Digestive System Flashcards
List the two subdivisions of the digestive system.
The alimentary tract (also referred to as the GI or just digestive tract) is the subdivision that food physically passes through. It includes the mouth, pharynx, esophagus, stomach, small intestine (3 sections: duodenum, jejunum, and ileum), large intestine (3 sections: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum). The accessory subdivision consists of organs that food does not physical pass through; but rather, the organs secrete chemicals to assist with digestion or have a mechanical responsibility in assisting with food breakdown. Examples of organs of the accessory subdivision are: teeth, tongue, liver, pancreas, salivary glands, etc.
How is the digestive system regulated?
The digestive system is regulated through neural control and hormonal control. Neurologically, the central nervous system stimulates motility of accessory organs and the alimentary tract.
The digestive system is also regulated through the endocrine system (hormonal). Hormones (chemical messengers) diffuse in the bloodstream to assist with digestion.
When is the living tissue of the tooth called, and why is it considered “living” tissue?
The dentin is the living tissue of a tooth. It is considered living because it receives neuromuscular supply through the root canal.
Describe the function of saliva.
Saliva (pH of approximately 7) moistens food in the mouth in preparation for binding chewed food together; it assists in the digestion of starch and fat; saliva cleans the teeth; and inhibits bacteria.
As the esophagus travels downward, it passes through a very thin muscle that assists with respiration. What is the respiratory muscle called and what complication can arise as a result of its track?
The esophagus travels through the diaphragm. In doing so, the esophagus and/or a small of the stomach can become pinched at the diaphragm. If it is pinched, it may become trapped above the diaphragm; this condition is called hiatal hernia.
There are several sphincters in the digestive system. They are present to prevent food from moving backwards along the track. Name a few and their location.
Cardiac sphincter: located between the esophagus and stomach.
Pyloric sphincter: located between the stomach and the duodenum.
Ileocecal sphincter: located between the cecum and small intestine (specifically the ileum)
Describe the function of the stomach.
The stomach has multiple layers of muscle that assist in motility of food. The stomach also assists in the breakdown (not absorption) of food through the production and secretion of hydrochloric acid.
What is the function of the duodenum?
The duodenum is part of the small intestine that is located/attached to the pyloric region of the stomach. Its function is to neutralize chyme after it empties from the stomach. Chyme, as it enters the duodenum, is very acidic; therefore, the duodenum produces base chemicals to reverse the acidic chyme. If acidic chyme was allowed to enter the jejunum, the lining could not handle the acidic chyme causing it to become very irritated and/or perforated causing toxins to enter the abdominal cavity.
Why is hydrochloric acid needed in the stomach?
Hydrochloric acid has the properties that allow it to break up connective tissue (animal tissue) and plant cell walls. Continued moistening of food so it can form into chyme.
Water balance in the digestive system is essential to maintain homeostasis (i.e., hydration). If too much water is absorbed into the tissues (not the intestine), what can occur?
If water is absorbed into the tissues of the body, blood becomes very viscous; however, the intestine (specifically the large intestine) is deprived of adequate water, which can cause constipation.
