T or F
Liver lesions are much more common than liver failure
True: diffuse disease, rather than focal lesions, is required to produce failure
How much of your liver do you need to function and still be alive?
~30%
What is the most frequently injured organs in the body?
The Liver
Can the Liver regenerate?
yes it can, but its not considered true regeneration-compensatory growth
When do you see clinical signs of liver disease?
When the reserve is exhausted. The onset of signs may be acute, but are often the end result of chronic disease.
What is the largest gland in the body?
The Liver!
What allows the liver to avoid infarction?
Because of its DUAL blood supply
Where does the portal vein receive blood?
From the GI tract and the Spleen
T or F
Mixing of arterial and venous blood in the sinusoids increases the O2 of hepatic blood, but overall this is a High oxygen system
False, this is a low oxygen system: 50% O2 from hepatic artery, 50% O2 from portal vein
Which animal doesn't have a gallbadder?
The Horse, so you won't be diagnosing them with a cholecystitis
Which cell makes up of 94% of hepatic cells?
Hepatocytes
What makes up a portal triad?
Hepatic arteriole, portal venule, bile duct
+ lymphatic vessels
Label this microscope slide
A.
B.
C.
D.
A. Portal Vein
B. Bile Duct
C. Lympatic vessel
D. Hepatic Artery
Where does blood enter in the liver?
Blood enters lobule via portal triads and flows toward CENTRAL veins through the hepatic sinusoids
What is hepatic sinusoids lined by?
FENESTRATED endothelium
Hepatocytes are in direct contact with plasma
What is the name of the APC cells in the Liver?
Phagocytic Kupffer Cells (tissue macrophages)
What is the purpose of stellate cells in the liver?
They are involved in vit. A storage and sinusoidal blood flow regulation. Can synthesize collagen when activated (important role in hepatic fibrosis)
They reside in the space of Disse (space between endothelium and hepatocytes)
Which cells receives the most O2 in the liver?
A. Periportal Cells
B. Centrilobular Cells
Periportal cells: they are exposed to blood that first enters lobule, thus receiving the most O2
Where is a majority of the metabolizing enzyme system (drug and toxin metabolism)?
In the smooth ER of the centrilobular hepatocyes
Where does bile flow in relation to blood flow?
It flows in the opposite direction of blood flow
where is bile secreted in the liver?
into canalculi
(formed by tight junctions between adacent hepatocytes, lead to protal triads and bile ductules)
Define Cholestasis
It is the stasis or reduced flow of bile often due to damged hepatocytes
What does the secretion of bile require because it is an active process?
It requires ATP
Any injury tat causes significant hepatocellular injury can inhibit bile secretion
What are the two models for the microarchitecture of the liver?
The lobule model
The acinar model
Define Metabolic hertogeneity in the liver
It means that the concentration of enzymes also change across the lobule
Where would you most likely see ischemic tissue in the liver due to hypoxia?
In the Centrilobular Region
Equine piroplasmosis is caused by one of two tick transmitted hemoprotozoal parasites that invade and destroy erythrocytes to complete their life cycle. Laboratory findings may include profound anemia, icterus, hemoglobinuria, and mild to moderately elevated liver enzymes. The gross lesions often include icterus and splenomegaly.
What is the most likely cause of the increased liver enzymes?
A. Hepatocellular damage due to infection of hepatocytes
B. Hypoxia of centrilobular hepatocytes due to anemia
C. bile duct obstruction
D. Occlusion of the hepatic artery
B. Hypoxia of centrilobular hepatocytes due to anemia (iron deficiency)
What are the functions of the Liver?
A. Detoxification of endogenous and exogenous compounds
B. synthesis of plasma proteins (e.g. albumin and clotting factors)
C. Secretion and conduction of bile (exretion of detoxified compounds, and secretion of bil salts (for enteric fat solubilization))
D. Energy metabolism (Lipids and carbs)
E. Surveillance of hepatoportal blood (kupffer cells) (immune function)
F. Secondary role in salt and water homeostasis
What is an endogenous toxin that the liver detoxifies?
Ammonia-which is a result of nitrogen from protein breakdown
What are examples of exogenous toxins cleared by the liver?
Chlorophyll (herbivores), drugs
What produces ammonia?
Bacteria in the large bowl mostly and also by deamination of amino acids
What does the liver do with ammonia when it is functioning properly?
It converts it to urea which is than eliminated in the urine
True or False
Hepatic Encephalopathy is considered a diagnosis
FALSE
It is considered a clinical sign which can be represented by: head pressing, depression, disorentation, ataxia, seizures, dementia, blindness, prolonged recovery from anesthesia
How do you treat for hepatic encephalopathy?
Diet: give low protein (decreased production of ammonia and other neurotoxins)
GI acting antibiotic-->decrease GI flora and decrease ammonia production
Lactulose: synthetic dissacharide metabolized by LI bacteria--> lactic acid formation-->decreased colonic pH-->traps intestinal NH4+
When could you see chlorophyl toxicity in animals?
With Intrahepatic cholestsis (reduced bile flow) or severe hepatocellular injury
Becasue phylloerythrin is not metabolized, it accumulates in the blood, binds to cells in the skin .
Normally absorbed and excreted in bile
What is a clinical sign as a result of phylloerythrin toxicity due to poor liver detoxification?
UV irradiation to non-pigmented areas of skin causes fluorescent pigment to emit damaging radiation at a longer wavelength--> inflammation and necrosis-->produces dermatitis-->Secondary (hepatogeous) PHOTOSENSITIZATION
What plasma proteins is the liver responsible for producing ?
Albumin: synthesized exclusively by hepatocytes (oncotic pressure, carrier proteins, etc)
Clotting Factors
What is a consequence of dysfunction in the liver in regards to plasma protein synthesis?
Clotting factor deficiency: Coagulopathy
Hypoalbuminemia: edema, ascites, abnormal drug metabolism (insensitive measure of function, requries severe injury/loss of hepatocytes)