Environmental Pathology and Climate Change
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Questions and Answers

Name three categories of environmental factors that can affect human health, as discussed in the lecture.

Climate change, chemical agents, and physical agents.

What are the three main greenhouse gases mentioned that contribute to the greenhouse effect?

Carbon dioxide (CO2), ozone, and methane.

What are two health impacts associated with climate change, as outlined in the slides?

Cardiovascular & respiratory diseases; Gastroenteritis, and water/food-borne diseases.

Besides lead, name two other types of air pollutants mentioned in the slides.

<p>Mercury and arsenic.</p> Signup and view all the answers

What are two uses of lead that have contributed to human exposure, as mentioned in the slides?

<p>Batteries, shields from radiation, and water pipes; Lead-containing paint.</p> Signup and view all the answers

What are two toxic effects of lead on the human body?

<p>Inhibition of Ferrochelatase; Inhibition of ALAD.</p> Signup and view all the answers

What is the major route of exposure to organometallic mercury (CH3Hg+)?

<p>Consumption of fish.</p> Signup and view all the answers

What are volatile organic compounds (VOCs)?

<p>Organic chemicals that easily evaporate at room temperature.</p> Signup and view all the answers

What is one mechanism by which hydrogen and oxygen can damage cells?

<p>Forming free radicals that attack DNA.</p> Signup and view all the answers

List three characteristics of radio-sensitive cells.

<p>High division rate, high metabolic rate, non-specialized type.</p> Signup and view all the answers

Give two examples of arachnids discussed in the text.

<p>Spiders and centipedes.</p> Signup and view all the answers

What is the effect of venom from Latrodectus species (Widow spiders) on neurons?

<p>It depolarizes neurons, increases intracellular [Ca2+], and stimulates exocytosis of neurotransmitters.</p> Signup and view all the answers

Name three classes of action exerted by complex snake venom mixtures.

<p>Neurotoxins, coagulants, myotoxins, cytotoxins, nephrotoxins.</p> Signup and view all the answers

Give two examples of how humans can be exposed to general toxicity of plants.

<p>Unintentional exposure on contact, accidental ingestion, intentional ingestion, drug-herbal interactions.</p> Signup and view all the answers

Describe the mechanism by which ricin II inhibits protein synthesis.

<p>The A-chain inactivates ribosomal RNA, thus blocking protein synthesis.</p> Signup and view all the answers

Name the two most dangerous types of mushrooms.

<p>Amanita phalloides and Amanita ocreata.</p> Signup and view all the answers

What property defines organic solvents, and list two examples mentioned in the text?

<p>Organic solvents dissolve, dilute, and disperse materials insoluble in water. Examples include dichloromethane and carbon tetrachloride.</p> Signup and view all the answers

What is passive tobacco smoke, and what are two potential health consequences associated with it?

<p>Passive tobacco smoke is the inhalation of tobacco smoke from the environment (secondhand smoke). Health consequences include lung cancer in nonsmokers and SIDS in babies.</p> Signup and view all the answers

Name three types of mechanical trauma and briefly describe what causes them.

<p>Abrasion (scraping of skin), contusion/bruise (blunt trauma), and wounds (internal and external).</p> Signup and view all the answers

Differentiate between hyperthermia and hypothermia, focusing on their causes.

<p>Hyperthermia is caused by exposure to elevated temperatures, while hypothermia results from prolonged exposure to low ambient temperatures.</p> Signup and view all the answers

What distinguishes radioactive material from other materials?

<p>Radioactive material is unstable and emits radiation.</p> Signup and view all the answers

Explain the key difference between ionizing and non-ionizing radiation.

<p>Ionizing radiation has enough energy to remove electrons from an atom, creating ions, while non-ionizing radiation does not have enough energy to do this.</p> Signup and view all the answers

Give two examples of ionizing radiations and two examples of non-ionizing radiations.

<p>Ionizing radiations: alpha, beta, gamma rays, x-rays, higher ultraviolet cosmic rays. Non-ionizing radiations: lower ultraviolet, visible light, infrared, microwaves, radio &amp; TV waves, power transmission.</p> Signup and view all the answers

Describe the difference between direct and indirect ionization relating to DNA damage.

<p>Direct ionization involves direct energy deposits in DNA leading to ionization. Indirect ionization involves the ionization of other molecules closely associated with DNA.</p> Signup and view all the answers

Flashcards

Greenhouse Effect

The warming of Earth’s atmosphere due to greenhouse gases trapping heat.

Impact of Climate Change on Health

Climate change increases risks for diseases like cardiovascular and respiratory issues.

Air Pollutants

Substances in the air that can harm human health and the environment, e.g., metals and chemicals.

Lead Absorption in Children

Children absorb 42% of ingested lead, leading to higher retention compared to adults.

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Methylmercury Exposure

Mainly comes from fish consumption and is 95% absorbed from the gastrointestinal tract.

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Neurotoxicity of Mercury

High levels can cause symptoms like paresthesia and ataxia due to brain distribution.

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Volatile Organic Compounds (VOCs)

Organic chemicals that easily evaporate at room temperature, contributing to air pollution.

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Inorganic Mercury Toxicity

Poorly absorbed from the gastrointestinal tract, but can bind with other elements and be excreted.

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Free Radicals

Highly reactive atoms/molecules that can damage DNA.

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Radio-sensitive Cells

Cells that are most affected by radiation due to high division and metabolic rates.

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Neurotoxins

Substances that disrupt normal neuron function causing paralysis.

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Coagulants

Agents that affect blood clotting, leading to bleeding or inhibition of normal clotting.

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Myotoxins

Substances that directly affect muscle contraction, leading to paralysis.

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Cytotoxic

Agents that cause damage to tissues through necrosis or proteolysis.

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Ricin Poisoning

A dangerous toxin from castor beans that inhibits protein synthesis.

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Amanita mushrooms

Highly toxic mushrooms known for causing severe poisoning.

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Organic solvents

Substances that dissolve or dilute materials not soluble in water.

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Passive tobacco smoke

Smoke inhaled from the environment by non-smokers.

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Mechanical trauma

Injury caused by physical forces like collision or scraping.

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Burns

Skin damage caused by hot liquids or fire.

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Hypothermia

Injury from prolonged exposure to cold temperatures.

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Ionizing radiation

Radiation that removes electrons from atoms, making them ionized.

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Non-ionizing radiation

Radiation that doesn't have enough energy to ionize atoms.

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Direct ionization

When radiation directly deposits energy in DNA, causing ionization.

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Study Notes

Environmental Pathology

  • Environmental pathology studies diseases caused by environmental factors
  • Environmental diseases factors include climate change, chemical agents, physical agents, environmental pollution, animal and plant toxins, bacteria, and viruses

Climate Change

  • Greenhouse effect: Solar radiation reaches the atmosphere but some is reflected back into space, while the rest is absorbed. This absorbed energy warms the Earth. Some of this heat is trapped by greenhouse gases in the atmosphere, keeping the Earth warm enough to sustain life. Human activities increase the amount of greenhouse gases released into the atmosphere.
  • Increase in atmospheric level of greenhouse gases (CO2, ozone, methane) leads to climate change
  • Climate change has health impacts like cardiovascular and respiratory diseases, gastrointestinal issues from water/food-borne diseases, vector-borne infectious diseases, and malnutrition.

Environmental Pollutants

  • Air pollutants affect various populations based on specific conditions.
  • Metals like lead, mercury, and arsenic are harmful
  • Industrial chemicals and agricultural chemicals
  • Tobacco smoke
  • Substance abuse (alcohol, hallucinogens)

Metals Pollution - Lead

  • Lead (Pb) has been used by humans for at least 7000 years.
  • Lead alloys are used in batteries, radiation shields, and water pipes.
  • Lead-containing paint is a primary source of lead exposure in children.
  • Adults absorb 5-15% of ingested lead and retain less than 5%. Children absorb 42% with 32% retention.
  • Lead in blood is primarily in erythrocytes bound to hemoglobin, only 1% in serum is available for tissue distribution

Methylmercury

  • Organometallic, CH3Hg+
  • The major exposure route is through the consumption of fish.
  • Cooking does not lower the methylmercury content.
  • Almost all (95%) of methylmercury absorbed from fish is absorbed from the gastrointestinal tract.
  • 10% is distributed to the brain, and 5% remains in the blood.
  • Neurotoxicity, with symptoms including paresthesia and ataxia, is a common effect.

Inorganic Mercury

  • Inorganic mercurous (Hg¹+) or mercuric (Hg2+) salts bind to other elements chlorine, sulfur, oxygen
  • Poorly absorbed from the gastrointestinal tract (GIT). It does not readily pass the blood-brain barrier (BBB), and is excreted in urine and faeces.

Organic Solvents & Vapors

  • Solvents are organic liquid chemicals with varying lipophilicity and volatility.
  • Volatile organic compounds (VOCs) evaporate easily at room temperature.
  • Organic solvents dissolve, dilute and disperse materials that are insoluble in water.
  • Examples include dichloromethane, carbon tetrachloride, and benzene.

Physical Injury - Mechanical Trauma

  • Mechanical trauma is caused by mechanical forces such as collisions, scraping of the skin, or tearing/disruptive stretching of tissues.
  • Types include abrasions, contusions/bruises (blunt trauma), wounds (internal and external), and fractures.

Physical Injury - Thermal Injury

  • Caused by excess heat or cold.
  • Burns: Primary cause is hot liquids causing skin damage, complications include wound infection, and death.
  • Hyperthermia: Exposure to elevated temperature can lead to heat cramps, heat exhaustion, and heat stroke.
  • Hypothermia: Prolonged exposure to low ambient temperature causes chilling/freezing of cells and tissues.

Physical Agents - Radiations

  • Radiation is energy in the form of particles and waves.
  • Radioactive material is unstable material that emits radiation.
  • Ionizing radiation produces ion pairs and enough energy to remove electrons from an atom.
  • Non-ionizing radiation does not have enough energy to separate molecules or electrons from atoms.

Radiation-Induced Effects on DNA

  • Direct ionization: Direct energy deposits in DNA, producing ion radicals that react forming DNA radicals.
  • Indirect ionization: Ionization of other molecules (e.g., hydrogen, oxygen) near DNA forms free radicals that attack DNA.
  • Resulting DNA damage disrupts chemical bonds.

Variations in Sensitivity

  • Tissues and cells have different sensitivities to radiation. Some, like white blood cells and intestinal epithelium, are highly sensitive, while others, like mature bone and cartilage, are relatively less sensitive.

Cell Radiosensitivity

  • Highly radiosensitive cells: Rapid cell division, high metabolic rate, non-specialized type, are well nourished.

Effects on the Fetus

  • Fetus consists of rapidly dividing cells.
  • Dividing cells are more sensitive to radiation.
  • Low-level radiation effects are tough to measure.
  • A lower dose limit is applied to the fetus.

Animal Toxins & Venoms

  • Animal toxins and venoms include those from spiders, snakes, centipedes, and millipedes

α-Latrotoxin

  • High-molecular weight protein from widow spiders' venom
  • Toxic only to vertebrates (not insects or crustaceans)
  • Tetrameric structure inserts into lipid bilayers
  • Affects CNS depolarizing neurons, increases intracellular calcium, stimulates exocytosis of neurotransmitters.

Reptiles - Snakes

  • Complex venom mixtures: proteins, peptides, enzymes, non-enzymatic components, and inorganic cations.
  • Class of actions: neurotoxins (produce paralysis), coagulants (inhibit normal clotting), myotoxins (direct muscle contraction), cytotoxic (proteolytic or necrotic properties of tissue), nephrotoxins (kidney damage).

Plant Toxins

  • Unintentional exposure (e.g., plant pollen, hay fever)
  • Accidental ingestion, e.g., biting leaves, children
  • Intentional ingestion (e.g., herbal supplements, chronic use, herb-drug interactions).
  • Examples of toxins include ricin and other toxins associated with fungi and their compounds

Fungi - Mushroom Poisoning

  • The most dangerous mushrooms are Amanita phalloides and Amanita ocreata.
  • Children under 10 are more susceptible than adults.
  • Initial symptoms include nausea, vomiting, diarrhea, and abnormal heart rate.
  • Amatoxin damages liver and kidney cells causing failure and death. Amatoxin is very potent with a small amount, 0.1 to 0.3 mg/kg, potentially lethal.

Aflatoxins

  • Toxins produced by Aspergillus flavus and Aspergillus parasiticus.
  • Grow predominantly on grains.
  • Causes toxic effects on the liver, often associated with liver cancer.

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Description

Explore the interplay between environmental factors and diseases in this quiz on Environmental Pathology. Learn about the impact of climate change, the role of pollutants, and how various agents contribute to health issues. Test your knowledge on how the environment affects human health and well-being.

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