Topic D.3: Functions of the Liver

Essential Idea:  The chemical composition of the blood is regulated by the liver.

At SHS, Topic D.3 is taught in the following class unit(s):

• Liver Structure and Function (unit 40)

Statements & Objectives:

D.3.U1  The liver removes toxins from the blood and detoxifies them.

• Define “detoxification” as related to liver function.
• Explain the role of the liver in the detoxification of alcohol (including role of ethanol dehydrogenase).
• Outline the role of the liver in the detoxification of ammonia (and formation of urea).

D.3.U2  Components of red blood cells are recycled by the liver.

• State the length of a typical red blood cell life span.

D.3.U3  The breakdown of erythrocytes starts with phagocytosis of red blood cells by Kupffer cells.

• Explain how the structure of Kupffer cells fits their endosymbiosis function.
• Create a flowchart to illustrate the steps and products of the splitting of hemoglobin
  

D.4.U4  Iron is carried to the bone marrow to produce hemoglobin in new red blood cells.

• Explain how and why iron is transported to the bone marrow bound to transferrin.
• List three anatomical structures that have transferrin receptors on their cell membranes.
• Outline the storage of iron in the liver and spleen (including the role of ferritin).

D.3.U5  Surplus cholesterol is converted to bile salts.

• Outline the roles of hepatocytes in the conversion of excess cholesterol into a component of bile.
• Explain the synthesis of VLDL cholesterol by hepatocytes for transport of triglycerides.
• Describe how the amount of saturated fat in a diet affects the amount of VLDL cholesterol synthesis by the liver.

D.3.U6  Endoplasmic reticulum and Golgi apparatus in hepatocytes produce plasma proteins.

• Define and list examples of “plasma proteins.”
• Explain why hepatocytes have a lot of RER and Golgi.

D.3.U7  The liver intercepts blood from the gut to regulate nutrient levels.

• Explain the storage and release of glucose (including the role of glycogen, insulin and glucagon).
• Outline the role of the liver in protein metabolism (and resulting nitrogenous waste formation).

D.3.U8  Some nutrients in excess can be stored in the liver.

• List four example nutrients that can be stored by the liver.

D.3.A1  Causes and consequences of jaundice.

• Outline the function and source of bilirubin.
• Explain the role of hepatocytes and glucuronic acid in the conversion of bilirubin.
• List components of bile.
• Outline the role of bile ducts and gall bladder in the transport and storage of bile.
• Describe when, where and why bile is secreted during digestion.
• Define and list causes and symptoms of jaundice.
• Describe the use of UV light as a treatment for jaundice.

D.3.A2  Dual blood supply to the liver and differences between sinusoids and capillaries.

• Draw and label a diagram of the liver, including the left and right lobes, hepatic portal vein, hepatic artery and the hepatic vein.
• Compare liver blood supplies in terms of blood source (arrives from…), blood destination (flows towards…), and relative oxygen concentration.
• Draw a labeled diagram of a sinusoid, inclusive of:  bile canal cells, bile duct, hepatocytes, Kupffer cells, arterioles and venules.
• Compare sinusoids to capillaries.
• Outline the relationship between liver lobes, lobules and sinusoids.

D.3.NOS  Educating the public on scientific claims—scientific studies have shown that high-density lipoprotein could be considered “good” cholesterol.

• Compare and define LDL, HDL, IDL, VLDL and chylomicrons.
• Explain the structure of lipoproteins, including the types of molecules found in the hydrophobic core and hydrophilic surface.

In the News:

• One-off injection may drastically reduce heart attack risk (2019-05-10)
  
• To Fight Fatty Liver, Avoid Sugary Foods and Drinks (2019-01-19)
• More Americans Are Dying of Cirrhosis and Liver Cancer (2018-07-18)
• A South American amphibian could potentially hold the key to curing cirrhosis (2017-12-06)
• Fancy Juice Doesn’t Cleanse the Body of Toxins (2016-04-20)
• Your Liver Doesn’t Know It’s the Holidays (2016-12-22)
• Supercooled livers last for days (2014-06-29)
• New regulator of liver metabolism discovered​ (2017-09-29)
• Fattened livers prep white sharks for extreme migrations (2013-07-13)
• The Liver: A ‘Blob’ That Runs the Body (2017-06-12)