DOCSLIB.ORG

Infusion Therapy and Solutions Neonatal

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Infusion Therapy and Solutions Neonatal Clinical Care Topic Vascular Access Device Infusion Therapy – Neonates Purpose of Infusion Therapy To understand the purpose or rationale for the infusion therapy prescribed, information can be obtained from the authorized prescriber’s order, the patient health record, and patient assessment. Indications for infusion therapy include: • Restoration and/or maintenance of fluid and electrolyte balance • Restoration, maintenance, and/or promotion of nutritional status (parenteral nutrition) • Administration of medication, blood components/products, diagnostic reagents, and general anesthesia or procedural sedation Orders related to the initiation and management of infusion therapy may include: • Patient identification • Route • Date and time order was written • Infusion solution type • Volume over time for bolus infusions • Medication name, dosage, standard concentration, and patient weight • Duration of continuous infusions • Frequency of intermittent infusions • Prescribers name, signature, and designation • Communications regarding special considerations • Total fluid intake: volume of all fluids/kg/day The source of truth for guidance related to medication orders is the AHS Medication Orders Policy and Procedure. © 2019, Alberta Health Services. This work is licensed under the Creative Commons Attribution-Non- commercial-No Derivatives 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/4.0/. Disclaimer: This material is intended for use by clinicians only and is provided on an "as is", "where is" basis. Although reasonable efforts were made to confirm the accuracy of the information, Alberta Health Services does not make any representation or warranty, express, implied or statutory, as to the accuracy, reliability, completeness, applicability or fitness for a particular purpose of such information. This material is not a substitute for the advice of a qualified health professional. Alberta Health Services expressly disclaims all liability for the use of these materials, and for any claims, actions, demands or suits arising from such use. General Information 2019-07-05 Infusion Therapy & Solutions Contact Clinical Knowledge Topics Page 1 of 4 Clinical Care Topic Vascular Access Device Infusion Therapy – Neonates Intravenous Solutions Intravenous (IV) infusion solutions are used to prevent or correct problems with fluid and/or electrolyte status. Many prepared IV solutions are available for use, and can be categorized by two main types: crystalloid and colloid. Two Main Types of Volume Expanders Colloid Crystalloid Description Contains substance particles in water Contains solutes that are completely Particles do no dissolve completely dissolved in water Particles do not pass through a semi- Solutes readily pass through a semi- permeable membrane permeable membrane Particles stay within the intravascular Solutes are comprised of dextrose, space electrolytes, or a combination of the two Can be classified into isotonic, hypertonic, and hypotonic solutions Examples Natural: human blood and blood Saline solutions products including albumin and Dextrose solutions plasma Ringers Lactate Artificial: gelatine and dextran See Types of Crystalloid Solutions solutions, hydroxyethyl starches (HES) Warning: Do not use HES products in neonates Uses Plasma expanders used to replace To expand intracellular or extra circulating blood volume cellular fluid volumes and replace electrolytes Choice of solution depends on desired outcome General Information 2019-07-05 Infusion Therapy & Solutions Contact Clinical Knowledge Topics Page 2 of 4 Clinical Care Topic Vascular Access Device Infusion Therapy – Neonates Types of Crystalloid Solutions Osmolarity Indications Precautions Examples 250–330 No net increase in Excessive amounts Dextrose 5% in Water mOsm/L cell size can lead to circulatory (D5W)* overload and Increases the NaCl 0.9% intravascular volume pulmonary edema Blood plasma is Lactated Ringers Monitor electrolytes: 280–300 mOsm/L Replaces water loss Dextrose 3.3% alterations can occur ic Treats dehydration n depending on the and fluid replacement to volume of solution o Is administered Use with caution in patients with impaired renal or cardiac function Less than Causes fluid to shift Contraindicated in D5W 0.45% NaCl ic 250 mOsm/L into the cells increased intra- NaCl 0.45% n cranial pressure (ICP) to Rehydrates cells NaCl 0.33% o and hypovolemia p y H Monitor for water intoxication Greater than Causes fluid shift Ce llular dehydration Dextrose 10% and ic 330 mOsm/L from the cells into Fluid overload greater n intravascular space o NaCl 3-5% t r e Restores electrolytes Mannitol 10–20% p y and nutrients Dextrose 5%-Lactated H Ringers *Dextrose in IV solutions is rapidly metabolized. Dextrose-only solutions become hypotonic in the body once all the dextrose is metabolized. Close monitoring for water intoxication is therefore indicated. Signs and symptoms include lethargy, vomiting, and increased work of breathing. General Information 2019-07-05 Infusion Therapy & Solutions Contact Clinical Knowledge Topics Page 3 of 4 Clinical Care Topic Vascular Access Device Infusion Therapy – Neonates Osmolarity Osmolarity, or osmotic concentration, is the concentration of osmotically active particles in solution, which may be quantitatively expressed in osmoles (Osm) of solute per liter (L) of solution (Osm/L). A solution is considered isotonic in the body if osmolarity is the same as blood plasma (range of 280 – 300 mOsm/L), and therefore expands the body’s fluid volume without causing a fluid shift from Osmolarity in milliOsmoles per Litre one compartment to another. An example of an isotonic solution is 0.9% sodium chloride. Figure 1 Osmolarity of NaCl 0.9% (Normal Saline) A hypertonic solution, such as 3% sodium chloride, has a higher osmotic pressure than plasma and pulls fluid from cells through osmosis, causing them to shrink. Solutions/emulsions with a high osmolarity pose a risk of damage to local tissues with peripheral administration and are better administered through a central venous access device. A hypotonic solution, such as 0.45% sodium chloride, has an osmotic pressure lower than plasma and pulls fluids into the cells, causing them to enlarge. This cell-enlargement can occur to cells at the catheter insertion site which may lead to them bursting, exposing the vein’s basement membrane and potentially leading to infiltration and local tissue damage. In general, isotonic fluids are mostly commonly used for extracellular volume replacement. The use of hypertonic or hypotonic solutions depends on the specific fluid and electrolyte imbalances. Colloids, unlike crystalloids, are solutions in which particles do not dissolve or break down into smaller pieces in water. Colloid solutions contain larger molecules that typically cannot penetrate the capillary wall, thus tend to stay within the vascular space (blood vessels). General Information 2019-07-05 Infusion Therapy & Solutions Contact Clinical Knowledge Topics Page 4 of 4 .
Load more

Recommended publications
  • ZOOLOGY Animal Physiology Osmoregulation in Aquatic
    Paper : 06 Animal Physiology Module : 27 Osmoregulation in Aquatic Vertebrates Development Team Principal Investigator: Prof. Neeta Sehgal Department of Zoology, University of Delhi Co-Principal Investigator: Prof. D.K. Singh Department of Zoology, University of Delhi Paper Coordinator: Prof. Rakesh Kumar Seth Department of Zoology, University of Delhi Content Writer: Dr Haren Ram Chiary and Dr. Kapinder Kirori Mal College, University of Delhi Content Reviewer: Prof. Neeta Sehgal Department of Zoology, University of Delhi 1 Animal Physiology ZOOLOGY Osmoregulation in Aquatic Vertebrates Description of Module Subject Name ZOOLOGY Paper Name Zool 006: Animal Physiology Module Name/Title Osmoregulation Module Id M27:Osmoregulation in Aquatic Vertebrates Keywords Osmoregulation, Active ionic regulation, Osmoconformers, Osmoregulators, stenohaline, Hyperosmotic, hyposmotic, catadromic, anadromic, teleost fish Contents 1. Learning Objective 2. Introduction 3. Cyclostomes a. Lampreys b. Hagfish 4. Elasmobranches 4.1. Marine elasmobranches 4.2. Fresh-water elasmobranches 5. The Coelacanth 6. Teleost fish 6.1. Marine Teleost 6.2. Fresh-water Teleost 7. Catadromic and anadromic fish 8. Amphibians 8.1. Fresh-water amphibians 8.2. Salt-water frog 9. Summary 2 Animal Physiology ZOOLOGY Osmoregulation in Aquatic Vertebrates 1. Learning Outcomes After studying this module, you shall be able to • Learn about the major strategies adopted by different aquatic vertebrates. • Understand the osmoregulation in cyclostomes: Lamprey and Hagfish • Understand the mechanisms adopted by sharks and rays for osmotic regulation • Learn about the strategies to overcome water loss and excess salt concentration in teleosts (marine and freshwater) • Analyse the mechanisms for osmoregulation in catadromic and anadromic fish • Understand the osmotic regulation in amphibians (fresh-water and in crab-eating frog, a salt water frog).
    [Show full text]
  • Osmoregulation in Pisces Osmoregulation Is a Type of Homeostasis Which Controls Both the Volume of Water and the Concentration of Electrolytes
    Osmoregulation in Pisces Osmoregulation is a type of homeostasis which controls both the volume of water and the concentration of electrolytes. It is the active regulation of the osmotic pressure of an organism’s body fluids, detected by osmoreceptors. Organisms in aquatic and terrestrial environments must maintain the right concentration of solutes and amount of water in their body fluids. The nature of osmoregulatory problem is quite different in various groups of fishes in different environments. There is always a difference between the salinity of a fish’s environment and the inside of its body, whether the fish is fresh water or marine. Regardless of the salinity of their external environment, fish use osmoregulation to fight the process of diffusion and osmosis and maintain the internal balance of salt and water essential to their efficiency and survival. Kidneys do play a role in osmoregulation but overall extra-renal mechanisms are equally more important sites for maintaining osmotic homeostasis. Extra-renal sites include the gill tissue, skin, the alimentary tract, the rectal gland and the urinary bladder. 1. Stenohaline and Euryhaline Fishes: Stenohaline (steno=narrow, haline=salt): Most of the species live either in fresh water or marine water and can survive only small changes in salinity. These fishes have a limited salinity tolerance and are called stenohaline. e.g., Goldfish Euryhaline (eury=wide, haline=salt): Some species can tolerate wide salinity changes and inhabit both fresh water and sea water. They are called euryhaline. e.g., Salmon . 2. Osmotic challenges Osmoconformers, are isosmotic with their surrounding and do not maintain their osmolarity.
    [Show full text]
  • In Latin America
    Diarrheal Disease and Health Services in Latin America ALFRED YANKAUER, M.D., and N. K. ORDWAY, M.D. PERCENT of deaths from diar¬ deaths in children under 5 years of age occurred NINETYrhea in the middle and southern sections during the first 6 months of life while in Co¬ of the Americas are in children under 5 years lombia the proportion is almost one-third. of age. It is estimated that this disease has The incidence of diarrhea appears to vary been the cause of death of almost a fourth of with infant feeding practices related to supple- the million young children who die annually mentation of or substitution for breast milk. in this part of the world. If the diarrheal dis¬ Some Latin countries show reduced morbidity ease death rates of North America were to pre- as early as the sixth month and others as late as vail throughout the Western Hemisphere, the the third year of life. number of deaths would exceed by 98 percent Diarrhea in young children is frequently the number expected. associated with other infeetions and with pro- Diarrhea is conceived of as a disturbance of tein-calorie malnutrition. The epidemiologic intestinal motility and absorption, which once relationship between diarrheal disease and mal¬ and by whatever means initiated may become nutrition has been extensively documented in self-perpetuating as a disease through the pro¬ recent studies carried out by The Institution of duction of dehydration and profound cellular Nutrition in Central America and Panama (3). disturbances, which in turn favor the continu¬ A recent study by Heredia and associates (4) ing passage of liquid stools (1).
    [Show full text]
  • Urea Transport in the Proximal Tubule and the Descending Limb of Henle
    Urea transport in the proximal tubule and the descending limb of Henle Juha P. Kokko J Clin Invest. 1972;51(8):1999-2008. https://doi.org/10.1172/JCI107006. Research Article Urea transport in proximal convoluted tubule (PCT) and descending limb of Henle (DLH) was studied in perfused segments of rabbit nephrons in vitro. Active transport of urea was ruled out in a series of experiments in which net transport of fluid was zero. Under these conditions the collected urea concentration neither increased nor decreased when compared to the mean urea concentration in the perfusion fluid and the bath. 14 Permeability coefficient for urea (Purea) was calculated from the disappearance of urea- C added to perfusion fluid. Measurements were obtained under conditions of zero net fluid movement: DLH was perfused with isosmolal ultrafiltrate (UF) of the same rabbit serum as the bath, while PCT was perfused with equilibrium solution (UF diluted with raffinose -7 2 solution for fluid [Na] = 127 mEq/liter). Under these conditions Purea per unit length was 3.3±0.4 × 10 cm /sec (5.3±0.6 × 10-5 cm/sec assuming I.D. = 20μ) in PCT and 0.93±0.4 × 10-7 cm2/sec (1.5±0.5 × 10-5 cm/sec) in DLH. When compared to previously published results, these values show that the PCT is 2.5 times less permeable to urea than to Na, while the DLH is as impermeable to urea as to Na. These results further indicate that the DLH is less permeable to both Na and urea than the PCT.
    [Show full text]
  • Fluid and Electrolyte Therapy Lyon Lee DVM Phd DACVA Purposes of Fluid Administration During the Perianesthetic Period
    Fluid and Electrolyte Therapy Lyon Lee DVM PhD DACVA Purposes of fluid administration during the perianesthetic period • Replace insensible fluid losses (evaporation, diffusion) during the anesthetic period • Replace sensible fluid losses (blood loss, sweating) during the anesthetic period • Maintain an adequate and effective blood volume • Maintain cardiac output and tissue perfusion • Maintain patency of an intravenous route of drug administration Review normal body water distribution • 1 gm = 1 ml; 1 kg = 1 liter; 1 kg = 2.2 lbs • Total body water: 60% of body weight • Intracellular water: 40% of body weight • Extracellular water (plasma water + interstitial water): 20% of body weight • Interstitial water: 20 % of body weight • Plasma water: 5 % of body weight • Blood volume: 9 % of body weight (blood volume = plasma water + red blood cell volume) • Inter-compartmental distribution of water is maintained by hydrostatic, oncotic, and osmotic forces • Daily water requirement: 1-3 ml/kg/hr (24-72 ml/kg/day) o 50 ml x body weight (kg) provides rough estimate for daily requirement • Requirements vary with age, environment, disease, etc… 1 Figure 1. Normal body water distribution Body 100% Water Tissue 60 % (100) 40 % Intracellular space Extracellular space 40 % (60) 20 % (40) Interstitial space Intravascular space 15 % (30) 5 % (10) Fluid movement across capillary membranes • Filtration is governed by Starling’s equation as below • Net driving pressure into the capillary = [(Pc – Pi) – (πp – πi)] o Pc = capillary hydrostatic pressure (varies from artery to vein) o Pi = interstitial hydrostatic pressure (0) o πp = plasma oncotic pressure (28 mmHg) o πi = interstitial oncotic pressure (3 mmHg) • If colloid osmotic pressure (COP) in the capillaries decreases lower than the COP in the interstitium, fluid will move out of the vessels and edema will develop.
    [Show full text]
  • Urea Concentration and Hsp70 Expression in the Kidney of Thirteen-Lined Ground Squirrels During Diuresis and Antidiuresis
    College of Saint Benedict and Saint John's University DigitalCommons@CSB/SJU Honors Theses, 1963-2015 Honors Program 5-2015 Urea Concentration and Hsp70 Expression in the Kidney of Thirteen-lined Ground Squirrels during Diuresis and Antidiuresis Ryan M. O'Gara College of Saint Benedict/Saint John's University Follow this and additional works at: https://digitalcommons.csbsju.edu/honors_theses Part of the Biology Commons Recommended Citation O'Gara, Ryan M., "Urea Concentration and Hsp70 Expression in the Kidney of Thirteen-lined Ground Squirrels during Diuresis and Antidiuresis" (2015). Honors Theses, 1963-2015. 86. https://digitalcommons.csbsju.edu/honors_theses/86 This Thesis is brought to you for free and open access by DigitalCommons@CSB/SJU. It has been accepted for inclusion in Honors Theses, 1963-2015 by an authorized administrator of DigitalCommons@CSB/SJU. For more information, please contact [email protected]. Urea Concentration and Hsp70 Expression in the Kidney of Thirteen-lined Ground Squirrels during Diuresis and Antidiuresis AN HONORS THESIS College of St. Benedict / St. John’s University In Partial Fulfillment of the Requirements for Distinction in the Department of Biology by Ryan O’Gara May, 2015 Abstract. During bouts of torpor hibernating animals have greatly reduced metabolic rates leading to profound decreases in body temperature and blood pressure. As a result of these conditions, kidney filtration and the ability to concentrate urine cease. Once a week, however, hibernators rewarm to euthermic body temperatures and regain kidney function. This is associated with rapid changes in extracellular osmotic gradients within the kidney, a remarkable feat but one that is potentially damaging to kidney cells.
    [Show full text]
  • Jhe Effects of Naphthalene on the Physiology and Life
    JHE EFFECTS OF NAPHTHALENE ON THE PHYSIOLOGY AND LIFE CYCLE OF CHIRONOMUS ATTENUATUS AND JANYTARSUS DISSU1ILIS By ROY GLENN DARVILLEp Bachelor of Science Lamar University Beaumont, Texas 1976 Master of Science Lamar University Beaumont, Texas 1978 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY July, 1982 The5£,-:> l q 't;)_O .. b~~'1-G . ~P·~ , i' ' THE EFFECTS OF NAPHTHALENE ON THE PHYSIOLOGY AND LIFE CYCLE OF CHIRONOMUS ATTENUATUS AND TANYTARSUS DISSIMILIS Thesis Approved: Dean of Graduate College ii PREFACE I wish to sincerely thank Dr. Jerry Wilhm, who served as my major advisor, for all of his assistance, patience, and encouragement throughout this study. Appreciation goes out to Drs. Sterling Burks, John Sauer, and Donald Holbert who served as members of the advisory committee, provided guidance, and critized the manuscript. I also wish to thank Drs. H. James Harmon and Mark Sanborn who made the mode of action studies possible. Facilities and equipment were kindly provided by Drs. Bantle, Burks, Harmon, Sanborn, and Sauer. I appreciate the assistance of the many graduate students and t_echnicians for help on various aspects of this work. I would like to thank my parents for their prayers and financial support which made this degree possible. Most of all, I want to thank my wife, Debbie, for her incredible patience -and support through all of these years of graduate school. The final manuscript was typed by Helen Murray. This study was suppo_rted in part by Oklahoma State University through a Presidential.
    [Show full text]
  • Colligative Properties of Solutions
    LESSON 10 THEME: colligative properties of solutions. Medicobiological value: Colligative properties of solutions are: the decrease in the vapor pressure of a solvent above a solution, boiling point elevation, freezing point depression, osmosis. The osmotic phenomena are most important for biology and medicine. It is caused by that the travel of nutritious substances and yields of an exchange occurs first of all by means of a diffusion and osmosis. In too time a diffusion and osmosis in alive organisms are adjusted by a function state of tissues of an organism and depend on their structure. The change of physicochemical properties of phases till both parties of biological membranes results in change of rate of an osmosis, and intensity of metabolic processes. Due to an osmosis entering water in cells and intercellular frames is adjusted. The osmotic pressure, incipient at it, provides elasticity of cells (turgor), elastance of tissues and shape of bodies, the water-salt exchange etc. All this is necessary for normal current of manifold physical and chemical processes in an organism: reactions of a hydrolysis, oxidizing, hydration, dissociation etc. It explains a constancy of osmotic pressure (osmotic homeostasis) blood and other biological fluids. The basic body of an osmoregulation at the human, are the kidneys. The osmotic pressure of a blood at the man is supported at a level 740- 780 kPa. The drugs for injection should be isotonic to biomediums (except for hypertonic salt solutions - for example, 25 % a solution of magnesium sulfas at hypertonic crisises). The introduction of hypotonic salt solutions can give in fracture of erythrocytes shells and yield of a haemoglobin in plasma (hemolysis).
    [Show full text]
  • Concentration of Urine in a Central Core Model of the Renal Counterflow System
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Kidney International, Vol. 2 (1972), p. 85—94 Concentrationof urine in a central core model of the renal counterfiow system JOHN L. STEPHENSON National Heart and Lung Institute and Mathematical Research Branch, National Institute of Arthritis and Metabolic diseases, National Institutes of Health, Bethesda, Maryland Concentration of urine in a central core model of the renal de Na+ dans la médullaire externe et le cortex a la concentration counterflow system. In this model descending Henle's limbs dans Ia médullaire interne. (DHL), ascending Henle's limbs (AHL) and collecting ducts (CD) exchange with a central vascular core (VC) formed by vasa recta Since the original proposal by Kuhn and Ryffel [1], it has loops—assumed so bighly permeable that the core functions as a single tube, open at the cortical end and closed at the papillary gradually become accepted that in some way the mammalian end. Solute supplied to the VC primarily by AHL increases VC kidney utilizes the renal counterfiow system to concentrate osmolality and so extracts water from Dh and CD, increasing urine. Experimentally it is firmly established that osmolality their osmolality while diluting AHL fluid. This single effect in blood vessels, nephrons and interstitium increases from multiplied by the counterflow arrangement leads to a high papillary osmolality in all structures. Some of the solute may cortex to papilla [2—4]. Micropuncture data from late enter DHL to be recycled. In single solute system energy require- proximal and early distal tubules indicate that solute in ments for transport out of AHL decrease from outer to inner excess of its isotonic complement of water is removed medulla.
    [Show full text]
  • MKT04050701 Rev0.Qxd
    The Physical Chemistry, Theory and Technique of Freezing Point Determinations Table of Contents Chapter 1 — Physical Chemistry Review 1 1.1 Measuring the concentration of solutions 1 1.2 Comparison of concentrative indices 7 1.3 Osmotic concentration and fluid movement 8 Chapter 2 — Freezing Point Theory & Technique 11 2.1 Definitions 11 2.2 Theory 12 2.3 Thermodynamic Factors 16 2.4 Conclusion 17 1 Physical Chemistry Review 1.1 Measuring the concentration of solutions 1. Definition of a solution: A homogeneous single-phase mixture of solute and solvent, where: a. Solvent = the liquid component. b. Solute = the solid component, or liquid in lesser proportion. Suspensions or colloids are not solutions. The solvent must fully dissolve the solute. 2. Two common expressions of concentration: a. Molarity = grams of solute per liter of solution. b. Molality = grams of solute per kilogram of solvent. fluid volume liter mark displaced by solute molar molal Figure 1: A 1 molal solution is generally more dilute than a 1 molar solution. 1 The Physical Chemistry, Theory and Technique of Freezing Point Determinations 3. Methods of molality measurement... definition of osmolality a. Colligative properties: When one mole of non-ionic solute is added to one kilogram of water, the colligative properties are changed in the following manner and proportion: • freezing point goes down 1.86°C • osmotic pressure goes up 17000mmHg (17000mmHg = 22.4 atmospheres) • boiling point goes up 0.52°C • vapor pressure goes down 0.3mmHg (vapor pressure of pure water = 17mmHg) b. Osmolality: • One mole of non-ionic solute dissolved in a kilogram of water will yield Avogadro's number (6.02 × 1023) of molecules.
    [Show full text]
  • Physiology by Numbers: an Encouragement to Quantitative Thinking, SECOND EDITION
    Physiology by Numbers: An Encouragement to Quantitative Thinking, SECOND EDITION RICHARD F. BURTON CAMBRIDGE UNIVERSITY PRESS Thinking quantitatively about physiology is something many students find difficult. However, it is fundamentally important to a proper understanding of many of the concepts involved. In this enlarged second edition of his popular textbook, Richard Burton gives the reader the opportunity to develop a feel for values such as ion concentrations, lung and fluid volumes, blood pressures, etc. through the use of calculations that require little more than simple arithmetic for their solution. Much guidance is given on how to avoid errors and the usefulness of approximation and ‘back-of-envelope sums’. Energy metabolism, nerve and muscle, blood and the cardiovascular system, respiration, renal function, body fluids and acid–base balance are all covered, making this book essential reading for students (and teachers) of physiology everywhere, both those who shy away from numbers and those who revel in them. R F B is Senior Lecturer in the Institute of Biomedical and Life Sciences at the University of Glasgow, Scotland, UK. Biology by Numbers by the same author is also published by Cambridge University Press. This page intentionally left blank Physiology by Numbers An Encouragement to Quantitative Thinking SECOND EDITION richard f. burton University of Glasgow,Glasgow PUBLISHED BY CAMBRIDGE UNIVERSITY PRESS (VIRTUAL PUBLISHING) FOR AND ON BEHALF OF THE PRESS SYNDICATE OF THE UNIVERSITY OF CAMBRIDGE The Pitt Building, Trumpington
    [Show full text]
  • Osmosis, Tonicity, and Concentration
    Lab #5: Osmosis, Tonicity, and Concentration. Background. The internal environment of the human body consists largely of water-based solutions. A large number of different solutes may be dissolved in these solutions. Since movement of materials across cell membranes is heavily influenced by both differences in the concentration of these various materials across the cell membrane and by the permeability of the lipid bilayer to these materials, it is critical Fig 5.1. An example of simple diffusion. Molecules of that we understand how the concentration of a red dye gradually diffuse from areas of higher particular solute is quantified, as well as how concentration to areas of lower concentration until the differences in concentration influence passive concentration of dye is uniform throughout the volume of the solution. membrane transport. membranes (i.e., small uncharged molecules or Diffusion, Osmosis, and Tonicity moderate-sized nonpolar molecules) are transported across cell membranes via simple Simple diffusion . diffusion. For example, the exchange of gases such as O 2 and CO 2 across the plasma membrane Particles in solution are generally free to move occurs through simple diffusion. randomly throughout the volume of the solution. As these particles move about, they randomly Osmosis collide with one another, changing the direction each particle is traveling. Like some other small, uncharged molecules, If there is a difference in the concentration water (H 2O) can pass quite readily through a cell of a particular solute between one region of a membrane, and thus will diffuse across the solution and another, then there is a tendency for membrane along its own concentration gradient the substance to diffuse from where it is more independent of other particles that may be concentrated to where it is less concentrated.
    [Show full text]