Liver Function Flashcards
1
Q
Where is the liver located?
A
beneath and attached to the diaphragm and is protected by the lower rib cage
2
Q
The liver is composed of how many lobes?
A
4
3
Q
Left and Right lobes are the largest and are separated by the ________ __________
A
falciform ligament
4
Q
The right lobe is about 5 to 6 times ______ than the left lobe
A
larger
5
Q
small lobe that extends from the posterior side of the right lobe and wraps around the inferior vena cava
A
Caudate lobe
6
Q
small lobe that is inferior to the caudate lobe and extends from the posterior side of the right lobe and warps around the gallbladder
A
quadrate lobe
7
Q
A branch of the aorta and supplies nutrient rich arterial blood, 25% of blood supply
A
hepatic artery
8
Q
it brings nutrient rich blood (collected as food is digested) to the liver from the gastrointestinal tracts, 75% of blood supply
A
portal vein
9
Q
The hepatic artery and the portal vein merge into the ______ ______
A
hepatic sinusoid
10
Q
The sinusoid is lined with ______ that remove toxic substances from the blood
A
hepatocytes
11
Q
After leaving the sinusoid the blood flows into the _______ _______ of each lobule, then through a collecting system of veins and empties into the _______ veins and finally the ______ _______ _______
A
central canal
hepatic
inferior vena cava
12
Q
Hepatic veins and the vena cava return what to the heart
A
processed/cleaned blood
13
Q
Where does the excretory system begin?
A
bile canaliculi
14
Q
What are small spaces between the hepatocytes that form intrahepatic ducts called?
A
bile canaliculi
15
Q
The intrahepatic ducts join to form the what?
A
The left and right hepatic ducts which allow the filtered waste and toxic products from the cells to drain
16
Q
How is the common bile duct formed?
A
The left and right hepatic ducts merge into the common hepatic duct and join the cystic duct of the gallbladder
17
Q
The combined waste and digestive secretions are then passed into the _________
A
duodenum
18
Q
What is the functional unit of the liver?
A
lobules
19
Q
What are responsible for all of the metabolic and excretory functions
A
Lobules
small hexagonal shaped functional units
approx 100,000 total
20
Q
Each lobule consists of what?
A
a central vein surrounded by 6 hepatic portal veins, 6 hepatic arteries, and 6 bile ducts
21
Q
In each corner of the lobule is a ______ _______ composed of a portal vein, hepatic artery and bile duct surrounded by connective tissue
A
portal triad
22
Q
The blood vessels are connected by capillary-like tubes called ______ which extend from the portal veins and arteries to meet the _____ ______
A
sinusoids
central vein
23
Q
What are the two cell types in the liver lobules
A
Kupffer cells
hepatocyes
24
Q
tissue macrophages that line the sinusoids and capture and break down old or damaged red blood cells, bacteria, toxins, and debris passing through the sinusoids
A
Kupffer cells
25
cuboidal shaped epithelial cells that radiate out from the central vein to the periphery of the lobule, they perform most of the livers functions (metabolism, storage, digestion, and bile production)
hepatocytes
26
Which cell type has a high regenerative ability?
hepatocytes
27
Which cell type makes up 80% of the liver's mass?
hepatocytes
28
What is made up of bile salts, bilirubin, cholesterol, and other waste products removed from the blood?
Bile
29
Excretion and secretion of the liver
removal of exogenous and endogenous waste products into the bile or urine
30
After approx. ______ days RBCS are phagocytized and hemoglobin is released
126
31
Hemoglobin is degraded into (3)
heme
globin
iron
32
What is bound to transferrin and returned to the liver and bone marrow stores?
Iron
33
What is degraded to amino acids to be reused?
Globin
34
What is converted into bilirubin and transported to the liver by albumin?
Heme
35
Form of bilirubin that is bound to albumin and transported to the liver, insoluble in water, and must be removed from the body.
Unconjugated/indirect
36
Bilirubin that has glucuronic acid attached, is soluble in water and can be excreted into the bile and travels to the small intestine where it is converted to urobilinogen
Conjugated/direct
37
Liver metabolizes (3)
carbohydrates
lipids
proteins
38
Forms glycogen from excess glucose through ______ for storage
glycogenesis
39
During stress or fasting conditions the liver can break down ______ to use for energy
glycogen
40
Brief fast (<1day)
glycogenolysis
breakdown of stored glycogen
41
Long fast (>1day)
gluconeogenesis
use of non-sugar carbon substrates to create glucose
42
The liver gathers and stores lipids as ______ ________
fatty acids
43
Fatty acids can be converted into ______ to make ________, _________, __________, and __________
acetyl-coA
phospholipids
cholesterol
vitamins
triglycerides
44
70% of the body's daily lipid (_________) requirements is made by the liver (___________), 30% is ingested (_________)
cholesterol
endogenous
exogenous
45
The liver produces almost all proteins in circulation except
hemoglobin and immunoglobulins
46
The liver serves as a ______ _______ for free amino acids from protein degradtion.
storage pool
47
uses transaminases to exchange an amino group on one acid with a ketone on another
transamination
48
after transamination, degrades the acids to produce ammonium ions that are consumed in the synthesis of urea and then urea is excreted in the urine
deamination
49
Will not see a decrease in protein synthesis until approx. _____ of the liver is damaged
2/3
50
What is the degradation/alteration of a substance taken by mouth, after absorption, by removing some of the active substrate from the blood before it enters the body's circulation?
First pass metabolism
51
What are 2 methods for the detox of metabolic waste (ammonia, bilirubin) or foreign substances (drugs or poisons)
binding
modifications
52
The material can be reversibly bound to inactivate the compound
binding
53
The material may be chemically modified so it can be excreted
Modifications
54
A yellow discoloration of the eyes, skin, mucus membranes due to the retention of bilirubin
Jaundice (Icterus)
55
Why is jaundice commonly seen in infants?
because of the increased destruction of RBCs with fetal hemoglobin
56
The three classifications of jaundice
Prehepatic
Hepatic
Posthepatic
57
Prehepatic
Problem prior to the liver
Usually due to an increased amount of bilirubin being presented to the liver for processing (ex. hemolytic anemia)
Will see elevated levels of unconjugated bilirubin
58
Hepatic
Problem in the liver
Due to a genetic defect or disease that effects bilirubin metabolism or transport
Can also be caused by cirrhosis, carcinoma, or hepatitis
will see elevated total bilirubin (conjugated and unconjugated will depend on the disease involved)
59
Posthepatic
Problem after the liver
Usually due to a physical obstruction in the biliary ducts (ex. gallstones, tumors)
Will see elevated conjugated and unconjugated bilirubin
60
An autosomal recessive disorder that affects approx. 5% of the population.
It is a result of the genetic mutation in the gene for the enzyme UGT1A1 (one of the enzymes important for bilirubin metabolism)
Gilbert's disease
Generally, has no adverse clinical consequences. Most commonly diagnosed after puberty, when alterations in sex hormone levels cause the blood bilirubin levels to rise.
Liver enzymes will be normal (the livers conjugation system is working at about 30% of normal)
61
More severe form of Gilbert's disease.
Crigler-Najjar Syndrome
Can be divided into two types, type 1 and type 2.
62
What type of Crigler-Najjar syndrome is more severe?
Type 1
There is a complete absence of bilirubin conjugation and affected individuals can die in childhood due to kernicterus
63
Type 2 Crigler-Najjar
Causes a major deficiency in the enzyme that conjugates bilirubin
Most affected individuals survive into adulthood.
64
A rare autosomal recessive condition caused by a deficiency in the protein required to remove conjugated bilirubin from the liver cells and excrete it into the bile
Dubin-Johnson Syndrome
65
How is Dubin-Johnson Syndrome characterizied?
Conjugated hyperbilirubinemia with normal liver enzymes and the deposition of a pigment that gives the liver a characteristic black color.
Patients have a normal life expectancy and no treatment is necessary.
66
Similar to Dubin-Johnson syndrome but the defect causing the syndrome is unknown.
Rotor syndrome
It is suspected to be caused by a deficiency in the intracellular binding proteins
Will see elevated levels of conjugated bilirubin, but no dark pigment in the liver.
Good prognosis and no treatment is needed.
67
Jaundice in newborns results in the deficiency of what enzyme?
Uridine Diphosphate glucuronosyltransferase (UDPGT)
*Responsible for bilirubin conjugation
68
What is the term for bilirubin build up in the brain
Kernicterus
69
How is jaundice in newborns treated?
UV light to destroy bilirubin as it passes through the capillaries in the skin
Severe cases may require an exchange transfusion
(levels greater than 20 mg/dL)
70
Scarring of the liver tissue that eventually blocks the blood flow to certain portions of the liver and prevents it from functioning properly
Cirrhosis
71
Causes of Cirrhosis (6)
Chronic drug and alcohol abuse
Hepatitis (B, C, and D)
inherited disorders (alpha1-antitrypsin deficiency, Wilson's Disease)
blocked bile ducts
nonalcoholic steatohepatitis
toxins or infections
72
Symptoms of Cirrhosis
* Will not see symptoms in early disease stages
*Fatigue
*Nausea
*weight loss
*Jaundice
*edema
*increased PT
GI bleeding
Intense itching
73
Treatment for cirrhosis
*Damage is not reversible, but progression and symptoms can be managed
*Treatment focuses on underlying causes
-for example hepatitis use medications (interferon) to treat
74
Primary Tumors
*begins in the liver
*usually associated with chronic hepatitis
*approx. 80% caused by hepatitis B or C
75
metastatic Tumors
*begins elsewhere in the body and moves to the liver
*More common form (90-95%)
*commonly caused by colon, lung, or breast cancers
76
Common types of benign tumors
hepatocellular adenomas and hemangiomas
77
Most common type of malignant liver tumor
hepatocellular carcinoma (HCC)
*poor prognosis (survival times of months)
*high percentage is in places where HBV is endemic
*In US patient with chronic HBV or HCV infection account for 30-40% of HCC cases
78
Causes abnormal deposits of fat to develop in the liver and other organs of the body, along with severe increase of pressure in the brain
Reye's Syndrome
79
When is Reye's syndrome normally seen?
In children recovering from a viral infection (flu or chickenpox)
*has been linked to aspirin administration to children with a viral syndrome
80
True or false
Reyes syndrome can be seen in adults
True (rare)
81
Symptoms of Reye's syndrom
increased ammonia, AST, ALT levels in the blood
encephalopathy
neurodegenerative disorders (confusion, personality changes)
vomiting
82
Treatment for Reyes Syndrome
Must be treated quickly with IV fluid, diuretic to relieve pressure on the brain, and medications to prevent bleeding
83
Drug and alcohol abuse accounts for _____ to ______ of all acute liver failures
1/3 to 1/2
84
Most common mechanism drugs cause damage to liver
Immune-mediated injury to the hepatocytes
*the drug indices and adverse immune response against the liver itself resulting in inflammation and eventually cirrhosis
85
What is one of the most commonly abused substances?
Alcohols (ethanol)
86
Early alcohol damage begins where?
Begins as fatty deposits in the liver with elevations in AST, ALT and GGT
*This stage can be cured if patient abstains from alcohol
87
Long term excessive alcohol use leads to what?
Moderate elevations in AST, ALT, and GGT with lower elevations of ALP
Will also see decreased protein levels and elevated bilirubin
88
Swelling and inflammation of the liver
Hepatitis
89
Causes of hepatitis
Viral (most common, major concern)
Bacterial/parasitic
drug/alcohol induced
autoimmune
radiation induced
90
Common forms of viral Hepatitis
A
B
C
91
Less common forms of viral Hepatitis
D
E
F
G
92
Why is fasting best for bilirubin?
Because high lipid levels will increase bilirubin concentration
93
Why avoid hemolysis with Bilirubin?
It can decrease the reaction with the diazo reagent (falsely low results)
94
Bilirubin must be kept away from light, why?
Light breaks down bilirubin, sample exposed to light will have a decrease in bilirubin of 30-50% per hour.
95
Commonly used bilirubin methods that are based on the diazo reaction
Malloy-Evelyn
Jendrasski-Grof
*colormetric methods
*use different accelerators
96
Bilirubin +sulfamic acid + accelerator =
Bilirubin + sulfamic acid =
Total bilirubin
Conjugated/direct bilirubin
97
Total bilirubin determinations include what 3 fractions?
Conjugated
unconjugated
delta
98
Conjugated bilirubin that is bound to albumin
Delta
Only seen when there is a significant hepatic obstruction or with dubin-johnson syndonrome
99
What is the end product of bilirubin metabolism?
Urobilinogen
100
What is urobilinogen converted to
It is converted to urobilin by the intestinal bacteria
101
Urobilinogen uses what reagent
Colorimetric reaction using Ehrlich's reagent
102
Specimen (2)
1. fresh 2 hour urine, kept cool and away from light
2. Aqueous extract of fresh feces
103
Common methodology used for serum bile acids
(not commonly done - only reference labs)
Uses GCMS, requires extraction with organic solvents prior to analysis
104
Will see an increase in bile acids with what?
with certain liver disorders
Can use the ratio of certain bile acids to differentiate between disorders
105
Liver Enzymes (6)
ALT
AST
ALP
5'-Nucleotidase
GGT
LDH
106
ALT/AST increased with...
hepatocellular disorders
highest with hepatitis
107
ALP increased with...
biliary obstruction
bone disorders
pregnancy
growth
108
5' Nucleotidase increased with...
biliary obstructions
*but not with bone disease, pregnancy, or childhood growth
*can be used to differentiate the cause for elevated ALP levels
109
GGT increased with...
biliary obstruction
chronic drug/alcohol abuse
110
LDH increased with...
**not specific for the liver**
hepatocellular disorders
111
When liver is functioning properly should have ______ protein levels, if liver is damaged will see ______ protein levels and _______ test results
normal
decreased
abnormal
112
Albumin
_______ levels can indicate systemic inflammation and liver disease/failure
decreased
113
Clotting Factors
Decreased with _______ ________
Will see ________ PT times
Liver damage
increased
114
Immunoglobulins
will see _________ levels with liver disease because there are _______ concentrations of the liver proteins
increased
lower
115
The liver is responsible for converting _______ to urea
ammonia
116
Elevated ammonia levels indicates what?
That the liver is damaged and can not perform the conversion
117
Elevated ammonia levels can lead to what?
Hepatic coma
*patient becomes increasingly disoriented and gradually lapses into unconsciousness
*more likely due to the build-up of toxic substances in the blood
118
Bilirubin (Adults)
Total =
Conjugated =
Unconjugated
Total = 0.2-1.0 mg/dL
Conjugated = 0.0-0.2 mg/dL
Unconjugated = 0.2-0.8 mg/dL
118
Bilirubin (Full Term Infants)
Total 24hr =
Total 48hr =
Total 3-5days =
Total 24hr = 2.6 mg/dL
Total 48hr = 6-7 mg/dL
Total 3-5days = 4-6 mg/dL
118
Urobilinogen
Urine =
Feces =
Urine = 0.1-1.0 Ehrlich units per 2h
Feces = 75-400 Ehrlich units per 24h
119
When does full term infants bilirubin normally peak?
between day 2 and 4
