There are ive types of cells associated with the glands. Regen- 1. Exocrine glands liver and pancreas de- erative cells are found at the boundary between liver their secretions bile and digestive en- the isthmus and the gastric pit. These cells are few zymes into the duodenum by way of the in number and not readily distinguished in routine cystic duct and main pancreatic ducts.
These cells divide and migrate up- 2. Submucosal glands. They secrete mucus and resem- gastric glands. Mucous neck cells are found in ble the pyloric glands of the stomach. These cells are scat- tered among parietal cells and secrete an acidic 3. Intestinal crypts glands are invagina- form of mucus. Parietal cells are distinctive eo- tions of the surface epithelium down into sinophillic cells with a centrally located nucleus and the underlying lamina propria.
The eosinophilia is due e to the large quantity of mitochondria in these cells. Cell types found in the intestinal epithelium in- Some parietal cells are also be found in the base of clude: the gland. The primary cell type in the base is the chief cell which has a basophilic cytoplasm in its basal region. Chief cells secrete pepsinogen and gastric lipase. Gastric enteroendocrine cells are part of the diffuse neuroendocrine system DNES pl 1. Simple columnar epithelium absorptive cells have a microvillus striate border and are involved in nutrient digestion and ab- sorption.
The pylo- 2. Goblet cells secrete mucin. Columnar crypt cells transport secretory absent. Paneth cells at the base of intestinal crypts produce antibacterial substances. These One of the main functions of the small intestine is cells have very eosinophillic secretion nutrient absorption.
Specializations for increasing granules due to their content of lysozyme. M cells occur in regions where lymphoid nodules abut intestinal epithelium. Here 1. Circular transverse folds plicae circu- the columnar cells are replaced by the lares or valves of Kerckring of the en- cuboidal to squamous M cells. M cells be- tire mucosa with a core of submucosa long to the mononuclear phagocytic sys- project permanently into the lumen. The tem of macrophages and antigen present- plicae are prominent in the duodenum and ing cells.
Stem cells are located in the base of the intestinal crypts 2. Villi are projections evaginations of the mucous membrane with a core of lamina 7. Enteroendocrine cells DNES produce propria into the lumen.
The shape of villi hormones and are not readily distinguished varies in the different regions of the small in routine preparations.
The in the distal ileum. Microvilli are cytoplasmic projections and sends ibers into the core of the villi. The colon is mostly covered by a serosa. Its epithelium is controls the muscularis mucosa. In the duodenum similar to the colon, but with fewer goblet cells. The submucosal glands are found.
The muscularis crypts are short um in comparison to the externa, is responsible for peristalsis, and has an colon. Enteroendocrine cells are found in the base inner circular and outer longitudinal layer. Auer- of the crypts. When nodules muscle layers. The muscularis The small intestine is divided into three regions: mucosa is very thin. The muscularis externa is in- duodenum, jejunum and ileum. The pyloric stom- ner circular and outer longitudinal layers of smooth ach transitions to the duodenum at the pyloric muscle.
The appendix is covered by a serosa. The duodenum is the shortest seg- ment 25 cm and receives secretions from the liver bile and pancreas digestive enzymes. The jejunum and ileum have a similar e appearance. Lymphoid tissue in the lamina propria progressively increases from the jejunum to the il- eum. Villi become shorter, broader and have pl increasingly larger lacteals blind ending lymphoid vessels in the core of villi in the ileum.
Frequency of goblet cells and Paneth cells increases as one m progresses from the duodenum to the ileum. The parts of the large intestine are the cecum, appendix, colon, rectum and anal ca- nal. The cecum and colon are histologically indis- tinguishable. Having no villi, the inner surface is smooth and even. The intestinal glands crypts of Lieberkuhn are frequent and closely packed together.
The two ma- jor cell types are simple columnar absorptive cells with striated border and numerous goblet cells. Paneth cells may or may not be present.
Enteroendocrine cells may be seen at the base of the crypts. Lymphocytes are common in the lamina propria. The muscularis mucosa is found at the base of the glands.
The submucosa is well de- veloped with prominent blood and lymph vessels. The muscularis externa con- sists of an inner circular layer and an unusual outer longitudinal layer. The outer layer is gathered into three distinct bundles taenia coli that are equally spaced around the gut. Muscularis mucosa Tongue 2.
Submucosa consisting of: 1. Striated muscle a. Submucosal glands with ducts pass- 2. Lingual minor salivary glands ing through the mucosa 3. Foliate and iliform papillae.
Muscularis externa: inner and outer layers 4. Taste buds 4. Taste pore outer muscle layers of the muscularis externa. The mucosa consisting of: 1. Abrupt transition from stratiied squamous a. Epithelium: stratiied squamous non- non-keratinizing epithelium to a simple keratinizing columnar epithelium.
Lamina propria the connective tis- 2. Lamina propria ii. Pyloric mucosal glands b. Muscularis mucosa b. Submucosa 3. Gastric pits 3. Duodenum 4. Cardiac glands a. Mucosa a. Mucous cells i. Villi b. Parietal cells ii. Crypts glands 5. Submucosa b. Submucosa 6. Muscularis externa i. Adventitia duodenum fundIC sTomaCh 1. Mucosa 1. Rugae a. Villi 2. Crypts glands e 3. Muscularis externa c. Surface absorptive cells 4. Gastric pits and glands 5. Simple columnar epithelium of the pl Four ive types of cells characteristic of the stomach: d.
Brush border — microvilli Goblet cells Lamina propria m surface f. Mucous neck cells 2. Submucosa c. Parietal cells Sa a. Chief cells glands e. Enteroendocrine cells cannot be eas- 3. Pits and glands 1. This site comply with DMCA digital copyright. We do not store files not owned by us, or without the permission of the owner. We also do not have links that lead to sites DMCA copyright infringement.
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