BIOL10002 Lecture Notes - Lecture 19: Osmotic Pressure, Uric Acid, Extracellular Fluid
Lecture 19
Osmoregulation/The Excretory System, part 1
Excretory Organs
Main functions:
1. Maintain osmotic concentrations
2. Maintain body fluid volume
3. Maintain proper concentrations of ions
4. Remove metabolic end products
5. Remove foreign substances
Interstitial fluid is vital for regulation.
Vocab
Osmolarity concentration of solutes, specifically solutes that will cause the movement of water
Osmotic pressure force associated with water movement
Osmolality concentration of solutes per kilogram of solvent
Tonicity Concentration of non-permeable solutes per litre of solvent
low osmolarity = high osmotic pressure
calculation?
Osmolality is controlled by excreting excess water and solutes
Kidney function
composed of the cortex (where blood is filtered), medulla (contains collecting ducts which carry filtrate to pelvis)
and the pelvis (accumulates urine to drain into the ureter)
excretes nitrogen (nitrogenous was te) via ammonia, urea or ureic acid
Ammonia Urea Uric Acid
NH3(NH2)2CO C5H4N4O3
Very toxic Toxic Slightly toxic
Formation uses no energy Formation uses energy Formation requires a lot of energy
Very soluble Moderately soluble Slightly soluble
Excreted by marine animals Excreted by terrestrial animals Excreted by reptiles and birds
Marine animals have to conserve water and excrete excess salts
Freshwater animals have to excrete excess water and conserve salts
Terrestrial animals must conserve water and salts
Osmoregulators internal environment does not change if external environment changes
Osmoconformers internal environment will change is external environment changes
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Document Summary
Main functions: maintain osmotic concentrations, maintain body fluid volume, maintain proper concentrations of ions, remove metabolic end products, remove foreign substances. Osmolarity concentration of solutes, specifically solutes that will cause the movement of water. Osmotic pressure force associated with water movement. Osmolality concentration of solutes per kilogram of solvent. Osmolality is controlled by excreting excess water and solutes. Composed of the cortex (where blood is filtered), medulla (contains collecting ducts which carry filtrate to pelvis) and the pelvis (accumulates urine to drain into the ureter) Excretes nitrogen (nitrogenous was te) via ammonia, urea or ureic acid. Marine animals have to conserve water and excrete excess salts. Freshwater animals have to excrete excess water and conserve salts. Osmoregulators internal environment does not change if external environment changes.
