serology hair.docx

**Morphology and Structure of Hair** - Hair is a filamentous biomaterial that grows out of the skin of humans and animals. - It is composed of a protein called keratin and has a complex structure. - The structure of hair can be divided into three parts: the medulla, the cortex,...

**Morphology and Structure of Hair** - Hair is a filamentous biomaterial that grows out of the skin of humans and animals. - It is composed of a protein called keratin and has a complex structure. - The structure of hair can be divided into three parts: the medulla, the cortex, and the cuticle. - The medulla is the innermost part of the hair shaft and is made up of round or hexagonal cells that contain air spaces. - The cortex is the middle layer of the hair shaft and is made up of spindle-shaped cells that contain keratin. - The cuticle is the outermost layer of the hair shaft and is made up of overlapping scale-like cells that protect the cortex. - The shape and structure of hair can vary greatly between different species and even between different individuals of the same species. - Hair growth and development is a complex process that is regulated by a variety of factors, including genetics, hormones, and nutrition. **Forensic Importance of Hair Evidence** - Hair evidence can be an important tool in forensic science for identifying suspects and victims. - Each individual\'s hair is unique in terms of its physical and chemical properties. - Forensic hair analysis can be used to determine the origin and species of a hair sample. - This can be useful in cases where other forms of evidence, such as fingerprints or DNA, are not available. - However, it is important to note that hair evidence is not infallible and should be used in conjunction with other forms of evidence in order to build a strong case. **Forensic Importance of Hair Evidence** **Hair Analysis in Forensic Science** - Hair analysis is a valuable tool in forensic science - Can provide information on individuals involved in a crime - Can help establish a connection between a suspect and a crime scene **Identification and Comparison of Hair** - Microscopic analysis is used for identification and comparison - Characteristics such as color, diameter, and cuticle patterns are examined - Examination can also reveal damage or treatment to the hair **Types of Hair: Human and Animal** **Identification and Comparison of Hair** - Hair is a filamentous biomaterial that grows out of the skin of humans and animals - Human hair is unique in its texture, color, and shape, while animal hair varies between species - A trichogram is a microscopic examination of hair, which can be used for identification and comparison **Morphology and Structure of Hair** - Hair has three parts - the root, the follicle, and the shaft - The shaft has three layers - the medulla, the cortex, and the cuticle - The medulla is the innermost layer and is only present in thick human hair - The cortex is the middle layer and determines the strength, texture, and color of the hair - The cuticle is the outermost layer and is responsible for the hair\'s shine and protection **Forensic Importance of Hair Evidence** - Hair evidence can provide information about the victim or the perpetrator in a criminal investigation - Hair can be found at the crime scene, on the victim, or on the perpetrator - Forensic hair examination includes the identification of the type of hair (human or animal), its racial origin, and the comparison of hair samples **Hair Analysis in Forensic Science** - Hair analysis can identify drugs, toxins, and heavy metals in the body - Hair grows at a rate of about 0.3-0.5mm per day, making it possible to estimate the time of drug or toxin intake - Hair analysis can also provide information about the geographical origin of an individual **Determination of Hair Origin and Species** - The origin and species of hair can be determined through microscopic examination and DNA analysis - The diameter, cuticle shape and scale pattern, medulla, and pigment distribution can help identify the species of animal hair - Human hair can be identified through DNA analysis, which can also provide information about the individual\'s gender, ancestry, and physical characteristics. **Hair Growth and Development** - Hair growth and development occur in three stages - the anagen phase, the catagen phase, and the telogen phase - The anagen phase is the active growth phase, which can last for 2-7 years - The catagen phase is the transitional phase, which lasts for about 2-3 weeks - The telogen phase is the resting phase, which lasts for about 3-4 months - Hair grows at an average rate of 0.3-0.5mm per day, and the growth rate varies between individuals and between different body sites. **Identification and Comparison of Hair** **Introduction** - Hair is a common form of evidence found at crime scenes - The identification and comparison of hair can provide valuable information for forensic investigations **Morphology and Structure of Hair** - Hair is composed of three parts: the medulla, cortex, and cuticle - The medulla is the innermost part of the hair shaft and is usually not present in fine hair - The cortex makes up the majority of the hair shaft and determines the hair\'s color, texture, and strength - The cuticle is the outermost layer of the hair shaft and protects the cortex **Microscopic Examination** - Microscopic examination of hair is used to determine its physical characteristics - These characteristics include length, width, color, cuticle pattern, and medulla pattern - The presence or absence of the medulla is a key characteristic used to differentiate human hair from animal hair **Comparison of Hair** - Hair samples can be compared to determine if they could have come from the same source - This is done by examining and comparing the physical characteristics of the hairs - A statistical analysis may be used to determine the likelihood that the hairs came from the same source **Determination of Hair Origin and Species** - The determination of hair origin and species is based on the comparison of hair samples to known reference samples - Human hair can be distinguished from animal hair based on the presence or absence of the medulla - The comparison of hair samples from different animal species is based on the examination of physical characteristics such as length, width, cuticle pattern, and medulla pattern **Conclusion** - The identification and comparison of hair is a valuable tool in forensic science - Microscopic examination of hair can reveal important physical characteristics that can be used for comparison and identification - The determination of hair origin and species is based on the comparison of hair samples to known reference samples - The likelihood that hair samples came from the same source can be determined through statistical analysis. **air Analysis in Forensic Science** **Identification and Comparison of Hair** - Microscopic examination is used to identify and compare hair samples - Characteristics such as diameter, color, and cuticle patterns are examined **Morphology and Structure of Hair** - Hair is composed of a protein called keratin - Made up of three parts: medulla, cortex, and cuticle - Medulla is the innermost part, cortex forms the majority of the hair shaft, and cuticle is the outermost layer **Forensic Importance of Hair Evidence** - Hair evidence can be used to link a suspect to a crime scene - Can provide information about the victim or perpetrator, such as race and age **Determination of Hair Origin and Species** - Examination of the medulla and cuticle patterns can help determine the origin and species of the hair - Human head hair has a medulla, while hair from other parts of the body and from animals may not **Hair Growth and Development** - Hair growth occurs in three phases: anagen (growth phase), catagen (transitional phase), and telogen (resting phase) - Each hair follicle has its own growth cycle, which can vary from person to person - Hair growth rate can also vary, with head hair growing about 1/2 inch per month on average. **Determination of Hair Origin and Species** **Types of Hair** - Human hair - Animal hair **Human Hair** - Unique characteristics - Can be used to identify individual - Can provide information on race and ethnicity **Animal Hair** - Variation in animal hair - Can provide information on animal type and species **Identification and Comparison of Hair** - Microscopic examination - Comparison of physical characteristics - Can provide information on origin and species **Morphology and Structure of Hair** - Shape, size and composition - Medulla, cortex and cuticle - Can provide information on animal type and species **Forensic Importance of Hair Evidence** - Can provide valuable evidence in criminal investigations - Can be used to link suspects to crime scene - Can provide information on victim or suspect **Hair Analysis in Forensic Science** - Techniques used in hair analysis - Microscopy, DNA profiling and chemical analysis - Can provide information on individual identity, drug use and exposure to chemicals **Hair Growth and Development** - Stages of hair growth - Anagen, catagen and telogen - Can provide information on time of hair deposition and growth rate.