Lab Exam 2 Flashcards
Why is glucose important to the CNS?
Because the central nervous system as well as RBC’s require glucose for their energy needs and without it they die
What is a monosaccharide?
A single unit sugar
What is hexose?
Simple sugars whose molecules contain six carbon atoms
Why is the liver important in reference to glucose?
It synthesizes, stores, converts and releases glucose
What is the excess glucose stored as in the liver?
Glycogen
What organ releases insulin?
The pancreas
What hormones control the concentration of glucose?
Insulin and glucagon; insulin lowers BG levels while glucagon elevates it
How is glucose metabolized?
Via glycolysis followed by the TCA cycle (aka krebs cycle)
How many glucose atoms are produced as a result of glycolysis?
It produces 4 total, but 2 are eliminated, leaving a net gain of 2 glucose atoms
How many ATP atoms are produced at the conclusion of the TCA cycle?
36 ATP for every glucose molecule
What is required for the complete oxidation of glucose?
Because it is an aerobic response, it requires oxygen
What by-products are released by the oxidation of glucose?
- CO2, H2O, ATP, and heat
- The heat produced helps maintain body temperature
What is fermentation of glucose?
Anaerobic metabolism that can produce ATP if the body is experiencing hypoxia
Is fermentation an effective way to produce ATP?
It is less effective than glycolysis because it only produces 4 ATP for every glucose molecule
Where is the highest concentration of glycogen stored?
In the liver, but because muscle tissue has a greater mass, there is more glycogen contained within it
What cells produce, monitor and control glucose?
Beta cells, which are created in the endocrine portion of the pancreas
What cells within the islets of langerhaans produce glucagon?
Alpha cells
What do the delta cells within the pancreatic islets produce?
Somatostatin, which regulates insulin and glucagon
What cell is the only cell in the body that does NOT require insulin to function?
Beta cells
At what concentration would a beta cell be triggered to release insulin?
When the blood glucose concentration exceeds 110 mg/dl
At what concentration is insulin synthesis and concentration inhibited?
When the blood glucose concentration falls between 60 mg/dl
What is euglycemia?
Normal concentration of glucose in the blood
How can euglycemia be maintained?
Exogenously, which is from outside the body, mainly through diet; or endogenously which is inside the body derived from the liver
What is gluconeogenesis?
The creation of more glucose
What hormone is the most dominant when lowering glucose?
Insulin
What hormones may elevate glucose?
Glucagon, epinephrine, growth hormone, and cortisol
What is Diabetes Mellitus?
Results from a decrease in insulin secretion from the beta cells and/or a decrease in insulin action
What is Type I Diabetes?
- Insulin dependent diabetes mellitus
- There is a low amount of insulin in the body and it can’t produce enough to meet the need
What is the most common form of diabetes in dogs and cats?
Type I IDDM
What is the second most common form of diabetes in cats?
Type II NIDDM
What is Type II Diabetes?
- Non-insulin dependent diabetes mellitus
- Spikes in BG levels usually after eating that require insulin which the body can produce
How is type I diabetes managed?
With insulin injections
How is type II diabetes managed?
With dietary therapy and oral hypoglycemic medications
What is Type III Diabetes?
- Impaired glucose tolerance
- Can be caused by hormones or medications
Which type of diabetes can affect pregnant animals?
Type III
What long term medication use can result in type III diabetes?
Corticosteriods
What is thought to be the cause of canine diabetes?
It is considered to be immune mediated in which the body thinks beta cells are foreign and attacks them
What are some other causes of canine diabetes?
Genetic predisposition, chronic pancreatitis, and medication induced
At what percentage of destruction of pancreatic islets do diabetic clinical signs occur?
Progression is slow and 90% of islets are lost before diabetes mellitus occurs
What are the common causes of feline diabetes?
Obesity, pancreatitis, amyloidosis of pancreatic beta cells
What is amyloidosis?
Deposition of material around beta cells which prevents their measurement of glucose
What canine gender is typically afflicted with diabetes?
3x more likely to occur in females
At what age do canines typically become diagnosed with diabetes?
Peak incidence at 7-9 years
What breeds are genetically predisposed to diabetes?
Australian terriers, samoyed, mini and standard schnauzers, mini and toy poodles, pugs, fox terriers, keeshonds, bichon fries, finnish spitz, lhasa apso, cairn terriers
What feline gender is typically affected by diabetes?
Males generally greater than 6 years old
What feline breed is diabetes common in?
None, all can be affected equally
What are the clinical signs of diabetes?
Polyuria, polydipsia polyphagia, weight loss, cataracts in dogs, peripheral neuropathy in cats, plantigrade posture
How can diabetes be diagnosed?
- CBC: red blood cells may be decreased
- Chem panal: hyperglycemia; BG > 200 mg/dl
- UA: glucosuria or ketonuria
What are some goals of diabetes treatment?
- Elimination of clinical signs
- Prevention or slowing or cataract formation and resulting blindness
- Prevention of hypoglycemia or overtreatment
- Prevention and/or treatment of concurrent diseases such as cushing’s, skin infections, or UTI’s
How is diabetes treated?
Dietary management, exercise, insulin injections, or oral hypoglycemic agents
What are some goals of dietary management?
Eliminate obesity and maintain consistency in the timing and caloric content of meals to minimize fluctuations by having slow release of carbohydrates in BG concentrations
What should a diabetic diet contain?
High fiber and low fat, cats should also be fed a high protein, low carb diet and semi moist foods should be avoided
What are some goals of exercise?
To promote fat loss and increase mobilization of insulin from its injection site, but avoid strenuous and sporadic exercise as it can cause severe hypoglycemia
What are the three types of insulin?
- Short acting: emergency use of R insulin
- Intermediate acting: canine use of NPH and Vetsulin
- Long acting: feline use of Lantise and glargine
What are some problems with insulin therapy?
- Rapid insulin metabolism
- Insulin resistance if there is another disease present
- Hypoglycemia aka insulin overdose
- Somogyi phenomenon aka insulin induced hyperglycemia
How can hypoglycemia be treated at home?
If a diabetic animal is exhbiting signs of weakness, shaking, ataxia and seizures, they can be given karo syrup rubbed on the their gums
What is renal disease?
When something is physically wrong with the kidneys, but the function may not be affected
What is renal failure?
When something is functionally wrong with the kidney, at least 75% of total nephron population is non-functional
What happens to the kidneys in renal failure?
The kidneys are no longer able to maintain the regulatory, excretory and endocrine functions required
What happens to hormone production to kidneys in renal failure?
The kidney produces less erythropoietin hormone, which results in anemia especially in cats
What is the result of renal failure?
It results in retention of nitrogenous solutes and derangement of fluid, electrolyte, and acid balance
What is azotemia?
A build up of waste in the blood due to failure of kidneys and an increased concentration of non-protein nitrogenous waste products in the blood
What us pre-renal azotemia?
A problem occurring before the kidney involving impaired blood flow to the kidney
What is pre-renal azotemia due to?
A decrease in glomerular filtration rate from circulatory disturbances causing decreased renal perfusion
What is renal azotemia?
A primary failure of the kidney which results from decreased GFR, check functionality with a specific gravity
What is post-renal azotemia?
When the urine does not leave the body and results from obstruction or rupture of urinary outflow tracts and hyperkalemia
What is uremia?
A condition involving abnormally high levels of waste products in the blood from a critical loss of functioning nephrons
What are the clinical signs of uremia?
- PU/PD
- Mild non-regenerative anemia
- Vomiting
- Weight loss
- Depression
What is ammonia?
Produced from dietary proteins and by catabolism of proteins and nitrogenous wastes in peripheral tissues
What converts amino acids and urea into ammonia?
Gastrointestinal micro-organisms in the colon and cecum which are then absorbed into the portal circulation
How much ammonia is shunted to the liver?
80-90% and then it is converted into urea via the urea cycle
What peripheral tissues metabolize 10-20% of ammonia?
The kidneys, heart and brain
How is ammonia measured?
With arterial blood collection and heparinized plasma samples
What can result of increased ammonia?
Ammonia is toxic to the CNS and is one cause of hepatic encephalopathy (damage to the CNS due to the build up of ammonia)
What could be a physiologic normal body function that would result in elevated ammonia?
A high protein diet, can also result in increase GFR and urea excretion
What kind of artifact may result in a increased ammonia?
It may not be an accurate number
What kind of disease may result in an increased ammonia level?
It can be a liver shunt, dehydration or a tumor
How is urea formed?
2 NH3 molecules are combined with 1 molecule of CO2
What is the chemical formula of urea?
CO(NH2)2
What is urea?
The end product of protein and amino acid catabolism
How is urea metabolized?
Synthesized in the liver using ammonia derived from amino acids
How is urea excreted?
By the kidneys which is the most important route of urea excretion
Where is urea filtered?
At the glomeruli and requires no metabolic work by the kidneys because glomerular filtration is driven by cardiac output
How is urea concentration measured?
As blood urea nitrogen, and is a screen for decreased GFR
What are the non-renal factors contributed to increased BUN?
- High protein meal
- Hemorrhage into gastrointestinal tract
- Increased catabolism (breakdown of protein)
- Drugs
What are the renal factors contributing to increased BUN?
- Pre-renal: shock, dehydration, congestive heart failure
- Primary: kidney is not functioning properly
- Post-renal: Urethral obstruction, ruptured bladder
What are some reasons that could contribute to a decreased BUN?
- Low protein diet
- Severe liver disease of portosystemic shunting
- Anabolic steroids due to building protein instead of breaking it down
What is creatinine?
Spontaneous, non-enzymatic breakdown product of phosphocreatine in muscle and is released into the blood from muscle at a constant rate
Which gender tends to have more creatinine?
Males due to higher muscle mass
Where is creatinine excreted?
By glomerular filtration and the rate of excretion is relatively constant and a good estimate of GFR
What is creatinine a measurement of?
It is a screen for decreased GFR?
What might be some reasons for increased creatinine?
- Non renal: massive muscle necrosis and prolonged strenuous exercise
- Pre-renal: shock, dehydration, congestive heart failure
- Post-renal: urethral obstruction, ruptured bladder
What does an increased BUN:creatinine ratio suggest?
Non-renal azotemia, may be due to an increased protein diet
What does a decreased BUN:creatinine ratio suggest?
Chronic liver failure
What are plasma proteins?
Total proteins consist of albumins and globulins, also includes fibrinogen
What could decreased plasma protein level indicate?
- Glomerular disease
- Liver disease
- Starvation
- Malabsorption
- Hemorrhage
What organ produces albumin?
The liver
What could a increased plasma protein level indicate?
- Severe dehydration
- Neoplasia (lymphoma and plasm- Infection
What is albumin?
It contributes to plasma colloid oncotic pressure and synthesized in the liver and catabolized by all metabolically active tissues, serves as a carrier protein for many insoluble organize substances
What can contribute for hypoalbuminemia?
- Physiologic: low protein diet
- Increased loss: kidney, liver, gut and bleeding
- Catabolism
Where are globulins produced?
- Alpha and beta are synthesized by the liver, and gamma globulins are produced by b-lymphocytes and plasma cells
What does a high total protein with a normal A:G ratio indicate?
Dehydration
What does a high total protein with a low A:G ratio suggest?
Hyperglobulinemia
What us hyperglobulinemia?
Decreased gamma globulins are seen when there is a deficiency of immunoglobulins
What are the biochemical functions of the liver?
- Detoxification of toxins
- Synthesis of all coagulation factors
- Synthesis of plasma proteins (mainly albumin)
- Catabolism, degradation and storage of lipids
- Formation and elimination of bile
What tests can be used to diagnose liver disease?
Chem panel, CBC, bile acids, U/A, fecal, RADS, US, biopsy
What are the clinical signs associated with liver disease?
- Depression/lethargy
- Anorexia, diarrhea, vomiting, weight loss
- Fever, hemorrhage
- Abdominal pain
- CNS signs
- Icterus/jaundice
- PU/PD, dark brown urine, dark or light brown stool
What is hematemesis?
Vomiting blood, which may occur in a patient with liver disease
What is hemoptysis?
Coughing up blood, which may occur in a patient with liver disease
What bleeding disorders may a liver patient suffer from?
- Hematemesis
- Hemoptysis
- Hematochezia
- Melena
- Hematuria
- Petecchia
- Eccymoses
- Pale MM
Why would a patient with liver disease suffer from hepatic encephalopathy?
Due to the build up of ammonia not being converted to urea
What kind of heart failure may a patient with liver disease suffer from?
Right sided heart failure, often associated with hepatomegaly
What may hepatomegaly be due to?
- Inflammation
- Steatosis aka fatty liver
- Neoplasia
- Congestion or cholestasis (low bile flow)
What is hepatodynia?
Liver pain
Why would a patient with liver disease suffer from microhepatica aka small liver?
May be due to a congenital portosystemic shunt or cirrhosis
What may ascites in the abdomen occur in a liver disease patient?
May be due to hypoalbuminemia or liver hemorrhage
What is the only test that can determine the functionality of the liver?
Bile acids test
What are the major enzymes found in the liver?
- ALT
- AST
- ALKP
- GGT
Aside from the liver, where else may would you find ALT?
Mainly in the hepatocellular cytoplasm in the liver, but smaller amounts may be found in the kidney, heart, muscles and pancreas
What would a increased ALT suggest?
Persistent hepatocellular disease
When being treated, how often should ALT values decrease?
By 50% every 1-2 days, as the serum half life is <24 hours
Where would you find AST?
As it is not liver specific, it may be found in RBC’s, heart, muscle tissue, pancreas and kidney in addition to the liver
Which liver enzyme is a more sensitive indicator of hepatobillary (liver and gallbladder) disease in cats?
AST, in general it tends to parallel ALT with respect to liver damage
What is ALKP?
- A membrane bound enzyme present in many tissues
- Dogs have 4 isoenzymes: bone, liver, corticosteroid, and intestines
- Cats have 2 isoenzymes: bone and liver
What would an elevated ALKP possibly indicate?
- Osteoblast activity (2-3 times the normal range)
- Feline hyperthyroidism
- Canine glucocorticoids
- Synthesis induced by other drugs aside from glucocorticoids
- Primary or secondary hepatocellular disorders
- Mammary neoplasia (will result in a milder increase)
If a dog is on a prescription of prednisone, which liver enzyme may be elevated?
ALKP
Where is most serum GGT activity in the dog and cat?
It is derived from the liver
Where is the largest tissue GGT activity in the dog and cat?
In the kidney and pancreas
What may an increased GGT level indicate?
- Intrahepatic or extrahepatic cholestasis
- Pancreatitis
- Drug induction by corticosteriods or anticonvulsants
What is intrahepatic cholestasis?
Cholestasis due to either a blockage, tumor, or tissue inflammation in the liver
What is extrahepatic cholestasis?
Cholestasis due to either a gallstone or a tumor outside the liver
Which liver enzyme is the most sensitive to diagnose liver disease than ALKP in cats?
GGT
What diseases may have secondary effects on the liver?
- Endotoxemia/septicemia
- Diabetes
- Hyper and hypothyroidism
- Hyperthermia
- Decreased hepatic perfusion with hepatocellular hypoxia due to shock, CHF, Hw disease, or anemia
What is stercobilin?
It provides brown color to feces, if it lacks that it is referred to as acoholic or without bile
What is bilirubin?
It is produced from the breakdown of RBC’s, when hemoglobin is converted to bilirubin
Is bilirubin a normal finding in the urine of a cat?
Never
When does jaundice in an animal develop?
When the bilirubin levels exceed 2.0 mg/dl to 3.0 mg/dl or 10x the normal amount
How is jaundice classified?
- Prehapatic: high RBC, typically seen in DIC
- Hepatic: liver disease
- Posthepatic: liver blockage
What is the major plasma protein produced in the liver?
Albumin
When would albumin decreased on a chem panel?
When greater than 70% of hepatobilary function has been compromised
Where are alpha and beta globulins synthesized?
In the liver
What are the primary bile acids synthesized in the liver?
Cholic acid and chenodeoxycholic acid come from cholesterol
What is the secondary bile acids for cats?
Taurine
Where are bile acids stored and concentrated?
In the gallbladder
What stimulates the release of CCK into the small intestine?
The presence of hydrochloric acid, dietary fats and proteins after eating
What does CCK do?
It stimulates the contraction of the gallbladder with the release of bile acids
What does the small intestine do with bile acids?
It facilitates fat to emulsification, digestion and absorption, then most of the bile acids are reabsorbed in the ileum by active transport
What is bile acids functionality based on?
The efficiency of the enterohepatic circulation
What kind of food should you feed an animal with encephalopathic tendencies for a bile acids test?
High fat low protein, as it helps produce less ammonia
What may happen to an animal with a liver shunt if fed a high protein meal?
They may develop seizures
