T3 Liver and Pancreas Flashcards
What is the path of blood flow through the veins of the lobule?
portal vein –> sinusoids –> central vein –> hepatic veins.
What is the path of blood flow through the arteries of the lobule?
hepatic artery –> sinusoids –> central veins –> hepatic veins
How many layers of hepatocytes are liver cell places composed of?
two
Bile canaliculi lie between how many layers of hepatocytes in each cell plate?
two
What are liver lobule sinusoids lined with?
Endothelial cells and Kupffer cells
What is found between endothelial cells and hepatocytes of the liver lobule?
Space of Disse
The liver has _____ blood flow and ____ vascular resistance.
high; low
How much of the resting cardiac output does the liver use?
27%
What is the portal pressure into the liver?
9 mmHg
What is the pressure from liver to vena cava?
0 mmHg
What is the effect of cirrhosis on blood flow?
increases blood resistance to blood flow
What is the effect of a clot blocking portal vein or a major branch?
- blockage of return blood from spleen and intestines
- increase in capillary pressure in intestinal wall –> loss of fluid –> death
How much of the body’s blood volume is in the liver?
10%
High pressure in the atria increases back-pressure on the liver, increasing the blood volume in the liver. When might this occur?
during cardiac failure with peripheral congestion.
What organ can store blood in times of excess and supply blood in times of diminished volume?
Liver
Hepatic sinusoids are highly permeable to what?
proteins
What is the protein concentration of efferent lymph?
6 g/dl, almost equivalent to plasma concentration
What are the effects of higher than normal pressure in hepatic veins?
- back pressure causes fluid to transude into lymph
- fluid leaks through liver capsule into abdominal cavity
- fluid is almost pure plasma
- large amount of fluid in abdominal cavity = ascites
What are the functions fo the liver?
- Carbohydrate metabolism
- Fat metabolism
- Protein metabolism
- Vitamin storage
- Immune function
- Formation of coagulation factors
- Removal or excretion of drugs, hormones, and other substances
What are the main points of carbohydrate metabolism in regards to the liver?
- stores glucose as glycogen
- converts galactose and fructose to glucose
- gluconeogenesis
- forms many intermediate products of carbohydrate metabolism
- releases stored glucose into the circulation
What are the main points of fat metabolism in regards to the liver?
- oxidation of fatty acids for energy
- synthesis of cholesterol, phospholipids, and lipoproteins
- synthesis of fats from proteins and carbohydrates
What are the main points of protein metabolism in regards to the liver?
- deamination of amino acids
- formation of urea
- formation of plasma proteins
- interconversion of various aa and synthesis of other compounds from aa
What are the main points of vitamin storage in regards to the liver?
Vits A, D, and B12
What are the main points of formation of coagulation factors in regards to the liver?
Fibrinogen, prothrombin, accelerator globulin, Factors VII, IX, and X
What are the main points of removal or excretion of drugs, hormones, and other substances in regards to the liver?
- detoxifies or excretes into the bile: sulfonamides, penicillin, ampicillin, and erythromycin
- excretes excess calcium into the bile
- detoxification and removal of ammonia and ethanol
What factors stimulate the release of bile from the gall bladder?
presence of fatty food in duodenum
Bile is continuously secreted by what cells?
hepatocytes in the liver
Where is bile stored until its secreted?
gall bladder
Where is bile concentrated by active transport of sodium followed by secondary absorption of chloride ions, water, and other diffusible constituents?
gall bladder
Synthesis of bile salts are done by what?
liver
Bile salts are:
A. Hydrophobic
B. Hydrophilic
C. Amphipathic
Amphipathic
Bile salts orient themselves around lipid droplets and keep them dispersed. What is the name for this mechanism?
emulsification
What is the function of bile salts?
emulsification; complex with lipids to form micelles for absorption across the intestinal mucosa.
What is the map of a micelle?
bile salts are positioned on the outside of the micelles, and free fatty acids and monoglycerides are inside the micelle
Bile acids are concentrated in the gall bladder as a result of what?
absorption of solutes and water
Hepatic bile is produced and secreted by what?
liver
bile from the gall bladder is _______ that has been stored and concentrated
hepatic bile
What are the components of bile?
Bile acids, water and electrolytes, cholesterol and phospholipids (esp lecithin), and pigments and organic molecules (major pigment is bilirubin).
Free bilirubin is transported in the blood stream attached to what and transported to liver hepatocytes?
plasma albumin
Free bilirubin is released from plasma albumin within the liver cells and what?
conjugated