Introduction to Medical Laboratory Technology

F. J. Baker,R. E. Silverton

• Éditeur: Butterworth-Heinemann
• Année: 2014
• ISBN:
  9781483182568
• Édition: 5
• Sujet: Medicina
• Sous-sujet: Medicina interna e diagnosi

Introduction to Medical Laboratory Technology presents the development in the medical laboratory science. It discusses the general laboratory glassware and apparatus. It addresses a more specialized procedure in mechanization, automation, and data processing. Some of the topics covered in the book are the composition of glass; cleaning of glassware; the technique of using volumetric pipettes; technique for centrifugation; the production of chemically pure water; principal foci of a converging lens; micrometry; magnification; setting up the microscope; and fluorescence microscopy. The precautions against infection are covered. The storage of chemicals and treatment of accidents are discussed. The text describes the collection and reporting of specimens. A study of the fundamentals of chemistry and endocrine systems is presented. A chapter is devoted to the elementary colorimetry and spectro-photometry. Another section focuses on the introduction to clinical chemistry and blood gas analysis. The book can provide useful information to scientists, physicists, doctors, students, and researchers.

SECTION TWO

CLINICAL CHEMISTRY

Outline

Chapter 5: Some Fundamentals of Chemistry

Chapter 6: Instrumentation

Chapter 7: Introduction to Clinical Chemistry

Chapter 8: Gastric and Pancreatic Function Tests

Chapter 9: Liver Function Tests

Chapter 10: Renal Function Tests

Chapter 11: Chemical Analysis of Cerebrospinal Fluid

5

Some Fundamentals of Chemistry

Publisher Summary

This chapter discusses some fundamentals of chemistry. It discusses the four fundamental laws of chemistry, that is, Law of Conservation of Mass, Law of Constant Composition, Law of Multiple Proportions, and Law of Reciprocal Proportions. It also describes the gas laws: (1) Boyle’s Law, (2) Charles’ Law, and (3) Avogadro’s Law. There are several definitions of acids and bases, but the one that is particularly helpful is that of Bronstead–Lowry, who defined acids and bases in terms of proton exchange. An acid is a substance existing as molecules or ions that can donate a proton, that is, a proton donor. A base is a molecule or ion that can accept a proton, that is, a proton acceptor. The chapter further presents the dissociation of water. Pure water is a bad conductor of electricity. The presence of small amounts of dissolved substances, however, increases the conductance considerably. Neutralization indicators are substances that dissociate in solution into two (or more) differently coloured forms, the nature of the form present being governed by the pH of the solution.

The student should have previous knowledge of the following-elements, atoms, isotopes and formulas; chemical units such as atomic weight, molecular weight, gram-atom and gram-molecule. Familiarity with the four fundamental laws of chemistry is also assumed but they have been included because of their importance.

1 Law of Conservation of Mass

Mass can neither be created nor destroyed. This means that in a chemical reaction, there are the same number of atoms of each element in the products as there were in the reactants.

2 Law of Constant Composition

A given chemical compound always contains by weight the same elements in the same proportions.

Note–Many compounds do not obey this law, e.g. ferrous sulphide has variable composition and rarely has the precise formula FeS. Such compounds are called non-stoichiometric or Berthollide compounds.

3 Law of Multiple Proportions

When two elements, A and B, combine to form more than one compound, the masses of element B, which combine with a fixed mass of element A, are in simple numerical proportion to one another.

4 Law of Reciprocal Proportions (or equivalent proportions)

The masses of two elements A and B which combine separately with a fixed mass of element C are in a simple ratio to the mass ratio in which A and B combine with each other.

Equivalents

The law of reciprocal proportions means that to every element may be assigned a number representing the mass of element which will combine with a fixed mass of the substance of reference. This number is called the equivalent weight. The equivalent weight expressed in grams is called the gram-equivalent.

THE GAS LAWS

Although an ideal gas is purely hypothetical, the usefulness of the laws is that they are obeyed very closely by gases under normal conditions.

1 Boyle’s Law

The volume of a given mass of gas at constant temperature is inversely proportional to its pressure, i.e.

$p\upsilon =k$

where p is the pressure and v is the volume of a fix...