Digestive System Part I -nsu
This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA
Overview
Download & View Digestive System Part I -nsu as PDF for free.
More details
- Words: 821
- Pages: 40
Histology 10a Gregory Rodocker NSU Class Taken: Spring 2009
Digestive tract
Composed of
Oral cavity, esophagus, stomach, small and large intestines, rectum and anus Associated glands such as the salivary glands, liver and pancreas
Digests and absorbs food for the entire body
General Structure
Composed of four layers
mucosa, Submucosa Muscularis Serosa
Mucosa
Composed of
An inner epithelial layer peculiar and appropriate to the regions A lamina propria composed of loose CT A muscularis mucosae of smooth muscle
An inner circular layer An outer longitudinal layer
Known collectively as the mucous membrane
Submucosa
Composed of
Dense CT Many blood and lymph vessels Submucosal nerve plexus (Meissner’s) (glands and lymphoid tissue)
Muscularis
Smooth muscle layer
Inner circular Outer longitudinal Myenteric nerve plexus (Auerbach’s) between two layers Blood vessels and lymph vessels between two layers
Serosa
Composed of
Thin layer of loose CT Blood vessels and lymph vessels Adipose tissue A thin epithelium called the mesothelium
Chagas Disease
Between 16 to 18 million people worldwide have Chagas disease, and although most are in South America, the number of cases in the US is growing. Chagas disease is an incurable infectious disease, and its longterm sequelae include cardiomyopathy, megaesophagus and megacolon. Important in these complications is the fact that Trypanosoma cruzi , the infective agent of Chagas disease, invades myocytes, neurons and glial cells.
Megacolon/megaesophalus Chagas Disease Trypanosoma cruzi, the causative organism of American trypanosomiasis attacks Auerbach’s plexus (proposed)
Triatome Bug
Romana’s Sign
Megacolon Man
Functions of the digestive tract
Lubricate, digests and absorb foods Produce hormones for the control of the tract Protect from infective agents in the gut Produce antibodies Propel food along tract
The oral cavity
Various regions covered by keratinized and non-keratinized stratified squamous epithelium
Keratinized – gingiva and hard palate Nonkeratinized – soft palate, lips, cheeks and floor of mouth
Interesting transition can be seen in lips where keratinized of skin changes into oral nonkeratinized epithelium
Tongue
Mass of striated muscle with fibers running in at least three planes Lots of CT Dorsal surface marked by papillae
Filiform – poorly developed in humans Fungiform – mushroom-shaped Circumvalate – largest
Some have taste buds
Taste bud
Taste or gustatory pore
Taste buds
50 -100 cells with most being taste cells with some supportive cells Located basally are basal cells relace all cell types Sweet and bitter work via receptors and bitter, sour and salty work via ion channels
Esophagus
Carries foodstuffs from the mouth to the stomach Lined by nonkeratinized, stratified squamous epithelium Upper third - striated muscle Middle third - striated and smooth muscle Lower third – smooth muscle
Stomach
Mix of exocrine and endocrine glandular columnar epithelium Partitioned into four regions
Cardiac
Lysozyme?
Fundus Body Pylorus
Lysozyme?
Stomach wall
The mucosa of the stomach is highly folded resulting in gastric pits
Stem cells - totipotent Mucous neck cells Oxyntic/parietal cells – HCl, intrinsic factor (vitamin B-12)
Mid to upper wall
Chief/zymogenic cells – pepsinogen and lipase
Lower wall
Goblet cells - mucus
Gastric gland of fundal region
Parietal cells
Chief/zymogenic cells
Oxyntic/Parietal Cell Oxyntic from Gr. “sour”; “make acidic”
Small Intestine
Food digestion, absorption and hormone production Composed of (5 meters)
Duodenum Jejunum Ileum
Common features
Plicae circulares
Intestinal villi
Semilunar, circular and spiral fold of the wall most obvious in the jejunum Leaf-like (duodenal) or finger-like (ileal) folds of the mucosa and lamina propria
In between villi are pits called intestinal glands or glands of Lieberkühn
Common features (cont’d)
Glands contain stem cells, absorptive cells, Paneth’s cells and enteroendocrine cells
Absorptive cells with microvilli
Each cell with 3000, 1 mm2 contains 200 million Plicae increase SA 3X, villi increase SA 10X, microvilli increase SA 20X equaling a 600X increase in SA in SI equaling 200 m2 total SA
Common features (cont’d)
Paneth’s cells produce lysozyme
Lysozyme is a generic antibacterial attacking the cell walls and capsids of bacteria and viruses May serve role in controlling intestinal flora
Duodenal glands in submucosa
Brunner’s Glands Alkaline mucus
Note the blood supply in the villus. What do you think happens to the oxygen level as blood makes it to the tip? Note lacteals in the villus
Large Intestine
No villi Muscularis is modified
Typical inner circular layer of muscle Outer longitudinal layer is congregated into three bundles called the teniae coli
What does that mean in a cross section of the large intestines?
Cell renewal
Digestive tract
Composed of
Oral cavity, esophagus, stomach, small and large intestines, rectum and anus Associated glands such as the salivary glands, liver and pancreas
Digests and absorbs food for the entire body
General Structure
Composed of four layers
mucosa, Submucosa Muscularis Serosa
Mucosa
Composed of
An inner epithelial layer peculiar and appropriate to the regions A lamina propria composed of loose CT A muscularis mucosae of smooth muscle
An inner circular layer An outer longitudinal layer
Known collectively as the mucous membrane
Submucosa
Composed of
Dense CT Many blood and lymph vessels Submucosal nerve plexus (Meissner’s) (glands and lymphoid tissue)
Muscularis
Smooth muscle layer
Inner circular Outer longitudinal Myenteric nerve plexus (Auerbach’s) between two layers Blood vessels and lymph vessels between two layers
Serosa
Composed of
Thin layer of loose CT Blood vessels and lymph vessels Adipose tissue A thin epithelium called the mesothelium
Chagas Disease
Between 16 to 18 million people worldwide have Chagas disease, and although most are in South America, the number of cases in the US is growing. Chagas disease is an incurable infectious disease, and its longterm sequelae include cardiomyopathy, megaesophagus and megacolon. Important in these complications is the fact that Trypanosoma cruzi , the infective agent of Chagas disease, invades myocytes, neurons and glial cells.
Megacolon/megaesophalus Chagas Disease Trypanosoma cruzi, the causative organism of American trypanosomiasis attacks Auerbach’s plexus (proposed)
Triatome Bug
Romana’s Sign
Megacolon Man
Functions of the digestive tract
Lubricate, digests and absorb foods Produce hormones for the control of the tract Protect from infective agents in the gut Produce antibodies Propel food along tract
The oral cavity
Various regions covered by keratinized and non-keratinized stratified squamous epithelium
Keratinized – gingiva and hard palate Nonkeratinized – soft palate, lips, cheeks and floor of mouth
Interesting transition can be seen in lips where keratinized of skin changes into oral nonkeratinized epithelium
Tongue
Mass of striated muscle with fibers running in at least three planes Lots of CT Dorsal surface marked by papillae
Filiform – poorly developed in humans Fungiform – mushroom-shaped Circumvalate – largest
Some have taste buds
Taste bud
Taste or gustatory pore
Taste buds
50 -100 cells with most being taste cells with some supportive cells Located basally are basal cells relace all cell types Sweet and bitter work via receptors and bitter, sour and salty work via ion channels
Esophagus
Carries foodstuffs from the mouth to the stomach Lined by nonkeratinized, stratified squamous epithelium Upper third - striated muscle Middle third - striated and smooth muscle Lower third – smooth muscle
Stomach
Mix of exocrine and endocrine glandular columnar epithelium Partitioned into four regions
Cardiac
Lysozyme?
Fundus Body Pylorus
Lysozyme?
Stomach wall
The mucosa of the stomach is highly folded resulting in gastric pits
Stem cells - totipotent Mucous neck cells Oxyntic/parietal cells – HCl, intrinsic factor (vitamin B-12)
Mid to upper wall
Chief/zymogenic cells – pepsinogen and lipase
Lower wall
Goblet cells - mucus
Gastric gland of fundal region
Parietal cells
Chief/zymogenic cells
Oxyntic/Parietal Cell Oxyntic from Gr. “sour”; “make acidic”
Small Intestine
Food digestion, absorption and hormone production Composed of (5 meters)
Duodenum Jejunum Ileum
Common features
Plicae circulares
Intestinal villi
Semilunar, circular and spiral fold of the wall most obvious in the jejunum Leaf-like (duodenal) or finger-like (ileal) folds of the mucosa and lamina propria
In between villi are pits called intestinal glands or glands of Lieberkühn
Common features (cont’d)
Glands contain stem cells, absorptive cells, Paneth’s cells and enteroendocrine cells
Absorptive cells with microvilli
Each cell with 3000, 1 mm2 contains 200 million Plicae increase SA 3X, villi increase SA 10X, microvilli increase SA 20X equaling a 600X increase in SA in SI equaling 200 m2 total SA
Common features (cont’d)
Paneth’s cells produce lysozyme
Lysozyme is a generic antibacterial attacking the cell walls and capsids of bacteria and viruses May serve role in controlling intestinal flora
Duodenal glands in submucosa
Brunner’s Glands Alkaline mucus
Note the blood supply in the villus. What do you think happens to the oxygen level as blood makes it to the tip? Note lacteals in the villus
Large Intestine
No villi Muscularis is modified
Typical inner circular layer of muscle Outer longitudinal layer is congregated into three bundles called the teniae coli
What does that mean in a cross section of the large intestines?
Cell renewal
Related Documents
Digestive System Part I -nsu
May 2020 7
Digestive System Part A
December 2019 17
Digestive System Part B
December 2019 30
Digestive System
October 2019 42
Digestive System
October 2019 37
Digestive System
December 2019 74More Documents from "Jen Passilan"
Nervous System -nsu
May 2020 13
Histology 11: Nsu Spring 2009 Taken By: Gregory Rodocker
April 2020 14
Histology 12: Nsu Spring 2009 Taken By: Gregory Rodocker
April 2020 11
Cardiovascular System:the Blood -nsu
May 2020 9
Histology 17: Nsu Spring 2009 Taken By: Gregory Rodocker
April 2020 10