Week 7 - Liver Anatomy & Portal Circulation

Question 1

where is the liver located

Answer 1

• in the RUQ below the diaphragm

Question 2

what is the portal triad?

Answer 2

area of the liver containing:

1. portal arteriole
2. portal venule
3. bile duct

Question 3

what is the portal arteriole

Answer 3

• artery that carries O2 rich blood to the liver from the heart

Question 4

what is the portal venule

Answer 4

aka the portal vein

- vein that carries nutrient rich blood from the GI tract, spleen, and pancreas

Question 5

what is the bile duct

Answer 5

• drains bile from the liver into the gallbladder

- carries bile away from cells

Question 6

what is the functional unit of the liver

Answer 6

• hepatic lobule

Question 7

what are sinusoids

Answer 7

• fenestrated blood vessels that carry blood from the hepatic arteriole & portal vein into the central vein

Question 8

what is the central vein

Answer 8

• the large vein found in the center of the hepatic lobeules

- it carries blood into the hepatic veins which then drains into the IVC

Question 9

what are hepatocytes

Answer 9

• liver cells

Question 10

what is the function of the fenestrations in the sinusoids

Answer 10

• allows O2 and nuterients to squeeze thru them and enter the hepatocytes

Question 11

list the functions of the liver (9)

Answer 11

• produce bile salts
• excrete bilirubin in the the bile
• destroy bacteria in the portal blood
• maintain BG
• produce urea
• regulate lipid profile
• metabolize & detoxify drugs, hormones, and toxins
• produce proteins
• produce IGF

Question 12

how does the liver help regulate BG

Answer 12

either:

• converst glucose into glycogen if BG is high
• or breaks down glycogen into glucose if its low

Question 13

what types of proteins (or protein-like substances) does the liver produce (4)? what happens to these proteins after?

Answer 13

• coagulation factors/clotting proteins
• albumin
• angiotensinogen (glycoprotein)
• IGF –> insulin-like growth factors
• then released into the blood

Question 14

how does the liver effect our lipid profile

Answer 14

produce

• FA
• triglycerides
• cholestrol
• lipoproteins (LDL, VLDL)

Question 15

how does the liver produce urea

Answer 15

• detoxifies ammonium to create urea

Question 16

how does the liver create bile salts?

Answer 16

• converts cholestrol into bile salts

Question 17

how does the liver destroy bacteria in the portal blood

Answer 17

• thru kupffer cells

Question 18

what are kupffer cells

Answer 18

• modified macrophages found in the sinusoids

Question 19

what is the function of kupffer cells

Answer 19

• destroy old red & white blood cells, bacteria, and foreign substances that enter the sinusoids

Question 20

what is bile

Answer 20

bile salts + water + bilirubin

Question 21

what is bilirubin

Answer 21

• biproduct of the breakdown of Hgb

Question 22

what is angiotensinogen

Answer 22

• a glycoprotein which renin acts on to convert it into angiotensin
• plays role in the stimulation of the adrenal gland & simulating vasoconstriction

Question 23

what is the function of aldo

Answer 23

• tells us to keep water & Na, and get rid of K+

Question 24

what is IGF

Answer 24

a peptide hormone that plays a role in stimulating growth

Question 25

what are the superior & inferior mesenteric veins

Answer 25

• veins that drain the blood from the GI tract that contains the absorbed nutrients
• come together to drain to the Hepatic portal vein into the liver

Question 26

when is bilirubin formed

Answer 26

• during the breakdown of Hgb

Question 27

where does Hgb get broken down?

Answer 27

• within macrophages in the spleen & liver sinusoids

Question 28

what does the globin portion of Hgb get broken into ?

Answer 28

• amino acids

Question 29

what does the heme portion of Hgb get broken into

Answer 29

• iron

- bilirubin

Question 30

how is bilirubin transported

Answer 30

• does not dissolve well in the blood

= must be transported bound to albumin

Question 31

is bilirubin initially water soluble? what does this mean

Answer 31

• no

= cannot be excreted in the urine or bile

Question 32

how does bilirubin become water soluble? what is this called?

Answer 32

conjugation:

- it is conjugated to glucuronic acid

Question 33

where does conjugation take place?

Answer 33

• in the smooth ER of the hepatocytes

Question 34

why does bilirubin need to be conjugated?

Answer 34

• so it can be excreted in the bile

Question 35

what is another word for conjugated bilirubin? what about unconjugated bilirubin?

Answer 35

• conjugated = direct

- unconjugated = indirect or free