Question

In: Biology

in digestive system the main and accessory organs and their main function.? type don't write

in digestive system the main and accessory organs and their main function.?

type don't write

Solutions

Expert Solution

DIGESTIVE SYSTEM OF HUMAN:

It is a system of alimentary canal and digestive glands that takes part in ingestion of food, its crushing , digestion , absoption of digested nutrient and egestion of undigested materials.

Alimentary canal:

It is a tube of variable diameter having muscular wall and glandular epithelium. Alimentary canal starts at mouth and ends at anus. It is very long ( 6- 9) m long and consists of many specialised parts like mouth, vestibule , buccal cavity, pharynx , oesophagus , stomach, small intestine and large intestine and anus.

DIGESTIVE GLANDS : They include salivary glands , gastric glands, liver, pancreas , and intestinal glands. Their sectretions contain enzymes called hydrolases. The latter perform extracellular digestion.

DIGESTION: Conversion of complex insoluble constituents of food into simple, soluble forms is called digestion. It begins in buccal or oral cavity and is completed in small intestine. In buccal cavity the food is tasted and mixed with saliva which has a lot of water and mucin. Tongue manipulates the food and brings it in between the cheek teeth. Movement of lower jaw help in crushing the food into pulpy mass.

It is known as mastication. Saliva has lysozyme and other antibacterial ingredients for preventing growth of bacteria. Ptyalin or salivary amylase is the only enzyme contained in saliva. It changes atarch and glycogen into limit dextrins, maltose and isomaltose. About 30% of starch is hydrolysed by ptyalin. Tongues rolls up the masticated moistened food into small ball called bolus. Bolus is pushed to pharynx. A number of involuntary actions occur. Soft palate is raised to close the internal nares. The larynx also rises to come in contact with epiglottis. Walls of pharynx now contracts. Contraction of pharynx pushes the bolus into oesophagus. The phenomenon is known as swallowing. .In oesophagus, the food is mixed with mucus and passed on into stomach through peristalsis by the opening of guirding sphincter. Peristalsis is accomplished by sequential alternate contraction and relaxatoon of circular and longitudnal muscles of the gut walls. Ptyaline action continues in oesophagus.

Food is kept in stomach for 1 - 5 hrs. Here , it is mixed with gastric juice. Action of saliva stops. Stomach undergoes churning movements. Food doesnot pass back into oesophagus due to cardiac sphincter. Gastric pepsin further softens the foods. The pulpy food is now called chyme. Chyme passes into duodenum through the opening of pyloric sphincter. Burner's glands of duodenum is activated by vagus and secretin hormone. They secrete a lot of alkaline watery and mucoid fluid for protection against acidity of chyme. Thereafter, the food mixes with bile and pancreatic juices. Action of pepsin stops. Food becomes alkaline. Food continues to move forward by peristalsis. It is mixed with intestinal juice and churned further through pendular movements. In small intestine all constituents of food except cellulose are broken and hydrolysed into soluble state. The soluble food is absorbed by large intestine. Water is absorbed in the region of colon. Colon has bacteria that feed on undigested food. Some of them produce B- vitamins. Small quantities of vitamin K and odoriferous gases like phenols and hydrogen sulphide. In colon the undigested matter is changed into faeces. With the accumulation of faecal matter , colon develops a strong peristaltic movement for pushing it into rectum. This develops an urge for defaecation. Mass constraction of colon - rectal complex occurs. Internal anal sphincter relaxes. The external anal sphincter is relaxed through volantary action to pass out faeces or egestion.


Related Solutions

-Endocrine system - Nerve system - Cardiovascular system - Digestive system What are their primary organs...
-Endocrine system - Nerve system - Cardiovascular system - Digestive system What are their primary organs and functions? What are some primary lifestyle choices to help live a healthier life? What are some risk factors to avoid for a healthier life?
Describe and discuss two disorders of the GI system or accessory organs (liver, gallbladder, pancreas) that...
Describe and discuss two disorders of the GI system or accessory organs (liver, gallbladder, pancreas) that can affect nutritional status. Discuss the nursing implications while caring for a patient with these disorders.
What organs are included in the upper digestive system? Mention and explain at least three other...
What organs are included in the upper digestive system? Mention and explain at least three other conditions of the upper digestive system that may be a cause of digestive bleeding. What organs are included in the lower digestive system? What are some causes of lower digestive system hemorrhages, and how do you differentiate them from upper digestive system hemorrhages?
Topic: Animal physiology and human physiology. Digestive System 1.) Identify the parts and organs of the...
Topic: Animal physiology and human physiology. Digestive System 1.) Identify the parts and organs of the human digestive system, and give the functions of each. 2.) How are the digestive organs modified for the efficient mechanical digestion in the following: a.) grazers (ruminants) b.) seed eaters without teeth (birds)
– Take one part of the digestive tract (not esophagus) or a major accessory gland (liver...
– Take one part of the digestive tract (not esophagus) or a major accessory gland (liver or pancreas), describe its structure and makeup (diagrams are helpful), cell types that are important for digestion (excretions etc..) and what happens within this part of the digestive tract or the purpose of the accessory organ?
In C Write a main function with a function call to a function called GetLetter which...
In C Write a main function with a function call to a function called GetLetter which has two double arguments/parameters. The function returns a character. Declare and initialize the necessary data variables and assign values needed to make it executable and to prevent a loss of information
26. Explain the anatomy of the nervous system function of the sense organs. 27. Does separate...
26. Explain the anatomy of the nervous system function of the sense organs. 27. Does separate sexes in nematodes establish that they are dioecious or monoecious? Explain the meaning of the term dimorphism. 28. Compare the anatomy of the male vs. the female. 29. What does the term eutelia mean in nematodes?
How and where are the digestive system and respiratory system interconnected?
How and where are the digestive system and respiratory system interconnected?
What are the organs of the immune system? Primary vs Secondary immune organs? What is the...
What are the organs of the immune system? Primary vs Secondary immune organs? What is the difference between these?
How do the lungs function as excretory organs?
How do the lungs function as excretory organs? Give details
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT