Human Digestive System

Mucus released as a part of secretion of Brunner gland and bicarbonates from pancreas protects the intestinal mucosa from acid as well as provide an alkaline medium. if mucus is not released then the pH of the small intestine will decrease means acid nature in the small intestine will increases.

Succus entericus which is also known as the intestinal juice is secreted by Crypts of Lieberkuhn which moderates the pH of acidic chyme come from the stomach and also contains various digestive enzymes that take part in the final digestion of carbohydrate, fat and protein,

Succus entericus is the intestinal juice. It is secreted by crypts of Lierberkuhn. Succus entericus brings about complete digestion of all the bio molecules in the small intestine.

Small slit like space is found at the base of villi. These spaces are called crypts of  Lieberkuhn. Brunner's gland are small spherical multicellular glands. They open into crypts of  Lieberkuhn with the help of fine tubules. Paneth cells are found in mucosal layer of crypts of Lieberkuhn of jejunum. They are unicellular glands. They synthesize and secretes enzymes of intestinal juices. The secretory substances of Brunner's glands and Paneth cells are combinedly called intestinal juice or succus entericus. 

Succus entericus also called, intestinal juice is a fluid that is secreted in small quantity in the small intestine. The secretions of the brush border cells of the mucosa along with the secretions of the goblet cells constitute this intestinal juice. It is highly variable in constitution, and contains various enzymes (such as erepsin, lipase, lactase, invertase, enterokinase, dipeptidases, nucleosidases and maltase) and mucus.

Succus entericus is the alkaline secretion produced by glands in the wall of the duodenum, consisting of water, mucoproteins, and hydrogencarbonate ions. It helps to counteract the highly acidic and proteolytic chyme entering the small intestine from the stomach, and thus protects the duodenum from damage.

Crypts of Lieberkuhn are simple tubular glands. They occur throught the small intestine between the villi. The glands and intestinal villi are covered by epithelium, which contains multiple types of cells: enterocytes (absorbing water and electrolytes), goblet cells (secreting mucus), enteroendocrine cells (secreting hormones), tuft cells and, at the base of the gland, Paneth cells (secreting anti-microbial peptides) and stem cells. The secretion of this gland is called intestinal juice or the succus entericus, which is alkaline in nature and having pH 8.3.

While the chyme is present within the small intestine, glands within this structure begin to secrete different types of digestive enzymes called carbohydrases (amylase, proteases, and lipases or fat splitting enzymes). The glands responsible for these enzymatic secretions are called the crypts of Lieberkuhn. Another set of glands called Brunner's glands are responsible for the secretion of mucus. Collectively, the intestinal secretions are referred to as succus entericus.

Haustra are sac like structures which are arranged on the side of three longitudinal muscles cords called taeniae in colon (intestine).

Succus entericus, or intestinal juice, is primarily secreted by the Crypts of Lieberkuhn. While Brunner's glands contribute alkaline mucus, the term succus entericus specifically refers to the secretion from the crypts.

Crypts of Lieberkuhn are found in the small intestine and secrete various components of the intestinal juice, including enzymes and mucus.

Brunner's glands secrete an alkaline, bicarbonate-rich mucus that protects the duodenal mucosa from the acidic chyme coming from the stomach.

Enterogastrone inhibits gastric secretion, while gastrin stimulates it. Pancreozymin and cholecystokinin stimulate pancreatic and bile secretions, respectively.