Digestive Regional Histology Flashcards
There are four distinct layers of the tract:
- mucosa.
- submucosa.
- muscularis.
- Adventitia.
Muscularis mucosae separates which layers
lamina propria from the submucosa layer.
generally the lamina propria has what tissues
lymphoid tissues and plasma cells.
except in the stomach which may also have lymphoid cells in some certain cases.
submucosa consist what tissues?
collagenous tissues and adipose connective tissues which bind mucosa to the main bulk of the muscular wall.
is scatted throughout the submucosa and forms the submucosal plexus.
tiny parasympathetic ganglia.
In the oesophagus the mucosa id folded in a relaxed state why?
allows for swelling (distention) during the passage of bolus.
what type of the epithelium lines the lumen surface
stratified squamous epithelium.
lamina propria
is narrowed.
contains scattered lymphoid tissue.
submucosa in the oesophagus.
loose, several elastin fibers
seromucous glands, similar to salivary glands.
Muscularis propria in the oesophagus.
is thick and contains both outer longitudinal muscle and inner circular muscle layers.
part of the esophagus that is under voluntary control.
the first part of swallowing.
therefore, skeletal muscle is present.
this is predominant in the upper third of the oesphagus.
gradual transitions occur.
lower oesphagus has only smooth muscle.
Oesophago-gastric Junction
From the esophagus to the stomach there is a change in the epithelium.
stratified squamous epithelium is replaced with tightly packed glandular secretory mucosa.
Muscularis mucosae is continuous
Muscularis mucosa will appear in patches
Not easily seen in the stomach, when directly beneath the glands.
Submucosa and muscularis propria in the oesophago-gastric junction.
continue uninterrupted beneath the mucosal junction
Defined anatomical sphincter is not defined by muscularis propria
A physiological sphincter mechanism is described
Body of the stomach
mucosa
thrown into regular folds- rugae.
Consists of regular gastric glands which extend from muscularis mucosae to open in the stomach lumen – occurs via gastric pits or foveolae.
the submucosa of the stomach
relatively loose
contains larger blood vessels.
muscularis propria
added a reinforcement layer- inner oblique layer.
inner oblique layer lies internal to the circular layer.
layer that covers peritoneal surface thin and barely visible.
serous layer.
Pylorus of the stomach?
glands of the pylorus region:
> branched and coiled.
> Gastric pits occupy about 1/2 mucosal thickness.
> lined by mucosa-secreting cells and a small number of acid-secreting cells (parietal cells).
Prominent muscularis mucosae
separate glands from underlying submucosa.
G-cells
secrete gastrin ( peptide hormone).
scattered among pyloric cells
promotes secretions of pepsin and acid by gastric glands to enhance gastric motility.
pyloric sphincter.
transition from glandular secretory type mucosa.
stomach to villious
Brunners Glands
> Secrete a thin, alkaline mucosa
found in the submucosa of the duodenum, often extending into the mucosa.
Muscularis propria.
thickening of the circular layer of muscularis propria at the gastroduodenal junction.
Circular and longitudinal layers of muscularis propria are continuous between pylorus and duodenum.
small intestine
mucosa and submucosa are arranged in circular folds - plicae circulares, particularly numerous in the jejunum.
mucosal surface: several villi with microvilli present on the luminal surface of enterocytes.
enterocytes are columnar epithelial cells that cover villi.
Muscularis mucosae in the small
lie beneath the crypts, separating mucosa from submucosa..
vascular submucusa
Muscularis mucosae in the small
lie beneath the crypts, separating mucosa from submucosa..
vascular submucosa extends into and forms plicae circularis.
Peritoneal aspect of muscular propria is invested by loose collagenous serosa
Muscularis mucosae in the small
lie beneath the crypts, separating mucosa from submucosa..
vascular submucosa extends into and forms plicae circularis.
Peritoneal aspect of muscular propria is invested by loose collagenous serosa
