Chapter 12 - Blood Spatter - Vocabulary

Agglutination

The clumping of molecules or cells caused by an antigen-antibody reactions

Antibodies

Y-shaped proteins secreted by white blood cells to attach to antigens to destroy them

Antigen-Antibody Response

A reaction in which antibodies attach to specific antigens

Antigens

Any foreign substance or cell in the body that reacts with antibodies

Cell-Surface Protein

Proteins embedded in the cell membrane that play a key role in cell recognition and communication.

Lines of Convergence

Two or more blood spatters that can pinpoint the location of the blood source

Point of Origin

The common point (area) in a three dimensional space to which the trajectories of several blood drops can be traced

Red Blood Cells

Carries oxygen to the body’s cells and carbon dioxide away from the cells. They are essential for respiration and are produced in the bone marrow.

White Blood Cells

Fights disease and foreign invaders and, alone, contain cell nuclei

Satellite Drop of Blood

When blood falls from a height, or at high velocity, it overcomes its natural cohesiveness, and separates from the main droplet

Gunshot Spatter

Includes both forward spatter from the exit wound and back spatter from the entrance wound

Cast-Off

Results when an object swung in an arc flings blood onto nearby surfaces. Occurs when an assailant swings the blood-stained object back before inflicting another blow.

Arterial Spray

Refers to the spurt of blood released when a major artery is spatterd

Expirated Spatter

Is usually caused by blood from an internal injury mixing with air form the lungs being expelled through the nose, mouth, or an injury to the airways or lungs

Passive Bloodstains

Patterns created from the force of gravity; can be a single drop, series of drops, flow patterns, blood pools, etc.

Projected Bloodstains

Patterns that occur when a force is applied to the source of the blood; includes low, medium, or high impact spatters, cast-off, arterial spurting, and expiratory blood blown out of the nose, mouth or wound

Transfer or Contact Bloodstains

The pattern created when a wet, bloody object comes in contact with a target surface; may be used to identify an object or body part

Blood Reagent Tests

Also called presumptive tests; are used to detect blood at crime scenes based upon the properties of hemoglobin in the blood

Luminol

This chemical is used by crime scene investigators to locate traces of blood, even if it has been cleaned or remove

Fluorescein

Ideal for fines stains or smear. After the solution is sprayed onto the substance or area suspected to contain blood, a UV light and goggles are used to detect any illuminated areas.

Leuco Crystal Violet

Reacts with a heme-group in blood to give a violet color. Can be used to identify blood stains that are not visible

Satelites

A smaller bloodstain that originated during the formation of the parent stain as a result of blood impacting a surface.

Angle of Impact

The bottom of the spatter stain will be more dense than the top of the stain