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35 Cards in this Set
- Front
- Back
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What cells in the body contain the highest concentration of glycogen?
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The Hepatocytes.
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This stimulates the liver to produce somatomedins.
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HGH.
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In what tissue do we find the most glycogen?
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Skeletal muscle.
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During fasting, how does the liver release glucose into the blood?
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Through glycogenolysis and gluconeogenesis.
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What is Gluconeogenesis?
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The generation of glucose from non-carbohydrate carbons like pyruvate, lactate, glycerol and AAs (alanine). This glucose is used during fasting.
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What is Glycogenolysis?
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The breakdown of glycogen during fasting. This provides blood glucose to keep neurons functioning.
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What does the liver have that the muscle cells don't that allows the liver to release glucose?
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Glucose-6-phosphatase.
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Liver transporters are insulin __________. Muscles' are insulin __________.
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Liver--Insulin independent.
Muscle--Insulin dependent. |
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What are 3 ways in which hepatocytes contribute to lipid regulation?
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1. Production of VLDLs.
2. Production of HDLs. 3. FAs-->Ketones |
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What are VLDLs?
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Very low density lipoproteins.
Made by hepatocytes which package triglycerides to be sent out into the blood for distribution of the FAs to cells of body. |
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What are HDLs?
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High density lipoproteins.
Made by hepatocytes. They scavenge cholesterol from the blood and peripheral tissues. |
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What are ketones?
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Soluable FA analogs. Hepatocytes can make ketones (acetoacetate and 3-OH-butyrate) from FA metabolism.
The significance of the ketones is that they're water soluble while FAs are poorly soluble. Therefore the liver can distribute FA carbons to cells of the body during fasting. |
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What is gluconeogenesis a virtual reversal of?
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Glycolysis.
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What are two things to remember about the liver and AAs?
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1. The liver may have to use skeletal muscle AAs, proteolysis, during fasting to make glucose via gluconeogenesis.
2. Hepatocytes are primarily responsible for the ability to synthesize a number of amino acids (making them nonessential dietarily). |
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Where does the primary nitrogenous waste product that makes up urea come from?
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The liver's removal of amine groups from amino acids during gluconeogenesis.
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What is the enzyme that produces urea?
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Arginase.
Arginine->Urea & Ornithine |
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This enzyme allows the liver to efficiently synthesize glycogen during "Good Times".
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Glucokinase.
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In what form does the liver store lipids?
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As triglycerides.
This can also be a disease state resulting from prolonged "Good Times". |
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Why is it hard to get rid of cholesterol?
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It is hydrophobic.
90% recycled. |
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Where are plasma proteins made?
Exception? |
In the hepatocytes.
Except for gamma globulins. |
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What are the 2 most noteworthy types of plasma proteins?
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1. Clotting Factors
2. Albumin |
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What is important about the clotting factors?
Examples? What vitamin is important in their synthesis? |
They are plasma proteins involved in regulating homeostasis.
Examples: Fibrinogen, prothrombin, Factor VII Vitamin K--without it one can have prolonged bleeding. |
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What is significant about albumin?
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It is the most abundant of the plasma proteins.
It is a good non-specific reversible binder of hydrophobic compounds. Helps distribute a broad variety of steroid hormones, drugs, etc. Because of its abundance it plays a major role in osmolality of the plasma. (Fluid mvmt. between caps & interstitum). W/o it edema may result. |
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What is the function of bile?
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To emulsify lipids into micelles.
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What are the two bile salts/acids called?
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1. Taurocholate
2. Glycocholate They have a polar (taurine or glycine) and nonpolar (cholesterol) component to each molecule. |
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What are the 3 dietary fats?
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1. Triglcerides
2. Phospholipids 3. Cholesterol |
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What is bilirubin?
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The waste product of heme catabolism.
Macrophages release iron from heme group and the remaining compound is converted to biliverdin and then bilirubin. |
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What happens to bilirubin before being excreted in bile?
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The liver conjugates it with glucuronate and/or sulfate.
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What are the 2 primary functions of drug metabolism?
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1. Making the drug hydrophilic in order to facilitate excretion by the kidneys.
2. Make the drug less active--most become less active when metabolized. |
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The liver metabolizes drugs and hormones with 2 types of reactions, what are they?
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Phase I reactions: Biotransformations of drug to make it more polar (hydrophilic). This takes place at the SER--most commonly oxidations by cytochrome P-450 oxidases.
Phase II reactions: Some drug metabolites pass from phase I to phase II. Some pass directly to phase II. This makes the drug or metabolite even more polar (hydrophilic) by conjugation with compounds (glucuronate especially). |
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What is 'first-pass metabolism'?
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When drugs are absorbed in the small intestine and immediately enter the hepatic portal system. They are exposed to inactivation before ever having a chance to circulate throughout the body.
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What vitamins does the liver store?
How long can it store each? |
Vitamin A--10 months
Vitamin D--4 months Vitamin B12--over a year |
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What notable mineral does the liver store?
What protein is this mineral bound to? What is the combination of this mineral and protein called? |
Iron
It is bound to the protein apoferritin. Together it is called ferritin. Storage for red blood cells. |
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What are somatomedins/Insulin-like Growth Factors (IGF)?
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They act to increase chondrocyte and osteoblast cell activity and cell number.
They also promote conversion of chondrocytes to osteogenic cells--increase bone synthesis. Produce direct effects for HGH. |
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What cells of the liver assist in cleansing the blood of bacteria?
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Kuppfer Cells--phagocytic macrophages.
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