Chapter 26 - Fluid, electrolyte, and acid-base balance

Body fluid compartments

1.) Intracellular fluid (ICF)

2.) Extracellular fluid (ECF)

Intracellular fluid

60% of total body water found here

Extracellular fluid (ECF)

33% of remaining body water found here

ECF two compartments

1.) Plasma

2.) Interstitial fluid Int

Interstitial fluid (IF) includes…

Lymph, cerebrospinal fluid, humors, serous fluid, synovial fluid

Composition of body fluids

1.) Electrolytes

2.) Non-electrolytes

Electrolytes

Anything that dissociates into ions in water

Characteristics of electrolytes

1.) (+) or (-) charge

2.) Most abundant solutes

What are electrolytes responsible for? Why?

Fluid shifts/movement of water

-Electrolytes bc H2O does not care about type of solute; cares about amount

Non electrolyte characteristics

1.) No charge

2.) Make up the bulk of body fluids E

Example of non electrolytes

Glucose, urea, lipids

Where is sodium highest in body

Blood plasma and interstitial fluid

Where in body is K+ the highest

Intracelullar fluid

Where is Ca2+ the highest

Blood plasma and interstitial fluid

Where is magnesium the highest in body

Intracellular fluid

Where is HCO3- found highest in body

Interstitial fluid

Where is Cl- found the highest in the body

Interstitial fluid

Where is HPO42- found in the highest amounts?

Intracellular fluid

Where is SO42- found in highest amount body?

Intracellular fluid

Where are protein anions found in highest amount in body?

Intracellular fluid

Fluid movement

Water moves freely, solutes do not

-Changing the osmolarity of one compartment will lead to net water flow

optimal body water content depends on

1.) Age

2.) Body mass

3.) Sex

4.) Body fat%

Age and optimal body water content

Infants and children have more water

Sex and optimal body water content

Males have higher body water content than women

Body fat % and optimal body water content

Fat is the least hydrated of all body tissues

Sources of water intake

1.) Ingested food and liquid

2.) Metabolic water

Sources of water output

1.) Insensible water loss (lungs and skin)

2.) Sensible water loss (sweat, urine, feces)

When properly hydrated, water intake is

Equal to water output

Importance of water intake = water output

Allows body to maintain osmolality of 300 mOsm

Regulating intake of water involves what structure

Hypothalamic thirst center

Hypothalamic thirst center includes…

Thirst mechanism Thirs

Thirst mechanism is activated by…

1.) Osmoreceptors

2.) Dry mouth

3.) Decreasing blood volume/pressure

Osmoreceptors

Detect changing ECF osmolality

Dry mouth

Salivary glands cannot draw water from blood to produce saliva