Lecture10 copy

Lecture10 copy - Lecture #10 7/18/2008 10:14:00 AM D....

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Lecture #10 18/07/2008 12:14:00 D. Compact bone Functional unit: compact bone= Haversian canal system o Central canal: actual Haversian canal- vessels and nerve o Osteon: contains lacuna with osteocyte E. Bone turnover ~occurs on a continual bases- replace 7-10% of skeleton annually Parathyroid hormone: most important for bone turnover; increases blood  calcium levels 1. increase osteoclast activity 2. increase intestinal absorption of Ca2+ 3. increase renal re-absorption of Ca2+ Calcitonin: opposite of parathyroid hormone: decrease blood Ca2+ levels 1. decrease osteoclast activity: can stimulate osteoblasts 2. Decrease intestinal absorption 3. decrease renal re-absorption calcitriol Growth hormone (GH) decrease deposition of bone
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Osmoregulation 18/07/2008 12:14:00 I. Challenges A. osmoregulation: control of tissue osmotic(water) pressure B. ionoregulation: control of ionic composition of body tissues C. nitrogen excretion  to excrete the nitrogenous end-product of protein catabolism: ammonia NH3 + H2O  Nh4+ + OH- II. Strategies A. ionic + osmotic regulation iono conformers      – little control over solute profile iono regulators     - control ion profiles of extracellular fluids osmoconformers     - internal osmolarity similar to externa environment osmoregulators     - maintain internal osmolarity w/in a narrow range regardless  of the external environment B. nitrogen excretion Strategy Product excreted Examples Ammonioteles: lots of water NH4+ (ammonium) Simple inverts. aquatic molluscs fish Uricoteles: slightly soluble Uric acid Terrestrial molluscs insects reptiles birds Ureoteles Urea All mammals relative H2O required: ammonium>urea>uric acid
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(figure 4) terms: o isoosmotic= same concentration of solutes as…(surroundings) o hypoosmotic= lower solute concentration compared to surroundings o hyperosmotic=higher solute concentration compared to surroundings III. elasmobranchs- sharks + rays (cartilaginous fish)
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This note was uploaded on 07/23/2008 for the course BIO 131 taught by Professor Mostman during the Summer '08 term at UCSC.

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Lecture10 copy - Lecture #10 7/18/2008 10:14:00 AM D....

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