Lecture 18: GI II Flashcards
Is the Stomach Intra or Retroperitoneal?
Intraperitoneal
Which quadrant is the Stomach in?
The LUQ
Which section of the gut is the stomach in?
The Foregut
What is the stomach vascularized by?
Celiac Trunk
How does the stomach mechanically break down food?
Through mixing and churning using contractions of the muscular wall
How does the the stomach chemically and enzymatically digest food?
Through actions of secreted acid and enzymes
Where does Chyme form?
In the stomach
What is chyme?
The mixture of the bolus and gastric juices
Which part of the Stomach does the Esophagus enter?
The Cardia
What is the Fundus of the stomach do?
Detects when food comes in allowing the rest of the tube in the stomach to know when to secrete enzymes
What is the Pyloric canal continuous with?
The duodenum
What does the Pyloric sphincter do?
Stops chyme from being released into the Duodenum until its ready
What attaches to the greater and lesser curvature of the stomach?
The greater omentum and the lesser omentum
What is the less general name for the greater and lesser Omentum?
The mesentery
What is the Greater Omentum?
An apron that drapes from the greater curvature of the stomach over the abdominal wall organs
What is the Omentum made of?
Two layers of Serosa with lots of fat
What is the immunological function of the Omentum?
It will go wherever there is disease
What is found in the Greater Omentum?
Blood, nerves and lymphoid tissues
How does the Greater Omentum control temperature?
Using the lipid deposits
What are the three muscle layers of the stomach?
Inner Oblique, Middle Circular, Outer Longitudinal
What kind of epithelium goes from the Stomach to the Rectum?
Simple Columnar Epithelium
What are Rugae?
Folds in the stomach created by the muscle layers that stretch when there is food in it
What are the 5 Gastric gland secretory cells?
- Surface mucous
- Mucous neck
- Parietal
- Chief
- Neuroendocrine
What are the secretory cells at the lumen of the stomach?
Surface Mucous Cells
What do Surface Mucous cells do?
Produce a thick mucus in the stomach that prevents hydrochloric acid from chewing through
What do Mucous Neck cells do in the stomach?
They produce mucus that is more watery
Which cells in the stomach produce the Hydrochloric Acid?
Parietal cells
What do the chief cells in the stomach produce?
Enzymes Pepsin and Lipase
What do Parietal and Chief cells actually release in order to protect the stomach lining?
Pre Enzymatic and pre hydrochloric secretions
How do do the secretions released by Parietal cells and Chief cells become activated?
By passing through the secretions of the Mucous neck cells
Where are Neuroendocrine cells found?
Close to the base of the stomach wall near the submucosa
What do Neuroendocrine cells in the stomach do?
Detect food coming in and release gastrin
What does Gastrin released by Neuroendocrine cells do?
Stimulate the Parietal and Chief cells to release their secretions
What helps to break down lipids?
The small intestine
Where does most of the absorption occur?
In the Jejunum and Ileum of the small intestine
What kind of tissue is the small and large intestine made of?
Simple Columnar Epithelium
Where does the small intestine span?
From the pyloric sphincter of the stomach to the ileocecal valve in the ileum
What is the small intestine specialized for?
Absorption
What in the small intestine is specialized for absorption and how?
Circular folds, villi and microvilli by increasing the surface area
What is different about the folds in the stomach and the folds in the small intestine?
The folds in the stomach stretch out, the folds in the small intestine never stretch out
Where in the small intestine is the transition from the midgut and foregut?
The duodenum
What is different about the vascularization of the small intestine?
Half of it is vascularized by the foregut and half of it is vascularized by the midgut
What provides blood to the Duodenum?
The first half is the celiac and the second half is the superior mesenteric artery
What are the Jejunum and the Ileum vascularized by?
The Superior Mesenteric Artery
What Quadrant is the Duodenum in?
RUQ
Which organs does the Duodenum have a relationship with?
The Pancreas and the Gallbladder
What stores the bile from the liver?
The gallbladder
What secretions does the duodenum receive?
Bile and pancreatic juice
Where is the Bile produced?
In the liver
What does the Gallbladder store?
Bile from the liver
What stimulates the secretions from the pancreas and the liver to enter the duodenum?
The entrance of Chyme
Which part of the GI tract does digestion finish?
The end of the Duodenum
Why does the Esophagus have submucosal glands?
To protect it from acids of the stomach
What are Brunner’s glands?
Glands in the duodenum that secrete mucus to protect the duodenum from acid chyme from the stomach
Which layer are Brunner’s glands found in?
The submucosa layer
Which parts of the entire GI tube have submucosal glands?
Where the esophagus meets the stomach and where the stomach meets the duodenum
Why would the Hepatopancreatic ampulla open?
To release the bile from the gallbladder and the pancreatic juices into the duodenum in response to hormones
Which hormones stimulate the opening of the Hepatopancreatic ampulla and why?
Secretin and CCK in response to chyme entering the duodenum
Which gland secretes the buffer into the duodenum?
The pancreas
What does Bile aid in the digestion of?
Lipids
Where does the Pancreas sit?
Behind the stomach, between the duodenum and spleen
Is the Pancreas Intra or Retroperitoneal?
It is Retroperitoneal
Which quadrant does the Pancreas sit in?
Both upper quadrants
Which part of the Duodenum is retroperitoneal?
The middle part that is associated with the pancreas and liver
What is the Pancreas vascularized by?
The Celiac and SMA
What kind of Gland is the pancreas?
Both an endocrine and an exocrine glands
What is the Exocrine function of the pancreas?
All the stuff that goes into the tube and is released by the Duodenum
What does the Pancreas Secrete?
Digestive enzymes and bicarbonate buffers
What is the drainage of the pancreas done by?
The splenic vein
Which part of the Pancreas is associated with the duodenum?
The head
Which part of the pancreas is associated with the spleen?
The body and tail
What part of the pancreas fo to the Hepatopancreatic Ampulla?
The main pancreatic duct
What tissue is the pancreas made of?
Epithelium
Which cells of the Pancreas have the endocrine function?
Islet cells
What are Islet cells closely associated with in the pancreas?
Blood vessels
What does the Endocrine portion of the Pancreas secrete?
Hormones such as Glucagon (alpha), insulin (beta), and somatostatin (delta)
Which does the Exocrine function of the pancreas secrete?
Pancreatic juice
Which cells in the pancreas secrete pancreatic juice?
Pancreatic acini
What do Pancreatic Acini produce?
Water, ions and digestive enzymes and buffers
What are the two types of Pancreatic acinar cells?
Acinar cells and Centroacinar cells
What do Acinar cells secrete?
Digestive enzymes
What do Centroacinar cells do?
Secrete Bicarbonate buffer and regulate pre-enzyme release from acinar cells
Where do the bile duct and the main pancreatic duct join?
The hepatopancreatic ampulla
What is the biggest gland in the body?
The liver
Where does all food that is absorbed first go to?
The liver
What is the Liver vascularized by?
The celiac trunk and the hepatic portal vein
What are the Metabolic functions of the liver?
- Carb, protein and fat metabolism
- Regulates circulating levels of things absorbed by intestine
- Inactivates toxic compounds and metabolic waste absorbed
What is the Hematological regulation of the liver?
- Destroys aged/damaged red blood cells, cellular debris and pathogens
- Secretes plasma proteins into blood
What is bile required for?
Digestion of lipids
What does the Portal triad contain?
- Bile duct
- Hepatic artery proper
- Hepatic portal vein
Where is the Porter Triad found?
Lesser omentum
What does the Lesser Omentum connect to?
The lesser curvature of the stomach to the liver
What mixes in the liver?
Oxygenated and deoxygenated nutrient rich blood
Where does all the fat in the body go to before the liver?
The heart because it is too big for the liver
Where does blood from the hepatic portal vein and the hepatic artery proper mix?
In the sinusoids of the liver
Where does blood from the hepatic portal vein and the hepatic artery proper mix?
In the sinusoids of the liver
Where does blood from the hepatic portal vein and the hepatic artery proper mix?
In the sinusoids of the liver
Where does blood from the hepatic portal vein and the hepatic artery proper mix?
In the sinusoids of the liver
Where does blood from the hepatic portal vein and the hepatic artery proper mix?
In the sinusoids of the liver
Where does blood from the central vein in the liver go to?
The right and left hepatic veins and the to the inferior vena cava
What is bile synthesized by in the liver?
Hepatocytes
Where is bile secreted in the liver after being synthesized by the Hepatocytes?
The bile canaliculi
Where does bile flow from the Canaliculi?
To the periphery of the lobules into small biliary ducts that merge and empty into the right and left hepatic ducts to the common hepatic duct
Through what ducts is bile released?
The cystic duct then the bile duct
What is the difference between the glands of the Pancreas and the Liver?
In the liver, all the cells have both an endocrine and exocrine function
What allows the gallbladder to contract?
The muscle
What characteristics of the jejunum allow it to do majority of the absorption?
Thicker walls, larger diameter, redder color and more folds
What is the connection between the small intestine and the large intestine?
The Ileum
Why does the Ileum have extra lymph nodes?
To protect it from the different bacteria in the Cecum
What are the fold like in the Ileum?
Very concentrated folds for absorption
What will be associated with each villus?
Vasculature, Lymphatics and Innervation
What is the major cell of the Villi and what do they contain?
Absorptive cell and they contain microvilli
What are the four cells around the Villi?
- Absorptive cell
- Goblet cell
- Enteroendocrine cell
- Panteth cell
What does the Goblet cell of the Villi produce?
Mucus
What do the Enteroendocrine cells of the villi do?
Release hormones to indicate what should happen next with digestion
What do the Paneth cells of the villi do?
Determine the gut flora
Where does fat go from the Villi?
Into the Lacteal to go to the thoracic duct
Why is the Bacteria in the Large intestine so important?
Because it breaks down certain things in order to release specific vitamins
Which part of the large intestine in Retroperitoneal?
The Ascending and Descending and Rectum
Which part of the Large intestine is Intraperitoneal?
The Cecum, transferse, and Sigmoid
When does the Cecum open?
When the esophageal sphincter opens to the stomach
What is the purpose of the Appendix?
It is filled with lymphatics and crucial for the gut flora
What is the transition of the LI of the superior mesenteric and inferior mesenteric vessel?
The left colic flexure
Which part of the LI is found in the pelvis?
The rectum
What are Hastra?
The cups of the large intestine
What causes Haustra?
The Teniae
What are Teniae?
The bunching of the longitudinal smooth muscle layer of the large intestine
Why are there still absorptive cells in the LI?
To absorb the water, vitamins, and electrolytes
What do Goblet cells in the LI do?
Produce mucus to move waste
What is the purpose of the rectum?
It is a storage area
What is the transition of tissue in the Anal Canal?
It goes from stratified squamous epithelium to keratinized stratified squamous epithelium
What is the different between the two sphincters of the Anal Canal?
One is autonomically controlled with smooth muscle and one is associated with the skin and it associated with the somatic nervous system
