Blood Evidence and Spatter Analysis: Forensic Blood Typing and Crime Scene Clues

What clues can blood evidence reveal about a crime?

Blood evidence can reveal information about the crime scene, the victim, and potential suspects.

What is the main component of blood that scientists rely on for investigations?

Scientists primarily rely on white blood cells for DNA and red blood cells for their unique antigens.

What are surface markers on cells called, and what are they made of?

Surface markers are called antigens, and they are made of proteins or carbohydrates.

What is the role of antigens in blood?

Antigens help determine blood types and play a crucial role in immune responses.

List the 4 main blood types and their corresponding antigens.

Type A: A antigens, Type B: B antigens, Type AB: A and B antigens, Type O: No antigens.

Who can Type O individuals receive blood from, and why?

Type O individuals can receive blood from other Type O individuals because they have no antigens to react against.

Who can Type A individuals donate blood to, and why?

Type A individuals can donate blood to Type A and AB individuals because they have A antigens.

Who can Type AB individuals receive blood from, and why?

Type AB individuals can receive blood from all blood types (A, B, AB, O) because they have both A and B antigens.

What evidence comes from white blood cells, and what type of evidence is it?

White blood cells provide individual evidence as they contain DNA.

What evidence comes from red blood cells, and what type of evidence is it?

Red blood cells provide class evidence since they do not contain DNA.

Which type of evidence (class or individual) is considered better, and why?

Individual evidence is considered better because it can be linked to a specific person.

What are the three main types of blood stains?

The three main types of blood stains are passive stains, transfer stains, and projected stains.

What are passive stains and their main sub-types?

Passive stains are caused by gravity and include drops, flows, and pools.

How does height affect blood drops?

Higher drops create larger and more irregular stains due to increased velocity upon impact.

What are parent drops and satellite drops?

A parent drop is the original drop of blood, while satellite drops are smaller droplets that break off from the parent drop.

What are flows in blood spatter analysis?

Flows are blood stains that flow in a particular direction, often indicating movement.

What are trails in blood spatter analysis?

Trails are blood stains left by a person or object moving through blood.

What are splashes in blood spatter analysis?

Splashes are blood stains created when blood is projected onto a surface.

What are impact spatters?

Impact spatters are blood droplets created when a force impacts a blood source.

What are the characteristics of low velocity spatters?

Low velocity spatters are larger, typically greater than 3 mm in diameter, and result from a low force impact.

What are arterial gushes and what causes them?

Arterial gushes are blood spurts from an artery caused by the force of blood pressure during injury.

What do void patterns indicate?

Void patterns indicate the absence of blood in an area, suggesting the position of a person or object during the event.