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24 Cards in this Set
- Front
- Back
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What are Ionic and Osmotic challenges faced by terrestrial animals?
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Animal tend to lose water
Many animals move between environments and must be able to alter their homeostatic mechanisms |
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Ionoregulator
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Control ion profile of extracellular space
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Osmoregulator
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Osmolarity constant regardless of environment
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What are sources of water?
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Dietary water: Water preformed in plant and animal tissue
Metabolic water: Generated as a result of oxidative phosphorylation Drinking |
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How are solutes classified?
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Perturbing: Disrupt macromolecule function (Na+, K+, Cl-, charged amino acids)
Comptatible: Little affect on macromolecule function. (Polyols, like glycerol and glucose, and uncharged amino acids) Counteracting: Disrupt function on their own; Counteract disruptive effects of other solutes when employed in combination |
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How do cells control cell volume?
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Transport solutes in and out of extracellular fluid (ECF) to control cell volume.
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What is the purpose of the skin?
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Forms boundary between animal and environment
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What are the four features that allows tranpsort epithelia to move ions?
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Asymmetrical distribution of membrane transporters
- Solutes selectively transported across membrane Cells interconnected to form impermeable sheet of tissue, so little leakage between cells High cell diversity within tissue Abundant mitochondria, so larger energy supply |
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How do animals regulate the flux of water across the body?
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They mediate the permeability of the integument.
-Using aquaporins increases permeability 100-fold - Covering external surfaces with layer of hydrophobic molecules |
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What are the two main forms of solute transport used by epithelial cells?
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Transcellular Transport: Movement through cell across the membrane
Paracellular Transport: Movement between cells |
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What type of transporters are used in solute movement by epithelial cells?
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•Na+/K+ ATPase
•Ion channels (Cl-, K+, Na+) •Electroneutral cotransporters •Electroneutral exchangers |
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Why is nitrogen excretion necessary?
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Ammonia produced during amino acid breakdown is toxic and must be excreted
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What are the three forms nitrogen compounds can be excreted in?
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Ammonia
Uric acid Urea |
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What nitrogen compund do terrrestrial animals excrete?
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Urea or Uric acid
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What are the roles of the kidney in maintaining homeostasis?
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o Ion balance
o Osmotic balance o Blood pressure o pH balance o Excretion of molecule wastes and toxins o Hormone production |
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What are the two layers of the mammalian kidney?
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The outer cortex and inner medulla
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What is the functional unit of the kidney?
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The Nephron
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What is the structure of the nephron?
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Renal Tubule: Lined with transport epithelia, various segments with specific transport functions.
Vasuclature: - Glomerulus: Ball of capillaries surrounded by Bowman's capsule - Capillary beds surrounding renal tubule |
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What are the four processes of urine production?
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Filtration
Reabsorption Secretion Excretion |
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Filtration
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Filtrate of blood formed at glomerulus
*Water and small solutes, not blood and macromolecules |
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Reabsorption
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Specific molecules removed from filtrate to body
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Secretion
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Specific molecules added to filtrate exiting body
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Excretion
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Urine is excreted from the body
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What are the tubule regions of the Nephrons and their functions?
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Proximal tubule: Most of solute and water reabsorption
Loop of Henle: Urine volume reduction and selective ion transport occurs here -Descending permeable, ascending impermeable to water Distal tubule: Reabsorption completed for most solutes, hormonally regulated fine tuning of reabsorption secretion Collecting duct: Hormonally regulated reabsorption or secretion and concentration of urine occur |
