Unit 2: Liver

List some distinct cell types found within the liver

Kupffer cells, natural killer cells, liver sinusoidal epithelial cells, cholangiocytes, hepatocytes

Kupffer cells are ___ and serve as resident ___ that line the hepatic ___ and belong to the ___ system

Phagocytic, macrophages, sinusoids, reticuloendothelial

___% of the body’s total blood is typically present in the liver. Some of this blood can shift to ___ ___. During rest, about ___% of cardiac output goes to the liver

10%, skeletal muscle, 25%

What are the two pathways for blood to reach the liver?

Hepatic arteries, veins of portal system

In each hepatic lobule, arriving blood flows through the ___ of the liver to the ___ ___

Sinusoids, central vein

___ flows in the opposite direction of blood in the liver towards the ___ ___

Bile, bile duct

Hepatic sinusoids lack ___ ___ and a ___ ___, which increases the liver’s effectiveness at filtering and processing blood. There is free flow of ___ to the ___ space and into the sinusoidal ___

Tight junctions, basement membrane, proteins, perisinusoidal, blood

The perisinusoidal space is also known as the space of ___

Disse

___ cells are epithelial cells of the bile ducts that secrete a ___-rich fluid into the ducts

Cholangiocytes

___ cells are present in the ___ space and store ___, as well as vitamin ___

Stellate, perisinusoidal, lipids, A

Overactive stellate cells can produce ___ tissue (___) and participate in the progression of ___ ___

Scar (fibrosis), liver disease

The bile canaliculi normally start in spaces between adjacent ___. Bile flows towards the ___ of liver lobules, where canaliculi join together to form ___ ___

Hepatocytes, periphery, bile ducts

Due to the lack of tight junctions in the hepatic endothelium, about half of the body’s ___ forms in the liver

Lymph

During liver disease, large volumes of lymph accumulate in the ___ ___, resulting in a condition known as ___

Peritoneal cavity, ascites

Fibrosis and cirrhosis of the liver can decrease blood flow within the liver and lead to ___ ___

Portal hypertension

Many ___ and ___ are metabolized by the liver. For example, ethanol is a substrate for ___ ___. Many hormones are metabolized as well, such as ___ being metabolized to ___

Drugs, xenobiotics, alcohol dehydrogenase, T4, T3

In a phase 1 reaction, typically ___ occurs with the addition of ___ groups to a parent compound. The most common groups are ___ and ___ groups. Most phase 1 enzymes are located in the ___ ___ ___

Oxidation, polar, carboxyl, hydroxyl, smooth endoplasmic reticulum

Typically, carboxyl or hydroxyl groups are added by ___ ___ enzymes. Oxidation of drugs via these mechanisms allows for the excretion of ___ molecules

Cytochrome P450, hydrophilic

Phase 2 reactions involves ___ of drugs with other molecules such as glucuronic acid, glycine, taurine, and sulphates. This also makes the parent compounds more ___-___ and reduces their ___

Conjugation, water-soluble, toxic

Which hormone can be conjugated via glucuronidation and excreted in the urine?

Progesterone

Phase 3 reactions involve various ___ that work to ___ the products of phase 2 reactions

Transporters, eliminate

Glycogen can be ___-___% of the mass of the liver. Excess sugars are converted into ___ for storage

7-10%, glycogen

Typical fasting blood glucose levels are between ___-___ mg/dL. After a meal, it spikes to around ___-___ mg/dL

70-100, 120-150

When blood glucose levels fall between meals, the liver utilizes which enzyme to release free glucose into the bloodstream?

Glucose-6-phosphatase

Dysregulated ___ in diabetes contributes to high blood glucose levels

Gluconeogenesis

___ ___ converts glutamate and ammonia into glutamine. ___ levels are unusually high in hepatocytes

Glutamine synthase, ammonia

The liver produces about 3 grams of serum ___ per day, as well as other plasma proteins like ___ factors

Albumin, clotting

Hepatocytes efficiently take up ___ ___ when it comes to fat metabolism

Chylomicron remnants

When free acetyl-CoA increases, hepatocytes produce ___ ___, which can be an important fuel source for the ___ during fasting

Ketone bodies, brain

Hepatocytes package triglycerides into ___, which are important for transporting triglycerides from the liver to ___ ___

VLDLs, peripheral tissues

___ is a major component of oxidized LDL, playing a significant role in diseases like ___ and ___

Lysophosphatidylcholine, atherosclerosis, cancer

LPC is transported through the bloodstream bound to ___

Albumin

Patients with defective LDL receptors have (elevated/reduced) plasma LDL. This constitutes a condition known as ___ ___ because the liver cannot ___ LDL from the blood

Elevated, familial hypercholesterolemia, remove

___ are medications that inhibit ___ synthesis in hepatocytes to (raise/lower) plasma cholesterol levels

Statins, cholesterol, lower

Hepatocytes obtain ___ ___ from chylomicron remnants. When needed, ___ is released from within hepatocytes

Retinyl esters, retinol

Hepatocytes make ___ ___ ___, which binds to retinol and can be ___ from hepatocytes

Retinol-binding protein, exocytosed

When it comes to iron metabolism, hepatocytes have receptors for ___, which allows for ___-___ ___ to occur. ___ is a major iron storage protein inside cells

Transferrin, receptor-mediated endocytosis, ferritin

___ is made and released by hepatocytes, and serves to transport free heme in the blood. ___ cells can phagocytose old RBCs. Hepatocytes release ___ when stored iron levels are high, which slows intestinal absorption of iron, which normally prevents iron ___

Hemopexin, Kupffer, hepcidin, toxicity