Chapter 20 - Fluid & Electrolyte Balance

What main principle governs fluid and electrolyte balance?

Mass balance

What is insensible water loss?

Loss of water without knowing

Example of insensbile water loss:

Exhalation of humidified air

What is the role of the kidneys in water balance?

Conserve water

What is the only way that fluid lost from urination can be replaced?

From the environment

What is diuresis?

Removal of excess water in urine

What are diuretics?

Drugs that make you urinate

How does vasopressin affect water balance?

Increases reabsorption of water in the kidneys

T/F: Vasopressin is a graded molecule.

True (more vasopressin = more reabsoprtion)

What is membrane recycling?

Alteration of cell membrane by exocytosis and endocytosis

What are some factors that will cause vasopressin release?

Low BP, Low blood volume

What is low pH called?

Acidosis

What is high pH called?

Alkalosis

How does the body cope with minute to minute changes in pH?

1. Buffers

2. Ventilation

3. Renal regulation of H+ and HCO3-

What is a buffer?

A molecule that moderates but does not prevent pH changes.

How do buffers moderate pH chages?

Prevent spikes in pH

What are some examples of buffers in blood?

Cellular proteins, phosphate ions, hemoglobin

T/F: Hyperventilation and hypoventilation can affect blood pH

True

How does hyperventilation affect blood pH?

Increased CO2, leading to a more acidic state

How does hypoventilation affect blood pH?

Less CO2, leading to a more alklaline state

How do the kidneys buffer pH?

Ammonia and phosphate

What causes respiratory acidosis?

Hypoventilation leads to higher CO2 and high PCO2

What is the marker of respiratory acidosis?

Decreased pH and high bicarb levels

How do you treat respiratory acidosis?

Kidneys excrete H+ and reabsorb HCO3-

What causes metabolic acidosis?

Occurs when metabolic and dietary input of H+ exceed H+ excretion

What is the marker for metabolic acidosis?

High H+ concentration and low HCO3- levels

How does the body compensate for metabolic acidosis?

Hyperventilation and the kidneys secrete H+ and reabsord HCO3-

What causes respiratory alkalosis?

Hyperventilation

What are the markers of respiratory alkalosis?

Low PCO2 and low H+ and HCO3- levels

What are the causes of metabolic alkalosis?

Excessive vomiting and excessive ingestion of bicarb antacids

What are the markers for metabolic alkalosis?

Decrease in PCO2 and increase in HCO3-

How does the body compensate for metabolic alkalosis?

Hypovenitlation and kidneys excrete HCO3- and H+