Liver W12

Question 1

The liver is located in the upper right of the abdominal cavity.
What are the vessels into the liver?
What are the vessels out of the liver?

Answer 1

IN: Hepatic artery + Hepatic portal vein
OUT: Central vein, hepatic vein, vena cava, Bile cana. Lymphatics.

Leaves through the hepatic veins into the Inferior Vena Cava.

Question 2

The functional unit of the liver, called Functional lobule, has cells. What are they?

Answer 2

Hepatocytes: synthesise proteins, produce bile, process nutrients and store fat-soluble vitamins. Detoxify.
Endothelial cells: line sinus, porous.
Kupffer cells: resident macrophages- defence cells.

Question 3

Inside the stomach, carbs are broken down into lactose, glucose or fructose, which is absorbed into where?

Answer 3

The hepatic portal vein then to the liver

Question 4

Digestion is completed in the ___.
Nutrients are absorbed into the ____.
Move to ___ for processing.

Answer 4

Digestion is completed in the small intestine. Nutrients are absorbed into the bloodstream (hepatic portal vein) and move to the liver for processing.

Question 5

The pancreas releases glucagon and insulin- where those two hormones are acting is in the liver.
What is the livers involvement in metabolism of carbohydrates?

Answer 5

The liver helps regulate blood glucose.
It converts glucose to glycogen (because can’t store too much glucose, too much osmotic pressure) then glycogen back to glucose.
Performs gluconeogenesis - glucose from non-carbs. And Glycogenlyosis breakdown of glycogen to glucose.

Question 6

What is the liver’s response to insulin?

Answer 6

Pancreas releases insulin which stimulates glucose uptake from blood/ Force glucose to glycogen. Which lowers blood sugar.

Question 7

What is the bodies response to low blood sugar?

Answer 7

Pancreas releases glucagon, acts in liver. Which breaks down glycogen converts to glucose and raises blood sugar.

Question 8

What is the metabolism of fat in the liver’s role in synthesis of??

Answer 8

Synthesis of cholesterol = plasma Membrane, bile salts, steroid
Synthesis of phospholipids = plasma membrane
Excess proteins = adipose tissue storage

Question 9

It the metabolism of proteins in the liver, what does the deamination of amino acids do? And how does it bypass toxic hepatic coma?

Answer 9

Deamination of amino acids- leaves the carbon skeleton which can be used for making glucose, acetyl CoA.

The liver converts the ammonia to urea for excretion.

Question 10

What is the role of Albumin?

Answer 10

Maintains normal fluid balance between blood and tissues- to clean out system and get rid of waste.

Question 11

What is the liver’s role in protein synthesis?

Answer 11

1. Liver synthesises clotting factors- Vitamin K required for these.
   Fibrinogen is an activating factor.
2. Albumin- maintains fluid
3. Synthesis of non-essential amino acids

Question 12

Does the liver synthesise immunoglobulins?

Answer 12

NO

Question 13

The liver produces apoferritin, which combines with ___. To keep up red blood cells.
What other vitamins does the liver store and for what purpose.

Answer 13

Iron.

Vitamin A, D B12- for immune, calcium regulation and DNA synthesis.
Vitamin K for coagulation.

Question 14

What is the important component in the liver that contributes to the emulsification of fats for absorption and fat-soluble vitamins (K)?

What else does it assist in the excretion of?

Answer 14

Bile acids.
Hepatocytes secrete into canaliculi to bile ducts to gall bladder.

Excretion of cholesterol and bilirubin.

Question 15

A build up of what is one of the major signs of liver disease?

Answer 15

Bilirubin.
Which is a breakdown product of Haemoglobin.
It is conjugated in the liver and released into the intestine in BILE- usually excreted in faeces.

Question 16

What are the oral signs of liver disease?

Answer 16

Jaundice, xerostomia, smooth tongue, bruxism (grinding), cheilitis (cuts on tongue)

Question 17

What clinically do you have to watch out for with a patient of liver disease?

What are the causes of liver disease?

Answer 17

Excessive bleeding + Reduced metabolism of drugs

Loss of hepatocyte function or impaired blood flow- caused by infectious diseases, alcohol abuse and metabolic disorders.

Question 18

How many viruses are there of the liver? And what are dentists most concerned with?

Answer 18

5. A, B, C

Question 19

The metabolism of alcohol produces acetaldehyde- which affects mitochondria. It increases lipid and ketone synthesis - which leads to?

Answer 19

Fatty liver disease- cirrhosis (scarring of liver)

Question 20

What is cirrhosis?

Answer 20

Fibrosis and scar tissue- that blocks blood flow.

Question 21

What is a precursor to Type 2 Diabetes and Insulin resistance (cells can’t take up glucose) that is responsible for Non-alcoholic fatty liver disease?

Answer 21

Metabolic syndrome.

Question 22

Where are the two places liver cancer occurs?
What is liver cancer associated with & its risk factors?

Answer 22

Hepatocytes and bile ducts.

Liver cancer is associated with cirrhosis. Risk factors = Hepatitis B or C, Fatty liver disease, smoking and alcohol.

Question 23

What does hepatocellular failure lead to and what is it a buildup of?

Answer 23

Leads to jaundice, glucose imbalance, bleeding disorders, and disrupt steroid and calcium.
Due to buildup bilirubin (yellow substance when red blood cells break down).

Question 24

What does impaired blood flow impact?

Answer 24

Increases resistance due to fibrosis and pressure in circulation.
Decreases drainage from GI tract.

Question 25

In patient with Type II Diabetes: What role does insulin have in regulating the liver's metabolic function?

Answer 25

In uncontrolled diabetes, the body resorts to fat metabolism as insulin production is not sufficient. Glycogenolysis will be excessive and the liver will become the main site of fat metabolism for generation of energy.

Question 26

How does the liver increase glucose levels in excessive insulin?

Answer 26

Insulin increases uptake of glucose in the liver through glycogen storage, decreasing gluconeogensis. If there is too much insulin, leads too hypoglycaemia. Not enough glucose. The liver can increase blood glucose by converting glycogen into glucose via glycogenolysis.

Question 27

What are 2 processes the liver uses to increase blood glucose levels?

Answer 27

Gluconeogenisis= transforms non carbs into glucose Glycogenolysis= breakdown of glycogen to make glucose

Question 28

How does the liver's blood supply relate to its physiological functions?

Answer 28

Nutrients that are absorbed from the GIT go through to the liver first where nutrients can be processed. Blood comes to the liver from hepatic artery and portal vein. Within the liver, each lobule has blood supply from the hepatic artery and portal vein that drain into the sinusoid- which drain through central vein. Sinusoid is porous lined with Kupffer (macrophages) and endothelial cells, where blood moves through to hepatocytes that filter the blood. Controls metabolism and digestion. These then come together and forms the hepatic vein, which leaves the liver. Merges with Inferior Vena Cava --> right side of heart. If tricuspid valve is blocked, the liver holds back flow of blood.

Question 29

How does the liver breakdown haemoglobin from senescent red blood cells?

Answer 29

Occurs via reticuloendothelial system (immune system) and spleen. Takes up haemoglobin released from senescent cells. Broken down into heme and globin- heme ring to release iron. Heme is converted into Believerdin to bilirubin - which is transported to liver by plasma albumin. Conjugated in liver, released into intestine in bile to faeces, or, excreted in urine.

Question 30

What role does the liver play in drug metabolism?

Answer 30

End result is to make drugs more water soluble via two main phases. Phase I: cytochrome p450 oxidation and reduction reactions make it chemically reactive, lipid soluble. Phase II: conjugation reaction, make it water soluble and less toxic.

Question 31

Why do we need to be careful of medication dose prescription?

Answer 31

Liver is main site of drug metabolism. Reduce liver function = reduce drug metabolism. So, drug can build up toxic levels.

Question 32

What is Jaundice caused by?

Answer 32

High levels of bilirubin in blood, leads to discolouration of skin and tissues. Sclera of eye detected first. Bilirubin is formed from the breakdown of haemoglobin in senescent red blood cells. It is lipid soluble and toxic at high levels.

Question 33

Why do people with liver disorders experience high levels of bleeding?

Answer 33

They have decreased levels of blood clotting (which stops you from losing too much blood). = inhibited coagulation factors (proteins in blood that control bleeding). Risk of drug toxicity due to altered metabolism of drugs, need smaller doses.

Question 34

Why do people with liver disease and protein malnutrition develop oedema?

Answer 34

Plasma proteins especially albumin is important for maintaining normal fluid levels in tissues. Loss of albumin causes fluid accumulation in body tissues. Loss of liver cell function, leads to hypo albuminemia-

Question 35

What is Hep B?

Answer 35

A DNA Virus. Inflammation of liver parenchyma Spread by body fluids and verticle transmission

Question 36

How is Hep A spread?

Answer 36

RNA virus. Not need stick. Oral route. Liver fluke parasite and malaria.

Question 37

How is fat metabolised in the liver?

Answer 37

It is the breakdown of triglycerides into glycerol and FFA. FFA are split by B oxidation into 2 acetyl -forms- ACTEYL CoA Which is oxidised and generates large amounts of ATP and ketone bodies. Also, use of bile and bile salts to emulsify cholesterol and fats into micelles which can be broken down by the body.

Question 38

How is protein metabolised in the liver and why is this a vital function?

Answer 38

The liver is responsible for deamination of amino acids. This is vital because it is required before proteins can be used as an energy source. This results in large production of ammonia. Ammonia is toxic and the liver converts it to urea which is then excreted in urine by kidneys. *If not converted to urea can lead to hepatic coma and death.

Question 39

How much protein does the liver synthesise a day?

Answer 39

50g

Question 40

Bile is formed in the liver and stored in the gallbladder. What is bile important for?

Answer 40

Bile and bile salts are used to emulsify cholesterol and fats into micelles which can be broken down by the body. Absorbing fat soluble vitamins- K for coagulation. And to carry away waste. Damaged bile ducts leads to damage of hepatocytes = liver failure.