The digestive system breaks down the complex molecules of food to a simple form that the body can use. In this article I will introduce you to how the digestive system works.
It all begin with the teeth. The front teeth grab the grass and jerk their head sideways to rip the grass out. The take it into their mouths, and the large muscular tongue pushes the food into a ball at the same time as moving it around the mouth subject it too the molar teeth, which break the food up.
Three saliva glands positioned around the mouth (under the tongue, above and below the epiglottis) release saliva, a clear lubricating fluid. The chewed food, now called a bolus, travels down the oesophagus by wave like contractions known a peristalsis. Before it enters the stomach, the bolus passes through the cardiac sphincter, a valve which prevents the backflow of food, and means horses cannot vomit.
Food is broken down by acidic gastric juices and enzymes and remains in the stomach for approximately three hour. The pyloric sphincter (another valve) allows a small amount of food into the small intestine when it has been sufficiently digested.
The first part of the small intestine is called the duodenum and pancreatic enzymes, and those secreted from the liver combine with bile and break down the food to release basic nutrients,
The next part is called the jejunum and here the basic vitamins and minerals are absorbed, and utilized or stored by the liver.
The final part of the small intestine is called the ileum. Here calcium and phosphorus are absorbed. The ileum also controls the flow of food, which is now referred to as ingesta as opposed to the bolus, into the caecum.
The ileocaecal valve controls the the entrance of the ingesta. Once the ingesta enters the caecum, which is a part of the large intestine, it is assaulted by gut flora (good bacteria) which digest the complex cellulose in hay and grass. These are very sensitive to change, therefore, dietary adjustments must be made slowly. The fermentation produces volatile fatty acids, which are absorbed in the large colon, the second part of the large intestine. Carbohydrates, and most water is also absorbed here. The small colon absorbs the last of the water, and electrolytes, and the waste passes into the anus to be passed as droppings.
Colic is the most common digestive upset, and more about it is revealed here.