D.3 Liver functions

Question 1

Liver blood flow

Answer 1

O2 blood –> Hepatic Artery
CO2 blood to liver –> Hepatic Portal Vein (from small intestines)
CO2 blood to heart –> Hepatic Vein

Question 2

Hepatic Portal vein

+ Order of blood flow

Answer 2

Deoxygenated blood from small intestines to liver to be filtered, then through Hepatic vein to heart

Divides into sinusoids in the liver allowing blood to come into contact with hepatocytes, allowing proteins to entre and leave the blood

Hepatic Portal Vein -> Arterioles -> Sinusoids -> Venules -> Hepatic Vein

Question 3

Hepatocytes

Answer 3

The cells in the liver that filter –> allow blood in and out

Question 4

Differentiate between the hepatic portal vein, Hepatic vein, and the hepatic artery

Answer 4

Hepatic Portal Vein = Blood from small intestines to the liver with low O2

Hepatic Vein = Blood from liver to heart with low O2

Hepatic Artery = Blood from heart with high O2

Question 5

Role of fibrinogen in the body

Answer 5

When cut, thrombin activates fibrinogen which converts into fibrin (insoluble) to form a mesh layer which forms a blood clot

Question 6

Insuline

Answer 6

Released when blood suger is high (lowers blood suger levels)
Produced by pancreas => tells the liver toi store glucose and glycogen

Question 7

Glucagon

Answer 7

Released when blood sugar is too low (glucose is gone) => increases sugar levels

Produced by the pancreas => tells skeletal muscle and liver to release glycogen as glucose into bloodstream

Question 8

Lipids and excess proteins

Answer 8

Excess proteins:
- cannot be stored and must be broken down to be used as energy

Lipids:
- Hydrophobic –> surrounded by phospholipids = low density lipoproteins
- Very low density lipoproteins are synthesised by hepatocytes

Question 9

Surplus choletrole is converted into bile salts

Answer 9

Bile salts:
- Emulsifies lipids in the digestive system (physical digestion)

Cholestrole:
- regulated by the liver

Question 10

Production of plasma proteins

Answer 10

Rough endoplasmic reticulum:
- ER in hepatocytes produce 90% blood plasma proteins
- Create Fibrinogen & Albumin

Albumin transports bilirubin

Golgi bodies and ER numbers are high to produce plasma proteins

Question 11

Liver stores excess nutrients such as:

Answer 11

• Glycogen
• Iron
• Vitamin A
• Vitamin D

Vitamin A and D are fat soluble, allowing them to be stored in the liver

Question 12

Kupfer cells role

Answer 12

• They are macrophages that engulf warn out and old erythroctes (RBC) in the sinusoid
• They line the sinusoid in the liver

Question 13

Kupfer breaking down erythrocyte process

(6-8 mark Q)

Recycling of Red Blood Cells in the liver

Answer 13

1. A kupfer cell engulfs a RBC through phagocytosis
2. Hemoglobin is produced
3. Hemoglobin breaks into 4x Globin & 4x Heme
4. Globin is broken into amino acids
5. Heme is broken into iron and Bilirubin
6. Bilirubin turns into bile and is taken to the gall bladder
7. Iron is carried to bone marrow
8. Bone marrow produced new erythrocytes

Question 14

Causes and consequences of Jaundice

Define myoglobin & Cytochrome

Answer 14

* Occurs when bile cannot be excreted and there is too much bilirubin in the blood
* Hemoglobin transports O2 to myoglobin for muscles –> Myoglobin has higher affinity for O2 than hemoglobin –> O2 more likey to attach to myoglobin than hemogloobin

Myoglobin:
- skeletal muscle store O2

Cytochrome
- electron carrier

Causes:
- Hepatitis or Liver cancer
- Obstruction of bile duct by gallstones or pancreatic cancer
- Develeping livers of newborns (unluggy)

Consequences:
- Yellow eyes and skin
- Itchyness in adults
- Kernicterus in newborns

Question 15

Bile

Answer 15

Bilirubin => bile

expelled from the gall-bladder into the duodenum to break down lipids

Question 16

Liver role

Answer 16

• The liver removes toxins from the blood and detoxifies them.
• The liver intercepts blood from the gut to regulate nutrient levels.