SS-L Lecture

Question 0

What suspends the liver between the stomach & anterior abdominal wall?

Answer 0

Peritoneum via two peritoneal ligaments

Question 1

What is the largest gland in the body?

Answer 1

Liver

Question 2

What are the two peritoneal ligaments which suspend the liver b/w the stomach & anterior abdominal wall?

Answer 2

1. Lesser omentum: b/w liver & stomach, contains hepatic blood vessels & bile ducts
2. Falciform ligament: b/w liver & anterior abdominal wall; visceral peritoneum covers liver except bare area, top of liver attached to diaphragm & surrounded by coronal ligament

Question 3

What are the lobes of the liver & how are they determined?

Answer 3

Right, left, quadrate & caudate

Demarcated by blood vessels & ligaments however, do not represent internal organization

Question 4

Ligamentum teres is a vestige of what?

Answer 4

Umbilical cord carrying blood from placenta to fetus

Question 5

What is the porta hepatis?

Answer 5

‘hilum’ of the liver containing bile ducts, hepatic artery & portal vein

Question 6

The liver receives what percentage of CO?

Answer 6

29%

Question 7

What are the 5 fxns of the liver?

Answer 7

1. macrophages (kupffer cells) consume colonic bacteria
2. metabolizes 3 major components of food
   - CHO: stores as glycogen or secretes into circulation through gluconeogenesis
   - lipids: synthesizes lipoproteins, cholesterol & phospholipids; oxidizes FAs; converts CHOs & proteins into fat
   - proteins: synthesizes plasma proteins; forms urea
3. stores vitamins & iron
4. detoxifies drugs, hormones, etc
5. secretes bile

Question 8

What are the 4 blood pathways in the liver?

Answer 8

1. hepatic artery: brings oxygenated blood from the aorta via the celiac artery
2. portal vein: brings nutrient-filled, deoxygenated blood from the gastric, splenic & mesenteric veins
3. sinusoids: lined w/hepatocytes that detoxify, metabolize, store iron & vitamins, etc
4. hepatic veins: brings blood out of superior aspect of liver into the IVC

Question 9

What is the arrangement w/in the liver? (of the cells)

Answer 9

classic lobule, hexagonal

Question 10

What is the functional unit of the liver? What do they contain?

Answer 10

• liver lobule

- triads; they contain the hepatic artery, portal vein & bile duct; central vein lies in the middle

Question 11

What is the more functional unit of the liver?

Answer 11

Acinus

Question 12

Hepatocyte efficiency depends on what? What are the differences between the different zones?

Answer 12

• proximity to blood supply; from hepatic and portal vessels out
• zone 1 receives highest concentration of oxygen & nutrients
• zone 3 receives least oxygen & nutrients, but is the primary site of alcohol & drug detoxification; susceptible to hypoxia & toxic damage

Question 13

In terms of lymphatics, what is the structure which contains plasma & what space does this plasma flow into?

Answer 13

• plasma flows from sinusoids into space of Disse
• space of Disse b/w hepatocytes & endothelium of sinusoids
• lymph sent via channels to IVC or thoracic duct

Question 14

How does Portal Hypertension happen?

Answer 14

-back pressure of blood into portal circulation due to flow obstruction: varicosities in portal-caval anastamoses (hemorrhoids, caput medusae & esophageal varices)

Question 15

What are ascites?

Answer 15

• build of fluid into peritoneal cavity surrounding the liver due to an increase in portal hypertension–> increase in lymph flow into space of Disse–> lymph seeps through visceral layer of peritoneum= fluid build up
• drop in blood volume stimulates renal salt & H2O retention until blood volume is restored

Question 16

Bile is secreted from what through what and towards what?

Answer 16

Bile is secreted from hepatocytes through the canaliculi towards the bile ducts

Question 17

What are the constituents of bile?

Answer 17

• bile acids
• phospholipids
• cholesterol
• bicarbonate (from bile ducts & hepatocytes to neutralize stomach acid)
• bile pigments (bilirubin)
• melatonin (antioxidant to protect mucosa against damage)

Question 18

The right and left hepatic ducts are for outflow from where?

Answer 18

bile outflow from the liver

Question 19

The Common Hepatic Duct is what structurally?

Answer 19

junction of R and L hepatic ducts

Question 20

The Cystic Duct is for outflow from where?

Answer 20

outflow from gall bladder

Question 21

The Common Bile Duct is for outflow of what?

Answer 21

outflow of bile from gall bladder & liver

Question 22

The Hepatopancreatic Ampulla is what structurally?

Answer 22

the junction of bile and pancreatic ducts

Question 23

The main pancreatic duct is for outflow from where?

Answer 23

outflow from the pancreas

Question 24

The Major Duodenal Papilla is for secretions of what into where?

Answer 24

bile and pancreatic secretion into duodenum

Question 25

What are the functions of the gall bladder?

Answer 25

store & concentrate bile

Question 26

What is the purpose of the choledochal sphincter of Oddi?

Answer 26

creates back flow to fill the gall bladder

Question 27

What does the gall bladder release and into where?

Answer 27

- bile into the duodenum - CCK released in response to fats, contracts GB wall - vagus n. increases bile flow & contracts GB

Question 28

What does CCK promote?

Answer 28

- GB emptying - pancreatic secretion - gastric slowing - intestinal peristalsis

Question 29

What does secretin promote?

Answer 29

-promotes HCO3- secretion from bile ducts, pancreatic ducts & Brunner's glands

Question 30

Gall stones are precipitates of what due to what?

Answer 30

precipitates of cholesterol due to: - excess absorption of water - excess secretion of cholesterol - inflammation of epithelium - stasis of gall bladder smooth muscle layer * **Main one from SSL: reduction in terminal ileum reabsorption of bile salts

Question 31

In regards to the triad of biliary lithogenicity, what do we want our bile salt vs cholesterol vs phosphatidylcholine concentrations to be (to avoid gall stones)?

Answer 31

- bile salts high (above 70%) - cholesterol low (below 20%) - phosphatidylcholine high (above 80%)

Question 32

Bile is necessary for what?

Answer 32

- digestion & absorption of lipids | - elimination of endogenous products (cholesterol, bile pigments, etc) and exogenous substances (drugs, heavy metals)

Question 33

What is the sequence of fat digestion?

Answer 33

- lipases hydrolyze TGs into FFAs - digested FFAs transported into enterocytes via biliary micelles - FFA reconverted to TGs - TGs converted to chylomicrons - chylomicrons transported to the blood

Question 34

Bile emulsifies fat into what?

Answer 34

1 micrometer soluble droplets

Question 35

Pancreatic lipases do what to TGs?

Answer 35

-hydrolyze TGs to glycerides & FAs

Question 36

What does phospholipase A2 do?

Answer 36

hydrolyzes phospholipids

Question 37

What does cholesterol esterase do?

Answer 37

hydrolyzes cholesterol

Question 38

What is the structure of a micelle?

Answer 38

-bile acids, phospholipids & cholesterol form lipophilic center that emulsifies fats into a form digestible by lipases

Question 39

What is the sequence of bile acids to bile salts? Starting with synthesis

Answer 39

- bile acids synthesized in the liver - conjugated in liver to taurine or glycine to form bile salts - deconjugaed in intestine to form bile acids

Question 40

What do phospholipids align with? What makes cholesterol soluble?

Answer 40

- phospholipids align with bile acids | - cholesterol is solubilized by micelles

Question 41

Micelles transport & facilitate what? What can pass through the unstirred layer?

Answer 41

- absorption of glycerides & FAs through mucosa | - LCFAs can pass through unstirred aqueous layer to reach enterocyte membrane

Question 42

What do micelles transport and to where? What happens to them there? How, in contrast, is cholesterol absorbed?

Answer 42

- FAs & glycerides to enterocyte where they diffuse into cell - once inside the enterocyte, FAs & glycerides are re-synthesized into TGs - cholesterol is absorbed & processed in free form

Question 43

What is enterohepatic circulation?

Answer 43

- bile acids & salts are recycled back to the liver - most reabsorption is active transport in the ileum (less passive transport from rest of intestine) - bile acids & salts are returned to the liver and reconjugated with taurine or glycine

Question 44

What do chylomicrons transport? What are they formed from & coated with? Where are they transported to? Where are they stored?

Answer 44

- exogenous LCFAs into circulation - TGs, cholesterol & phospholipids & coated with apoproteins - transported into lacteals & thoracic duct - stored in liver & adipose tissue

Question 45

What happens to short/MCFAs?

Answer 45

-not converted to TGs-->transported directly into portal system of veins

Question 46

What are the lipoproteins? Where is each one made? What does it transport?

Answer 46

- Chylomicrons: made in SI, transport fat into blood - VLDL: made in liver, transport TG from liver to organs - LDL: made in plasma, transport cholesterol esters from liver to organs or tissues (LDL cholesterol deposits in atherosclerosis) - HDL: made in plasma, transport cholesterol from peripheral tissues to liver

Question 47

Where is bilirubin derived from? What is it converted to and by what?

Answer 47

- derived from hemoglobin - converted by colonic bacteria to urobilinogen, either: stercobilin= makes feces brown or excreted in urine= makes urine yellow

Question 48

What is jaundice?

Answer 48

-excess bilirubin due to increased hemolysis, liver damage or bile duct obstruction