METABOLISM OF CARBOHYDRATES

Metabolism is the term used to describe the interconversion of chemical compounds in the body, the pathways taken by individual molecules, their interrelationships, and the mechanisms that regulate the flow of metabolites through the pathways. Metabolic pathways fall into three categories.
(1) Anabolic pathways, which are those involved in the synthesis of larger and more complex compounds from smaller precursors—for example, the synthesis of protein from amino acids and the synthesis of reserves of triacylglycerol and glycogen. Anabolic pathways are endothermic.
(2) Catabolic pathways, which are involved in the breakdown of larger molecules, commonly involving oxidative reactions; they are exothermic, producing reducing equivalents, and, mainly via the respiratory chain , ATP.
(3) Amphibolic pathways, which occur at the “crossroads” of metabolism, acting as links between the anabolic and catabolic pathways, for example, the citric acid cycle.

INTERACTION WITH WATER INFLUENCES THE STRUCTURE OF BIOMOLECULES

Covalent and Noncovalent Bonds Stabilize Biologic Molecules

The covalent bond is the strongest force that holds molecules together (Table 2–1). Noncovalent forces, while of lesser magnitude, make significant contributions to the structure, stability, and functional competence of macromolecules in living cells. These forces, which can be either attractive or repulsive, involve interactions both within the biomolecule and between it and the water that forms the principal component of the surrounding environment.

WATER

Water is the predominant chemical component of living organisms. Its unique physical properties, which include the ability to solvate a wide range of organic and inorganic molecules, derive from water’s dipolar structure and exceptional capacity for forming hydrogen bonds. The manner in which water interacts with a solvated biomolecule influences the structure both of the biomolecule and of water itself. An excellent nucleophile, water is a reactant or product in many metabolic reactions. Regulation of water balance depends upon hypothalamic mechanisms that control thirst, on antidiuretic hormone (ADH), on retention or excretion of water by the kidneys, and on evaporative loss. Nephrogenic diabetes insipidus, which involves the inability to concentrate urine or adjust to subtle changes in extracellular fluid osmolarity, results from the unresponsiveness of renal tubular osmoreceptors to ADH. Water has a slight propensity to dissociate into hydroxide ions and protons. The concentration of protons, or acidity, of aqueous solutions is generally reported using the logarithmic pH scale. Bicarbonate and other buffers normally maintain the pH of extracellular fluid between 7.35 and 7.45. Suspected disturbances of acid-base balance are verified by measuring the pH of arterial blood and the CO2 content of venous blood. Causes of acidosis (blood pH <7.35) include diabetic ketosis and lactic acidosis. Alkalosis (pH >7.45) may follow vomiting of acidic gastric contents.

PROSEDUR ANTISEPSIS TANGAN

Teknik yang paling penting dan paling dasar dalam mencegah dan mengkontrol penyebaran dari infeksi adalah higiene tangan. Higiene tangan adalah istilah umum yang termasuk didalamnya mencuci tangan, mencuci tangan antiseptik, alat untuk menggosok tangan yang antiseptik, atau surgical hand antisepsis.

1. Mencuci tangan : Mencuci tangan dengan sabun dan air
2. Mencuci tangan antiseptik : Mencuci tangan dengan air dan sabun atau pembersih lain yang mengandung zat antiseptic
3. Gosok tangan antiseptik : Sediakan sebuah gosok tangan yang antiseptik untuk seluruh permukaan tangan untuk mengurangi jumlah mikroorganisme yang ada.
4. Surgical hand antisepsis : Sabun tangan yang antiseptik atau gosok tangan yang antiseptik yang disediakan sebelum operasi oleh personel bedah untuk mengeliminasi sementara dan mengurangi flora yang terdapat di tangan.

Tujuan prosedur ini adalah untuk mengangkat kotoran, minyak dan mikroorganisme dari tangan dan lengan operator. 

ASEPSIS

Asepsis dapat didefinisikan sebagai suatu keadaan bebas mikroorganisme patogen, sedangkan antisepsis merupakan segala tindakan untuk menjadikan suatu alat atau bahan menjadi bebas hama patogen, dengan cara membunuh semua mikroorganisme untuk mencegah terjadinya infeksi. Prosedur antisepsis yang dinamakan juga dengan sterilisasi, dapat dilakukan dengan beberapa cara yaitu, pemanasan, kimiawi, dan radiasi. Cara pemanasan dapat dilakukan dengan pemanasan tanpa tekanan dengan temperatur tertentu (>1000 Celcius), dan pemanasan dengan tekanan (autoclave). Secara kimiawi digunakan tablet formalin, gas etilen oksida, asam karbol, iodine tingtur 3-5%, alkohol 70%, larutan lisol, dan lain sebagainya. Cara radiasi dilakukan dengan menggunakan sinar X, atau sinar ultraviolet (UV). Kontrol asepsis terhadap alat dan bahan melalui prosedur antisepsis telah diketahui dapat mengurangi dan atau mengeliminasi sumber dan penyebaran infeksi sehingga dapat melindungi pasien dan penyedia kesehatan dari penyakit.