Option D.3 Function of the Liver

Question 1

Give an example of how the liver regulates nutrients in blood

Answer 1

• liver maintains correct amount of glucose
  when glucose level is high, liver releases insulin;
  to stimulate hepatocytes to take up glucose;
  to convert to glycogen;
  when glucose level low, hepatocytes are stimulated;
  to break down stored glycogen;
  to release glucose

Question 2

What occurs when transferring receptors are bound?

Answer 2

receptor iron complex enter cell and iron is either incorporated into heme/ or transferred to a storage molecule called ferritin

Question 3

What do developing red blood cell have high levels of?

Answer 3

transferrin receptors

Question 4

What is transferrin?

Answer 4

protein bound to iron

Question 5

What happens iron is absorbed by small intestine?

Answer 5

tranferred to blood bound to a protein

Question 6

Where is hemoglobin synthesized in?

Answer 6

red blood cells

Question 7

When are iron/vitamin A/ vitamin D released into blood when stored in lover?

Answer 7

deficit in blood

Question 8

What nutrients can be stored in excess in the liver?

Answer 8

glucose, when high causes insulin to stimulate hepatocytes to take up glucose and store as glycogen;
iron; Vitamin A; Vitamin D; vitamins are fat soluble

Question 9

What happens to excess amino acids?

Answer 9

deaminated in the liver; organic acid part is removed/respired or converted to fat/carbohydrate

Question 10

can the body store amino acids if in excess?

Answer 10

No

Question 11

When proteins are broken down what do they contribute to?

Answer 11

pool of amino acids in blood plasma for new synthesis

Question 12

What are examples of proteins that are produced for export from liver cells?

Answer 12

fibrinogen, globulins, albumin, prothrombin

Question 13

What is the effect of having the liver adjust level of amino acids?

Answer 13

regulated to support the constant synthesis of proteins that can function as enzymes/components of membranes /structural components

Question 14

What does the liver cell adjust as blood passes the sinusoids (supplies daily demand for protein)?

Answer 14

amino acids

Question 15

What happens to components of red blood cells by liver?

Answer 15

broke down when old and recycled

Question 16

What is bile used for?

Answer 16

break down fats into droplets that disperse for effective breakdown by digestive enzymes in duodenum

Question 17

What is surplus cholesterol from the liver converted into?

Answer 17

bile salts (emulsifies the bile)

Question 18

What does the liver produce other than bile?

Answer 18

cholesterol

Question 19

Explain the role of liver in hemoglobin breakdown

Answer 19

Kupffer cells take up erythrocytes through phagocytosis;
hemoglobin is broken into globin and heme;
globin is hydrolysed;
breakdown of heme causes iron to attach to carrier protein;
iron stored or exported to bone marrow (via blood plasma) for new red blood cell;
heme converted into bile pigments

Question 20

What are erythrocytes?

Answer 20

red blood cells

Question 21

What are Kupffer cells?

Answer 21

phagocytes attached to walls of sinusoids that take up old red blood cells; contain many lysosome; specialized leucocyte

Question 22

What are lovules?

Answer 22

rows of hepatocytes

Question 23

Give an example of how the liver removes toxins

Answer 23

alcohol is oxidized to become carboxylic acid; becomes part of metabolites; oxidized to CO2 and water

Question 24

What are bile channels?

Answer 24

bile from liver flows through (between liver cell rows but isolated from blood supply); merge into bile ducts to carry to gall bladder

Question 25

What is one of the major functions of the liver?

Answer 25

remove toxin; break down of red blood cells; Wstabilization of quantity of nutrients circulating blood; regulation through storage and release of nutrients when needed

Question 26

How does the blood from the heptic portal vein differ from normal blood?

Answer 26

- are wider - is low pressure , deoxygenated blood - varies in quantity of nutrients depending on food and timing - contain kuppfer cells (brekadown haemoglobin for recycling)

Question 27

After arterioles join with sunsoids what occurs?

Answer 27

Sinusoids merge with velues that lead to hepatic vein

Question 28

How do sinuiods differ from liver cells?

Answer 28

sinuids do not have walls separating blood from liver cells (blood and liver cells are in direct contact); allows proteins to enter /leave blood

Question 29

What are hepatocytes?

Answer 29

liver cells

Question 30

What are sinuiods?

Answer 30

blood filled channels (like capillaris)where arterial blood mixed with blood from heptic portal flows through

Question 31

What is a helptic portal vein?

Answer 31

bring blood to the liver directly from small intestine

Question 32

How is the liver supplied with blood?

Answer 32

supplied by HEPTIC artery; drains deoxygenated blood through HEPTIC vein

Question 33

What happens to fatty acids that reach the liver?

Answer 33

combine to form triclycerides; and proteins to be stored; transported to blood plasma; LDLs to tissues;

Question 34

What does an excess of LDLs result to?

Answer 34

blocking of receptor sites of cell membrane that metabolize/store lipids; causes more LDL in blood;

Question 35

How can monosaturated fats and polysaturated fats help?

Answer 35

help remove circulating LDL; | increase efficiency of receptor sites at removal of bad cholesterol

Question 36

What are the primary effects of long-term alcohol abuse?

Answer 36

- cirrhosis - scar tissues damaged from exposure to alcohol; - fat accumulation - damaged area build up fat instead of tissue / obesity - gastritis - irritates stomach mucosa - malnutrition - excess alcohol affects appetite - dementia - destroys neurons - weakened heart muscles

Question 37

What are the key events of the break down of hemoglobin?

Answer 37

Occurs inside kupffer cell; - four globin proteins are hydrolised into amino acid - amino acids released into bloodstream (available for more protein synthesis) - iron released can be stored within liver; some iron is sent to bone marrow (used in production of erythrocytes) - bile pigment bilirubin (iron removed from haem group) is absorbed by hepatocytes (becomes bile)

Question 38

What is bile used for?

Answer 38

added when fatty acids are being digested; emulsification of clump formed by lipids; does NOT chemically change lipids; breaks down coalesced clumps/increases surface area for catalisation

Question 39

How do hepatocytes produce bile in liver?

Answer 39

converts surplus cholesterol into bile salt

Question 40

What examples plasma proteins do hepatocytes release?

Answer 40

albumin: helps regulate blood pressure, acts as carrier for bile salts and other fat soluble substances; fibrinogen: converts to fibrin to form mesh of blood clot

Question 41

What is bilirubin?

Answer 41

bile salt, heme part of hemoglobin without iron

Question 42

What is jaundice?

Answer 42

condition where skin and whites of eyes develop yellow tinge; severe conditions are toxic to brain cells

Question 43

What is the immediate cause of discolouration of jaundice?

Answer 43

build up of bile pigment bilirubin in blood and tissues

Question 44

What are predicted causes of Jaundice?

Answer 44

any condition that disrupts movement of bilirubin; - breakdown of red blood cells at an abnormal rate (increased bile rubin in blood) - damage to liver (typically by alcohol-induced cirrhosis/malaria) cannot process bilirubin - blocked bile duct (cannot send bile to digestive system)

Question 45

Why do newborns sometimes suffer from Jaundice?

Answer 45

hemoglobin of fetus is different from hemoglobin our body forms after birth; after birth breakdown of fetal hemoglobin occurs at accelerated rate; bilirubin formed quicker than broken down; self-corrects;

Question 46

What is a common treatment for infants suffering from jaundice?

Answer 46

exposure to blue/green portion of light spectrum; | causes change in shape/structure of bilirubin

Question 47

What is pre-hepatic jaundice caused by?

Answer 47

malaria, sickle cell anemia, thalassemia

Question 48

What is intra hepatic jaundice caused by?

Answer 48

``` infection like hepatitis, leptospirosis or glandular fever; harmful substances (alcohol and drugs), also ecstasy overdose of paracetamol ```

Question 49

What is post hepatic jaundice caused by?

Answer 49

gallstones can cause

Question 50

Is alcohol considered as a drug?

Answer 50

Yes because of strong effects on central nervous system

Question 51

What happens once alcohol is consumed?

Answer 51

absorbed into blood; distributed through out body; can cross blood bain barrier; metabolised in liver

Question 52

What is cirrhosis?

Answer 52

a chronic inflammation of liver in which liver cells are destroyed and replaced by fibrous or adipose connective tissue