Histology of Stomach and small intestines Flashcards
Loubi
List the tissular organization of the digest system starting from the innermost layer
Mucosa
Submucosa
Muscularis Externa
Serousa
What kind of tissue is the submucosa made up of
Dense irregular connective tissue
What controls motricity of mucosa and secretory activity of mucosal gland in the submucosa
Meissner’s plexus(parasympathetic neurons)
Which 2 muscles comprises the muscularis externa
Circular smooth muscle( inner layer)
Outer Longitudinal smooth muscle
Which plexus is present between the circular and longitudinal layer of the muscularis externa
Myenteric ( Auerbach’s) Plexus
What type of fibres does the Auerbach’s plexus contain
Parasympathetic fibers
What kind of tissue makes up the Serosa of the digestive tract
Loose connective tissue- surrounding visceral organs
What kind of enzymes does the stomach secrete
Protein-digesting enzymes called Proteases
Name the four sections of the stomach and their functions
Cardia- Where the contents of the esophagus empty into the stomach
Fundus- Formed by the upper curvature of the organ
Body or Corpus- The main central region
Pylorus- The lower section of the organ that facilitates emptying the contents into the small intestines
What is the epithelium of the stomach
Simple columnar epithelium
What is the epithelium of the oesophagus
Stratified squamous epithelium
Define Rugae:
Longitudinal folds of mucosa and submucosa
note : all stomach regions have rugae
Rugae are temporary and disappear when stomach distended with fluid or solid material; True or FALSE
True
The stomach only has 3 histological regions name them:
Fundus and body
Cardia
Pylorus
Which region of the stomach are gastric glands located:
Fundus and body
There are 2 main cell types in the gastric glands located in the lamina propria of the mucosal layer; name them
Acidophilic parietal cells: in upper portions of glands
Basophilic Chief( zygomatic) cells- Lower portion of the glands
There are 3 layers of smooth muscle located in the Muscularis externa of the stomach; name them:
Inner oblique(not complete)
Middle circular
Outer Longitudinal
Describe the 3 regions of the gastric glands
Isthmus- junction of gastric pit with gastric gland; composed of acidophillic parietal cells
Neck- parietal cells
Base (fundus)- composed of chief (zymogenic cells), basophilic
3 Main types of cells in glands
Mucous neck cells: Round, basal nuclei
Parietal cells: large, pyramidal shape, round nuclei, acidophilic cytoplasm
Chief (zymogenic) cells: basophillic
What so parietal cells secrete
Intrinsic factor and HCL
Chief cells secrete
Pepsinogen and gastric lipase
What are G cells
Enteroendocrine cells that secrete gastrin into the blood
The gastric pits in the pyloric is deeper than in the body or fundus; True of False
True
There is only one type of cell in the pyloric region of the stomach; name it
Tall columnar cell
What separates the pylorus from the duodenum
Pyloric Sphincter- by thickened circular layer of muscularis externa of the stomach
What kind of epithelium is in the duodenum
Intestinal epithelium- goblet cells and columnar cells with microvilli
What type of glands are located in the submucosa of the upper duodenum
Brunner’s Gland (Duodenal glands)
When there is an overproduction of serotonin from enteroendocrine cells what is the result?
Ans: Tumors called Carcinogens are produced
What colour staining would an Isthmus of gland generate?
Ans: Clear
What are enteroendocrine cells
Aka APUD cells; secrete different peptides and proteins with hormonal activity
Where is serotonin secreted
Fundus
What is the primary function of the small intestines aka small bowel
absorption of nutrients and minerals found in food
Average length of small intestines found in adult male and female
Male: 6.9m; 22ft 6 inches
Female: 7.1m; 23ft 4 inches
What is the diameter of the small intestines
Approximately 2.5 - 3cm
Name he 3 structural parts that divide the small intestines
Duodenum
Jejunum
Ileum
Name the cells and glands located within the small intestines
Intestinal Glands(Crypts of Lieberkuhn)
Goblet Cells
Absorptive cells
Duodenal (Brunner’s) glands
Enterendocrine cells (APUD)
Paneth cells
Peyer’s patches
M cells
Which cell type is the most common in the intestinal epithelium
Absorptive cells
Brunner’s glands are tubular acinar true or false
True
Which cells contains granukes releasing antimicrobial substances, protects stem cells and are involved in innate immunity
Paneth Cells
Function of M cells
Phagocytose luminal antigens and present them to lymphocytes and macrophages (APCs)
Which parts of the duodenum ae serous and which are adventitia
1st part- Serous
2nd - 4t part: Adventitia
Which muscles make up the muscularis externa for the duodenum, jejunum and ileum
Longitudinal and Circular layers with Auerbach’s plexus in between
Name the only section of the intestines where you can find Brunner’s Glands and Meissner’s plexus
Duodenum
Which section of the small intestines has Peyer’s Patches
Ileum
What are Peyer’s Patches
Aggregations of lymphatic nodules
Which part of the small intestines is the smallest and is the site for which most absorption takes place
Duodenum
The duodenum begins with the duodenal bulb and end with the ligament of Treitz; True or False
True
How long is the duodenum
25-38cm (10-15inches)
How long is the Jejunum
2.5m
Which section of the small intestines has the longest villi
Jejunum
Which aspect of the small intestines specializes in the absorption of monosaccharides
jejunum
What separates the ileum from the caecum
Ileocecal valve
How long is the ileum and what is it’s pH
2-4m long
7 and 8 pH
What are the functions of the Ileum
absorb vitamin B12 and bile salts
What are Lacteals
Small lymph vessels
Absorb fatty acids and glycerol
