Quiz #2 Criminalistics

The shaft is composed of what three layers?

Cuticle, cortex, and medulla.

What are the three basic patterns that describe the appearance of the cuticle?

Coronal, spinous, and imbricate

Locard’s exchange principle

Every contact leaves a trace.

Trace evidence

Small, sometimes microscopic material, which is transferred during the commission of a crime.

Evidence associations

Class characteristics: associate an item to a particular class or group (ex., tread from footprint to a brand)

Individual characteristics: can attribute to a source with high degree of certainty (ex., DNA, fingerprint)

What is the purpose of collecting evidence?

To create linkages (linkage triangle)

Linkage triangle

Connects a crime’s suspect, victim, and scene through physical evidence

Routes of administration

Orally, contact, snorting, injection, and inhalation

Orally

20-30 minute reaction time

Contact

5-10 minute reaction time

Snorting

3-5 minute reaction time

Intravenous injection

15-30 SECOND reaction time

Intramuscular injection

3-5 minute reaction time

Inhalation (THE FASTEST)

7-10 SECOND reaction time

Types of drugs

Narcotics, hallucinogens, depressants, stimulants, club drugs, and steroids.

Narcotics

Lessens or eliminates pain

Hallucinogenics

Induces changes in mood, attitude, thought processes, and perceptions.

Depressants

Depresses the functions of the central nervous system; can calm irritability and anxiety and may induce sleep

Stimulants

Taken to increase alertness or activity; stimulates, or speeds up the central nervous system

Club drugs

Synthesized by chemists working in clandestine drug laboratories for profit

Anabolic steroids

Synthetic compounds that are chemically related to the male sex hormone testosterone

Controlled substances act

The federal law establishes five schedules of classification for controlled dangerous substances based on a drug's potential for abuse, potential for physical and psychological dependence, and medical value. (Schedule 1 = most dangerous with potentially sever psychological or physical dependence ex., heroin)

How should drug evidence be collected and preserved?

In original container in which it was seized

The analytical process of forensic drug analysis

Screening: a test that is nonspecific and preliminary in nature (color tests)

Confirmation: a single test that specifically identifies a substance (infrared spectrophotometry and mass spectrometry)

Color tests

Marquis 2 - purple or orange/brown

Dillie-Koppanyi - violet/blue

Duquenois-Levine - purple

Van Urk - purple

Scott Test - blue/pink

Chromatography

A technique used for separating the components of a mixture

Role of forensic toxicology

Detect and identify drugs and posions in body fluids, tissues, and organs

Pharmacokinetics

Specific branch of pharmacology that studies what the body does to a drug

Pharmacokinetic studies evaluate

The rate that a chemical is absorbed and distributed

The rate and pathways of drug metabolism and excretion

The plasma concentration of a drug over time

Absorption

Describes how a chemical enters the body, relating to the movement of a chemical from the administration site to the bloodstream.

Four main routes of administration

Ingestion - through the digestive tract

Inhalation - through the respiratory system

Dermal application - through the skin or eye

Injection - through direct administration into the bloodstream

4 ways through which a chemical can cross a membrane and enter the bloodstream

Passive diffusion, facilitated diffusion, active diffusions, and endocytosis

Passive diffusion

When a molecule moves from an area of high concentration to an are of low concentration. This is the most common way a drug is absorbed.

Facilitated diffusion

When an molecule moves from an area of high concentration to one of low concentration with the help of carrier proteins in the membrane.

Active diffusion

An energy-dependent process during which a molecule requires energy in the form of ATP to cross a membrane.

The route of administration infleunces…

Bioavailability, which is a measure of how much a drug is absorbed in an unchanged form.

After absorption it is…

Distributed, metabolized, and excreted

Most heavily used drug in western countries

Alcohol

During alcohol’s absorption phase…

It slowly enters the bloodstream and is carried to all parts of the body, being distributed uniformly through the watery portions of the body (about 2/3 of the body)

Factors that affect rate of alcohol absorption

Rate and amount at which it is consumed, alcohols content in beverage, quantity and type of food present in stomach

The teal mechanisms alcohol is eliminated through

Oxidation: combination of oxygen with other substances to produce new products

Excretion: elimination of alcohol from the body in an unchanged state; alcohol is normally excreted in breath, urine and perspiration