Forensic Science – Topics and Terms Exam 2 Content
Chapter 5 – Medicolegal Investigation of Death
Topics
Questionable/Questionable/Equivocal Deaths
Important considerations in determining the circumstances surrounding a death.
Roles and Responsibilities related to Medicolegal Investigations
Specific duties of professionals involved in investigating deaths, including forensic pathologists, medical examiners, and medicolegal death investigators.
4 Main Purposes of Death Investigation
Determining Cause of Death: The specific injury or disease that led to death.
Mechanism of Death: The physiological or biochemical process resulting in death.
Manner of Death: The category of death, e.g., natural, accidental, suicidal, or homicidal.
Time of Death: Estimating when the death occurred, relevant for legal purposes.
3 Stages of Death
Rigor Mortis: Stiffening of the muscles postmortem.
Livor Mortis: Settling of blood in lower parts of the body leading to discoloration.
Algor Mortis: Cooling of the body after death.
Relevant observations during each stage include timing and physical changes in the body.
4 Main Tools of Death Investigation
Medical History: Prior health records which may indicate causes of death.
Witness Statements: Eyewitness accounts to ascertain circumstances of death.
Scene Examination: Inspecting the environment where the death occurred for evidence.
Autopsy: A thorough medical examination postmortem to ascertain cause of death.
Each tool provides distinct pieces of information aiding the investigation.
Autopsy Process: Detailed steps and applications of imaging technologies in understanding cause of death.
Traumatic Death Classifications
Mechanical Trauma: Injuries resulting from physical forces.
Thermal Trauma: Damage due to extreme temperatures.
Chemical Trauma: Harm caused by toxic substances.
Electrical Trauma: Injuries from electric shocks.
Terms
Algor Mortis: The cooling of the body postmortem.
Asphyxia: Death due to lack of oxygen.
Autopsy: An examination of a body to determine the cause and manner of death.
Cause of Death: The medical term describing what led to the death.
Coroner: An official responsible for investigating deaths.
Decomposition: Biological breakdown of body tissues after death.
Equivocal Death: Death with uncertain causes or circumstances.
Forensic Pathologist: Medical professionals who perform autopsies and determine cause of death.
Incised Wound: A wound caused by a sharp object.
Laceration: A tear in body tissue caused by force.
Lead Snowstorm: A phenomenon related to gunshot injuries where lead particles scatter.
Livor Mortis/Lividity: The pooling of blood post-death causing discoloration.
Manner of Death: Classification of the death's circumstances.
Mechanical Trauma: Physical force leading to injury.
Mechanism of Death: The body functions leading to death (like cardiac arrest).
Medicolegal Death Investigator, MDI: Specialized personnel investigating fatality circumstances.
Medicolegal Investigation of Death: Examination of death involved legal considerations.
NASH: Atypical causes of death investigation (Natural, Accidental, Suicide, Homicide).
Pathology: The study of diseases.
Perimortem: Events taking place around the time of death.
Postmortem: Examination or events after death.
Questioned Death: Death requiring investigation due to suspicions.
Rigor Mortis: Postmortem muscle stiffening.
Stippling: Gunshot wound appearance indicating distance.
Tattooing: Similar to stippling but more extensive, indicating close-range gunfire.
Virtual Autopsy: Use of imaging for non-invasive autopsy processes.
Chapter 6 – Forensic Toxicology
Topics
Role of Toxicologist in Death Investigation: Analyzing bodily fluids for toxins and their implications on health and death.
Modes of Ingestion: Different ways substances can enter the body, affecting toxicity (oral, inhalation, dermal).
Dosages: The amounts of substances affecting toxicity outcomes.
ADME: Acronym for Absorption, Distribution, Metabolism, and Excretion of substances.
Shapes of Curves: Graphical representation of concentration vs time for substances in the body.
Toxicity of Xenobiotics:
Impact of Doses: How varying doses can result in different toxic effects.
Timing: Influence of time on level and impact of toxins.
Mode of Ingestion: Which affects the bioavailability of toxins.
ADME also influences the overall toxic effect.
Types of Post-Mortem Samples and Toxins:
Body Fluids: Blood, urine, and organ tissues are tested for toxins.
Relevant information obtained includes exposure levels, timing, and effects of chemicals.
Methods of Analysis: Techniques employed in forensic toxicology.
Presumptive vs Confirmatory Tests:
Presumptive Tests: Initial screenings indicating the presence of substances.
Confirmatory Tests: Detailed analyses confirming the specific substance found.
Two-stage Approach: Sequential testing combining screening and confirmation for accuracy.
Immunoassay: A testing method that uses antibodies for substance detection, detailing its design, function, and applications.
Separation by Chromatography: Technique for isolating substances in a mixture.
Confirmation by Mass Spectrometry: Advanced method for identifying substances post-separation.
Interpretation of Toxicological Findings: Considerations for forensic toxicologists including physiological variances, existing medical conditions, and limitations in testing.
Challenges: Issues related to interpretation including postmortem redistribution and sample degradation.
Selection of Forensic Method: Involves considering the use, sample type, performance characteristics, and type of information gleaned.
Terms
ADME: Absorption, Distribution, Metabolism, Excretion mechanisms influencing drug effects.
Antibody: Immune system protein targeting specific antigens.
Antigen: Substances inducing immune response.
Aqueous: Related to water solutions.
Central Blood: Blood from the heart or major vessels.
Confirmatory: Tests that validate the presence of a substance.
Chromatography: Technique for separating mixtures into components.
Cross-reactivity: When antibodies react with similar antigens, affecting test results.
Double Positive: Test results indicating the presence of both target substances.
Drug ED50: The effective dose required for 50% of the population to achieve desired effect.
First-pass metabolism: Biochemical alteration of a substance before reaching systemic circulation.
Gastric Contents: Substances in the stomach used for testing toxic exposure.
Immunoassay: Techniques using antigen-antibody reactions for detection.
Ingestion: The act of taking substances into the body.
LD50: Lethal dose required to kill 50% of a test population.
Mass Spectrometry: An analytical technique for measuring mass-to-charge ratio of ions.
Mode of Administration/Ingestion: The method by which a substance is administered to an organism.
Peripheral Blood: Blood from around the body, away from the heart.
Poison: Any substance causing harm or death when ingested.
Postmortem Redistribution (PMR): Redistribution of substances in the body after death affecting toxicology results.
Postmortem Toxicology: Study of toxins in a deceased person’s body.
Presumptive Test: Initial screening test indicating potential presence of substances.
Screening: The process of testing for potential presence of toxic substances.
Separation: The process of isolating substances in a mixture.
Therapeutic Dose: Dose required to achieve a desired medical effect.
Therapeutic Index: Measure of a drug's safety margin.
Thin Layer Chromatography: A chromatography method for separating non-volatile mixtures.
Toxin: A poisonous substance.
Vitreous Humor: Gel-like substance in the eye, used for toxicology testing.
Xenobiotic: A chemical compound foreign to a living organism.
Chapter 9 – Biological Evidence
Topics
Finding and Identifying Biological Evidence: Techniques and methodologies in locating and recognizing biological materials at crime scenes.
Importance of Presumptive Tests: Initial tests to screen for biological materials, indicating presence without definitive identification.
Possible Outcomes of Presumptive Tests: Results that can affirm or negate the presence of biological fluids.
Important Controls for Presumptive Tests: Utilizing positive and negative control samples to ensure accuracy and reliability of test results.
Types of Questions Answered: The significance of biological evidence can lead to identifying victims, suspects, and timeline of events.
Relevant Presumptive Tests and Their Functions:
Blood: Tests like the Kastle-Meyer test for blood identification.
Seminal Fluid: Tests for prostate-specific antigen and others.
Saliva: Presence indicated through amylase testing.
Additional Measurement Methods:
Use of Alternate Light Sources: Techniques to locate biological evidence through luminescence.
Immunochromatography: Testing methods applying antibodies for rapid results.
Terms
Acid Phosphatase: Enzyme present in seminal fluid used as a presumptive test marker.
Alternative Light Source: Equipment used for enhancing visibility of certain evidence.
Amylase: An enzyme in saliva aiding in the identification of this biological fluid.
Azospermia: A condition indicating no sperm presence in seminal fluid, useful in forensic cases.
Background Sample: A comparison sample from a control area unrelated to the crime scene.
Catalyst: Substances increasing the rate of a reaction, relevant in chemical tests.
Christmas Tree Stain: A type of testing method for identifying seminal fluid.
Chemiluminescence: Emission of light during chemical reactions, used in forensic evidence detection.
Chromogenic Substance: Compounds producing colors used in tests for identification.
False Negative: A test result failing to detect the presence of a substance present.
False Positive: A test result indicating the presence of a substance not actually present.
Field Test: Tests conducted at the scene of an incident for rapid analysis.
Fluorescence: Emission of light by a substance after absorbing light, useful in forensic examination.
Forensic Serology: The study of bodily fluids in forensic contexts.
Hemastix: Test strips indicating the presence of blood through color change.
Heme Group: Component of hemoglobin, relevant in blood testing.
Hemoglobin: Oxygen transport protein in blood, tested to confirm blood presence.
Immunochromatography: Rapid tests employing antibodies for identification purposes.
Kastle-Meyer Test: A presumptive test for the presence of blood based on color reaction.
Luminol: A chemical producing light in the presence of blood, enhancing visibility.
Negative Control: A sample known not to contain the substance being tested, ensuring test validity.
Oxidation: A chemical reaction relevant in presumptive testing, where substances lose electrons.
Phadebas Reagent: A tested compound indicating amylase presence in saliva.
Phenolphthalein: A chemical used in tests to identify blood through color changes.
Positive Control: A sample known to contain the substance being tested, ensuring reliability.
Prostate-Specific Antigen: A marker used to identify semen in forensic examinations.
Press Test: A method to detect fluid presence through pressure application.
Presumptive Test: Initial screening indicating potential presence of biological materials.
Screening Test: Tests allowing a quick examination of potential biological evidence.
Semen/Seminal Fluid: Biological fluids tested for presence in sexual assault cases.
Serology: The study of blood serum and immune responses in forensic cases.
Spermatozoa: Male reproductive cells identified in semen tests.
True Negative: Correctly test indicating absence of a substance.
True Positive: Correctly test confirming presence of a substance.