week 11 - disorders of the liver/renal system

Question 1

What is the function of the liver?

Answer 1

Produces bile
Is important for metabolism
Helps remove toxins from blood

Question 2

Describe the liver’s blood supply?

Answer 2

Blood comes in via:
Hepatic artery (carries oxygenated blood) and hepatic portal vein (carries nutrient rich blood)

Blood exits via:
Hepatic vein

Question 3

What is the liver made out of?

Answer 3

Lobules

Question 4

What are the 3 zones of a lobule?

Answer 4

Zone 1 - periportal
Zone 2 - midlobular
Zone 3 - perivenular

Question 5

What is the function of zone 1?

Answer 5

It is the first zone to come into contact with blood
Deals with hepatotoxins

Question 6

What is the function of zone 2?

Answer 6

It is regenerative and is the source for new hepatocytes

Question 7

What is the function of zone 3?

Question 8

What do hepatocytes do?

Answer 8

They perform the majority of roles in the liver

Question 9

What is bile?

Answer 9

It breaks down fats into fatty acids

Question 10

W

Question 11

What is AST and ALT

Answer 11

stands for aspartate aminotransferase and alanine aminotransferase and they are both expressed in the liver.

If you have increased levels of ASL and ALT (a ratio higher than 1) then it’s a sign you have liver damage

AST and ALT can leak into your bloodstream when your cells get damaged

Question 12

What are the various tests to test your liver function?

Answer 12

???

Question 13

What are the stages of liver damage?

Answer 13

1. Healthy liver
2. Steatosis inflammation
3. Fibrosis
4. Cirrhosis
5. Liver cancer

Question 14

What is steatosis?

Answer 14

It is where there is a build up of fat in the hepatocytes.
The liver is a primary organ for lipid metabolism however when one has steatosis, the excess fat cannot be processed so accumulates in vesicles.

This can be seen as enlarged liver cells with many fat droplets present in the cytoplasm

Question 15

What are the signs of liver disease?

Answer 15

Jaundice
Itching (pruritus)
Ascites

Question 16

What is jaundice?

Answer 16

Presents as yellowish discolouration of the skin caused by hyperbilirubinaemia and the deposition of bile pigments.

Bilirubin is usually metabolised but in hyperbilirubinaemia bilirubin fails to get metabolised so patients have a high serum bilirubin level greater than 2mg/ml

Question 17

Explain the theory Why do people with liver failure experience itching aka pruritis?

Answer 17

An elevation of serum bile salts stimulate nerve endings to produce the itching sensation.

Question 18

What are other alternative explanations as to why liver disease patients experience itching?

Answer 18

Raised histamine levels in liver disease patients cause itching

Patients with liver disease are not able to clear toxins from the blood which may build up in the brain, leading to cognitive issues, producing an itching sensation.

Question 19

Describe what ascites is in patients with liver disease

Answer 19

It is a build up of fluid in the abdomen.

Caused by liver dysfunction and cirrhosis which can lead to portal hypertension.
Portal hypertension (high blood pressure in portal vein) causes fluid to leak out of the veins causing ascites.

Question 20

What is hepatomegaly and what is it caused by?

Answer 20

It is an enlarged liver caused by liver diseases such as GSD, carcinoma, hepatitis etc

Question 21

What is non alcoholic fatty liver disease (NAFLD)

Answer 21

It is a build up of fat in the liver NOT caused by alcohol

Question 22

What are some NAFLD risk factors?

Answer 22

Being obese
Diabetes
high BP/cholesterol
PCOS
hypothyroidism

Question 23

What are some thing that can prevent NAFLD?

Answer 23

Lose weight
exercise
healthy diet \

Question 24

how does chronic alcohol intake cause liver disease?

Answer 24

The liver is most exposed to alcohol as the liver is where metabolism of alcohol takes place.
This results in hepatocyte damage via oxidative stress and increases fat deposits in the liver
Over time, the structure of the liver changes due to damaged hepatocytes.

Question 25

Describe stage 1 of alcohol induced liver damage?

Answer 25

Steatosis occurs - build up of fats in the liver

Question 26

Describe stage 2 of alcohol induced liver damage?

Answer 26

Fibrosis occurs

Question 27

Describe stage 3 of alcohol induced liver damage?

Answer 27

Cirrhosis occurs

Question 28

What is liver cirrhosis?

Answer 28

It is when the scar tissue blocks blood flow of the liver - obstructs the portal blood flow causing portal hypertension.

Also results in hepatocyte damage meaning that when blood passes through the liver to get the toxins removed, there is a reduced amount in removed toxins from the blood.

Question 29

What is portal hypertension/

Answer 29

high blood pressure in the portal vein caused by cirrhosis which causes back pressure in the portal vein.

It can lead to varicose veins, ascites as back pressure forces fluid out and formation of collaterals which are thin walled vessels that can rupture.

Question 30

Symptoms of portal hypertension?

Answer 30

Enlarged gut due to ascites

Blood in vomit/stool bc of weak collateral vessels

Tiredness, pallor, breathlessness due to bleeding

Diarrhoea and poor weight gain due to swelling of blood vessels in intestine lining which reduces absorption of digested food.

Question 31

What are the causes of portal hypertension?

Answer 31

Post hepatic causes - thrombosis of the portal vein

Intra hepatic causes - cirrhosis

Post hepatic causes -b obstruction between the liver and right heart.

Question 32

What other issues can liver dysfunction cause?

Answer 32

Hepatorenal syndrome
Hepatopulmonary syndrome
Hepatic encephalopathy

Question 33

What is hepatorenal syndrome and what is ti caused by?

Answer 33

It is the rapid deterioration off the kidneys due to liver failure.

Caused by dilation of the gut which constricts renal circulation.
Results in low blood volume to the kidneys

Question 34

What is hepatopulmonary syndrome and what is it caused by?

Answer 34

??

Question 35

What is hepatic encephalopathy and what is it caused by?

Answer 35

Normally, the liver removes toxic substances from the blood but a person with liver dysfunction can’t do that properly so therefore, the toxic substances accumulate in the blood which damages brain cell function.

Symptoms include impaired cognition, reduced consciousness etc

Question 36

What are the stages of hepatic encephalopathy?

Answer 36

stage 1 - mild confusion, irritable, reduced attention, sleep disturbances

stage 2 - disorientation, inappropriate behaviour, drowsy

stage 3 - confusion, aggressive,

stage 4 - coma

Question 37

Give a brief function of the kidneys, ureters, bladder and urethra

Answer 37

kidneys - filter blood
ureters - transports urine to bladder
bladder - stores urine
urethra - discharges urine from the body

Question 38

What else does the kidney do other than filter blood?

Answer 38

regulation of blood ion composition, blood pH, blood volume
maintains blood osmolarity
release renin to reg blood pressure
excretion of waste products

Question 39

what are the 3 structures of the kidney?

Answer 39

renal cortex - filters the blood
renal medulla - regulates water, salts
renal pelvis - collects urine and sends the urine to the bladder

Question 40

What is the function of the nephron

Answer 40

glomerular filtration
tubular secretion/reabsorption

Question 41

What is the glomerulus?

Answer 41

start of the nephron
it is a network of capillaries which filters in water, glucose, amino acids, urea ions into the tubule but does not let in large proteins, red/white blood cells, platelets.

The glomerulus contains podocytes which regulate selective filtration of the blood

Question 42

Describe the function of podocytes?

Answer 42

highly specialised cells that regulate selective filtration of the blood
they wrap around capillaries,
they have slits in them so blood can be filtered through

Question 43

What is the Bowmans capsule?

Answer 43

structure that surrounds the glomerulus
It collects the content filtered out of the plasma then sends it into the PCT