Postmortem Changes | Quizlet

What is the postmortem period?

The period that begins after somatic death.

Do physical postmortem changes create new chemical substances?

No, they do not change the chemical composition or create new substances.

Do chemical postmortem changes create new substances?

Yes, they result in the formation of new chemical substances.

What is algor mortis?

Postmortem cooling of the body to ambient temperature.

What intrinsic factors affect algor mortis?

Body weight, surface area, body temperature at death.

What extrinsic factors affect algor mortis?

Clothing, environmental temperature and humidity, cause and manner of death.

What is hypostasis?

Settling of blood into dependent tissues.

What is contact pallor?

Areas where blood flow is inhibited, preventing discoloration.

How does blood thickness affect hypostasis?

Thinner blood causes more hypostatic changes.

What is livor mortis?

Intravascular red-blue discoloration resulting from postmortem hypostasis of blood.

What is dehydration (in postmortem context)?

Loss of moisture from body tissue, can occur before or after death.

What is desiccation?

Extreme dehydration, often leading to post-embalming discolorations.

What are reasons for moisture loss in a dead body?

Surface evaporation, imbibition, gravitation of fluids.

What is viscosity?

The thickness of a liquid.

What causes increased blood viscosity after death?

Dehydration and agglutination of formed elements.

What is agglutination?

Clumping of blood's formed elements, increasing viscosity.

How does imbibition affect blood viscosity?

Other cells draw moisture out of the vascular system, thickening the blood.

What is microbial translocation?

Movement of microbes through the body postmortem due to motility or fluid shifts.

What is the normal pH of the human body?

Around 7.4.

What is the pH shift after death?

Slightly basic → acidic → basic again.

Why does pH become acidic after death?

Breakdown of carbs into pyruvic acid and lactic acid.

When does the acidic phase occur?

Usually within the first three hours following death and continues during rigor mortis.

What is the neutral period of pH shift?

Time when protein breakdown produces basic nitrogenous products (like ammonia), neutralizing acids.

What happens to pH during the later decomposition process?

It shifts to alkaline as nitrogenous products increase.

What is rigor mortis?

Postmortem stiffening of muscles by natural body processes.

What muscles are affected by rigor mortis?

All muscles, but first seen in smaller ones.

When does rigor mortis typically appear?

2-4 hours after death.

How long does rigor mortis last?

Passes naturally within 36-72 hours.

Where does rigor mortis start?

In the involuntary muscles of the eye, then jaw, face, neck, upper extremities, trunk, and finally lower extremities.

What is cadaveric spasm?

Instantaneous stiffening of muscles at the moment of death.

What is primary flaccidity?

Muscle relaxation before rigor mortis begins.

What is secondary flaccidity?

Muscle relaxation after rigor mortis has passed.

What factors influence the severity of rigor mortis?

Temperature, age, gender, cause of death, muscle condition.

What is the ideal temperature for rigor mortis to occur?

98°F.

At what temperatures will rigor mortis not occur?

Below 32°F or above 120°F.

What is postmortem stain?

Extravascular discoloration from heme leaking into tissues after hemolysis.

When does postmortem stain typically occur?

About 6-10 hours after death.

What is postmortem caloricity?

A temporary rise in body temperature after death due to continued cellular metabolism.