Bodily fluids Flashcards
What are the two main categories of forensic evidence?
Physical and Biological
Physical evidence refers to tangible items that can be collected at a crime scene, while biological evidence involves bodily fluids or tissues.
What are bodily fluids?
Liquids excreted or secreted by the body, including:
* Excreted - e.g. faeces, vomit, urine
* Secreted - e.g. blood/plasma, semen, saliva
Bodily fluids can provide critical forensic evidence in investigations.
What is the role of bodily fluids in forensic applications?
Help forensic scientists determine how/when a victim died and who the offender was.
What does forensic pathology focus on?
Cause, manner, and time of death.
What can diatoms in pleural liquid indicate?
They can help in determining drowning cases.
What is vitreous humour, and why is it important in forensic science?
It is the liquid inside the eye used to estimate time since death by measuring chemical changes.
True or False: The presence of bodily fluids at a crime scene can always be guaranteed.
False.
What is the forensic value of bodily fluids?
They are present at various crime scenes, can persist over time, and are useful for opening cold cases.
What are the two types of tests used in forensic analysis of bodily fluids?
Presumptive tests and confirmatory tests.
What are presumptive tests used for in forensic analysis?
Indicate potential sources of biological material.
What do confirmatory tests do?
Conclusively identify the type of biological material.
What is the most common bodily fluid encountered in forensic cases?
Blood.
What are the main components of blood?
55% plasma and 45% cellular material.
What two systems classify blood types?
ABO and RhD antigen systems.
What does the ABO blood group system denote?
The presence of A or B antigens on red blood cells.
What is the RhD antigen?
The most important and immunogenic antigen in the Rh blood group system.
What is blood pattern analysis (BPA)?
The analysis of blood patterns to determine what happened during a violent crime.
What are active bloodstains?
Blood that travels by force other than gravity.
What are passive bloodstains?
Blood formed solely under the influence of gravity.
What is the purpose of presumptive tests for blood?
Determine presence of blood at trace levels.
What is the most common presumptive test for blood?
Luminol test.
What is saliva commonly found in?
Burglary, assault, and sexual offense cases.
What is the primary function of saliva?
A digestive aid.
What type of fluid is semen?
A complex fluid produced by male reproductive glands.
What is the average volume of an ejaculate?
2-5 ml.
What does the presence of seminal acid phosphatase indicate?
The presence of semen.
What are vaginal fluids used for in forensic cases?
Important in sexual assault cases.
What is the average daily production of vaginal secretions?
6 grams.
What is the composition of urine?
91-96% water, and contains inorganic salts and organic compounds.
What is sweat primarily composed of?
Mostly water with dissolved minerals.
True or False: Sweat is commonly found at crime scenes.
False.
What is the primary role of sweat?
Thermoregulation.
