Topic 11.3 Flashcards
Osmolarity
The solute concentration of a solution
Osmoregulators
- Maintain a constant internal solute concentration, even when living in marin environental with very different osmolarities
- All terrestrial animals, freshwater animals, and some marin organisms (bony fish)
- Maintain their solute concnetration at about 1/3 of the concentration of seawater
Osmoconformers
- Animals whose internal solute concentration tends to be the same as the cocnetration of solutes in the environment
Hemolymph
circulating fluid in arthropods that combines the characteristics of tissue fluid and blood
Malpighian tubule system
- a system in insects that carries out osmoregulation and the removal of nitgroneous wastes
- insects have tubes that branch off from their intestinal tract known as Malpighian tubules
- cells lining the tubules actively transport ions and uric acid from the hemolymph into the lumen of the tubules
- this draws water by osmosis from the hemolymph through the wals of the tubules into the lumen
- the tubules empty their contents into the gut
- in the hindgut, most of the water and salts are reabsorbed while the nitrogenous waste is excreted with the feces
Annotate the following diagram of the malpighian tubule system
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Draw and label a diagram of the human kidney
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Compare and contrast the composition of blood in the renal artery and renal vein
Blood in the renal vein (i.e. after the kidney) will have (in comparison to the renal artery):
- Less urea (large amounts of urea is removed via the nephrons to form urine)
- Less water and solutes / ions (amount removed will depend on the hydration status of the individual)
- Less glucose and oxygen (not eliminated, but used by the kidney to generate energy and fuel metabolic reactions)
- More carbon dioxide (produced by the kidneys as a by-product of metabolic reactions)
- The same amount of plama proteins because they are not filtered by the kidney
Outline the three components of the ultrastructure of the glomerulus
- Fenestrations between the cells in the wall of the capillaries
- about 100nm in diameter
- allow fluid to escape, but not blood cells - The basement membrane
- covers and supports the wall of the capillaries
- made up of negatively
- charged glycoproteins, which form a mesh
- prevents plasma proteins from being filtered out, due to their size and negative charges - Podocytes
- form the inner wall of the Bowman’s capsule
- have extensions that wrap around the capillaries of the glomerulus
- have many short side branches called foot processes
- very narrow gaps between the foot processes help prevent small molecules from being filtered out of blood in the glomerulus
Define ultrafiltration
- The separation of particles differeing in size by a few nanometres
Label the following diagram of the ultrafiltration system of the glomerus
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Label the following diagram
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Label the following diagram of the proximal convoluted tubule
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What is the role of the proximal convoluted tubule?
- selective reabsorption of useful substances
List the substances that the proximal convoluted tubule reabsorbs
- All glucose
- All amino acids
- Most water
- Most sodium ions
- Most chloride ions
How are sodium ions reabsorbed by the PCT?
- moved by active transport from fiiltrate to space outside the tubule where they pass to the peritubular capillaries
- pump proteins are located in outer membrane of tubule cells
How are chloride ions reabsorbed by the PCT?
- attracted from filtrate to the space outside the tubule because of the charge gradient set up by active transport of sodium ions