Liver and Pancreas

Question 1

What is the blood flow from the portal vein through the lobule?

Answer 1

Portal vein –> sinusoids –> central vein –> hepatic veins

Question 2

What is the blood flow from the hepatic artery through the lobule?

Answer 2

hepatic artery –> sinusoids –> central vein –> hepatic vein –> IVC

Question 3

How many layers are the liver cell plates composed of?

Answer 3

two layers of hepatocytes

Question 4

Where are the bile canaliculi located?

Answer 4

Between two layers of hepatocytes in each cell plate

Question 5

What are sinusoids lined with?

Answer 5

Endothelial cells
Kupffer cells (marophage derived)

Question 6

Where is the Space of Disse located?

Answer 6

between endothelial cells and hepatocytes

Question 7

What do the bile canaliculi secrete?

Answer 7

bile down into the bile duct

Question 8

What is the blood flow and resistance like in the liver?

Answer 8

High blood flow and low vascular restistance

Question 9

What percent of cardiac output is the liver vascular supply?

Answer 9

27%

Question 10

What is the portal pressure into the liver?

Answer 10

9 mmHg

Question 11

What is the pressure from the liver to the vena cava?

Answer 11

0 mmHg

Question 12

What is the effect of cirrhosis on blood flow?

Answer 12

Cirrhosis increases liver resistance to blood flow

Question 13

What is the effect of clot blocking potak vein or a major branch?

Answer 13

Blockage of return blood from spleen and intestine

Increase in capillary pressure in intestinal wall –> loss of fluid –> death

Question 14

What is the normal volume of the liver?

Answer 14

450 ml (10% of body’s blood volume)

Question 15

How will the liver vascular supply change during cardiac failure with peripheral congestion?

Answer 15

high pressure in right atrium –> backpressure of liver –> increased blood volume in liver up to 1.5 L

Question 16

T/F Liver can store blood in times of excess and supply blood in times of diminished volume

Answer 16

True

Question 17

What are hepatic sinusoids highly permeable to?

Answer 17

proteins – efferent lymph has a protein concentration of 6g/dl

Question 18

What happens when there is higher than normal pressure in hepatic veins?

Answer 18

• back pressure causes fluid to transude into lymph
• fluid leaks through liver capsule into abdominal cavity
• fluid is almost pure plasma
• large amount of fluid in abdominal cavity = ascites

Question 19

What are the functions of the liver concerning carbohydrate metabolism?

Answer 19

• stores glycogen
• converts galactose and fructose to glucose
• gluconeogenesis
• forms intermediate products of carb metabolism

Question 20

What are the functions of the liver concerning fat metabolism?

Answer 20

• oxidation of fatty acids for energy
• synthesis of cholesterol, phospholipids, lipoproteins
• synthesis of fats from proteins and carbs

Question 21

What are the functions of the liver concerning protein metabolism?

Answer 21

• deamination of amino acids
• formation of urea
• formation of plasma proteins
• interconversion of various amino acids and synthesis of other compounds from amino acids

Question 22

What are the functions of the liver concerning vitamin storage?

Answer 22

• vitamin A
• vitamin D
• vitamin B12

Question 23

What are the functions of the liver concerning formation of coagulation factors?

Answer 23

• fibrinogen
• prothrombin
• accelerator globulin
• Factors VII, IX, X

Question 24

What are the functions of the liver concerning removal or excretion of drugs, hormones, and other substances?

Answer 24

• detoxify or excrete into bile (sulfonamides, penicillin, ampicillin, erythromycin)
• excretes excess calcium into bile
• detoxification and removal of ammonia and ethanol

Question 25

Where is hepatic bile produced and secrete?

Answer 25

the liver

Question 26

Where is hepatic bile stored?

Answer 26

gallbladder

Question 27

What are the 4 components of bile?

Answer 27

1. Bile acids 2. Water and electrolytes 3. Cholesterol and phospholipids 4. Pigments and organic molecules

Question 28

What is the major pigment in bile?

Answer 28

bilirubin

Question 29

What are the 2 major bile acids synthesized by hepatocytes?

Answer 29

Cholic acid and chenodeoxycholic acid

Question 30

What are the 2 major bile acids converted by bacteria?

Answer 30

Deoxycholic acid and lithocholic acid

Question 31

What are the fates of Urobilinogen?

Answer 31

- oxidized into excreted products | - reabsorbed into blood and carried back to the liver to be re-excreted by liver or excreted in urine

Question 32

What are the characteristics of jaundice?

Answer 32

- yellowish tint to the body tissues | - caused by quantities of bilirubin in extracellular fluids

Question 33

What are the common causes of jaundice?

Answer 33

- Increased hemolysis | - obstruction of bile ducts or damage to liver

Question 34

What are the three main types of inlet cells?

Answer 34

Alpha, Beta, Delta

Question 35

What are the characteristics of alpha cells?

Answer 35

- secrete glucagon | - 25% of total cells

Question 36

What are the characteristics of beta cells?

Answer 36

- secrete insulin and amyling | - 60% of total cells

Question 37

What is the function of insulin?

Answer 37

inhibits glucagon secretion

Question 38

What is the function of amylin?

Answer 38

inhibits insulin secretion

Question 39

What are the characteristics of delta cells?

Answer 39

-secrete somatostatin

Question 40

What is the function of somatostatin?

Answer 40

inhibit insulin and glucagon secretion

Question 41

How is insulin found in the blood?

Answer 41

unbound form

Question 42

What is the half-life of insulin?

Answer 42

6 minutes

Question 43

Where is insulin destroyed if not bound to receptor?

Answer 43

liver

Question 44

What are the four potential outcomes of insulin binding to a receptor?

Answer 44

1. Increased uptake of glucose 2. Increased permeability to amino acids, potassium and phosphate ions 3. Increased activity for many enzymes 4. Changes in rates of translation and transcription

Question 45

What is the structure of proinsulin?

Answer 45

a, b. and c chains are linked together | a and b chains are linked by sulfide bonds

Question 46

What are the insulin receptor substrates due to phosphorylation of enzymes

Answer 46

1. glucose transport 2. protein synthesis 3. fat synthesis 4. glycogen synthesis 5. growth and gene expression

Question 47

Where is most glucose absorbed after a meal?

Answer 47

stored as glycogen in the liver

Question 48

What is the glucose uptake mechanism for the liver?

Answer 48

insulin inactivates liver phosphorylase --> insulin activates glucokinase and enhance uptake of glucose from blood --> insulin increases activities of enzymes needed for glycogensis

Question 49

What is the process that causes glucose to be released into the blood?

Answer 49

- decreased blood glucose from decrease insulin - lack of insulin reverses glycogen synthesis pathway - lack of insulin activates phosphorylase which splits glycogen into glucose phosphate - glucose phosphatase remoces phosphate from glucose and allows it to diffuse into blood - insulin inhibits gluconeogenesis