Describe the movement in small and large intestine
The movement in the small and large intestine is primarily governed by two types of movements known as peristalsis and segmentation.
Peristalsis is a rhythmic contraction and relaxation of the smooth muscles that propels the contents along the digestive tract. In the small intestine, peristaltic waves sequentially contract and relax segments of the smooth muscles, pushing the chyme (partially digested food) forward. This movement helps mix the chyme with digestive enzymes and absorb nutrients.
Segmentation, on the other hand, involves the contraction and relaxation of smaller sections of the intestinal wall simultaneously, which serves to mix the chyme more effectively. This movement also ensures that the chyme comes into close contact with the absorptive surfaces of the small intestine, facilitating nutrient absorption.
In both the small and large intestine, the movement is regulated by the enteric nervous system, which is a complex network of nerves located within the gut wall. These nerves coordinate the contractions of the smooth muscles, ensuring an organized and efficient movement of the intestinal contents.
Additionally, the large intestine has a slower movement compared to the small intestine. This slow movement allows for further absorption of water and electrolytes from the chyme, consolidating the waste into feces. The slow contractions in the large intestine, known as haustral contractions, move the chyme back and forth, promoting water reabsorption and compaction of the feces.
Overall, the movement in the small and large intestine is crucial for digestion, absorption of nutrients, and elimination of waste. These coordinated muscle contractions ensure the effective processing of food as it progresses through the digestive system.
The movement in the small and large intestines is predominantly referred to as peristalsis. Peristalsis is a rhythmic contraction and relaxation of the smooth muscles lining the walls of the intestines, causing movement of food and waste materials through the digestive system.
In the small intestine:
1. Contractions: The small intestine exhibits two types of contractions: segmentation and peristalsis. Segmentation occurs when the muscles contract and relax in segments, mixing the chyme (partially digested food) with digestive enzymes and promoting absorption of nutrients. Peristalsis, on the other hand, involves coordinated contractions that propel the chyme forward along the length of the small intestine.
2. Villi and Microvilli: The inner lining of the small intestine contains numerous tiny finger-like projections called villi, which increase the surface area available for nutrient absorption. The villi are further covered with even smaller projections called microvilli, which further enhance absorption by increasing the surface area.
3. Contractions of Circular and Longitudinal Muscles: Within the small intestine, circular muscles constrict and lengthen, propelling the chyme in a forward direction. At the same time, the longitudinal muscles contract above and relax below the bolus, squeezing the chyme inward and propelling it along.
In the large intestine:
1. Slow Movement: Compared to the small intestine, the movement in the large intestine is slower. This allows for further absorption of water, electrolytes, and vitamins produced by intestinal bacteria.
2. Haustral Contractions: The large intestine is divided into pouches called haustra. Haustral contractions occur when these pouches fill with chyme and then contract to move it along to the next pouch. This helps to further mix and squeeze the contents for water absorption.
3. Mass Movements: Mass movements are powerful contractions that occur a few times a day in the large intestine, primarily after meals. These contractions propel waste materials, mainly feces, toward the rectum for elimination.
Overall, the movement in both the small and large intestines is necessary for the digestion and absorption of nutrients, as well as the elimination of waste products from the body.