What are the organs of the chicken's digestive system and what are their functions

    What are the organs of the chicken's digestive system and what are their functions

The digestive system of a chicken is composed of the beak, mouth, pharynx, esophagus, crop, glandular stomach, muscular stomach, intestine, cloaca, and digestive glands (liver and pancreas). The digestive system of native chickens is composed of structures or digestive processes. , Is significantly different from domestic animals.

(1) The beak is formed by keratinization of the upper and lower jaws. The beak of the native chicken is sharp and hard, the root is thick, slightly curved and tapered, it is suitable for eating on the ground, it can tear large food, and can also eat tender grass and vegetables growing on the ground.

(2) Oral chickens have no teeth in their mouths, and their cheeks are degenerated, and they have no chewing function. The food stays in the mouth for a short time. In addition, the salivary glands are underdeveloped, and saliva contains a small amount of amylase, which plays a small role in digesting food. The tongue muscles are underdeveloped, the tongue is hard, and there are no taste papillae on the tongue mucosa, and the taste of feed has little effect on its feed intake. The main factors affecting the feed intake are the shape and color of the word material.

(3) The esophagus and the crop esophagus are located under the skin of the neck, on the right side of the trachea, which is easy to expand, which facilitates the passage of feed, and esophagus is rarely blocked. The upper part of the esophagus is connected with the pharynx, and the lower part is connected with the glandular stomach. Before entering the chest cavity, an enlarged crop is formed. The crop can store food, and the mucus secreted by the inner gland can soften the dry food.

The length of time the feed stays in the crop is related to the type of material. The feed in the crop is initially digested under the action of microorganisms and amylase.

(4) Provencal stomach and muscular stomach The proventriculus (anterior stomach) has a fusiform shape with a thick stomach wall and a small internal cavity. The main function of the glandular stomach is to secrete digestive juice and mix it with feed thoroughly. The food stays in the glandular stomach for a short time and quickly enters the muscular stomach.

Immediately after the glandular stomach, the muscular stomach is 2 to 3 times the size of the glandular stomach and is slightly oblate. The stomach wall of the musculostomia is mostly composed of thick smooth muscle, which can produce huge pressure when contracting. With this pressure and the hard inner stratum corneum and the grit in the musculo-gastric cavity, larger grains of material are ground up.

(5) Intestinal system. The small intestine of an adult chicken is about 1.5 meters long. The front part of the small intestine forms a duodenal support, and the pancreas is embedded in the support. The pancreas secretes pancreatic juice, which contains pancreatic amylase, pancrelipase, and trypsin. The wall of the small intestine can also secrete a small amount of enzymes to digest protein and carbohydrates.

(6) The cecum, there is a blind pocket on each side of the junction of the small intestine and the large intestine, which is called the cecum. The length of the cecum of a normal healthy adult chicken is about 15 cm. The exact role of the cecum is still very clear, but it has little effect on food digestion. There is some bacteria activity in the cecum, which seems to be related to the immunity of chickens.

(7) Large intestine. The large intestine of a chicken is just a relatively short rectum. The large intestine of a grown-up chicken is 10 cm long, and its diameter is about twice that of the small intestine. The large intestine is connected to the end of the small intestine, followed by the cloaca. The function of the large intestine is to reabsorb water to increase the water content in the chicken body cells and maintain the water balance in the body. The cloaca is the digestive tract.

Extended information

The intestinal tube of a chicken is about 6 times the body length, the small intestine mucosa has villi, and the entire intestinal wall has intestinal glands.

The small intestine is divided into duodenum, jejunum and ileum, and there are two extramural glands, namely liver and pancreas. There is no central chylo organ in the intestinal villi, and the absorption of fat is not through the lymphatic route, but directly into the blood.

The large intestine of a chicken is composed of a pair of cecum and rectum. The entrance of the cecum is the dividing line between the large intestine and the small intestine. There is an obvious muscular ileocecal valve, and there are abundant lymphoid tissues distributed in the posterior intestinal wall, forming the cecal tonsils, there is no obvious colon, only a short rectum. The rectum starts at the entrance of the cecum and extends back to the final enlarged part called the cloaca.

The secretions of the large intestine do not contain digestive enzymes. The cecum mainly absorbs fatty acids that are fermented and decomposed by crude fiber. It also absorbs water and nitrogenous substances, as well as some vitamins synthesized by bacteria. The rectum mainly absorbs a part of water and salt, which is mixed with urine and excreted through the cloaca after the stool is formed.

The cloaca is divided into three parts: front, middle, and back by two annular folds: the front is the fecal tract, which is directly connected to the rectum; the middle is the cloaca, where the vagina of the ureter, vas deferens or fallopian tube opens; the back is the anal tract, It is the last segment of the digestive tract. There is a dilator muscle in the wall, and there is an upper cavity on the dorsal side of the junction of the cloaca and anal tract.

Because the cloaca integrates the fecal tract, urethra and fallopian tube outlet, the eggs produced are susceptible to fecal contamination, especially when the hen’s digestive tract contains pathogens, which can spread diseases through contaminated eggs. When dystocia leads to anal prolapse, it is easy to cause ascending infections of pathogens from the cloaca to the offspring, the fallopian tube and even the whole body.