Chapter 5: Communication, homeostasis, excretion - Liver

Question 1

Which two sources supply the liver with blood?

Answer 1

Oxygenated via hepatic artery (from heart)
Deoxygenated via hepatic portal vein (from digestive system)

Question 2

Why does deoxygenated blood from the small intestine enter the liver?

Answer 2

To absorb and metabolise nutrients from the small intestine

Question 3

Where and how does the deoxygenated blood leave the liver?

Answer 3

Hepatic vein travels to the heart

Question 4

What do bile salts and bile pigments do? Where are they found?

Answer 4

Gall bladder
Bile salts - help digest fats
Bile pigments - waste product from breakdown of heamaglobin

Question 5

What is the Liver divided into?

Answer 5

Lobules separated by connective tissue

Question 6

What are wide capillaries in the Liver known as?

Answer 6

Sinusoids

Question 7

What are sinusoids lined with?

Answer 7

Incompleted layer of endothelial cells - so blood can reach hepatocytes

Question 8

Why do hepatocytes have a large surface area?

Answer 8

To maximise exchange of substances

Question 9

What cells make up the central vein?

Answer 9

Hepatocytes and Kupfer

Question 10

What are Kupfer cells?

Answer 10

They break down RBC into bilirubin

Question 11

What does the central vein do?

Answer 11

Removes detoxified substances and metabolic end products

Question 12

Why are excess amino acids deaminated?

Answer 12

Their amine group is removed to convert Ammonia to Urea

Question 13

Which is more soluble: Ammonia or Urea?

Answer 13

Ammonia

Question 14

What functions do hepatocytes carry out?

Answer 14

Storage of glycogen, formation of urea, detoxification

Question 15

True or false: Glycogen is a polysaccharide

Answer 15

TRUE

Question 16

Glycogenesis is one of the liver’s key roles. What is it?

Answer 16

The conversion of glucose to glycogen to help regulates blood glucose concentration

Question 17

What process does Insulin trigger?

Answer 17

Glycogenesis

Question 18

Give three examples of substances broken down in the liver

Answer 18

Hormones, alcohol, lactate

Question 19

What is lactate and how is it produced?

Answer 19

Energy-rich compound that can be respired by cardiac muscle - end product of anaerobic respiration

Question 20

What is lactate converted into in the liver?

Answer 20

Pyruvate

Question 21

What happens to the pyruvate

Answer 21

Some enters mitochondria to be respired aerobically to provide energy for the rest of the lactate to be converted to glucose

Question 22

Which enzyme converts ethanol into ethanal?

Answer 22

alcohol dehydrogenase

Question 23

How does alcohol cause fatty liver?

Answer 23

Ethanol generates large amounts of ATP so hepatocytes don’t metabolise as much fat, instead they store it, causing fatty liver. Hepatocytes aren’t able to carry out normal functions.

Question 24

How are hormones metabolised?

Answer 24

Peptide and protein hormones are hydrolysed into amino acids which can be converted into urea