1. Functions of The Liver!
Option D.3

2. The Liver Largest internal organ 2nd largest organ overall
Many different functions
Hepatic = liver
Hepatocytes = liver cells
Hepatitis = disease affecting liver
Hepatic cancer = liver cancer
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3. U: The liver intercepts blood from the gut to regulate nutrient levels.
CARBS: stores glucose as glycogen or breaks glycogen down to glucose
PROTEINS: breaks down excess protein to use as energy since can’t be stored (results in nitrogenous waste (urea) which is then processed
LIPIDS: chylomicrons from intestine are broken down; VLDL synthesized in hepatocytes, then they transport triglycerides synthesized in liver into blood for storage or use; excess cholesterol is converted into bile salts
Note: chylomicrons = lipoproteins made of triglycerides, phospholipids, cholesterol & protein (from the lipids in your food)

4. U: Some nutrients in excess can be stored in liver.
Glucose is stored as glycogen
Iron, vitamins A & D are stored when in excess and released when deficit

5. U: Components of red blood cells are recycled by the liver.
RBC’s live ~120 days
Removed from blood, broken down in spleen and liver
Liver breaks down RBC’s and hemoglobin
Products recycled

6. U: The breakdown of erythrocytes starts with phagocytosis of RBCs by Kupffer cells.
RBCs engulfed by Kupffer cells = macrophages that line sinusoids in liver
phagocytosis
Inside, hemoglobin is split into heme and globin
Amino acids from globin chains are recycled or deaminated into NH3 (ammonia), which is then converted into urea
Heme group further broken down into iron & bilirubin
Bilirubin transferred to bile
Iron sent to liver and spleen for storage or bone marrow to be used in making new RBCs

7. U: Iron is carried to bone marrow to produce hemoglobin in the new RBC.
Hemoglobin is synthesized in RBCs, and iron is added to heme group
Iron needed for RBCs because it is a part of the hemoglobin molecule and toxic at high conc.
Iron is transferred in blood via being bound to protein called transferrin
Once iron is bound to transferrin, iron is either incorporated into heme molecule or transferred to storage molecule called ferritin.

8. U: Surplus cholesterol is converted to bile salts.
FACTs about Cholesterol:
Where we obtain it:
Liver synthesizes it
Eat it in our diet
How much is made in the body:
Amount of cholesterol synthesized in liver varies with diet
Excess saturated fat in diet increases production of cholesterol
Needed for:
synthesis of vitamin D
synthesis of steroid hormones
component of cell membranes
used in production of bile

9. U: Endoplasmic reticulum and Golgi apparatus in hepatocytes produce plasma proteins
A single hepatocyte typically has 13 million ribosomes attached to ER
Also great numbers of Golgi body
Indicates high protein synthesis
Hepatocytes produce 90% of plasma proteins in blood
Albumin = carrier protein that binds to bilirubin
Fibrinogen = protein involved in blood clotting

10. U: The liver removes toxins from the blood & detoxifies them.
Liver absorbs toxins from blood and converts them into non-toxic or less toxic
Examples:
alcohol converted into less toxic substance by enzyme ethanol dehydrogenase
ammonia converted into urea
poisons and drugs converted from hydrophobic to hydrophilic (more easily excreted)

12. NOS: Educating the public on scientific claims: Scientific studies have shown that high-density lipoprotein could be considered “good” cholesterol
Lipoprotein = lipid + protein complex
allows fat & cholesterol to move through water/blood
Structure:
Exterior: hydrophilic, made of phospholipids, proteins, cholesterol
Interior: cholesterol & triglycerides
5 types of lipoprotein:
Chylomicrons = transport fat from intestine to liver
Some change their density if molecules removed from them

13. HDL vs LDL HDL LDL 20% cholesterol 50% protein 50% cholesterol

16. What is the leading cause of death in US?

18. App: Dual blood supply to the liver & differences between sinusoids & capillaries
Hepatic artery = oxygen-rich blood
Hepatic portal vein = lower oxygen because it’s already been to intestines, but nutrient-rich
Hepatic vein = oxygen-poor blood

19. Blood is always red!

20. Sinusoids Sinusoid = type of capillary with pores (fenestrations)
Wider than capillaries
fewer tight junctions
special locations (liver, spleen, bone marrow)
Highly permeable
Allows for exchange of large molecules (like albumin & RBCs)
serves as location for mixing of oxygen-rich blood from hepatic artery & nutrient-rich blood from portal vein
Contain Kupffer cells

21. App: Causes & consequences of jaundice http://visualhealthsolutions
App: Causes & consequences of jaundice Newborn jaundice