Chapter 6 Body Systems © 2012 Cengage Learning. All Rights Reserved

2 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Introduction o Anatomy—the study of the structure of the human body o Physiology—the study of the function of the body systems o Homeostasis—a stable internal environment

3 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved The Circulatory System (Obj 6.1, 6.2) o Systemic—the heart pumps oxygenated blood through arteries to body cells o Pulmonary—the heart pumps the deoxygenated blood, carbon dioxide and other wastes to the lungs

4 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Properties of Blood o Red Blood Cells o White Blood Cells o Platelets o Plasma

5 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Red Blood Cells o Also called erythrocytes o Carries oxygen throughout the body o Concave shape creates a large, efficient surface area o Hemoglobin—a protein that binds oxygen for transport

6 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved White Blood Cells o Also called leukocytes o Protects the body against infection and fight viruses and bacteria.

7 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Platelets o Also called thrombocytes o Helps form blood clots that act as a plug at open wounds o These clots become scabs when hardened

8 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Plasma o The liquid potion of blood—92% water o Blood cells and platelets are suspended in plasma o Transports important nutrients, vitamins and gases

9 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Human Heart o Atria—upper chamber o Ventricles—lower chamber

10 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Forensic Implications of the Circulatory System o Blood type—class characteristic o DNA—individual characteristic o Blood—biological evidence o Hemastix ® —a presumptive test for blood o Luminol—another presumptive test o Collect samples of blood evidence

11 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Lividity o Lividity—the pooling of blood in the direction of gravity o Livor mortis— the change in color caused by lividity Bluish purple or reddish purple

12 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Petechiae o Often occurs when a limb is in a hanging position o Small red dots underneath the surface of the skin

13 Blood Splatters- low velocity 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 o 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. o This type of spatter can be caused by a blunt object, such as a bat or an intense beating with a fist. 14

High-velocity spatters o are usually caused by gunshot wounds, although they can be caused by other weapons if the assailant exerts an extreme amount of force. o They travel more than 100 feet per second and usually look like a fine spray of tiny droplets, less than one millimeter in diameter. 15

16 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved The Respiratory System (Obj 6.3, 6.4)

17 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved The Respiratory System—Structures

18 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Forensic Implications of the Respiratory System o Cellular respiration Oxygen from the air combines with glucose to create energy for the cells in your body o Asphyxiation—when the available oxygen decreases sharply while the level of toxic gases increases

19 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved The Muscular System (Obj 6.5, 6.6)

20 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved Forensic Importance of the Muscular System o Actin and myosin—two proteins that form fibers within muscles o Muscles contract when myosin attaches to the actin, forming a bridge o Lack of oxygen after death prevent muscles from relaxing o Rigor mortis—the process in which the muscles of a body begin to stiffen

21 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved The Forensic Implications of Other Body Systems

22 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved The Forensic Implications of Other Body Systems

23 Forensic Science II: Body Systems, Chapter 6 © 2012 Cengage Learning. All Rights Reserved The Forensic Implications of Other Body Systems