Lecture 23 Large intestine and Liver Flashcards
what does the large intestine consist of?
- Cecum
* Colon
the colon of the LI is divided into 4 parts what are they?
- Ascending
- Transverse
- Descending
- Sigmoid
the Ascending and descending colon of LI are?
retroperitoneal
the Transverse and sigmoidal colon of LI are?
intraperitoneal
what does the Ileocecal Valve do?
Regulates the passage of material into the cecum
whats the appendix?
- Reserve of LI bacteria population
- Variety of locations
- Inflammation = appendicitis
whats Barium enema?
enables x-ray image to be taken of LI to assess function
no backflow into the ileum
whats included in the gross structure of the LI?
Teniae Coli:
Haustra:
Omental appendices:
whats Teniae Coli?
- Modification of Muscularis layer
- 3 bands of longitudinal smooth muscle
- Stronger contraction
whats Haustra?
• Series of pouches in the wall of colon
whats Omental appendices?
• Sacs of fat
is there lots or little villi in LI?
lack of villi
in the gut tube, the Mucosa invaginates to form what?
intestinal glands
the muscularis mucosae does not invaginate
what does the mucosa consists of?
- Epithelium
- Lamina propria
- Muscularis mucosae
whats the function of the mucosa of the colon?
Water and salt absorption
Goblet cells produce mucous (protection and lubrication)
whats the rectum?
- Anal columns mark boundary where epithelium changes.
* Before this point: simple columnar
whats the epithelium of the anal canal?
stratified squamous
what are the 2 anal sphincters?
internal anal sphincter
external anal sphincter
whats the internal anal sphincter?
smooth muscle (under involuntary control)
whats the external anal sphincter?
skeletal muscle (under voluntary control)
whats Defecation Reflex?
• Movement of faeces into rectum stimulates stretch receptors
• Internal anal sphincter relaxes
(involuntary)
• Conscious decision to defecate – external anal sphincter relaxes
summary of LI
- Mucosa invaginated into glands
- Significant number of mucous secreting cells.
- Lack of villi
- Longitudinal muscle layer in 3 bands (Teniae coli)
summary of anal canal
- Sphincters important for control
* Stratified Squamous epithelium
where is the liver located?
• Superior right quadrant of abdominopelvic cavity
whats the main function of liver?
• Produce bile – stored in the gall bladder
how much cardiac output does the liver receive?
~25%
whats the liver blood supply?
- ~25% CO
- 1/3 from hepatic artery
- rest is venous blood from hepatic portal vein
what kind of blood is from hepatic portal vein?
venous blood
- Nutrient rich, deoxygenated blood from SI
- Processed by hepatocytes
where does the hepatic portal vein, the hepatic artery, and the bile duct travel within?
lesser omentum
what does the liver structure consist of?
Lobules (functional units)
rows of hepatocytes
between rows liver sinusoids
Portal triad
what do hepatocytes do?
produce bile
wheres Liver sinusoids?
between rows, bile canaliculi between cells.
what makes up the portal triad?
- Branch of hepatic artery
- Branch of hepatic portal vein
- A bile duct
whats the flow of blood and bile in liver?
- Blood flows towards central vein
- Processed by hepatocytes, which produce bile
- Bile secreted into canaliculi, travels to bile duct
whats the venous drainage of the liver?
Central veins drain into hepatic vein which drains into inferior vena cava
where does bile travel to?
gall bladder, where it is stored and concentrated
what does the bile duct join?
pancreatic duct at hepatopancreatic ampulla
