Hp-Akis:liver Physiology

Front 1

What are the functions of the liver?

Back 1

Detoxifier
Hormone processor
Protein creator - albumin and clotting agents
Heat production

Front 2

What is the blood supply for the liver?

Back 2

Hepatic - 30%, oxygenated blood from heart, 12 kPa

Portal Vein- 70%, deoxygenated blood rich in nutrients, 1.3 kPa

Drains through hepatic vein

Front 3

Where is the liver located?

Back 3

Right upper quadrant of the abdominal cavity

Front 4

What are the features of sinusoids?

Back 4

Fenestrated vessel

Wide capillaries

Lined with endothelia with fenestrae

Selective sieve

No basal lamina

Front 5

What is the journey of bile?

Back 5

Transported in hepatocytes
Secreted in bile canaliculi to bile ductules
Drained in small intestine

Front 6

What is the structure of the portal venule?

Back 6

Large lumen, collapsed structure and attenuated wall

Front 7

What is the structure of the hepatic arteriole?

Back 7

Single layer of smooth muscle cells
Small lumen

Front 8

What is the structure of the bile ductule?

Back 8

Simple cuboidal to columnar ciliated epithelium (to move bile)

Front 9

What is the structure of the lobules in the liver?

Back 9

80% - parenchyma
20% - stroma

50-100k lobules

Front 10

What is the structure of hepatocytes?

Back 10

Cuboidal Epithelial Cell

Single cell columns radiate from central vein

Rich in: Tight junctions, microvilli, Mi, peroxisomers, RER, SER, glycogen

Front 11

What does the liver metabolise?

Back 11

Metabolise fats, carbohydrates and proteins

Front 12

How are fats metabolised in the liver?

Back 12

Triglyceride Oxidation for energy production

Plasma lipoprotein synthesis

Cholesterol and phospholipid synthesis

Front 13

How are carbohydrates metabolised in the liver?

Back 13

Carbohydrates are converted into fatty acids and triglycerides

Glucose concentration regulation:

glycogenolysis--gluconeogenesis

Front 14

How are proteins metabolised in the liver?

Back 14

Amino acid synthesis, Plasma protein synthesis – albumin/clotting factors

Detoxification of metabolism waste products e.g.Amino acid deamination- Urea formation

Front 15

What does the liver detoxify?

Back 15

Alcohol and other drugs

Front 16

What else does the liver secrete?

Back 16

Bile - contains products of metabolism - billirubin

Acts a detergent to emulsify fats

Front 17

What is acinus?

Back 17

Constructed around portal triad with Central vein as corners

Front 18

What occurs in the three zones of the liver acinus?

Back 18

Zone 1 - receives oxygen, nutrients, hormones first. Hepatocytes synthesizeglycogen and plasma proteins

Zone 3 - hypoxic, drug detoxification

Front 19

What is the function of the endothelial cells?

Back 19

Contain large fenestrae

Passage of large plasma-proteins - chylomicrons

Lacks BM

Endocytosis and transcytosis

Front 20

What are Kupffer cells?

Back 20

Mononuclear phagocytes
Found on the luminal endothelial face
Phagocytosis of bacteria, virus particles, damaged erythrocytes, immune complexes

Front 21

What are hepatic stellate cells?

Back 21

Quiescent; fat-containing/storing; Vitamin A storage; found in the space of Disse

Front 22

What is the function of Canals of Hering?

Back 22

Contain a reserve compartment of hepatocyte and bile duct progenitor cells – stem cell location

Front 23

Where is the space of Disse?

Back 23

Between hepatocytes and sinusoidal endothelial cells with fenestrae of 100 nm which are dynamic with Ca

Front 24

How are fenestrae linked to arteriosclerosis?

Back 24

Cannot take up cholesterol-rich chylomicrons

Stay in circulation

Front 25

What affects size of fenstrae?

Back 25

Actin disruption increases fenestrae numbers and size

Calcium addition yields fenestrae contraction

Serotonin and drugs

Front 26

How does alcohol affect the liver sinusoidal endothelial cells?

Back 26

Yields endothelium defenestration

Sinusoidal porocity decreases

Yields Hyperlipoproteinemia

Front 27

Why is some alcohol considered good for you?

Back 27

Enlarges fenestrae

Dietary lipid clearance by the liver

Front 28

What is the function of Sphincter of Oddi

Back 28

Smooth muscle ring

Controls entry of both bile and pancreatic juice into the duodenum

Front 29

What is gall bladder concentrated in?

Back 29

Bile is highly concentrated

20x fold increase in bile salt concentration

Front 30

What is bile composed of?

Back 30

Bile salts (50%)

Bile pigments (e.g. bilirubin) (2%) - colour

Phospholipids (40%)

Cholesterol (4%)

Front 31

What are the precursors of bile salts?

Back 31

Bile acids

Front 32

What are primary bile acids?

Back 32

Cholic Acid (CA; 31%) and Chenodeocholic acid (CDCA; 45%)

Synthesised in liver from cholesterol

Front 33

What are primary bile acids conjugated to?

Back 33

Conjugated to aa like taurine (tauroconjugates) or glycine (glycoconjugates) to be excreted

Front 34

Where are primary bile acids reabsorbed?

Back 34

95% reabsorbed

Distal ileum and returned to the liver via portal vein

Front 35

Are bile acids hydrophobic or hydrophilic?

Why is it important?

Back 35

Both - amphipathic

Key feature for the emulsification of fat

Front 36

What is the difference between primary and seccondary bile acids?

Back 36

Secondary are more hydrophilic - more OH groups

Front 37

What is the function of bile?

Back 37

Contains Bile Acids that aid in fat absorption

Transports material (drugs, bilirubin etc.) to the intestine for excretion

Front 38

What is an issue of too much secondary bile acids?

Back 38

Colon cancer, gallstones, GI diseases

Front 39

What do conjugated bile acids in the small intestine prevent?

Back 39

Bacterial overgrowth

Bile salts - Bacteriostatic agents

Front 40

Which direct does blood and bile flow in ?

Back 40

oppositedirections

Front 41

Where are portal triads

Back 41

Periphery

Front 42

How are bile salts excreted?

Back 42

95% of bile salts are reabsorbed by small intestine.

5% lostin faeces