Term
| Name at least 5 functions of the liver. |
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Definition
- storage and filtration of blood
- metabolic functions (carbs, fat, protein)
- secretion of bile
- vitamin storage
- production of coagulation factors
- iron storage
- detoxification/excretion of drugs
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Term
| You are doing liver segmentectomy case. After listening to Gayle's lecture you know that this nomenclature is based on what? |
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Definition
| Division of the liver into segments is based on blood supply to certain liver areas. This is better than the older term "lobe" which was based on anatomy and doesn't reflect patterns of blood supply. |
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Term
| T or F: the hepatic artery delivers 75% of hepatic oxygen supply but provides only 50% of the blood flow. |
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Definition
| False. Hepatic artery=50% oxygen supply but only 25% of total blood flow. (It's an artery so it has more oxygen, duh) |
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Term
| If I told you that the liver recieved roughly 1.25 liters of blood per minute would you believe me? |
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Definition
| You should. Gayle's notes say it recieves 25% of CO. If we assume a CO of 5L/min, then .25*5=1.25 |
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Term
| What's the name of the peritoneum that surrounds pretty much all of the liver? |
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Definition
| Glisson's capsule (special name for that area of peritoneum) |
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Term
| T or F: the hepatic portal vein generates 75% of total blood flow and provides 25% of the liver's oxygen supply. |
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Definition
| False. Portal vein=75% blood flow and 50% of O2 supply |
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Term
| What are the two major vessels that come together to form the hepatic portal vein? |
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Definition
| splenic vein and superior mesenteric vein |
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Term
| You are reading an endovascular report for your patient that tells you that their portal vein pressure is 15 mmHg. What do you think about that? |
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Definition
| You should think it's a little high. Normal is 6-10mmHg. |
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Term
| The functional unit of the liver is the lobule, which is hexagonal in shape. The liver is made up of 50-100,000 lobules. The lobule is made up of "plates" according to Guyton, which Gayle describes as consisting of a portal triad...what makes up the portal triad? |
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Definition
- a portal vein
- hepatic artery
- bile duct
These structures extend out from a central hepatic vein. |
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Term
| The liver lobule is functionally divided into zones. Which zone is mostly involved in aerobic metabolism and why? |
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Definition
| Zone 1. It's closest to the oxygen rich blood vessels so it has the best access to O2 and contains a lot of mitochondria. |
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Term
| What lobule zone is most vulnerable to toxicity? |
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Definition
| Zone 3. It's the primary site for drug detox and functions in anaerobic metabolism. |
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Term
| Since the liver can directly regulate portal venous flow, how does it compensate when flow is drastically reduced (50%). What's the most potent "driver" of this mechanism? |
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Definition
| hepatic arterial buffer response. Adenosine vasodilates the hepatic artery to double the flow. This response maintains oxygen supply to the liver and maintains blood flow so that the liver can clear the blood of harmful compounds |
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Term
| If the parasympathetic tone to the liver increases what happens to glucose metabolism? |
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Definition
| glucose uptake by the liver is increased. Subsequently, glycogen synthesis and storage increases. (Think: there's no stress, it's time to eat and get fat. Once stress hits, the sympathetic system is activated-->glycogen is broken down to glucose and glucose is release to the bloodstream) |
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Term
| T or F: the hepatic portal vein system will respond to parasympathetic stimulation via cholinergic receptors. |
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Definition
| False, the venous system only response to sympathetic stimulation via alpha-1 (vasoconstriction) and D-1 receptors (vasodilation-->very small effect that is dwarfed by alpha-1 effect). |
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Term
| Let's say that there's been a lack of sympathetic stimulation to the liver for quite some time. What's the size of the blood reservior that the liver might be holding? |
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Definition
| 10-15% or roughly 500mL that could be released with a big sympathetic discharge! |
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Term
| T or F: synthesis of factors II, VII, IX, and X would be reduced in the patient with total biliary obstruction. |
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Definition
| True. These are vitamin K dependent coag factors. Vit K absorption is dependent on bile secretion and transformation to its active form by gut bacteria. No bile=no vit K=reduced vit K dependent cofactors |
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Term
| What does Gayle say is the only coag factor not dependent on liver production? |
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Definition
von Willebrands (VIIIvWF)
Actually, factor III (tissue factor or thromboplastin) is produced in the vascular wall and factor IV (calcium) is dependent on diet...so, if they asked on boards I would say there are 3. |
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Term
| What does the liver synthesize that regulates the production of platelets? |
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Definition
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Term
| The liver makes most of the body's coag factors as well as anticoag factors. List the anticoag factors. |
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Definition
- antithrombin III
- protein C
- protein S
- fibrinolytic factors (tissue-type plasminogen activator(tPA), and urokinase-type plasminogen activator(uPA))
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