liver

Question 1

3 key functions of liver

Answer 1

metabolic and catabolic (synthesis and utilization of carbohydrates, lipids and proteins), secretory and excretory functions (synthesis and secretion of bile and waste products), detoxification and immunological functions (breakdown of ingested pathogens and processing of drugs)

Question 2

where is bile stored and what is it secreted into

Answer 2

gallbladder into duodenum

Question 3

3 key functions of bile

Answer 3

emulsification and absorption of fat to increase SA for lipase activity, cholesterol homeostasis for excreting excess as needed, toxic excretion (endogenous e.g. billirubin and exogenous e.g. drugs)

Question 4

principle source of blood entry

Answer 4

hepatic portal vein

Question 5

what is present in hepatic portal vein blood

Answer 5

nutrients, breakdown products of erythrocytes from spleen, toxic substances, lower oxygen content (hence hepatic artery)

Question 6

liver perfusion percentages

Answer 6

portal vein: 80%, artery: 20%

Question 7

what happens to branches of portal vein

Answer 7

split into sinusoids (large calibre vessels); hepatic arterial branches also join

Question 8

why are the sinusoids wider

Answer 8

slower blood flow

Question 9

where does plasma and plasma-born substances flow through

Answer 9

fenestrations in epithelial cells

Question 10

where does plasma and plasma-born substances flow into

Answer 10

extravascular space between sinusoids and hepatocytes (space of disse)

Question 11

what is adhered to the internal wall of the sinusoids

Answer 11

kupffer celss

Question 12

what are kuppfer cells and relate to function

Answer 12

sinusoidal macrophages, so phagocytose some bacteria and toxins; release cytokines to activate hepatic stellate cells in space of disse

Question 13

what shape are kuppfer cells

Answer 13

stellate shaped

Question 14

where are hepatic stellate cells (ito cells) present

Answer 14

perisiusoidal (space of disse)

Question 15

function of hepatic stellate cells when in quescent state

Answer 15

act as vitamin A storage reservoir, possible APC

Question 16

what activates hepatic stellate cells

Answer 16

kuppfer cells or liver damage (e.g. alcoholic liver disease)

Question 17

outcome of hepatic stellate cell activation

Answer 17

fibrogenesis and proliferation (e.g. collagen to ECM), causing fibrosis and cirrhosis

Question 18

consequence on hepatocytes of fibrosis and cirrhosis

Answer 18

reduce functionality and number

Question 19

name of activated hepatic stellate cells

Answer 19

fibroblasts

Question 20

what shape are hepatocytes

Answer 20

cubical

Question 21

function of hepatocytes

Answer 21

synthesis (including of albumin, clotting factors/products, bile salts), drug metabolism

Question 22

where do hepatocytes receive nutrients from

Answer 22

sinusoid

Question 23

function of cholanglocyte

Answer 23

secrete bicarbonate and water to form bile

Question 24

7 organelles present in hepatocytes

Answer 24

nucleus, rough ER, smooth ER, mitochondria, Golgi apparatus, lysozomes, peroxisomes (detoxification)

Question 25

2 other substances present in hepatocytes

Answer 25

glycogen, cytoplasmic enzymes

Question 26

4 other liver functions

Answer 26

control of synthesis and metabolism of protein, maintenance of blood sugar, lipid metabolism, metabolism and excretion of bilirubin and bile acids

Question 27

what circulating protiens are not synthesised in the liver

Answer 27

Y-globulins made by lymphocytes

Question 28

4 examples of proteins made by liver relevant to other functions

Answer 28

albumin, transport and carrier proteins e.g. transferrin, factors involved in coagulation, components of complement system

Question 29

function of albumin

Answer 29

maintains intravascular oncotic pressure and transports water-insoluble substances e.g. bilirubin, some drugs in plasma

Question 30

what does the liver do to nitrogenous waste (proteins)

Answer 30

degrades amino acids, converts to urea, renal excretion

Question 31

how does the liver maintain blood sugar

Answer 31

releases glucose into blood in fasted state

Question 32

how does the liver release glucose into blood in fasted state

Answer 32

glycogenolysis, gluconeogenesis

Question 33

what does the liver synthesise involved with lipid metabolism

Answer 33

cholesterol, lipoproteins, triglycerides

Question 34

what is cholesterol used for

Answer 34

manufacture of bile salts and steriod hormones