Gastrointestinal Anatomy: Large Intestine Flashcards
This is an organ which facilitates the absorption of water and storage of feces until defecation.
Large intestine
Where is the large intestine located?
Ascending and descending colon are retroperitoneal
Transverse and sigmoid colon are intraperitoneal
This serves as a reserve of large intestine bacteria and can become inflamed.
Appendix
What region of the large intestine is the appendix attached to?
The cecum
What are the 3 regions of the large intestine?
Cecum, colon and rectum
This regulates the passage of material into the large intestine.
Ileocecal valve
What are the 3 main modifications of the large intestinal wall? Which layer do these modifications belong to?
Teniae coli (muscularis), haustra, omental appendices
These are bands of longitudinal muscle which allows for stronger contractions.
Remember the outer longitudinal layer is discontinous to form these bands of longitudinal muscle.
Teniae coli
What are the 2 main cells found in the large intestine mucosa?
Remember: lack of villi in the large intestine means a greater number of glands.
Goblet cells (mucus for protection and lubrication)
Absorptive cells (for water and salt)
This is the last part of the large intestine. It stores feces.
Rectum
This connects the rectum to the anus.
Anal canal
These are responsible for marking the boundary where the epithelium changes.
Additional question: how does the epithelium change coming from the large intestine into the anus?
Anal columns
- epithelium changes from simple columnar epithelium (which is good for absorption and secretion) into stratified squamous to protect against abrasion (in the anus)
These 2 structures found within the rectum are responsible for controling defecation.
Additional question: what type of muscle is in both of them?
Internal anal sphincter (smooth muscle - for involuntary movement)
External anal sphincter (skeletal muscle - for voluntary movement)
Movement of feces into the rectum stimulates what receptors?
stretch receptors
The contractions in the rectum that move feces towards the anus are what kind of contractions?
Peristaltic contractions
The defecation reflex is mediated by the _________________ in the _______ _________ and the ___________.
myenteric plexus; sigmoid colon and the rectum.
When there is a conscious decision to defecate, the external anal sphincter relaxes/contracts?
It relaxes
- voluntary relaxation of external anal sphincter allows defecation to occur at a convenient time. Similarly with the internal anal sphincter, peristaltic contractions moving the feces down relaxes the internal anal sphincter (just think that as the pressure increases, it will relax the sphincter and therefore open it)
True or false. Teniae coli are bands of circular muscle.
False. They are bands of longitudinal muscle.
True or false. The regions of the large intestine are the ascending, descending, transverse and sigmoid colon.
False. These are the layers of the colon
The three regions of the large intestine are the: cecum, colon, and rectum
This is a wedge shaped organ that detoxifies blood and produces bile. It is also involved in a lot of metabolic processes.
Liver
Where is the liver located?
Right side of the body, superior right quadrant of abdominopelvic cavity
This is a hollow organ below the liver which is responsible for storing and concentrating bile.
Gallbladder.
The gallbladder is connected through which two ducts?
Cystic duct to bile duct
How much of the blood supply to the liver comes from the hepatic artery?
1/3 a third
How much of the blood supply to the liver comes from the hepatic portal vein?
2/3
This is where nutrient rich, deoxygenated blood from small intestine comes from. These then proceed into the liver where they will be processed by what type of cells?
Hepatic portal vein; hepatocytes
- hepatocytes process deoxygenated blood and turn it into bile.
What 3 vessels of that supply and connect the liver travel through the lesser omentum?
What is the lesser omentum?
hepatic artery, hepatic portal vein, bile duct
Lesser omentum is what attaches the liver to the stomach.
What cells produce bile?
Hepatocytes in the liver
What are the functional units that make up the liver?
Lobules
These are in between rows of cells in the liver structure.
Liver sinusoids
These are located in between cells, and is responsible for receiving bile and carry bile to bile duct.
Canaliculi
What is the portal triad?
Branch of hepatic artery, hepatic portal vein and bile duct
Where does the central vein drain into?
Hepatic vein
Where does the hepatic vein drain into?
inferior vena cava
Bile duct joins the pancreatic duct at the?
hepatopancreatic ampulla
- ampulla is a small reservoir where bile duct and pancreatic duct meet. This is where the bile from the liver travels to to get to the gallbladder to be stored and concentrated.
