What were some of the morphological differences between the head hair and the other types of body hair?
OF THE BODY Each hair type has its own shape and characteristics. One of the ways in which hairs from the different parts of the body are distinguished is their cross-sectional shape. Head hair is generally circular or elliptical in cross section. Eyebrows and eyelashes are also circular but often have tapering ends.
What does the medulla look like in hair?
The medulla is a central core of cells that may be present in the hair. If it is filled with air, it appears as a black or opaque structure under transmitted light, or as a white structure under reflected light.
What does the medulla do hair?
Medulla (hair) The medulla is the innermost layer of the hair shaft. This nearly invisible layer is the most soft and fragile, and serves as the pith or marrow of the hair.
What is one difference between the medulla in human hair and the medulla in animal hair?
Explain the difference between human and animal hair. – Medulla in a human is smaller (medullary index of less than one-third); and medulla in animals is very thick (medullary index of one-half or greater). – Cuticle in humans is imbricated; and the cuticle in animals is coronal or spinous.
What are the 3 medulla types?
There are three types of medulla.
What are some differences between human and animal hair?
Pigment concentration: Human hair has even distribution of pigment throughout cortex, while animal hair is more concentrated toward the center/medulla area. Medullary Index: Animal hair ratio of medulla to shaft diameter is much greater than humans—1/2 or more the width of the shaft!
What animal hair is closest to human hair?
The keratin content of human head hair is different than what’s found in fur on chimpanzees and gorillas, our closest biological relatives.
How can you identify human hair?
If you burn a piece of the hair product you will be able to tell which it is. Human hair will turn into ashes after burning and will have a smell of a burning feather or barbecue. But if the product is mixed with any synthetic fiber, it will melt into hard solid and will have a strong chemical smell.
What characteristics can be used to identify hair samples?
A number of microscopic characteristics associated with the cuticle are used in a hair comparison. The thickness of the cuticle, the variation in the thickness, the presence of pigment, and the color are all useful characteristics.
What are the three major types of hair analysis?
Forensic scientists perform 3 major types of hair analysis: (1) testing the hair shaft for drugs or nutritional deficiencies in a person’s system, (2) analyzing DNA collected from the root of the hair, and (3) viewing hair under a microscope to determine if it’s from a particular person or animal.
When can hair be used as individual evidence?
Hair is considered class evidence when the follicle is not attached because the follicle is the part that contains DNA. When the follicle is attached, it is considered individual evidence.
Does every hair on a person’s head have the same medulla pattern?
Only one medulla pattern type is found in human hair. The hairs found in Asians and Native Americans would be crescent moon shaped in cross-section. It is fairly easy to determine the body area from which a hair came.
Can hair provide clues about someone’s ancestry?
Hair can yield DNA evidence, if hair is pulled out by the root, as in some violent struggles, it will contain root pulp which is a good source of nuclear DNA (nDNA), the type of DNA most often used in forensics.
Are all hairs on a person head identical?
Hairs located in a single area can have different characteristics.
How is the medulla different in human pubic hair?
Pubic hair are short, curly with a wide range of variations in shaft diameter and a continuous medulla. Beard hairs: coarse and usually triangular in cross-section with blunt tips from cutting or shaving.
What are the 4 types of Medullas?
In the Present Study medulla has been classified into Absent, Fragmented, Discontinuous and Continuous types (Photo attached).
What are the three possible medulla patterns in humans?
Human medulla may be continuous, fragmented, or absent. Determined by measuring the diameter of the medulla and dividing it by the diameter of the hair.
What are the 4 different medulla patterns?
Core of the hair which can be found in many patterns like hollow or filled, absent, fragmented, continuous, doubled, pigmented or unpigmented.
What medulla patterns do humans have?
When the medulla is present in human hairs, its structure can be described as—fragmentary or trace, discontinuous or broken, or continuous. Figure 14 is a diagram depicting the three basic medullary types. The cortex is the main body of the hair composed of elongated and fusiform (spindle-shaped) cells.
How do I know my medulla pattern?
Human medulla may be continuous, fragmented, or absent. Determined by measuring the diameter of the medulla and dividing it by the diameter of the hair. Medullary index for human hair is generally less than 1/3.