6.1 - regulation of the composition of body fluids

recap of kidneys & homeostasis of body fluid conc

how are body fluid concs maintained?

explain the proportions of total body fluid of different bodily fluids & include the components of each body fluid

total volume = approx 42L - approx 60% of body weight

• intracellular fluid/cytosol compartment = approx 28L

• extracellular fluid compartment = approx 14L

  • intravascular fluid (plasma) = approx 3L

  • interstitial fluid = approx 10.5L

  • Transcellular fluid = approx 0.5L

identify the parts of the kidney & a nephron

what are the functions of a kidney

identify the 3 steps of urine formation

1. glomerular filtration

2. selective reabsorption

3. tubular secretion

explain glomerular filtration

explain selective reabsorption

explain facultative reabsorption

explain tubular secretion

explain the kidney’s role in fluid balance

explain selective water reabsorption relating to dehydration & using key words: salt, aldosterone, water & antidiuretic hormone

define osmotic pressure

The tendency of a solution to take in the pure solvent

define osmotic conc

The concentration of solutes; also known as osmolarity

define & explain dehydration

• Excessive loss of water and accompanying salts from the body; results when the body loses more uid than it takes in

• occurs when there is insufficient water in the body. If untreated, it can be fatal as the body cannot carry out essential functions.

define & explain water intoxication

• A potentially life-threatening condition caused by drinking too much water when the amount of salt (and other electrolytes) in the body is low; commonly caused by long bouts of intensive exercise during which electrolytes are not replenished and large amounts of water are consumed

• Drinking excessive amounts of water can lead to water intoxication. The body fluids become too dilute and the cells swell due to osmosis.

define metabolic water

Water formed as a by-product of cellular respiration