Snake Physiology and Venom Quiz

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Questions and Answers

Which structure is responsible for secreting snake venom?

Modified parotid salivary gland (correct)

Submandibular gland

Mandibular gland

Sublingual gland

What type of toxins are found in snake venom?

Hemotoxins and neurotoxins only

Hemotoxins, neurotoxins, and cytotoxins (correct)

Only neurotoxins

Cytotoxins and allergens only

What is one economic benefit of snakes to farmers?

They pollinate crops.

They save farmers a significant amount on rodent control. (correct)

They provide snakeskin for clothing.

They enhance crop yields through pest reduction.

What is the primary function of the alveolar sac in snake physiology?

To store venom Signup and view all the answers

What is Eicosapentaenoic acid (EPA) believed to offer in terms of health benefits?

Reduction of inflammation Signup and view all the answers

What is the primary antidote used for gastric lavage in cases of poisoning associated with thickening of the gastric mucosa?

Magnesium sulphate Signup and view all the answers

Which of the following substances is NOT mentioned as a dissolving antidote for gastric lavage?

Acetic acid Signup and view all the answers

How many species of snakes are considered to be dangerous out of the total number of species?

300 Signup and view all the answers

What percentage of the snake species are venomous in the United States?

20% Signup and view all the answers

Which of the following measures is indicated for managing pulmonary oedema in a snake bite victim?

Using atropine to stimulate respiration Signup and view all the answers

What is a common clinical sign of oral poisoning from inorganic acids?

Local corrosion on skin Signup and view all the answers

Which of the following treatments is contraindicated for corrosive acid poisoning?

Gastric lavage Signup and view all the answers

In the event of inhalation of acid fumes, which symptom is least likely to occur?

Loss of vision Signup and view all the answers

What color is the mucosa of the mouth typically observed after exposure to corrosive alkalies?

White Signup and view all the answers

Which of these is a recommended antidote for neutralizing corrosive acid poisoning?

Lime water Signup and view all the answers

What is the primary composition of snake venom by dry weight?

Proteins Signup and view all the answers

Which of the following is NOT a symptom associated with corrosive alkaline poisoning?

Black charring of tissues Signup and view all the answers

Which of the following snake venoms is primarily known for its neurotoxic effects?

Gaboon Viper Signup and view all the answers

What is a potential long-term complication for a patient who survives corrosive acid ingestion?

Esophageal stricture Signup and view all the answers

Which enzyme activity is commonly associated with the synergistic effects of snake venoms?

Proteolytic activity Signup and view all the answers

What is the fatal oral dose of concentrated inorganic acid?

4 ml Signup and view all the answers

Which of the following is NOT a typical side effect of snake venom exposure?

Rapid weight gain Signup and view all the answers

What is the purpose of injecting horses with snake toxins to create antivenin?

To induce an immune response in the horse Signup and view all the answers

Which vital sign was found to be abnormal in the case study of the snake bite victim?

Prothrombin time Signup and view all the answers

What type of treatment did the patient receive for lymphangitis following a snake bite?

Intravenous antibiotics Signup and view all the answers

How many vials of SAIMR antivenin did the patient receive in treatment?

Five 10ml vials Signup and view all the answers

What is the recommended antidote for alkali poisoning?

Diluted lemon or orange juice Signup and view all the answers

What are the symptoms associated with carbolic acid (phenol) poisoning?

Colic and vomiting with drowsiness Signup and view all the answers

What type of necrosis is primarily caused by the local action of carbolic acid?

Coagulative necrosis Signup and view all the answers

Which symptom is NOT typically observed in patients with phenol poisoning?

Persistent coughing Signup and view all the answers

What is the fatal dose range for solid phenol in grams?

2-4 gm Signup and view all the answers

Which of the following effects can occur after the absorption of carbolic acid?

Acute toxic glomerulonephritis Signup and view all the answers

What change occurs to urine from a patient who has ingested phenol and left it in the air?

Turns green due to oxidation Signup and view all the answers

Which condition is NOT associated with alkaline substance poisoning?

Severe allergic reaction Signup and view all the answers

Study Notes

Corrosive Poisons

Inorganic Acids:
- Examples: concentrated sulfuric acid, nitric acid, hydrochloric acid
- Action: local corrosion only
- Fatal oral dose: 4 ml
- Poisoning methods: accidental skin contamination, ingestion, inhalation of fumes, or homicidal attacks
Corrosive Burns:
- Visible physical damage to skin
Clinical Signs:
- Local corrosion on skin
- Severe oral burning pain from mouth to stomach
- Severe colic and bloody vomitus with pieces of gastric mucosa; vomitus highly acidic
- Dark vomitus due to acid haemation
- Black charring in sulfuric acid; yellow in nitric acid
- Dehydration with thirst
Additional Clinical Signs:
- Oliguria and constipation
- Shock with weak rapid pulse and hypotension
- Evidence of corrosion on lips and mouth
- Oedema of the glottis and stridor and cyanosis
- Death: few hours from shock and dehydration or days from perforation and peritonitis
- Possible esophageal stricture and dysphagia in survivors
Inhalation of Acid Fumes:
- Burning pain in the chest
- Severe cough and dyspnea
- Oedema of the glottis and stridor
- Pulmonary oedema
- Cyanosis and death from asphyxia
- Bronchopneumonia may occur

Corrosive Alkalies (K+ and Na+ Hydroxide)

Potassium hydroxide (caustic potash) and sodium hydroxide are common in household cleaning products
Accidental poisoning frequently occurs in children
Fatal dose: 3-5 grams of the solid or the corresponding amount of solution
Picture:
- Mouth mucosa is white
- Vomit is whitish, slimy, alkaline, and contains blood
- Diarrhea may occur
- Stomach perforation is delayed
- Esophageal strictures are common

Organic acids: Acetic Acid

Glacial acetic acid is a strong corrosive acid when ingested or inhaled as fumes.
Presents with similar findings to other corrosives, with the added smell of vinegar
Treatment: same as corrosive acids

Carbolic Acid (Phenol)

Forms white crystals with a strong characteristic smell
Crude form is used as a toilet disinfectant
Lysol, cresol, and dettol have similar effects
Action:
- Local: coagulative necrosis with thickening of the tissue; superficial ulcers with local anesthetic effects on sensory nerve endings; gangrene of skin with prolonged exposure
- After absorption: CNS and respiratory depression; acute toxic glomerulonephritis
Fatal Dose: 2-4 gm of the solid phenol or the corresponding amount of the crude acid
Poisoning:
- Mostly accidental ingestion or skin contamination in children
- Used suicidally due to its availability and painlessness
Picture:
- Temporary burning pain from mouth to stomach
- Colic and vomiting
- Whitish buccal mucosa and brownish carbolic eschars on lips and chin that turn darker with oxidation
- Drowsiness, then coma due to CNS depression
- Slow, difficult respiration; cyanosis; pulmonary edema; death from asphyxia after a few hours
Further signs:
- Pupils constrict, then dilate before death
- Smell of phenol from breath
- Acute toxic glomerulonephritis with oliguria, albuminuria, haematuria, and casts
- Urine turns green from oxidation of hydroquinone and pyrocatecn
- Delayed death from anemia can occur in 7-10 days

Treatment (general)

Emetics and gastric lavage are contraindicated due to fear of perforation; use bicarbonates and carbonates to avoid causing gastric distension and rupture
Give water orally to dilute the acid
Neutralize with weak alkalis such as magnesium oxide, lime water (Ca hydroxide), or soap solution
Milk, egg albumin, olive oil, or butter are also good, but important not to use heat
Morphine (8-15 mg IV) to relieve pain and treat shock and pulmonary edema
IV fluids for dehydration; tracheostomy for glottis edema; pulmonary edema treatment; treat with antibiotics and corticosteroids to prevent strictures; surgical treatment
Contaminated skin: wash with soap and water, and then treat surgically
Gastric lavage is performed, using magnesium sulphate (15-30 gm in a glass of water) to precipitate the poison; if this isn't available, 10% ethanol or glycerin for dissolving the poison as an antidote but needs to be rewashed
General measures for care of coma, and respiration; Atropine (1 mg IV) measures for controlling pulmonary edema; treat impaired renal function through 1.26% sodium bicarbonate IV or dialysis

Snake Bites

Introduction:
- Over 3,000 snake species globally, 15% are venomous
- Venomous snakes found on all continents except Antarctica
- 45,000 venomous snake bite incidents annually in the US
- 7,000-8,000 incidents involve venomous snakes
- 10 people die annually from snake bites
Snake Venom:
- Toxin (Hemotoxin, Neurotoxin, Cytotoxin)
- Excreted through a modified parotid salivary gland located behind eye on skull
- Combination of proteins and enzymes
- Venom flows through pumping mechanism in alveolar sac storage, proceeds through channel to tubular fang
- Not inhaled, therefore not classified as a poison
Benefits:
- Control animal populations
- Farmers: save up to $75 USD annually from removing rodents and insects that carry diseases
- Medicinal uses: oils extracted from snakes are used for pain relievers, such as rheumatoid arthritis, thought to contain Eicosapentaenoic acid (EPA) for inflammation reduction, pain relief, and may cure diseases.
Venom Composition:
- Primarily protein (90%) with enzymes and non-enzymatic toxins
- Carbohydrates (CHO), Metals, Lipids, and Free amino acids
Enzymes:
- Activate mammalian blood clotting cascade
- Phospholipase (A2), damaging mitochondria, RBCs, leucocytes, and skeletal muscles, and vascular endothelium
- Hydrolases: increase vascular permeability; cause edema, blistering, bruising, and necrosis
- Neurotoxins: interfere with acetylcholine release at neuromuscular junctions
- Histamine and 5-HT (5-hydroxy tryptamine): induce edema and local pain at the bite site
Mechanism of Action:
- Toxic effects of snake venom can be isolated for beneficial purposes, including antivenom production for multiple sclerosis treatment, and reduced cancer growth and metastasis
Side Effects:
- Respiratory paralysis, fever, rapid pulse, increased thirst, dizziness, local tissue damage, blurred vision, nausea/vomiting, diarrhea, coma, and death
Case Study #1:
- 41-year-old male bitten on left third finger by a Gaboon Viper
- Necrosis and blanching of the finger/hand
- Numbness and edema
- Prothrombin time (PT) 15.53 (normal range 11.0-13.0)
- International Normalized Ratio (INR) 1.2
- Moderate leucocytosis and normal platelets
- Treated with antibiotics, diphenhydramine, hydrocortisone, and SAIMR antivenom
- Developed lymphangitis of the left arm
- Required amputation of the left third finger
Antivenin production.
- Made by injecting horses with snake toxins and monitor for survival
- After immunity, process and extract blood into antivenin
African Snake Species:
- Echis carinatus: scaled or carpet viper
- Bitis arietans: puff adder
- Naja nigricicolis: black-necked spitting cobra
- Naja haje: Egyptian cobra
- Dendroaspis: mambas
- Snake bites are common in farming areas in Africa

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Description

Test your knowledge on snake physiology, venom composition, and the economic benefits of snakes. This quiz covers various aspects of snakes, including their venom characteristics and medical implications. Ideal for biology students or anyone interested in herpetology.