Digestive System Flashcards
What is digestion?
It is the physical and chemical breakdown of the food into particles small enough to cross the intestinal wall and enter the bloodstream.
What are three activities involved in physical digestion?
Chewing/grinding of food in the mouth, churning of food in the stomach, churning of food in the small intestine.
What is absorption?
It is the process by which small particles and simple compounds enter the bloodstream through the epithelial lining of the intestine.
What are the functions are the digestive system?
Digestion, absorption, elimination, storage and taste.
What regions is the GI tract made up of? What are each’s specific functions?
The mouth including lips, tongue and teeth. These ingest the food, grind it (physical digestion) and prepares it for swallowing. Saliva glands aid activities in this region and begins chemical digestion (enzyme action). The oesophagus is a pathway for transporting food from the pharynx to the stomach. The stomach is a storage chamber where some chemical and mechanical digestion occurs. The small intestine secretes intestinal juices. and with the aid of the secretions from the liver and the pancreas, enables (mostly) chemical digestion of most of the food. The digested food and water are absorbed into the bloodstream. The large intestine contains microorganisms that synthase vitamins. In this region water is reabsorbed, faeces are formed and the indigestible wastes are passed on to be stored in the rectum and expelled (egestion) through the anus.
What are the differences of digestive tracts between a dog, a horse and cattle?
The stomach in the cattle is the largest, with them having four stomachs, the dog’s stomach is the next biggest with the horse’s stomach being the smallest. The small intestine in the cattle and horse are very long, with the cattle’s being the longest. The cecum of the horse is very large with the cattle’s and dog’s being much smaller similar in size to each other. The cow has an extremely long large intestine, the horses’ is much shorter with the dog’s being very short in comparison to both. The cattle and the dog have short colons in comparison to the horses’ which is quite long.
What is the basic structure of the gut wall?
On the outside, it is covered by the peritoneum, a membrane which also lines the wall of the abdominal cavity. Under the peritoneum, the wall of the gut is composed of layers of smooth muscles. Food is moved along the digestive tract by peristalsis. A layer of epithelium lines the gut on the inside. In the small intestine, this layer is thrown into folds called villi.
What is peristalsis?
Alternating contraction and relaxation of smooth muscle layers in sections that bring about a wave-like motion.
What features increase the surface area of the intestines?
An increase in length, the formation of circular folds, the development of villi and the presence of microvilli.
What are the glands associated with the digestive tract?
Salivary glands, pancreas and the liver.
How does saliva help with digestion?
It moistens food for tasting, it lubricates food for swallowing, to begin starch digestion and to kill bacteria.
How does the pancreas help with digestion?
The pancreatic juice provides enzymes for digestion of all food groups.
How does the liver help with digestion?
Bile emulsifies lipids.
What is the buccal cavity?
It’s a pocket between the outside of the teeth and the cheek. The cheek pouches of some mammals are very distensible and are used to carry food or nesting materials.
What are the salivary glands in a dog?
Parotid, submandibular, sublingual and zygomatic.
