Lecture 23 Large intestine and Liver

Question 1

what does the large intestine consist of?

Answer 1

• Cecum

* Colon

Question 2

the colon of the LI is divided into 4 parts what are they?

Answer 2

• Ascending
• Transverse
• Descending
• Sigmoid

Question 3

the Ascending and descending colon of LI are?

Answer 3

retroperitoneal

Question 4

the Transverse and sigmoidal colon of LI are?

Answer 4

intraperitoneal

Question 5

what does the Ileocecal Valve do?

Answer 5

Regulates the passage of material into the cecum

Question 6

whats the appendix?

Answer 6

• Reserve of LI bacteria population
• Variety of locations
• Inflammation = appendicitis

Question 7

whats Barium enema?

Answer 7

enables x-ray image to be taken of LI to assess function

no backflow into the ileum

Question 8

whats included in the gross structure of the LI?

Answer 8

Teniae Coli:

Haustra:

Omental appendices:

Question 9

whats Teniae Coli?

Answer 9

• Modification of Muscularis layer
• 3 bands of longitudinal smooth muscle
• Stronger contraction

Question 10

whats Haustra?

Answer 10

• Series of pouches in the wall of colon

Question 11

whats Omental appendices?

Answer 11

• Sacs of fat

Question 12

is there lots or little villi in LI?

Answer 12

lack of villi

Question 13

in the gut tube, the Mucosa invaginates to form what?

Answer 13

intestinal glands

the muscularis mucosae does not invaginate

Question 14

what does the mucosa consists of?

Answer 14

• Epithelium
• Lamina propria
• Muscularis mucosae

Question 15

whats the function of the mucosa of the colon?

Answer 15

Water and salt absorption

Goblet cells produce mucous (protection and lubrication)

Question 16

whats the rectum?

Answer 16

• Anal columns mark boundary where epithelium changes.

* Before this point: simple columnar

Question 17

whats the epithelium of the anal canal?

Answer 17

stratified squamous

Question 18

what are the 2 anal sphincters?

Answer 18

internal anal sphincter

external anal sphincter

Question 19

whats the internal anal sphincter?

Answer 19

smooth muscle (under involuntary control)

Question 20

whats the external anal sphincter?

Answer 20

skeletal muscle (under voluntary control)

Question 21

whats Defecation Reflex?

Answer 21

• Movement of faeces into rectum stimulates stretch receptors

• Internal anal sphincter relaxes
(involuntary)

• Conscious decision to defecate – external anal sphincter relaxes

Question 22

summary of LI

Answer 22

• Mucosa invaginated into glands
• Significant number of mucous secreting cells.
• Lack of villi
• Longitudinal muscle layer in 3 bands (Teniae coli)

Question 23

summary of anal canal

Answer 23

• Sphincters important for control

* Stratified Squamous epithelium

Question 24

where is the liver located?

Answer 24

• Superior right quadrant of abdominopelvic cavity

Question 25

whats the main function of liver?

Answer 25

• Produce bile – stored in the gall bladder

Question 26

how much cardiac output does the liver receive?

Answer 26

~25%

Question 27

whats the liver blood supply?

Answer 27

* ~25% CO * 1/3 from hepatic artery * rest is venous blood from hepatic portal vein

Question 28

what kind of blood is from hepatic portal vein?

Answer 28

venous blood * Nutrient rich, deoxygenated blood from SI * Processed by hepatocytes

Question 29

where does the hepatic portal vein, the hepatic artery, and the bile duct travel within?

Answer 29

lesser omentum

Question 30

what does the liver structure consist of?

Answer 30

Lobules (functional units) rows of hepatocytes between rows liver sinusoids Portal triad

Question 31

what do hepatocytes do?

Answer 31

produce bile

Question 32

wheres Liver sinusoids?

Answer 32

between rows, bile canaliculi between cells.

Question 33

what makes up the portal triad?

Answer 33

* Branch of hepatic artery * Branch of hepatic portal vein * A bile duct

Question 34

whats the flow of blood and bile in liver?

Answer 34

1. Blood flows towards central vein 2. Processed by hepatocytes, which produce bile 3. Bile secreted into canaliculi, travels to bile duct

Question 35

whats the venous drainage of the liver?

Answer 35

Central veins drain into hepatic vein which drains into inferior vena cava

Question 36

where does bile travel to?

Answer 36

gall bladder, where it is stored and concentrated

Question 37

what does the bile duct join?

Answer 37

pancreatic duct at hepatopancreatic ampulla