Question

Plz write in your own text and don't copy answers that was answered before since my teacher has (Plagiarism checker) thank you

1. Why are goblet cells necessary for GI tract function? Was there a difference in the amount of goblet cells in the stomach, duodenum, ileum, and large intestine? Explain why this difference occurs or does not occur.

2. What are Peyer’s patches?

3. Which type of cell is present in most of the pancreatic tissue, endocrine or exocrine? How do you know based on the slide that you viewed?

4. List the four main layers of the GI wall. What is the composition of each layer?

5. What are the main functions of the duodenum? How is this reflected in the structure of the duodenal wall?

Answer 1

1.Goblet cells are a kind of single cell which primary function is to secrete mucus in the intestinal lumen.Mucus forms a protective layer in the intestinal epithelium which basically protect the mucosa from gastric acid,different eneymes,intruding pathogen and other potentially harmful things.

There is definitive variation in the distribution of goblet cells in the different parts of GIT which is mainly due to difference in their exposure to various pathogens and harmful irritants.Goblet cells are found in abundance in the large intestine where it has to protect the mucosa from all the small intestinal enzymes as well as the pathogens.The secreted mucus also takes part in formation of faecal matter.Relatively the distribution is lesser in small intestine than large intestine where the secreting mucus has to protect it from gastric acid and secretion. The mucus secreting glands of stomach are not actually goblet cells as these are sinlge individual cells rather are a group of cells.

2.Payer patches are collection of lymphoid aggregates present in the mucosa of small intestine,mostly in ileum.It has a role in preventing growth of bacteria and other pathogens in GIT.

3.Exocrine part of the pancreas is much more than the endocrine part.Exocrine part contains approximately 85% of total pancreatic mass.The most part of pancreas is occupied by cells secreting the pancreatic digestive enzymes which are arranged in the form of acini and in between the acini lies the islets of Langerhans which carry out the endocrine functions.

4.Layers of GIT can be enumerated as

a)Serosa:it contains loose connective tissue.

b)Muscularis propia: This layer contains longitudinal and circular muscle layer along with the Auerbach plexus.

c)Submucosa:This layer contains collagen fibres along with blood vessels and Meissner's plexus.

d)Mucosa:It is further subdivided into Muscularis mucosa,lamina propia,basement membrane and epithelium.Muscularis muscosa is a layer of smooth muscle layer where as lamina propia consists of myofibroblasts,nerves and blood vessels.The epithelium is glandular and contains different glandular cells.

5.The main fuctions of duodenum are

a)Digestion of chyme by bile from liver, digestive enzymes from pancreas.The mucus secreted from goblet cells protects it's mucosa.

b) Neutralisation of gastric acid: Secretion of Brunner's gland that is located in the submucosa of duodenum which is rich in bicarbonate along with bile neutralises gastric acid.

c)Absorption of water and electrolyte:The enterocyte present in the duodenal lining facilitate absorption.The crypts of liberkuhn and the microvilli increases the surface for absorption.