lecture 23 - large intestine & liver Flashcards
(50 cards)
What are the parts of the large intestine?
Caecum, colon, rectum
What are the parts of the colon?
Ascending, transverse, descending and sigmoidal colons
Which parts of the colon are retroperitoneal?
Ascending and descending colons
Which parts of the colon are intraperitoneal?
Transverse and sigmoidal colons
What valve regulates the passage of material from the SI to LI?
The ileocecal valve
Where does material pass from the SI to LI?
From the ileum of the small intestine to the caecum of the large intestine via the iliocecal valve
What is the appendix?
A finger shaped pouch that projects from the colon and is a reserve of large intestine bacteria
Where is the appendix located?
Variety of locations, on the inferior left side projecting from the colon of the LI
What are the functions of LI bacteria?
Digestion, energy, hormone secretion, pathogen defence
What type of tissue is prevalent in the appendix?
Lymphoid tissue
What are the teniae coli of the LI?
Bands of longitudinal smooth muscle on the surface of the colon - a modification of the muscularis externa
Where are teniae coli found?
All parts of the colon
What are haustra?
A series of pouches in the LI wall that allow for expansion
What feature of the LI is used for fat storage?
Omental appendages
What are the omental appendages of the LI?
Sacs of fat on the surface of the LI that provide fat storage
What is the teniae coli a modification of?
The muscularis layer of the LI
What is the structure of the teniae coli?
Made up of 3 bands of longitudinal muscle surrounding the Large Intestine
What is the function of the teniae coli?
Contract to move faeces along the large intestine
Why does the large intestine have no villi?
Very little absorption of nutrients happens in the LI - ~10%
How does the mucosa of the LI form glands?
The mucosa (except for the muscularis mucosae layer) invaginates
What layers of the GI tube invaginate to form glands in the LI?
The epithelium and lamina propria of the mucosa
What is the function of the mucosa in the LI?
Water and salt absorption - goblet cells also produce mucous for protection and lubrication
Where does the epithelium change in the rectum?
The anal columns mark the boundary
How does the epithelium change in the rectum?
Before the anal columns, it is simple columnar, afterwards it stratified squamous for protection from abrasion