BIO 1150 1st Edition Lecture 11Topic discussed: OsmoregulationOsmoregulation- regulation of osmotic pressure to achieve homeostasis of water concentration- Body fluids are regulated with changing environmental demands by osmoregulationWhat is Regulated- Cell volume o Structural integrityo Spherical- too much watero Biconcave-desirable concentration of watero Crenated- not enough water- Body fluid volumeo Blood pressureo Concentrations of body soluteso Extracellular – within body, outside of cell- Solute concentrationso “ionic strength” surrounding proteinso Specific ion gradiento Body water volume- especially sodium ionsAnimals respond to osmotic challenges in different ways- Osmoconformers (some marine animals) – isosmotic with their surroundings- Osmoregulators- can keep concentration of solutes (salts) higher or lower than environment concentrationThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Water and solutes can move into, out of, and within organisms by a variety of mechanisms- Each mechanism is a combination of a driving source and a specific pathwayFiltration- “leakage” of fluid and dissolved solutes out of vessels under pressureMammalian glomeruli-the filtering apparatus of the kidney- Urine is formed in most vertebrates in the kidneys by filtration- A kidney produces approximately 180L filtrate per day- Blood- brain barrier- Lymphatic system-for filtering lymphEvaporation- optimal environment= less than fully humidified- Animals can sometimes control evaporation rateOsmosis-water moving through semipermeable membrane to form and equilibrium of concentration- Osmolarity- concentration of dissolved solute particles (osmoles/L)- Molarity- moles/Liters- NaCl Na + Cl- Sodium Chloride dissociates into sodium and chloride ionsMany tissues are exposed or create osmotic gradients that drive water flow- Ions go into space between cells and raise osmotic pressure- Water follows the ions by osmosiso Gallbladder gets rid of water using osmosisAquaporins- proteins that facilitate water transport across cell membranesMembrane transport of ions- renal proximal tubule reclaims solute load filtered by glomeruli- Passive transport- moves down ion concentration gradient- Active transport- requires ATP and moves against concentration gradientTransporting sodium ions out of cell into blood (basolateral) creates gradient and allows passive uptake of sodium ions on apical sideNeurons use protein mediated ion transport to generate electrical signals Many tissues are involved in osmoregulatory ion transport- Osmoconformers (some marine animals)- isosmotic with surroundings and don’t regulateosmolarity- Osmoregulators- spend energy to control uptake or loss in hyperosmotic or hypoosmotic environmentOrganic matter and oxygen decompose into carbon dioxide and water- Insects- urine by “secretion” in malpighan tubules- transport of ions and water flow by osmosis- Mammals- produce urine by filtration in renal glomeruliOsmoregulation- regulated by
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