Transcript 21 The Forensic Implications of Other Body Systems

Chapter 6
Body Systems
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Introduction
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Anatomy—the study of the structure of the
human body
Physiology—the study of the function of the
body systems
Homeostasis—a stable internal environment
Forensic Science II: Body Systems, Chapter 6
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The Circulatory System (Obj 6.1, 6.2)
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Systemic—the heart pumps oxygenated
blood through arteries to body cells
Pulmonary—the heart pumps the
deoxygenated blood, carbon dioxide and
other wastes to the lungs
Forensic Science II: Body Systems, Chapter 6
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Properties of Blood
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Red Blood Cells
White Blood Cells
Platelets
Plasma
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Red Blood Cells
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Also called erythrocytes
Carries oxygen throughout the body
Concave shape creates
a large, efficient surface
area
Hemoglobin—a protein
that binds oxygen for
transport
Forensic Science II: Body Systems, Chapter 6
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White Blood Cells
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Also called leukocytes
Protects the body against infection and fight
viruses and bacteria.
Forensic Science II: Body Systems, Chapter 6
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Platelets
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Also called thrombocytes
Helps form blood clots that act as a plug at
open wounds
These clots
become
scabs
when
hardened
Forensic Science II: Body Systems, Chapter 6
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Plasma
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The liquid potion of blood—92% water
Blood cells and platelets are suspended in
plasma
Transports important nutrients, vitamins and
gases
Forensic Science II: Body Systems, Chapter 6
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Human Heart
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Atria—upper
chamber
Ventricles—lower
chamber
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Forensic Implications of the
Circulatory System
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Blood type—class characteristic
DNA—individual characteristic
Blood—biological evidence
Hemastix®—a presumptive test for blood
Luminol—another presumptive test
Collect samples of blood evidence
Forensic Science II: Body Systems, Chapter 6
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Lividity
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Lividity—the pooling of blood in the direction
of gravity
Livor mortis—
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the change in color
caused by lividity
Bluish purple or
reddish purple
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Petechiae
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Often occurs when a limb is in a hanging
position
Small red dots underneath the surface of the
skin
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Blood Splatters- low velocity
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is usually the result of dripping blood.
The force of impact is five feet per second or less, and the size of
the droplets is somewhere between four and eight millimeters.
• This type of blood spatter often occurs after a victim initially
sustains an injury, not during the infliction of the injury itself.
• For example, if the victim is stabbed and then walks around
bleeding.
A medium-velocity spatter
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Is one that had a force of anywhere from 5 to 100
feet per second, and its diameter is usually no
more than four millimeters.
This type of spatter can be caused by a blunt
object, such as a bat or an intense beating with a
fist.
High-velocity spatters
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are usually caused by gunshot wounds,
although they can be caused by other weapons
if the assailant exerts an extreme amount of
force.
They travel more than 100 feet per second and
usually look like a fine spray of tiny droplets,
less than one millimeter in diameter.
The Respiratory System (Obj 6.3, 6.4)
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Forensic Science II: Body Systems, Chapter 6
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The Respiratory System—Structures
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Forensic Implications of the
Respiratory System
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Cellular respiration
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Oxygen from the air combines with glucose to create
energy for the cells in your body
Asphyxiation—when the available oxygen
decreases sharply while the level of toxic gases
increases
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The Muscular System (Obj 6.5, 6.6)
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Forensic Importance of the
Muscular System
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Actin and myosin—two proteins that form
fibers within muscles
Muscles contract when myosin attaches to
the actin, forming a bridge
Lack of oxygen after death prevent muscles
from relaxing
Rigor mortis—the process in which the
muscles of a body begin to stiffen
Forensic Science II: Body Systems, Chapter 6
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The Forensic Implications of
Other Body Systems
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Forensic Science II: Body Systems, Chapter 6
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The Forensic Implications of
Other Body Systems
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Forensic Science II: Body Systems, Chapter 6
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The Forensic Implications of
Other Body Systems
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Forensic Science II: Body Systems, Chapter 6
© 2012 Cengage Learning. All Rights Reserved