Anatomy of the Gastrointestinal System
The gastrointestinal system is responsible for digestion, absorption, and elimination of food. It comprises various organs and tissues that work together to ensure proper functioning of the digestive process. These include:
- Mouth and Pharynx: The mouth and pharynx are the entry point for food into the digestive system. The mouth contains teeth, tongue, and salivary glands that help in the initial stage of digestion by breaking down food into smaller particles. The pharynx is a muscular tube that connects the mouth to the oesophagus.
- Oesophagus: The oesophagus is a muscular tube that transports food from the pharynx to the stomach. It contains a circular muscle, the lower esophageal sphincter (LES), that prevents the stomach contents from flowing back into the oesophagus.
- Stomach: The stomach is a muscular sac that mixes and grinds food with digestive juices to form a semi-solid substance called chyme. It contains gastric glands that secrete hydrochloric acid, enzymes, and mucus.
- Small Intestine: The small intestine is a long, narrow tube that receives chyme from the stomach. It is divided into three segments: the duodenum, jejunum, and ileum. The small intestine is responsible for the majority of nutrient absorption in the gastrointestinal system.
- Large Intestine: The large intestine, also called the colon, is a wider tube that receives undigested food from the small intestine. It absorbs water, electrolytes, and vitamins from the undigested material and forms faeces.
- Rectum and Anus: The rectum is a short tube that stores faeces until it is eliminated through the anus. The anus is the opening at the end of the digestive tract through which faeces are expelled.