurotransmitter release.

PO4^3- (Phosphate ion)

The primary anion in intracellular fluid and a component of DNA and RNA.

Mg2+ (Magnesium ion)

A vital mineral involved in numerous enzymatic reactions, found mainly in bone.

Aldosterone

A hormone that regulates sodium and potassium levels within the kidneys.

Antidiuretic hormone (ADH)

A hormone that promotes water reabsorption in the kidneys.

Renin

An enzyme released by the kidneys that initiates the formation of angiotensin II.

Angiotensin II

A hormone that increases blood pressure and promotes fluid retention.

Atrial natriuretic peptide (ANP)

A hormone that decreases blood volume and pressure by promoting water and sodium loss.

Acidosis

A condition where arterial blood pH falls below 7.35.

Alkalosis

A condition where arterial blood pH rises above 7.45.

Diabetes Insipidus

A condition characterized by excessive urination due to inadequate ADH.

Lactic acidosis

A type of acidosis caused by the accumulation of lactic acid.

Ketoacidosis

Acidosis caused by the accumulation of ketoacids, often seen in diabetes.

Buffering systems

Biological systems that resist changes in pH by neutralizing acids or bases.

Volatile acids

Acids that can be converted into gases, like carbonic acid.

Fixed acids

Acids that are produced from metabolism and must be eliminated by the kidneys.

Phosphate buffering system

A buffering system found intracellularly, using phosphate ions to stabilize pH.

Bicarbonate buffering system

The primary buffering system in extracellular fluid, using bicarbonate ions to maintain pH.

Chemical buffer

Substances that can release or bind hydrogen ions to stabilize pH.

Fluid homeostasis

The process of maintaining a stable internal environment of body fluids and their composition.

Homeostatic mechanisms

Regulatory processes that maintain physiological stability in the body despite external changes.

Normovolemia

The state of having a normal blood volume within the body.

Hypervolemia

An increased blood volume, often leading to swelling and hypertension.

Hypovolemia

A decreased blood volume, which can result in low blood pressure and decreased perfusion.

Tonicity

The ability of a solution to affect the volume and pressure of cells by promoting osmosis; includes isotonic, hypertonic, and hypotonic solutions.

Isotonic solution

A solution in which the solute concentration is equal to that inside the cell, resulting in no net movement of water.

Hypotonic solution

A solution that has a lower solute concentration than the cell, causing water to move into the cell and enlarge it.

Hypertonic solution

A solution that has a higher solute concentration than the cell, resulting in water moving out of the cell and causing it to shrink.

Fluid overload

The condition resulting from excess fluid intake or retention, potentially leading to pulmonary edema or heart failure.

Osmotic pressure

The pressure required to prevent the flow of water across a semipermeable membrane due to osmosis.

Hydration status

The degree of body hydration measured by the balance of fluid intake and fluid output.

Solvent

A substance, usually liquid, that dissolves solutes to form a solution, such as water in body fluids.

Solute

A substance that is dissolved in a solvent, such as electrolytes or nutrients in bodily fluids.

Fluid intake

The amount of fluid consumed, which influences hydration and overall fluid balance in the body.

Fluid output

The amount of fluid excreted or lost from the body through various means, including urine, sweat, and respiration.

Total body water (TBW)

The total amount of water in the body, constituting approximately 60% of body weight in adults.

Electrolyte imbalance

A disruption in the normal levels of electrolytes in the body, which can affect physiological functions.

Diuretic

A substance that promotes the production of urine, often used to treat conditions like hypertension.

Rehydration

The process of restoring lost body fluids and electrolytes, typically following dehydration.