University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

63

Pages:

2
Author:

Mariam A. A.

Small intestine ● ● ● ● ● ● ● Continuous with the stomach Start of the lower GI tract Takes up a lot of the peritoneal cavity 6m long Responsible for 90% of nutrient absorption, water and electrolytes because of the folds which increase the SA 3 parts → duodenum, jejunum and ileum Functions ○ Chemical digestion ○ Nutrient absorption ○ Propulsion ○ Mechanical digestion ○ Secretion Duodenum ● First part of the small intestine ● Only part of the small intestine which is retroperitoneal ● ● ● ● ● ● ● ● Initial part of the duodenum is intraperitoneal because its connected to the pyloric part of the stomach (intra organ) Wraps around the head of the pancreas Physically connected - secretions from the pancreas deposit themselves into the duodenum C shaped Receives digestive fluids and partially digested food from the stomach through the pyloric sphincter and receives fluids from the accessory glands of the liver, gallbladder and pancreas Attached to the posterior abdominal wall (can’t move because of where the accessory glands deposit their fluid) Circular folds in the tube = absorption Accessory structures/glands deposit into the wall of the duodenum Jejunum ● Continuous with the duodenum ● 2.5 m ● Have circular folds, thick and numerous = more villi for absorbing nutrients ● Large nutrient absorption ● Act as speed bumps and they keep the food in the jejunum for longer = more likely that more nutrients will be absorbed ● More muscles = more blood vessels are needed because they need a greater blood supply (difference in colour when looking at the blood going through) ● Palpate → jejunum is thicker and the ileum is thinner ○ Plicae circulares are more numerous ○ Thicker muscles for blood vessels ● Plicae circulares are the speedbumps to slow down the progression of the food to hold it for longer to maximise absorption Ileum ● ● ● ● ● ● 3.6m in length Decrease in circular folds Digested food passes through faster and less nutrient absorption Lymph nodules Longest part of the small intestine Continuous with the large intestine