Second, the stomach releases the hormone gastrin, which enhances ileal motility, thus relaxing
the ileocecal sphincter
. After chyme passes through, backward pressure helps close the sphincter, preventing backflow into the ileum.
Which valve prevents bacteria laden material from passing from the large intestine back into the small intestine?
The ileocecal valve
is preserved, as this structure prevents egress of bacteria from the colon into the small intestine, causing bacterial overgrowth and malabsorption.
What controls the entry of materials into the large intestine?
The 4 major functions of the large intestine are recovery of water and electrolytes, formation and storage of faeces and fermentation of some of the indigestible food matter by bacteria.
The ileocaecal valve
controls the entry of material from the last part of the small intestine called the ileum.
What controls the passage of chyme from the last region of the stomach to the duodenum region of the small intestine?
The pyloric sphincter
is a ring of smooth muscle that connects the stomach and small intestine. It opens and closes to control the passage of partially digested food and stomach juices from the pylorus to the duodenum.
Which modification of the small intestine creates a brush border appearance?
The simple columnar epithelial cells that make up the mucosa contain one of these modifications, called
microvilli
. Microvilli are tiny, hair-like projections that increase nutrient absorption. This microvilli-covered surface makes the cell look fuzzy, and this is referred to as the brush border.
What stimulus relaxes the ileocecal sphincter?
What stimulus relaxes the ileocecal sphincter?
Gastrin release
increases motility of ileum and relaxes ileocecal sphincter.
What causes inflammation of the ileocecal valve?
Intestinal tuberculosis (ITB)
, Crohn’s disease (CD), and adenocarcinoma are the most common causes. Enteric bacterial infections, cytomegalovirus, histoplasmosis, amebiasis, systemic vasculitis, lymphoma, etc.
Which of the following are absorbed in large intestine?
The purpose of the large intestine is to absorb
water and salts
from the material that has not been digested as food, and get rid of any waste products left over. By the time food mixed with digestive juices reaches your large intestine, most digestion and absorption has already taken place.
Why does large intestine not absorb water?
When the
colon’s muscle contractions are slow or sluggish
, the stool moves through the colon too slowly, resulting in too much water being absorbed. Some of the most common causes of constipation include the following: Medications. Lack of exercise.
What does the rectum do in the digestive system?
The rectum
receives stool from the colon
, sends signals to the brain if there is stool to be evacuated, and holds stool until evacuation can happen. Anus: The last part of the digestive tract, the anus, consists of pelvic floor muscles and two anal sphincters (internal and external).
Which of the following is the sphincter muscle that regulates the movement of chyme into the small intestine?
Pyloric Sphincter
. The pyloric sphincter is a circular band of muscle tissue that regulates the flow of semi-digested food from the stomach (termed ‘chyme’) into the small intestine.
In which organ or region is chyme mixed with pancreatic juice and bile?
Digestion in
the Duodenum
The process of chemical digestion begins in the stomach. Chemical digestion continues in the duodenum as pancreatic enzymes and bile are mixed with the chyme. Absorption of nutrients begins in the duodenum and continues throughout the organs of the small intestine.
Can the pyloric sphincter be repaired?
Pyloroplasty
involves cutting through and removing some of the pyloric sphincter to widen and relax the pylorus. This makes it easier for food to pass into the duodenum. In some cases, the pyloric sphincter is entirely removed.
What is the function of microvilli in the small intestine?
Every cell lining the small intestine bristles with thousands of tightly packed microvilli that project into the gut lumen, forming
a brush border that absorbs nutrients and protects the body from intestinal bacteria
.
What gives brush border appearance to intestine?
The brush borders of the intestinal lining are the site of
terminal carbohydrate digestions
. The microvilli that constitute the brush border have enzymes for this final part of digestion anchored into their apical plasma membrane as integral membrane proteins.
Why is the small intestine suitable for absorption?
The small intestine is good for
absorption since it has a large inner surface area
. This is formed due to the plicae circulares which project many tiny finger-like structures of tissue called villi. The individual epithelial cells also have finger-like projections, which are called known as microvilli.
