THE STOMACH

The stomach, which resembles a bag, is about a foot long and six inches wide. Its capacity is about two and a half pints, and a heavy meal may take as long as six hours to pass through it. The stomach wall has three layers of muscles-circular, Longitudinal], and oblique. tach contracts in a different direction, permitting the stomach to squeeze, twist, and churn its contents, actions that are important.

In addition to mucous glands, it contains other glands which secrete hydrochloric acid and several enzymes. One enzyme, rennin, acts on casein, a protein in milk, forming a curd to be digested by other enzymes. Lipase, an enzyme which splits some fats, including those in cream and egg yolk, plays a small role in the stomach, a larger one in the intestine. Hydrochloric acid helps in the digestion of proteins and has other useful chemical effects. 

Another enzyme produced by the stomach, pepsin, helps digest the milk curd resulting from the action of rennin. What emerges from the stomach after the activity there is a semifluid material called enthymeme. It takes little time, a matter of minutes, for fluids -water, beverages of various kinds-to pass through the stomach. But the rest of a meal spends from three to as much as six hours in the stomach.

The time is affected somewhat by the nature of the food. Carbohydrates pass through most quickly; proteins take longer; fats require the most time. Some fats, in fact, slow the digestive process in the stomach for other foods by slowing secretion of gastric juices, thus somewhat prolonging stomach emptying time.

 At both ends, stomach muscles form sphincters, ringlike valves. At the junction of stomach and esophagus, there is the cardiac sphincter. A similar but stronger valve, the pyloric sphincter, lies at the lower end of the stomach where it joins the small intestine. The two valves close the stomach during digestive activities. When chyme is ready to move on to the intestine, the pyloric sphincter opens and closes several times to allow the stomach to gradually empty. 

One phenomenon associated with the stomach is worth noting here. Somehow, the stomach, which secretes hydrochloric acid to digest proteins in foods, is not itself digested by the acid. How it resists the action of an acid that is capable of dissolving even iron is not fully understood. Yet it does resist, and it is normal to have a usual quota of acid in the stomach-this, despite the concern of millions of Americans who, with the help of constant reminders from the manufacturers of various ant- acids, spend about $100 million a year to neutralize stomach acid. 

How Dampness, Abnormal Air pressures and Abnormal Temperatures affect Industrial owrkers health?

DAMPNESS

Tankmen, vatmen, coal miners, and washers are among those who have to work exposed to almost constant dampness. As a result, they may suffer from coughs, respiratory troubles, rheumatic dis- eases, and skin changes. Such workers should be as completely protected as possible by waterproof clothing, rubber boots and gloves. In addition, efforts should be made to control dampness by drain channels through which excess water can be carried away.

ABNORMAL AIR PRESSURES

 Tunnel workers and divers do their jobs under unusually heavy air pressures. In going underground, tunnel workers travel in a chamber which descends slowly so there is a gradual increase in air pressure. If the descent is fast, the change in pressure is distressing. The first sensation is felt in the eardrums and can be relieved by swallowing. Extremely rapid decrease in pressure can produce the "bends" in which blood supply from different parts of the body is blocked off by small air bubbles. Decompression sickness is dangerous and can be fatal.

It may develop several hours after a diver has returned too rapidly to the surface. Treatment usually requires recompression and then gradual decompression. Rising rapidly to a high altitude, which means entering a lower air pressure situation, can be just as harmful. Ascent as well as descent should be gradual. Pilots who ascend too rapidly or take sudden dives may become dizzy, and the change in pressure may be violent enough to burst their eardrums. Commercial airliners are pressurized to avoid the effects of high altitudes.

ABNORMAL TEMPERATURES

Steelworkers, welders, furnace men, blacksmiths, and others may be exposed to very high temperatures which may lead to heatstroke, heat exhaustion, and cramps. Very low temperatures may cause frostbite, gangrene, or death. Insulation or air conditioning and protective clothing can help protect against temperature extremes and their effects. Additional salt, which can be taken in the form of tablets, is needed to make up for large amounts lost in perspiration. Relief periods-providing opportunity to return to normal temperature- are extremely important. Workers should be on the alert for symptoms and should ask for relief the moment any symptoms appear. They should also report any colds or other disturbances to the company doctor or their own physician.