Food Groups:Milk And Meat

Milk is an opaque white liquid produced by the mammary glands of mammals. It provides the primary source of nutrition for young mammals before they are able to digest other types of food. The early lactation milk is known as colostrum, and carries the mother's antibodies to the baby. It can reduce the risk of many diseases in the baby. The exact components of raw milk varies by species, but it contains significant amounts of saturated fat, protein and calcium as well as vitamin C. Cow's milk has a pH ranging from 6.4 to 6.8, making it slightly acid.

Meat is animal flesh that is used as food. Most often, this means the skeletal muscle and associated fat, but it may also describe other edible tissues such as organs, livers, skin, brains, bone marrow, kidneys, or lungs. The word meat is also used by the meat packing industry in a more restrictive sense—the flesh of mammalian species (pigs, cattle, etc.) raised and prepared for human consumption, to the exclusion of fish and poultry.

The composition of the diet, especially the amount of protein provided, is also an important factor regulating animal growth. Ruminants, who may digest cellulose, are better adapted to poor-quality diets, but their ruminal microorganisms degrade high-quality protein if supplied in excess. Because producing high-quality protein animal feed is expensive (see also Environmental impact below), several techniques are employed or experimented with to ensure maximum utilization of protein. These include the treatment of feed with formalin to protect amino acids during their passage through the rumen, the recycling of manure by feeding it back to cattle mixed with feed concentrates, or the partial conversion of petroleum hydrocarbons to protein through microbial action.

In plant feed, environmental factors influence the availability of crucial nutrients or micronutrients, a lack or excess of which can cause a great many ailments. In Australia, for instance, where the soil contains limited phosphate, cattle are being fed additional phosphate to increase the efficiency of beef production. Also in Australia, cattle and sheep in certain areas were often found losing their appetite and dying in the midst of rich pasture; this was at length found to be a result of cobalt deficiency in the soil. Plant toxins are also a risk to grazing animals; for instance, fluoracetate, found in some African and Australian plants, kills by disrupting the cellular metabolism. Certain man-made pollutants such as methylmercury and some pesticide residues present a particular hazard due to their tendency to bioaccumulate in meat, potentially poisoning consumers

Food Groups:Fruits And Vegetables

The term fruit has different meanings dependent on context, and the term is not synonymous in food preparation and biology. Fruits are the means by which flowering plants disseminate seeds, and the presence of seeds indicates that a structure is most likely a fruit, though not all seeds come from fruits.

A vegetable is an edible plant or part of a plant. However, the word is not scientific, and its meaning is largely based on culinary and cultural tradition. Therefore the application of the word is somewhat arbitrary and subjective. For example, some people consider mushrooms to be vegetables, while others consider them a separate food category. Some vegetables can be consumed raw, and some may (or must) be cooked in various ways.

Food Groups

Food groups refers to a method of classification for the various foods that animals consume in their everyday lives, based on the nutritional properties of these types of foods and their location in a hierarchy of nutrition. Eating certain amounts and proportions of foods from the different categories is recommended by most guides to healthy eating as one of the most important ways to achieve a healthy lifestyle through diet.

Digestive System:Small Intestine

The small intestines is the longest part of the digestive tract. It is 6 meters long but also the narrowest at 4 centimeters wide. It is looped, folded, and coiled into the lower part of the of the main body, the abdomen, and consist of 3 parts. First is the duodenum, about 25 centimeters long, which joins at the upper end to the stomach. It leads to the middle section, the jejunum which is 200 centimeters long. Third is the ileum which is 350 centimeters long. The ileum leads into the large intestine, in the lower right of the abdomen.

Similar as the lining of the stomach, the small intestine lining makes powerful enzyme-containing juices to break food into ever-smaller pieces. It also receives digestive juices from the pancreas and the liver, which also help the breakdown.

The small intestines is made up of many layers. The outer layer is called the serosa. The next 2 layers are muscles. The inner-most layer are villi.

The small intestine's inner-most lining is rippled into folds called plicae. These have thousand of tiny finger-like projections called villi. Each villus is about one millimeter long, and each has thousands os even tinier finger-like microvilli. The plicae, villi and microvilli give the small intestines a huge surface, bigger than the area of 5 single beds, to take in or absorb the greatest amount of digested nutrients from food.

Digestive System:Large Intestine

After the food leaves the small intestine or small bowel, comes the large intestine or large bowel, also called the colon. It is wide, about 6 to 7 centimeters across, but shorter than the small intestine, at about 150 centimeters. It passes up the right side of the abdomen, across below the liver and stomach, down the left side, and then curves in an S shape to the lower abdomen.

The large intestine contains microbes known as gut bacteria. These gut bacteria break down certain kinds of food, especially plant foods, so the body can absorb the nutrients. The large intestine also absorbs much of the water from the leftover digested food, turning it into squishy brown lumps called faeces or bowel motions.

The appendix is a small part of the digestive tract, about the size of a little finger. It is the junction of the small and large intestines, in the lower right of the abdomen. The appendix is hollow inside and links to the main digestive tract, but does not lead anywhere else. It does not seem to have an important role.

At the end of the large intestine, the leftover and undigested contents called faeces pass into the last part of the main tract. This is the rectum which is about 15 centimeters long. The faeces stay here until it is convenient to remove them from the body. This is done by squeezing the muscles of the abdomen, to push the faeces through the loosened ring of muscle at the end of the tract, called the anus.

Digestive System:Stomach

After the food travels down the oesophagus, it goes into the stomach. The stomach continues to break down the food both physically and chemically.

Foods usually stay in the stomach, to get digested, for at least one hour. If the meal contained lots of fatty foods, the stay is usually longer as fats takes longer to break apart.

The stomach walls contains three layers of muscles. These muscles squirm and churn the food to turn it into a mushy soup called chyme.

The glands in the stomach lining contains parietal cells which make a powerful hydrochloric acid that kills the germs in unwisely taken contaminated food.

The hydrochloric acid, along with protein-splitting enzyme pepsin made by other cells in the stomach lining prevents the stomach from digesting itself. If there is too much acid or the mucous coat is deficient, the acidic contents of the food will erode raw spots in the stomach wall. These are called gastric ulcers.

Gastritis

Inflammation of the stomach. Caused by stress, fungi, alkalis, poisons and corrosives. To cure, one should take more vitamin A and E which is found in seeds, nuts, corn and fish.

Digestive System:Gullet

The gullet is the 2nd part of the digestive system. Also known oesophagus, at the bottom of the throat (pharynx), there are two openings. One leads to the windpipe (trachea), and the other leads to the gullet (oesophagus). When you swallow food, muscles in the throat and neck raise the top of your windpipe and lower a flap called the epiglottis. These two actions close the windpipe to prevent food from entering the wrong pipe. Upon entering the gullet, the food does not 'fall' into the stomach, instead, the food is pushed along a track by a wave like motion called peristalsis