Forensic Science: Blood Typing and Spatter Analysis
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Questions and Answers

What type of evidence is blood typing?

Class evidence

What is the benefit of DNA STP analysis?

It provides a high degree of certainty regarding blood consistency.

What can we determine from blood spatter evidence?

The area of origin, direction, and angle of impact.

What type of tissue is blood?

<p>Connective tissue.</p> Signup and view all the answers

What are three functions of the blood?

<p>Transport, protection, regulation.</p> Signup and view all the answers

What are antibodies?

<p>Proteins secreted by white blood cells.</p> Signup and view all the answers

In what type of blood cell will we find nuclei?

<p>White blood cells.</p> Signup and view all the answers

Who made blood transfusion possible?

<p>Karl Landsteiner.</p> Signup and view all the answers

What did Karl Landsteiner discover about blood?

<p>Different blood types can cause clumping.</p> Signup and view all the answers

What is Rh factor?

<p>All of the above</p> Signup and view all the answers

What is the significance of blood spatter analysis in forensic science?

<p>Integral part of crime scene analysis.</p> Signup and view all the answers

What chemicals must investigators spray to detect blood?

<p>Luminol.</p> Signup and view all the answers

What is the Kastle-Meyer test?

<p>A test that detects hemoglobin.</p> Signup and view all the answers

How is blood evidence detected at a crime scene?

<p>Using light sources and blood reagent tests.</p> Signup and view all the answers

What is the relationship between blood velocity and spatter size?

<p>Higher velocity results in smaller spatter.</p> Signup and view all the answers

What can blood spatter analysis reveal?

<p>All of the above</p> Signup and view all the answers

What is passive bloodstains?

<p>Patterns created from the force of gravity.</p> Signup and view all the answers

What defines high velocity impact spatter?

<p>A fine mist with droplets less than 1mm.</p> Signup and view all the answers

What is the significance of the pointed end of a blood droplet?

<p>It indicates the direction of travel.</p> Signup and view all the answers

What does the area of convergence help determine?

<p>The height of the injury above the floor.</p> Signup and view all the answers

What is the area of origin in blood spatter analysis?

<p>The location of the blood source in three dimensions.</p> Signup and view all the answers

What are some factors that influence the shape of blood droplets?

<p>All of the above</p> Signup and view all the answers

Study Notes

Blood Typing and Evidence

  • Blood typing serves as class evidence, helpful in excluding suspects due to shared blood types among the population.
  • DNA analysis of white blood cells (WBC) offers high certainty in matching crime scene blood with a suspect or victim.

Blood Spatter Analysis

  • Blood spatter evidence reveals the area of origin, direction, and angle of impact of blood at a crime scene.
  • Key aspects determined from blood patterns include direction of travel, angle of impact, area of origin, and potentially the death's circumstances.

Composition of Blood

  • Blood comprises red blood cells, white blood cells, platelets, and plasma, which transports antibodies, hormones, nutrients, and minerals.

Historical Contributions

  • William Harvey described blood circulation in 1650, unveiling its properties.
  • Karl Landsteiner made significant strides in blood transfusion compatibility, discovering blood antigens and the risks of mismatched transfusions.

Blood Type Distribution in the U.S.

  • The distribution of blood types includes O (43% Rh+ 85%), A (42% Rh- 15%), B (12%), and AB (3%).

Rh Factor

  • The Rh factor, discovered in 1940, classifies blood as Rh+ (presence) or Rh- (absence) independent of A and B antigens.

Case Study: Ludwig Tessnow

  • Tessnow's conviction for murder in 1901 involved blood evidence analysis that distinguished between human and animal blood.

History of Blood Spatter Analysis

  • Edward Piotrowski first referenced blood spatter analysis in 1895; Dr. Victor Baltnazard advanced its understanding in 1939.
  • Blood spatter analysis played a crucial role in the exoneration of Sam Shepard in 1955.

Forensic Blood Detection Techniques

  • Investigators utilize UV light and reagents like luminol to detect blood traces, responding to hemoglobin.
  • The Kastle-Meyer test detects hemoglobin and can identify other nickel and copper-based substances.

Blood Stain Types and Their Characteristics

  • Passive stains are shaped by gravity, while projected stains result from applied force.
  • Transfer stains occur when a bloody object contacts a surface.

Blood Drop Dynamics

  • The shape and direction of blood droplets provide clues; the pointed end indicates travel direction.
  • The size of blood droplets correlates with the velocity and type of violence inflicted (high, medium, or low velocity).

Patterns and Their Implications

  • Arterial spurts are caused by heart pumping, while trails indicate movement.
  • Evidence examined reveals the nature of the incident, potentially distinguishing between homicide and suicide.

Key Factors in Spatter Analysis

  • Elements like gravity, cohesion, and surface tension influence blood droplet formation and spread.
  • The angle of impact is calculable, providing insights into the spatial dynamics of a crime scene.

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Description

Explore the critical role of blood typing and blood spatter analysis in forensic science. This quiz covers the biological composition of blood, historical contributions to blood analysis, and the significance of blood evidence in crime scene investigations. Test your knowledge on these essential forensic topics.

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