Lab Tech Exam 2 Flashcards
Total protein =
albumin + globulins
Albumin makes up __-__% of total plasma protein in most animals
35-50%
What organ is albumin produced by?
liver
This protein binds to & transports many substances
Albumin
Albumin accounts for about ___% of osmotic activity
75%
Too little albumin in the blood
hypoalbuminemia
What can cause hypoalbuminemia?
Hepatic disease, malnutrition, intestinal malabsorption, renal disease, blood/plasma loss
Too much albumin in the blood
Hyperalbuminemia
Hyperalbuminemia is _______; decreased plasma water content due to dehydration.
relative
All proteins other than albumin are collectively called ________. This includes fibrinogen.
globulins
What tube must you use to measure fibrinogen?
purple top
Globulins vary in size, structure, function & charge. Most are produced in the _____ and ____ tissue.
liver
lymphoid
Immunoglobulins aka
antibodies
Globulins are normally estimated by determining the difference between what?
total protein TP - ALB (albumin)
What are some causes of hypoglobulinemia?
liver disease, malnutrition, intestinal malabsorption, renal disease, blood/plasma loss, failure of passive transfer (from dam to neonate)
What are some causes of hyperglobulinemia?
Relative (decreased plasma water content due to dehydration); inflammation (infectious & noninfectious); lymphoid neoplasms; plasma cell myeloma
What does hepatobiliary refer to?
Liver enzymes and other substances made by the liver
Enzymes found _____ in the cytoplasm of the cell that leak out when the cell is injured.
free
The hepatocyte can be injured by what 2 broad categories?
Primary liver disease
Secondary
These are examples of what type of liver problem: toxins, medications; inflammatory reaction; direct trauma; cholestasis (due to toxicity of bile salts and bilirubin)
Primary liver disease
These are examples of what type of liver problem: leakage of pancreatic enzymes due to anatomical location; GI disease; hypoxia from anemia or poor circulation
Secondary liver disease
Magnitude of elevation of these leakage enzymes is dependent on the ______ of cells being affected, not on the ____ of the injury to these cells.
Number
Severity
Enzyme involved in biosynthesis of alanine.
Liver specific in dogs, cats & primates (major source is hepatocyte).
Alanine aminotransferase (ALT)
An increase in ALT is usually seen within ___ hours of hepatocyte damage.
Peak levels seen in __-___ hours.
Levels return to normal in a few weeks unless chronic insult is present.
12 hours
24-48 hours
Moderate increases in ALT can occur by overproduction produced by what 2 medications?
Glucocorticoids and anticonvulsants
This enzyme is involved in the synthesis of aspartate.
Not liver specific
Aspartate aminotransferase (AST)
This enzyme has a short half life in dogs and cats. There is no advantage over ALT in these species.
AST
AST has a longer half life in horses & cows. However, it is also a _____ enzyme so must be interpreted in light of _____ ______.
Muscle Creatine kinase (CK)
This enzyme is liver specific in large animals but is difficult to run because it is relatively unstable. Extremely short half life, may return to normal by time animal is presented.
Sorbitol Dehydrogenase (SDH)
This enzyme is found in high concentrations in hepatocytes of cattle, sheep, goats, and birds. No standardized test method has been developed for use in veterinary practice.
Glutamate Dehydrogenase (GLDH)
What are the Hepatocellular Leakage Enzymes? (4)
Alanine aminotransferase (ALT) Aspartate aminotransferase (AST) Sorbitol Dehydrogenase (SDH) Glutamate Dehydrogenase (GLDH)
This type of liver enzyme is present within the cell, bound to membranes, and does not leak out of cells when there is damage.
Inducible (Overproduction)
Elevations of inducible liver enzymes are induced by an ____ in the rate of synthesis. Some escape the cell into systemic circulation.
increase
A group of enzymes present in many tissues. Ex: Alkaline Phosphatase
Isoenzymes
High concentrations of this enzyme is found in the liver, bone, intestinal mucosa, kidney and placenta.
Alkaline Phosphatase
ALKP, ALP, AP
The half life of ALP in the intestines, kidneys and placenta is ____ (____) compared to bone and liver.
short (hours)
What drugs can cause an increase in ALP? This only occurs in dogs. Do not necessarily indicate liver pathology.
Glucocorticoids and anticonvulsants
Increased ALP can also be caused by ______. Accelerated production of ALP is induced by increased pressure in the bile ducts during blockage of bile flow.
Cholestasis
Cholestasis may be from ______ or _____ causes.
intrahepatic or extrahepatic
Intrahepatic cholestasis can occur secondary to a wide variety of conditions that affect the biliary tree in the liver, including:
inflammation or infection, hepatocyte swelling, and neoplasia
Extrahepatic cholestasis results from occlusion of the ______, which may be caused by similar conditions affecting the gall bladder, bile duct itselt, or the area of the duodenum where the bile duct empties.
common bile duct
Pancreatitis or pancreatic neoplasia may sometimes cause
extrahepatic bile duct obstruction
Cat’s livers are capable of less ALP production than dogs, consequently an increase of only - X the URL in cats in clinically significant
2-3X
ALP is considered an inducible enzyme, but mild increases (<5X URL) have been noted following _____ - probably because of release of membrane fragments containing ALP.
acute hepatic necrosis
Is it possible to differentiate the isoforms of ALP?
Yes: bone (BALP); corticosteriod-induced (CALP); liver cholestasis (LALP)
Increased osteoblastic activity of ALP can be due to what?
Young growing animals
Hyperparathyroidism
Fracture healing
Osteosarcoma
ALP is not use in what 2 species because there are wide fluctuations in normal blood ALP levels.
Cattle & Sheep
ALP increases are usually ____ with osteoblastic activity, fracture healing, etc.
mild
This enzyme is found in many tissues but the primary source is the liver. Blood ___ level is elevated with liver disease, especially w/obstructive liver disease.
Gamma glutamyltransferase (GGT)
Cattle, horses, sheep, goats, and birds have ___ (higher or lower) blood GGT activity than dogs and cats.
higher
This enzyme is synthesized in the highest amounts in the kidneys, pancreas & liver.
GGT
Why is the blood GGT specific to the liver?
GGT from renal tubules is excreted in urine.
GGT from the pancreas in excreted into the GI tract.
GGT present in the serum originates from the liver.
Increased GGT occurs with what pathologically?
Cholestasis
Biliary hyperplasia
Similar to ALP, GGT can be induced in dogs receiving what?
Corticosteriods and anticonvulsants
Because ALP is not very sensitive in large animals, what liver enzyme would you use to test for cholestasis?
GGT
Neonates of several species have markedly increased GGT due to ingestion of
colostrum
We can measure many substances that are taken up, modified, produced, and/or secreted by the liver - these are not enzymes. What are these tests called collectively?
Hepatocyte Function tests
2 general types of tests for what?
Those that test uptake, metabolism, and clearance of a substance from the blood.
Those that test the synthetic capabilities of the liver.
Hepatic Function tests
Bilirubin is a breakdown product of what?
hemoglobin
Aged RBCs are destroyed by macrophages in the
spleen
What portion of hemoglobin is converted to bilirubin?
Heme
The protein-bound (mainly albumin) bilirubin is called
unconjugated bilirubin
Inside the hepatocyte, bilirubine attaches first to a binding protein (ligandin), which helps keep it from refluxing back into the blood. Bilirubin is then ______ (usually to glucuronic acid), making it water soluble and excreted in the bile.
conjugated
Conjuaged bilirubin is also called
direct bilirubin
Some conjugated bilirubin may become protein-bound, termed
delta bilirubin
Protein-bound bilirubin, whether conjugated or unconjugated, does not pass through the normal glomerulus, and so is not usually present in
urine.
Conjugated bilirubin that is secreted in bile ends up in the intestine, where it is converted to ____ and excreted in feces.
Urobilinogen
In health, most serum bilirubin is ______, and a small amount is ______.
Most: unconjugated
small: conjugated
Conjugated bilirubin (which is _____ soluble) is excreted as a bile pigment into intestines.
Water
Conjugated bilirubin can be converted into urobilinogen by ______ in the intestines.
bacteria
Some urobilinogen is converted to stercobilinogen and excreted in stool as
stercobilin
Total bilirubin =
conjugated + unconjugated
When there is hyperbilirubinemia to a sufficient degree, the serum will be
icteric.
By the time the serum bilirubin reaches ___mg/dL, icterus can also be detected in the mucous membranes & sclera.
3 mg/dL
What are the three general causes of hyperbilirubinemia?
Pre-hepatic
Hepatic
Post-hepatic
Excess extravascular hemolysis red blood cell breakdown. One cause of hyperbilirubinemia.
Pre-hepatic
Liver disease that prevents liver from conjugating the normal amount of unconjugated bilirubin presented to it. One cause of hyperbilirubinemia.
Hepatic
Bile duct obstruction so that the conjugated bilirubin can’t be passed with bile into the intestines and backs up into the bloodstream and into the tissues. One cause of hyperbilirubinemia.
Post-hepatic
The enzymes induced by cholestasis (___ & ____) are generally more sensitive indicators of cholestasis than is increased serum bilirubin (particularly true in dogs & cattle, doesn’t always hold true for cats & horses).
ALP & GGT
The combination of increased induction enzymes (ALP & GGT) plus increased serum bilirubin supports
Cholestasis
Combination of regenerative anemia (typical of hemolysis) and increased serum bilirubin suggests a
pre-hepatic icterus
Leakage enzymes (ALT, AST) may be increased (indicating hepatocellular injury) from hepatic causes of icterus, but also from ______ because bile is an irritating substance that can solubilize membranes and cause hepatocyte injury.
post-hepatic causes
_____ and ______ causes of icterus cannot be reliably differentiated based on laboratory data. Additional diagnostic tests such as ultrasound, liver biopsy, or sx are usually required.
Hepatic and post-hepatic
Bilirubin in these 2 species is only elevated if significant liver disease is present.
Dog and cat
Increased bilirubin in this species can be seen in non-hepatic conditions such as anorexia.
Horse
Increased bilirubin in this species can be elevated in a variety of diseases. Increase due to liver disease is less than other species.
Cattle
Bile acids are synthesized by ______ from cholesterol.
hepatocytes
Bile acids are secreted in the ____ and stored in the _____.
bile
gallbladder
Bile acids are released into the ____ following a meal.
duodenum
Bile acids aid in ____ absorption.
fat
Bile acids get transported back to the _____ via portal circulation.
liver
Normally, there is a ____ level of bile acids in systemic circulation.
very low
What are 3 reasons for an elevation in bile acids?
Decreased hepatic function
Portosystemic shunt
Cholestatic disease
An elevation in bile acids because they are not effectively cleared from the blood is caused by what?
decreased hepatic function
When blood bypasses the liver and enters systemic circulation, this is called a
portosystemic shunt
Bile acids that get regurgitated to the liver and enter systemic circulation is caused by what?
cholestatic disease
These are techniques for what test: fast patient for 12 hours; draw blood sample; feed patient; draw blood sample 2 hours later; only fasting sample is taken in animals without a gallbladder.
Bile acids test
These 4 tests evaluate hepatic synthetic function.
Albumin, glucose, BUN, cholesterol
Albumin is synthesized in the ____, so hepatic insufficiency can result in hypoalbuminemia.
liver
Albumin has a long serum half-life (7-10 days), and so decreases are associated with ______ liver disease.
chronic
There are other causes besides chronic liver disease for hypoalbuminemia such as
urinary loss, blood loss, intestinal loss
The ____ is central to glucose metabolism, converting glucose to glycogen for storage, releasing stored glucose via glycogenolysis, and synthesizing glucose via gluconeogenesis.
Liver
Because of the liver’s reserve capacity, __-__% of hepatic function must be lost before glucose abnormalities and low albumin levels are seen.
60-80%
Typically, we think of hepatic insufficiency as causing hypoglycemia, but a prolonged ______ following a meal is also possible due to decreased glucose uptake by hepatocytes.
hyperglycemia
Urea is synthesized from ____ in the liver.
ammonia
Markedly decreased hepatic mass is result in ____ (increased or decreased) urea synthesis and therefore a _____ serum BUN, while blood ammonia levels increase.
decreased
decreased
Cholesterol is synthesized in the ____ and undergoes enterohepatic circulation via the bile.
liver
Cholesterol my be normal, decreased, or increased with liver disease, depending upon the balance between ____ and ____ ______.
cholestasis
hepatic insufficiency
What are 3 exocrine pancreatic enzymes?
Amylase, lipase & trypsin
What 2 pancreatic enzymes are measured directly?
amylase & lipase
_____ is an exocrine pancreatic enzyme that is measured using antibodies to detect it.
trypsin
What are the 2 endocrine pancreas tests?
Glucose
Fructosamine
Inflammation of the pancreas. The result of activation of the digestive enzymes (amylase, lipase & proteases) within the pancreas instead of activation in the intestine.
Pancreatitis
CSX of what disease?
vomiting, abdominal pain, systemic inflammation (leukocytosis, fever). Occurs in dogs and cats
Pancreatitis
The result of an absolute or relative lack of insulin production.
Diabetes mellitus (DM)
CSX of what disease?
polydipsia, polyuria, polyphagia & weight loss. Dogs: sudden blindness due to cataract formation can occur. Cats: decreased interaction, unkempt hair, rear limb weakness
Diabetes mellitus (DM)
____ and _____ are used to aid in the diagnosis of pancreatitis. Not useful for detection of pancreatic insufficiency because they are produced in other places.
Amylase and lipase
Pancreatitis occurs much more commonly in the ___ than other species.
dog
Pancreatitis occurs in ____ but is more difficult to diagnose.
cats
Pancreatitis is rarely diagnosed in ____ and ____.
horses & cattle
The primary source of ____ is the pancreas, but it is also produced in the salivary glands and small intestine.
Amylase
This enzyme breaks down starches and glycogen.
Amylase
Pancreatic duct ____ results in a backup of digestive enzymes into peripheral circulations.
inflammation
Amylase rises rapidly (w/in 12-48) with ____ and remains elevated for more than one ____.
pancreatitis
week
Normal amylase and lipase does not rule out _______
pancreatitis
Renal tubular cells normally degrade ______. Renal failure may cause elevations in _______.
Amylase
