The Nervous System: Membrane Potential 1. Record the intracellular and extracellular concentrations of the following ions (mM/L): | Intracellular | Extracellular | Sodium (Na+) | 15 | 150 | Potassium (K+) | 150 | 5 | Chloride (Cl–) | 10 | 125 | 2. Excitable cells‚ like neurons‚ are more permeable to K+ than to Na+. 3. How would the following alterations affect the membrane permeability to K+? Use arrows to indicate the change in permeability. a. An increase in the number of passive
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combination of membrane permeation and evaporation. It is often an attractive alternative to other separation methods. Pervaporation is a membrane process in which a liquid is maintained at atmospheric pressure on the feed or upstream side of the membrane and where permeate is removed as a vapor because of a low vapor pressure existing on permeate or downstream side. This low (partial) vapor pressure can be achieved by employing a carrier gas or using a vacuum pump. Membranes like poly dimethylsiloxane
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context of immediate release (IR) solid oral dosage forms. It is the scientific framework for classifying drug substances based on their aqueous solubility and intestinal permeability. It is a drug development tool that allows estimation of the contributions of three major factors‚ dissolution‚ solubility and intestinal permeability that affect oral drug absorption from immediate release solid oral dosage forms. The interest in this classification system is largely because of its application in early
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Tutorial 1 1. pK = 3.4 DH = ASA Plasma pH = 7.3 Stomach pH = 1.5 = 10pH – pK = 10pH – pK = 107.3 – 3.4 = 101.5 – 3.4 = 7943.2823 = 0.01259 [Total Drug] = [D-] + [DH] [Total Drug] = [D-] + [DH] = 7943.2823 + 1 = 0.0126 + 1 = 7944.2823 = 1.0126 [Total Drug] in stomach relative to plasma = 7944.2823/1.0126 = 7845.43 Conclusion: High absorption of ASA from the stomach lumen. Absorption from stomach is 7845.43 times
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interstitium‚ and microvascular endothelium)‚ which occurs in three phases; acute or exudative phase‚ resolution phase and fibrotic phase [8‚9]. 1. Acute or exudative phase (<72h)‚ which characterized by a disruption of the alveolar capillary membrane leading to leakage of protein rich fluid into the interstitium and alveolar space‚ and extended release of cytokines and neutrophil infiltration of the alveolar space (Figure 1) [8‚18]. Pathogenesis of acute phase associates with a variety of cellular
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the cell membrane‚ and some water does. "But the very rapid movement of water through some cells was not explained by this theory‚" said Agre. Aquaporins selectively conduct water molecules in and out of the cell‚ while preventing the passage of ions and other solutes. Also known as water channels‚ aquaporins are integral membrane pore proteins. Some of them‚ known as aquaglyceroporins‚ also transport other small uncharged solutes‚ such as glycerol‚ CO2‚ ammonia and urea across the membrane‚ depending
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Tuesday 2:00-4:50 22 OCTOBER 2012 Membrane Permeability Decreases as Molecular Size Increases Introduction: Red blood cells are vital to organisms functioning properly. They are microscopic cells that carry oxygen from the lungs to all the tissues throughout the body. Upon transporting oxygen‚ red blood cells also exports waste‚ such as carbon dioxide‚ to the lungs where it can be expelled. Red blood cells are made up of hemoglobin which is surrounded by a cell membrane (Barrilleaux 2012). Organisms
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to different molecules. This type of selectively is caused by a semi-permeable membrane‚ which allows the movement of certain molecules across it. Water exchange can be measured in two ways: RBC osmotic permeability is measured‚ and diffusional water permeability is measured (Benga and Borza 1995). Diffusion is the movement of high concentration to low concentration. The diffusion of water across a permeable membrane is called osmosis. Water concentration in red blood cells can cause three different
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action potentials are propagated. 12-7 Describe the structure of a synapse‚ and explain the mechanism involved in synaptic activity. 12-8 Describe the major types of neurotransmitters and neuromodulators‚ and discuss their effects on postsynaptic membranes. 12-9 Discuss the interactions that enable information processing to occur in neural tissue. The Nervous System Includes all neural tissue in the body Neural tissue contains two kinds of cells Neurons Cells that send and receive signals
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Signals Traveling in Neurons Two opposing ideas about the nervous system * Reticular theory ( the nervous system consisted of a large network of fused nerve cells) * Neuron theory ( the nervous system consisted of distinct elements or cells * Discovery of staining led to the acceptance of neuron theory. Staining is a chemical technique that caused nerve cells to become colored so they stood out from surrounding tissue * A way of electricity is transmitted in groups of neurons‚ such
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