Hepatic 3

Question 1

Does the liver have a lot of mitochondria?

Answer 1

YES, very metabolically active

Question 2

What % of systemic blood flow goes to the liver?

Answer 2

28%

Question 3

What % of oxygen used in the body goes to the liver?

Answer 3

~20%

Question 4

3 Roles of the Liver in Metabolism

Answer 4

1. Synthesis and degradation of carbohydrates, lipids, and proteins
2. Sorting molecules for metabolism, energy, or distribution
3. Export glucose and ketone bodies to provide energy to other tissues

Question 5

Two Locations of Glucose Synthesis

Answer 5

1. Liver (80%)
2. Kidneys (20%)

Question 6

2 Major Pathways for Liver to produce Glucose between meals (low insulin)

Answer 6

1. Gluconeogenesis
2. Glycogenolysis

Question 7

Glycogen accounts for ____% of liver weight

Answer 7

7-10%

Question 8

Where else besides the liver can the body store glycogen?

Answer 8

skeletal muscle

Question 9

Histological appearance of Heaptcytes with Glycogen Storage Disease

Answer 9

lacy, pale cytoplasm, swollen and obscuring any sinusoids

Question 10

What type of drug administration in dogs can promote glycogen storage in hepatocytes?

Answer 10

steroid (steroid hepatopathy)

Question 11

During the urea cycle in the liver, what % of ammonia is detoxified?

Answer 11

95%

Question 12

Where besides the liver detoxifies ammonia?

Answer 12

kidneys

Question 13

hepatic encephalopathy

Answer 13

caused by buildup of ammonia

seen in horses after eating toxic grasses and then the liver can’t fiilter and ammonia goes to the brain

Question 14

Major plasmaprotein made by the liver that’s important for transport?

Answer 14

albumin

Question 15

C-reactive protein

Answer 15

released during acute inflammation of the liver

Question 16

Most specific marker for heaptic injury?

Answer 16

Alanine Transaminase (ALT)

Question 17

What is the only clotting factor not synthesized in hepatocytes?

Answer 17

clotting factor VIII (8)

Question 18

Inhibitors of Coagulation

Answer 18

antitrypsin, antithrombin, a2 macroglobulin, protein S, protein C

Question 19

Fribrogen synthesis occurs where?

Answer 19

in the liver

Question 20

plasminogen

Answer 20

involved in fibrinolysis to breakdown the fibrin in the blood clot

Question 21

transamination

Answer 21

converts amino acids (alanine) to pyruvate, and eventually glucose via gluconeogenesis

Question 22

Why is ALT the best marker for hepatic injury?

Answer 22

alanine can be used as a substrate to produce lucose ONLY IN THE LIVER

Question 23

Metabolism of protein in the liver occurs via what main process?

Answer 23

transamination

Question 24

Aspartate transaminase (AST)

Answer 24

enzyme found in liver, heart, muscle, kidney, and brain

Question 25

Alkaline phosphatase (ALP)

Answer 25

many isoforms (ex: bALP for bone), can increase due to stress

Question 26

Liver specific enzymes in horses, ruminants, and swine?

Answer 26

sorbitol dehydrogenase (SDH) and ornithine carbamoyltransferase (OCT)

Question 27

Fat is stored in the liver as either ______ or ________

Answer 27

triglycerides or cholesterol

Question 28

3 Sources of Cholesterol for the Liver

Answer 28

1. Diet 2. De novo synthesis (not solely in the liver) 3. LDL via endogenous pathways

Question 29

What happens to most lipids in mammals?

Answer 29

secreted as bile

Question 30

4 Fates of Cholesterol in the Body

Answer 30

1. Secretion as bile 2. Sloughing of skin and intestinal epithelium 3. Hormone synthesis 4. Exported into blood as VLDLs from liver

Question 31

Trglyceride

Answer 31

a fatty acid and glycerol

Question 32

Fatty acids oxidized in the liver eventually become _______

Answer 32

acetyl CoA

Question 33

What happens to excess acetyl-CoA in the liver?

Answer 33

condensed to acetoacetate, eventually yields ketone bodies, which can be exported and used as fuel by the heart, brain, and skeletal muscle

Question 34

Can the liver use ketone bodies?

Answer 34

no, only export them

Question 35

Hepatic Lipidosis

Answer 35

condition caused by anorexic events in cats; fat accumulates in hepatocytes and liver becomes pale and firm; visible histologically

Question 36

Does liver normaly float or sink in formalin?

Answer 36

sink

Question 37

Oil Red O

Answer 37

stains lipids

Question 38

What is stored in stellate (Ito) cells?

Answer 38

fat soluble vitamins (A, D, E)

Question 39

What is stored in hepatocytes and Kupffer cells?

Answer 39

iron and copper

Question 40

Where is the majority of body iron stored?

Answer 40

hemoglobin of the RBCs (50-70%)

Question 41

What other body organs store iron?

Answer 41

liver, spleen, bone marrow

Question 42

Ferroportin

Answer 42

iron transporter within enterocytes (basolateral aspect), for exporting iron

Question 43

Transferrin

Answer 43

transports Fe3+ in the blood

Question 44

2 Forms of Fe2+ Storage

Answer 44

1. Ferritin (water soluble, mobile; in RBCs, enterocytes, hepatocytes) 2. Hemosiderin (brownish, main storage in macrophages of liver, spleen, and marrow)

Question 45

Hepcidin

Answer 45

peptide hormone produced by the liver that regulates iron [negatively]; prevents iron absorption or release from storage

Question 46

How does hepcidin work?

Answer 46

binds to ferroportin (the transporter of iron) and internalizes said transporter, so iron cannot be released

Question 47

Hypoxia effect on hepcidin?

Answer 47

decreases hepcidin, therefore inc. iron absorption/mobilization

Question 48

Inflammation effect on hepcidin?

Answer 48

increases hepcidin via IL-6 stimulation, therefore dec. iron absorption/mobilization (aka anemia)

Question 49

How does inflammation lead to anemia?

Answer 49

Inflammation increases hepcidin, ferroportin transporter internalized, iron not being released into blood so heme synthesis diminished, can't make RBCs = anemia