Digestion

Kai Tiaki : the journal of the nurses of New Zealand, Volume XIV, Issue 2, 1 April 1921, Page 83

Digestion

Some Notes for Probationer Nurses

(Works of Reference used: (1) '/Human Physiology," Furneaux ; (2) "Anatomy and Physiology for Nurses, ' ' Amy Pope.) According to a popular version of a dictionary of the English language, the word "digestion" is styled "act of digestion; classification; conversion of food into chyme; — preparation by heat and moisture." According to a pocket dictionary compiled by Honnor Morten for the use of nurses (and 1 may as well add now, m parenthesis, that the most useful place for it to be kept 'is m the pocket of one's uniform whilst on duty!), "digestion" is described as "the process of converting into chyme and chyle, so that it can be absorbed into the blood." With this latter we have to deal, and as the vsubject "digestion" is one of the bug-bears of the junior probationer's studies, it is interesting to note that as we must "digest" to learn, the meaning of the word "digest" is "to distribute into classes, or under heads — to think over; to reflect upon; to bear with patience; to dissolve m the stomach as food; to prepare by heat for chemical change; y.\., to undergo digestion ; to be prepared by heat!!" Probationers! After reading that, do you wonder now how hard we "swotted" digestion? "To bear with patience ; to reflect upon." A good thought to apply to any of our studies. "To distribute into classes, or" under heads." Another xevy excellent thought. In the busy life of a nurse she will find that if she prepares her lectures arranging the notes into classes or heads, she can assimilate a considerable amount of facts without any of the "ornaments." Learn first the fundamental principles. The average adult brain will easily grasp them ! Look upon your studies as a recreation and not as a penance !

It is the only philosophical thing' to do, because, after all, one must learn if one has to pass that first year's examination ! A good motto to bear m mind is the familiar Latin one: "Finis coronat opus" ("The end crowns the work"). PROCEDURE. Definition of Digestion. — "The process which takes places m the alimentary canal, whereby food is made soluble and of such a nature that it can pass through the walls of the intestinal blood-vessels, be absorbed by the blood, and be utilised by the body for the building and re-pair of tissue and the production of heat and energy." (Pope's "Anatomy and Physiology for Nurses.") "What the Digestive Apparatus Consists Of.— (1) The Alimentary Canal; (2) the Accessory Organs. The Alimentary Canal extends from the mouth to the opening leading from the rectum. Alimentary Canal. Accessory Organs. 1. Mouth. 1. Teeth. 2. Pharynx. 2. Tongue. 3. Oesophagus. 3. Salivary glands. 4. Stomach. 4. Pancreas. 5. Small intestine. 5. Liver and gall 6. Large intestine. bladder. There are two processes of digestion — (1) mechanical, (2) chemical. Mechanical. Chemical. 1. Mastication. Chemical diges2. Swallowing, or de- tion consists of "hyglutition. drolysis." This pro3. Peristaltic action cess is the absorpof the oesophagus, tion of water and stomach, and m- the splitting of the testines. complex molecules 4. Defecation. of the food substances into more simple ones, by means of the ferments contained m the digestive juices.

Foods are divided into two classes — | 1. Proteins. 1. Organic I 2. Carbohydrates. j 3. Fats. o t • *) 1- Mineral matter 2. Inorganic j 2 The Uses of Organic Food Substances ; (1) To build body tissues and to repair the constant waste that is igoing on m the body as the result of muscular activity. (2) To supply heat to keep the body warm. (3) To provide energy necessary to maintain the functional activities of the body. Organic Substances are divided into (1) nitrogenous, (2) non-nitrogenous substances. Proteins are called nitrogenous foodstuffs because they contain-nitrogen. Carbohydrates and fats are called nonnitrogenous because they contain only carbon, hydrogen and carbon. No nitrogen. Nitrogenous Compounds: (1) Albumininoids or proteins; (2) gelantinoids. The chief animal nitrogenous foods are: 1. Albumen (white of egg). 2. Casein (milk and cheese). 3. Fibrin (blood). 4. Myosin (muscle). 5. Gelatine (bone). Vegetable nitrogenous foods: 1. Gluten (cereal grains). 2. Legumen (leguminous plants or their seeds, as peas, beans, etc.). Definition of Protein, or Albuminoid: An organic -substance similar to white of ege\ Tt contains nitrogen. Definition of Carbohydrate: An organic substance composed of carbon, oxygen, and hydrogen only. Sugar and starch are examples of carbohydrate foods. Non-nitrogenous Compounds: (1) Carbohydrates; (2) Fats. Animal Non-nitrogenous Compounds : (1) Fats; (2) Sugar. Vegetable Non-nitrogenous Compounds : 1. Starch (all parts of plants). 2. Sugars (all parts of plants). 3. Gums (all parts of plants). 4. Oils (fruits). Inorganic Foods: (1) Mineral matter; (2) Water.

Mineral matter consists of (1) common salt, (2) calcium carbonate, and the phosphates of (3) calcium, (4) magnesium, (5) potassium, (6) and sodium; also salts of iron, etc. The uses of inorganic foodstuffs are absolutely indispensable to the body. (1) They form an essential part of the tissues of the body. (2) They regulate the flow of fluids to and from the tissues. (3) The calcium salts maintain the irritability of nerve and muscle and the firm consistency of bone and of the clotting* of the blood. These are some of the chief uses of inorganic foods. "Inorganic foods are not, with the exception of water and common salt, generally taken separately, but they all exist m the animal and vegetable substance we eat. Life cannot be maintained on mineral food alone, neither can life be permanently sustained by any one class alone of the organic foods. Our food must consist of a mixture of these. Various food-substances we use do generally consist of mixtures of these. For instance — Wheat Flour. (1) Gluten (nitrogenous substance). (2) Starch (non-nitrogenous). (3) Various mineral salts derived by the wheat plant from the soil. Meat. Myosin (nitrogenous). Fat (non-nitrogenous). Mineral salts. A model food is milk, on which young animals entirely subsist. It contains nitrogenous, non-nitrogenous, and mineral food substances m the proportions m which they are required to make good the waste of the body. The Uses of Water: (1) Tt enters into composition of hardest tissues ; (2) Supplies fluid for the body; (3) Acts as a solvent for food; (4) Ts necessary for the removal of waste .matter. Water and salts are absorbed into the system unchanged, but all organic foods,

except sugar (i.e., sugar can be dissolved m water) must undergo certain chemical changes before they are capable of passing through the walls of the stomach and intestines, thence into the blood-vessels and lacteals. Now if we look back on the two processes (mechanical and chemical) of digestion, we will notice under the heading of "chemical" the words "ferment" and "digestive juices." By learning about

these we can readily understand how organic foods are digested. Definition of Ferment. — Ferment : A substance produced by living cells and capable of setting up chemical changes m another substance without itself becoming changed. Ferments are contained m the digestivejuices of the body. They are shown m the following table: