Passage of a Needle through the Alimentary Canal

Enteral nutrition encompasses various methods of delivering nutrition directly to the gastrointestinal (GI) tract, bypassing traditional oral intake. It is particularly beneficial for patients who cannot eat by mouth but have a functioning digestive system. Key methods include nasointestinal feeding, gastrostomy, and jejunostomy, each suited to different clinical scenarios based on the patient's needs and condition.
Nasointestinal Feeding
Nasointestinal feeding involves placing a tube...

Enteral nutrition delivers nutrients directly to the stomach or small intestine through a tube. This method is appropriate for patients who cannot eat but still have a functioning digestive system. It is also beneficial for individuals with swallowing difficulties, anorexia, malabsorption, or those who have undergone gastrointestinal (GI) surgery.
Orogastric (OG) and nasogastric (NG) feeding are two standard methods used for enteral nutrition. Enteral nutrition is often preferred over...

Parenteral Nutrition (PN) delivers essential nutrients directly into the bloodstream, bypassing the digestive system. It is commonly used for individuals with severe digestive disorders or conditions that prevent normal nutrient absorption.
PN can be administered through two primary routes:
1. Central Parenteral Nutrition (CPN):
CPN involves delivering a high concentration of nutrients through a large vein. This is typically achieved using a Peripherally Inserted Central Catheter (PICC) or,...

In situ experiments, such as the Doluisio method and Single-Pass Perfusion technique, provide critical insights into drug uptake by simulating in vivo conditions for drug absorption.
The Doluisio method involves perfusing a prepared segment of a rat's small intestine with a solution of radiolabeled drug and a non-absorbable marker. This helps to differentiate between absorbed and non-absorbed drug concentrations. The intestinal segment is connected at both ends using tubing and syringes,...

The colon, or large intestine, is the final segment of the digestive system. Its primary functions include absorbing water and vitamins produced by gut bacteria and transforming waste from liquid to solid to form stool. In adults, the large intestine is approximately 5 feet long and consists of four main sections:

Splanchnic circulation refers to the network of blood vessels that supply and drain blood from the abdominal organs involved in digestion, including the stomach, liver, pancreas, intestines, and spleen. This circulation delivers essential nutrients and oxygen while removing waste products from these organs.
Blood Supply to the Digestive System: The splanchnic circulation involves three main arteries: the celiac artery (also known as the celiac trunk) and the superior and inferior mesenteric...