Lecture 21 Stomach and Pancreas Flashcards
what is the O/Esophagus and where is it located?
- Tube that connects the pharynx to the stomach
* Posterior to the trachea
what epithelium makes up the Oesophagus Mucosa and what is its function?
- Stratified squamous epithelium
* Protection from abrasion
what does the Oesophagus Muscularis do?
Modified to propel food down to stomach
what kind of shape is the stomach?
J-Shaped organ
wheres the Stomach Location?
Base of esophagus
whats the Esophageal hiatus?
Esophagus passes through diaphragm
what does the Lower esophageal sphincter (LES) do?
prevents reflux
whats the 4 main parts of the stomach?
- Cardia
- Fundus
- Body
- Pylorus (pyloric antrum)
whats the omentum?
a double layer of peritoneum
connects one organ to another
whats the Lesser omentum?
Stomach to liver
whats the Greater omentum:?
Stomach to transverse colon
what is the Muscularis modified / specialised for?
Motility
what are the 3 layers of the Muscularis of the gut tube?
- Oblique (inner)
- Circular (middle)
- Longitudinal (outer)
whats Rugae?
Temporary folds that allow for the expansion of the stomach (1.5L)
• Important for storage function
Internal Surface of the Stomach
Rugae:
Notice folded core of submucosa with overlying mucosa
Modifications of the Gut Tube Gastric Glands
what epithelium makes up the mucosa?
Simple columnar epithelium
whats the mucosa of gastric glands?
- In-folding increases surface area for secretion (1.5L/day)
* Glands are permanent!
what do Gastric glands need?
- Acid and enzymes for digestion
- Mucous for protection
- Hormones for regulation
what are Gastric glands cells?
Parietal cells - secrete acid and intrinsic factor
G cells - Secrete hormones (gastrin)
Chief cells - Secrete pepsinogen (an inactive precursor of pepsin)
what do Mucous epithelial cells secrete?
Secrete mucous (protection)
whats Chief Cells?
Produce enzymes
Abundant rough endoplasmic reticulum
Apical zymogen granules (contain enzymes)
Basal nucleus
whats Parietal Cells?
Produce acid (HCL)
Pump ions (H+)
Abundant mitochondria
Folded structure to increase SA
whats Endocrine Control?
- Endocrine cells in mucosa
* Gastrin and Ghrelin secreted into the bloodstream
whats Neural control?
- (ENS) - local reflexes (primary control)
* CNS modulates ENS function – long neural reflexes
what does the Stomach to Small Intestine need?
Pyloric Sphincter (PS)
Controlled release of digested material (chyme) into the small intestine
what do parietal cells secrete?
acid and intrinsic factor
what do G cells secrete?
hormones (gastrin)
what do chief cells secrete?
pepsinogen (inactive precursor of pepsin)
Stomach to Small Intestine
Acidic chyme enters the SI
what does it require?
Further digestion (enzymes)
Protection from acidic chyme
Mucous
Bicarbonate
Stomach to Small Intestine
what provides mucous thats needed for protection against acidic chyme?
glands in the submucosa of the duodenum.
Stomach to Small Intestine
what provides enzymes and bicarbonate thats needed for protection against acidic chyme?
Pancreas
wheres the pancreas located?
- Head in C-shaped duodenum
- Tail to spleen
- Posterior to stomach
- Duct into duodenal lumen
• Retroperitoneal
in the pancreas, where does the Bile duct meets pancreatic duct?
at the entrance to the duodenal ampulla
in the pancreas, whats the duodenal papilla?
projects into the duodenal lumen
in the pancreas, what controls release?
hepatopancreatic sphincter (Sphincter of Oddi)
in endocrine
what do the pancreatic islet alpha cells secrete?
what do the pancreatic islet beta cells secrete?
alpha = glucagon beta = insulin
in exocrine
what do acinar cells secrete?
what do duct cells secrete?
acinar = digestive enzymes
duct = bicarbonate
whats the structure of Pancreatic Acinar Cells?
- Apical zymogen granules
- Basal nucleus
- Abundant rough ER
whats the function of Pancreatic Acinar Cells?
Secrete enzymes
whats the Pancreatic Acinar Cells similar to?
- Chief cells of Stomach
* Salivary acinar cells
What structures allow storage?
sphincters
rugae - distension (folded submucosa)
For mechanical digestion you need?
smooth muscle, additional oblique layer in stomach
sphincters
What is needed for chemical digestion?
secretion of strong chemicals (acids, enzymes)
protective epithelium