5.2.2 structure of liver

Question 1

liver cells

Answer 1

hepatocytes

Question 2

two sources of blood to the liver

Answer 2

• hepatic artery
• hepatic portal vein

Question 3

describe the hepatic artery

Answer 3

• oxygenated blood from heart from aorta
• supplies oxygen essential for aerobic respiration
• liver cells active = carry out many metabolic processes (many require energy - ATP)

Question 4

describe the hepatic portal vein

Answer 4

• deoxygenated blood from digestive system enters liver
• blood rich in products from digestion
• concentrations of substances uncontrolled as entered from intestines
• blood may contain toxic compounds absorbed from intestine

Question 5

describe the hepatic vein

Answer 5

• blood leaves liver
• rejoins vena cava & blood returns to body’s normal circulation

Question 6

fourth vessel connected to liver

Answer 6

bile duct

Question 7

describe the bile duct

Answer 7

• bile = secretion from liver with functions in digestion/excretion
• bile duct carries bile from liver to gall bladder where it’s stored until required to aid digestion of fat in small intestine
• bile contains excretory products (eg. bile pigments) which will leave body with faeces

Question 8

histology of liver
1. lobes

Answer 8

• divided into lobes
• lobes divided into lobules = cylindrical

Question 9

inter-lobular vessels

Answer 9

hepatic artery/portal vein split into smaller vessels as enter liver which run between/parallel to lobules

Question 10

histology of liver
2. inter-lobular vessels

Answer 10

• hepatic artery & portal vein split into smaller vessels as enter liver which run between/parallel to lobules

Question 11

histology of liver
3. sinusoids

Answer 11

• at intervals, branches from hepatic artery/portal vein enter lobules
• blood is mixed & passes along special chamber = sinusoid
• sinusoid lined with liver cells
• liver cells able to remove substances from blood/return other substances to blood

Question 12

histology of liver
4. kupffer cells

Answer 12

• specialised macrophages = kupffer cells
• move about within sinusoids
• primary function: breakdown & recycle old blood cells

Question 13

histology of liver
5. bile canaliculi

Answer 13

• bile made in liver cells & released into bile canaliculi
• join together to form bile duct
• bile duct transports bile to gall bladder

Question 14

histology of liver
6. what happens when blood reaches end of sinusoid

Answer 14

• concentrations of many components modified & regulated
• centre of each lobule = branch of hepatic vein (intra-lobular vessel)
• sinusoids empty into this vessel
• branches of hepatic vein (from different lobules) join to form hepatic vein which drains blood from liver

Question 15

describe liver cells

Answer 15

aka hepatocytes

• relatively unspecialised
• simple cuboidal shape
• many microvilli on surface
• metabolic functions include: protein synthesis, transformation/storage of carbohydrates, synthesis of cholesterol/bile salts, detoxification etc.
• cytoplasm must be very dense & specialised in number of certain organelles