Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
36 Cards in this Set
- Front
- Back
|
What are the 4 main signs of tissue hypoxia?
|
1) Dyspnea
2) Cyanosis 3) Rapid pulse 4) Rapid respirations |
|
|
What are 3 general physiological mechanisms of tissue hypoxia?
|
-pulmonary disease
-inability of blood to carry or release oxygen -Circulatory disease, tissue not getting enough blood |
|
|
What are 3 toxins that cause abnormal hemoglobin or oxygen carrying?
|
1) Nitrates--> nitrites
2) Cyanide 3) CO |
|
|
What are 4 sources of nitrates & nitrites?
|
1) Plants
2) Fertilizer 3) Salt peter KNO3 4) Contaminated water, soluble in water |
|
|
*What are 8 nitrate/ nitrite containing plants?
|
1) Pigweed
2) Oats 3) Beets 4) Lambs quarters 5) Sorghum, milo, sudan grass 6) Corn 7) Curly dock 8) Russian thistle |
|
|
What is the circumstance of nitrate/nitrite poisoning?
|
Mostly ruminants NO3--> NO2
In water or added to pasture Accumulates in certain plants |
|
|
What are 5 conditions in which nitrates/ nitrites accumulate in plants?
|
1) Drought
2) Decreased light 3) Herbicide treatment 4) High soil content from fertilizing 5) Low temperatures |
|
|
Explain nitrate metabolism.
|
-Nitrate converted to nitrite by rumen micro-organisms
-Absorbed into blood stream -Comes in contact w/ RBC and other tissue -excreted in urine -tissue levels stable 48 h |
|
|
What is the mode of action of nitrite toxicity?
|
-Nitrites oxidizes ferrous iron (2+) in hemoglobin to ferric iron (+3) --> methemoglobin---> unable to bind or transport oxygen---> tissue hypoxia
|
|
|
Can methemoglobin be converted back to normal hemoglobin?
|
yes
|
|
|
How is methemoglobin produced?
|
Ferrous iron converted to ferric heme
|
|
|
What animal is most susceptible to nitrate toxicity?
|
Ruminants 10 x more susceptible
-bc take nitrates--> nitrites |
|
|
What are some clinical signs of acute nitrite toxicity?
|
Could be sudden death
-Dyspnea -Weakness -Tremors -T & R increased -Convulsions -Brown mm |
|
|
What blood tests can you do to diagnose nitrate toxicity?
|
-Blood a chocolate brown color
-Methemoglobin> 30% -Nitrate levels |
|
|
Methemoglobin is not stable in heparinized blood, how can you preserve it?
|
Adding phosphate buffer
|
|
|
What are 3 ways to diagnose nitrite toxicity?
|
1) field test for nitrate/nitrite
-diphenylamine 2) Nitrites or nitrates in blood 3) Methemoglobin levels |
|
|
Postmortem nitrates can be found in _____ fluid> 45 ppm.
|
Ocular fluids
|
|
|
What is the treatment for nitrate/ nitrite toxicity?
|
Methylene blue
|
|
|
What are 4 ways to prevent nitrite poisoning?
|
1) Test forage for nitrate
2) Feed cautiously to ruminants 3) Allow cattle to become accustomed -MOs use NO3--> NH3--> protein 4) Feed Propionibacteria -nitrate reducing |
|
|
What are 2 sources of cyanide?
|
1) As fumigant to kill rodents, other varmints
2) In some plants |
|
|
What are the 2 forms of cyanide in plants?
|
As HCN
As cyanogenic glycoside |
|
|
Why are there few cases of poisoning due to cyanide release in plants containing cyanogenic glycoside?
|
Remains bound to sugar
|
|
|
What are some cyanide containing plants.. under the right circumstances?
|
1) Choke cherry
2) Sudan grass 3) Arrow grass 4) Flax 5) Iris, blue flag 6) Apricot pits 7) Heavenly bamboo 8) Elderberry 9) Apple |
|
|
What's the mode of action of cyanide toxicity?
|
-Inhibits cytochrome oxidase (combines w/ iron)
-Prevents transport or release of oxygen -Oxygen saturated hemoglobin cannot release its oxygen -tissue hypoxia develops |
|
|
Describe the metabolism of CN or HCN in animals.
|
-rapidly absorbed
-some detoxified by rhodanese--< thiocyanate--> eliminated in urine -CN left in blood combines w/ cytochrome oxidase |
|
|
When is cyanide released from cyanogenic glycosides in plants?
|
When activation of beta glycosidease
-wilting, frosting, stunting, drought |
|
|
Where is CN released in ruminants?
|
In rumen by micro-organisms
|
|
|
Is cyanide toxicity slow or fast acting?
|
One of the most rapidly acting toxins
-gas chamber, spy lethal pill |
|
|
What animals are more susceptible to cyanide toxicity?
|
Ruminants
|
|
|
What are some clinical signs of cyanide toxicity?
|
-w/in 30 minutes
-Frothing at mouth -convulsions -coma--death -muscle tremors |
|
|
What color is blood with cyanide toxicity?
|
Blood bright red color
-clots slowly |
|
|
What are 3 diagnostic tests for cyanide toxicity?
|
1) Test plants for cyanide
-Picric acid impregnated paper 2) Urinary thiocyanate increased 3) Cyanide analysis |
|
|
What specimens do you want to take for cyanide analysis?
|
Liver, muscle, rumen
-CN lost rapidly, freeze air tight |
|
|
What are 4 postmortem findings of cyanide toxicity?
|
1) Hemorrhages sub-endocardial
2) bitter almond smell 3) congestion & cyanosis 4) blood clots slowly |
|
|
What are 2 treatments for cyanide toxicity?
|
1) Break CN-cytochrome oxidase bond
-Give Sodium nitrite 2) Sodium thiosulfate -forms thiocyanate (not toxic, excreted) |
|
|
What are 5 ways to prevent cyanide poisoning?
|
1) Prevent grazing in early growth stage
2) Don't graze after drought or frost 3) Allow sorghum forage to grow 2 feet tall 4) Silage destroys cyanogenic glycosides 5) Check cyanide content of plants |
