Liver structure and function

Question 1

Roles of the liver

Answer 1

Storage of glycogen, iron, vits.
Protein synthesis
detoxification (+drugs)
RBC destruction
hormone/cholesterol synthesis
bile production
macronutrient metabolism

Question 2

Liver lobule features and sinusoid

Answer 2

Contains sinusoid that connects a branch of the portal vein to the central vein. The sinusoid is lined with hepatocytes and kupfer cells (macrophages) to remove viruses and bacteria.

Question 3

the 2 phases of Liver disease

Answer 3

Compensated - still have capacity to perform liver functions. Initial stages

Decompensated - the liver function is insufficient. Normal function and metabolism is affected.

Question 4

Hepatitis pathology and causes

Answer 4

Inflammation of liver.

Caused by alcohol and viruses (e.g., hepatitis A/B/C)

Question 5

describe the phases of Alcoholic liver diseases

Answer 5

Progression of alcoholic liver diseases

1. Alcoholic fatty liver disease - build up of fatty acids in liver. Reversible
2. Alcoholic hepatitis - from prolonged use.
3. Cirrhosis - scarring and loss of function to liver. Irreversible.

Question 6

Other (non-alcoholic) liver diseases

Answer 6

Non-alcoholic fatty liver disease - caused by high body fat % - can lead to steatohepatitis and eventually cirrhosis

Liver cancer can be a result of cirrhosis (⅓ of cases due to alc). Smoking when you have hepatitis B/C increases risk of liver cancer.

DILI: e.g., ciglitazone, NAPQI (paracetamol), etc…

Question 7

Cirrhosis diagnosis and symptoms

Answer 7

Altered expression of liver enzymes from liver functional tests identify it.

Pain, jaundice, pruritus (itchiness from bile salts build up), tiredness, nausea, peripheral oedema, ascites (abdominal fluid build up)

Question 8

Bile disorders and symptomns

Answer 8

Cholestasis: Impaired bile flow to duodenum, caused by bile duct blockage (cancer or gallstones), or disturbance in bile formation (such as from cirrhosis).

Gallstones often form due to excess cholesterol in bile

Enterohepatic recycling of bile: bile bound to fats in the ileum is reabsorbed into the portal circulation and the bile is recycled by the liver - sent to gall bladder.

Pruritus can be treated by reducing bile acids (e.g., colestyramine which binds to bile acids), or can be treated symptomatically with antihistamines or cooling menthol creams.

Question 9

Hepatic encephalopathy causes, symptoms, and treatments

Answer 9

Hepatic encephalopathy: neuropsychiatric complication of cirrhosis - confusion, tiredness, disorientation, personality changes. Due to accumulation of toxins such as ammonia. Treated by targeting the bacteria that produce ammonia in the bowel (e.g., lactulose - prevents growth, or antibiotics such as neomycin or rifaximin).

Question 10

Wernicke’s encephalopathy causes and symptoms

Answer 10

Confusion, psychosis, ataxia, and oculomotor dysfunction as a result of vit B1 deficiency. Associated with reduced absorption and intake in alcoholics.

High bolus dose thiamine used to treat and prevent in susceptible individuals.

Question 11

Ascites treatments

Answer 11

Fluid accumulation in the abdomen.

Can be treated by reducing salt and water intake, or with the use of diuretics such as spironolactone (aldosterone antagonist), or the diuretic furosemide.

Can be drained manually (surgically) paracentesis

Question 12

Drug for treating alcoholism - stopping drinking

Answer 12

disulfiram inhibits acetaldehyde dehydrogenase

Causes an instant hangover following ethanol intake. used as a deterent to drinking to encourage cessation.