Upgrade to remove ads
Only $35.99/year

Functions of the liver

Terms in this set (8)

Outline the circulation of blood through liver tissue
- The liver contains huge number of cells called hepatocytes.
-The liver is supplied with blood by two vessels, the hepatic portal vein, and the hepatic artery.
-The Hepatic vein carries blood away, while blood brought by the hepatic portal vein is deoxygenated (as it has already flowed through the walls of stomach or intestines)
- One of the main functions of the liver is regulate level of nutrients before blood flows to the rest of the body
- Inside the liver, hepatic portal vein divides into vessels called sinusoids (wider than normal capillaries with porous walls)
- Many pores between the one cell layer, but no basement membrane
- Blood flowing through the sinusoids therefore in very close contact with surrounding hepatocytes
- Hepatic artery supplies liver with oxygenated blood from the left side of the heart via the aorta
- Branches of hepatic artery join the sinusoids at various points along length, providing hepatocytes with oxygen needed for aerobic respiration
- The sinusoids drain into wider vessels that are branches of the hepatic vein
- blood from liver is carried by the hepathic vein to the right side of heart via inferior vena cava
What are the 5 roles of the liver
Nutrient storage and regulation
Breakdown of erythrocytes
Synthesis of plasma protein
Synthesis of cholesterol
Detoxification
Explain the role of the liver in nutrient regulation
When certain nutrients are excess in the blood, hepatocytes absorb and store them, releasing them when the level is low.
Eg. when blood glucose is too high, insulin stimulates hepatocytes to absorb glucose and convert it to glycogen.
When too low, glucagon stimulates hypatocytes to break down glycogen and release glucose into the blood
Iron, vitamin A, Vitamin D are also stored in the liver
Explain the role of the liver in the breakdown of erythrocytes
Erythrocytes (red blood cells) have a fairly short lifespan (120 days). Plasma membrane becomes fragile and eventually ruptures, releasing the heamoglobin into the blood plasma. This hemoglobin is absorbed through phagocytosis mainly in the liver, using the phagocytic plasma cells called Kupffer cells.
Inside these cells, Hemoglobin is split into the heme and globin groups. Globins are hydrolysed into amino acids, which are released from the blood
Iron is removed from the heme groups, leacing a yellow substance called Bile pigments, or bilirubin
The iron and bile pigments are released into the blood, and the iron carried away by the blood marrow. Bile pigments are used for bile production in the liver.
Explain the role of the liver in the synthesis of plasma proteins
The rough endoplasmic reticulum of hepathocytes produces 90% of the proteins in blood plasma, including all the albumin and fibrinogen
Explain the role of the liver in the synthesis of cholesterol
Although some cholesterol is absorbed from food in the large intestine, a larger quantity is synthesised each day by hepatocytes
Detoxification
Hepatocytes absorb toxic substances from blood and convert them by chemical reactions into non-toxic or less toxic substances
Explain the liver damage caused by excessive alcohol consumption
Liver cells absorb alcohol and convert it into other substances to detoxify it
Excessive consumption of alcohol therefore damages liver cells.
Fatty deposits build up, which can cause hepatitis
Alcoholic hepathitis is inflammation of the liver, often associated with nausea and jaundice
If this is persistent, it could cause cirrhosis - normal liver tissue is gradually replaced with scar tissue
Liver cells gradually die and become replaced, leading to acute liver failure
Recommended textbook explanations

Essential Cell Biology

4th EditionBruce Alberts, Dennis Bray, Karen Hopkin
359 explanations

Elevate Middle Grade Science 2019 Physical

Prentice Hall
403 explanations

Campbell Biology

9th EditionJane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman
655 explanations

Biology Foundations Workbook Student Edition

1st EditionJoseph S. Levine, Kenneth R. Miller
485 explanations