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All About 
Hair 
Presented by: R, E. O. Gaas 
Grade 7-Neptune 
Alabel National Sciece High School 
Regional Science High S...
All About Hair 
What is a Hair? 
Anatomy of Hair 
Biological, Physical and Chemical 
Facts About Hair 
Types of Hairs 
Hai...
What is a Hair? 
• is a protein filament that grows 
from follicles found in the dermis, or skin. 
• is one of the definin...
Anatomy of Hair
Anatomy of Hair 
Hair is composed of three principal parts: 
Cuticle – outer coating composed of overlapping scales 
Corte...
Anatomy of Hair 
Cuticle 
The cuticle varies in: 
• Its scales, 
How many there are per centimeter, 
How much they overlap...
Anatomy of Hair 
Cortex 
The cortex varies in: 
• Thickness 
• Texture 
• Color 
• Distribution of the cortex is perhaps 
...
Anatomy of Hair 
Medulla 
The medulla may vary in: 
• Thickness 
• Continuity - one continuous 
structure 
or broken into ...
Facts About Hair 
• Hair is composed of the protein keratin, which is also the 
primary component of finger and toe nails....
Facts About Hair 
Hair shape (round or oval) and 
texture (curly or straight) is influenced 
heavily by genes. The physica...
Facts About Hair 
The body area (head, arm, leg, 
back, etc.) from which a hair 
originated can be determined by 
the samp...
Facts About Hair 
In order to test hair evidence 
for nuclear DNA, the root must be 
present. The hair may also be 
tested...
Facts About Hair 
The Cuticle of 
Human Hair is 
rough --- which is 
why we use 
Conditioner
Facts About Hair 
Animals have characteristic cuticle scales that 
scientists can use to determine the source of hair 
evi...
Types of Hair 
• Develops on an unborn baby 
• 3 months after baby’s 
conception 
• Fine and soft 
• grows all over the bo...
Types of Hair 
• Short, fine, downy, 
unpigmented hair 
covering most of the body 
except the palms and 
soles of feet 
• ...
Types of Hair 
• Long, thick pigmented hair 
found on the scalp, legs, 
arms & bodies of males & 
females 
• Coarser than ...
Cat 
Types of Animal Hairs 
Horse 
Pig 
Human 
Dog 
Deer 
Rabbit 
Rat 
Human
Hair Growth 
Myths 
and 
Facts
Hair Growth Myths and Facts 
• Gray hair is coarser and more resistant than pigmented hair. 
FACT: other than lack of pigm...
Hair Growth Myths and Facts 
• Clipping, shaving, trimming & cutting makes hair grow faster 
FACT: have no effect on hair ...
Hair Growth Myths and Facts 
• Hair with round cross-section is straight; hair with oval cross-section 
is wavy; hair with...
Credits to References 
http://library.thinkquest.org/04oct/00206/lesson.htm#t_hair 
http://www.fbi.gov/hq/lab/fsc/backissu...
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All about hair ppt

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hair, hair types, structure of hair, facts about hair

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All about hair ppt

  1. 1. All About Hair Presented by: R, E. O. Gaas Grade 7-Neptune Alabel National Sciece High School Regional Science High School for Region XII
  2. 2. All About Hair What is a Hair? Anatomy of Hair Biological, Physical and Chemical Facts About Hair Types of Hairs Hair Growth Myths and Facts
  3. 3. What is a Hair? • is a protein filament that grows from follicles found in the dermis, or skin. • is one of the defining characteristics of mammals. • an important biomaterial primarily composed of protein, notably keratin.
  4. 4. Anatomy of Hair
  5. 5. Anatomy of Hair Hair is composed of three principal parts: Cuticle – outer coating composed of overlapping scales Cortex – protein-rich structure around the medulla that contains pigment Medulla- central core (may be absent) The structure of hair has been compared to that of a pencil with the medulla being the lead, the cortex being the wood and the cuticle being the paint on the outside.
  6. 6. Anatomy of Hair Cuticle The cuticle varies in: • Its scales, How many there are per centimeter, How much they overlap, Their overall shape, and How much they protrude from the surface • Its thickness, and • Whether or not it contains pigment. Characteristics of the cuticle may be important in distinguishing between hairs of different species but are often not useful in distinguishing between different people.
  7. 7. Anatomy of Hair Cortex The cortex varies in: • Thickness • Texture • Color • Distribution of the cortex is perhaps the most important component in determining from which individual a human hair may have come. • Microscopic examination can also reveal the condition and shape of the root and tip.
  8. 8. Anatomy of Hair Medulla The medulla may vary in: • Thickness • Continuity - one continuous structure or broken into pieces • Opacity - how much light is able to pass through it • It may also be absent in some species. Like the cuticle, the medulla can be important for distinguishing between hairs of different species, but often does not lend much important information to the differentiation between hairs from different people.
  9. 9. Facts About Hair • Hair is composed of the protein keratin, which is also the primary component of finger and toe nails. • Humans develop hair follicles during fetal development, and no new follicles are produced after birth. • Hair color is mostly the result of pigments, which are chemical compounds that reflect certain wavelengths of visible light.
  10. 10. Facts About Hair Hair shape (round or oval) and texture (curly or straight) is influenced heavily by genes. The physical appearance of hair can be affected by nutritional status and intentional alteration (heat curling, perms, straightening, etc.)
  11. 11. Facts About Hair The body area (head, arm, leg, back, etc.) from which a hair originated can be determined by the sample’s length, shape, size, color, and other physical characteristics.
  12. 12. Facts About Hair In order to test hair evidence for nuclear DNA, the root must be present. The hair may also be tested using mitochondrial DNA whether or not the root is present.
  13. 13. Facts About Hair The Cuticle of Human Hair is rough --- which is why we use Conditioner
  14. 14. Facts About Hair Animals have characteristic cuticle scales that scientists can use to determine the source of hair evidence. Human, Cat, Dog, and Mouse respectively (photo below)
  15. 15. Types of Hair • Develops on an unborn baby • 3 months after baby’s conception • Fine and soft • grows all over the body at the same rate • Shed about 4 weeks before the baby is due to be born
  16. 16. Types of Hair • Short, fine, downy, unpigmented hair covering most of the body except the palms and soles of feet • women normally retain 55% more vellus hair than men • Follicle doesn’t have oil glands
  17. 17. Types of Hair • Long, thick pigmented hair found on the scalp, legs, arms & bodies of males & females • Coarser than vellus hair &, with the exception of gray hair, it is pigmented • Produced by follicles with sebaceous glands
  18. 18. Cat Types of Animal Hairs Horse Pig Human Dog Deer Rabbit Rat Human
  19. 19. Hair Growth Myths and Facts
  20. 20. Hair Growth Myths and Facts • Gray hair is coarser and more resistant than pigmented hair. FACT: other than lack of pigment, gray hair is exactly the same as pigmented hair. It is not resistant because it is gray, & is not more resistant than the pigmented hair on the same person’s head • Amount of natural curl is determined by racial background. FACT: anyone of any race can have straight or extremely curly hair
  21. 21. Hair Growth Myths and Facts • Clipping, shaving, trimming & cutting makes hair grow faster FACT: have no effect on hair growth • Scalp massage increases hair growth FACT: no evidence to indicate this is true. Minoxidil and Finasteride are the only treatments that have been proven to increase hair growth and are approved for that purpose by the FDAS.
  22. 22. Hair Growth Myths and Facts • Hair with round cross-section is straight; hair with oval cross-section is wavy; hair with flat cross-section is curly FACT: cross-sections of straight hair tend to be round and curlier hair tends to be more oval, but cross-sections of hair can be almost any shape, including triangular; the shape of the cross-section does not always relate to the amount of curl or the shape of the follicle
  23. 23. Credits to References http://library.thinkquest.org/04oct/00206/lesson.htm#t_hair http://www.fbi.gov/hq/lab/fsc/backissu/july2000/deedric1.htm#Index%20(Hairs) http://library.thinkquest.org/04oct/00206/lesson.htm#t_hair http://www.fbi.gov/hq/lab/fsc/backissu/july2000/deedric3.htm#Fiber%20Evidence http://www.fireflydiapers.com/articles/diaperarticle_naturalfibersabsorb.htm http://micro.magnet.fsu.edu/primer/techniques/polarized/gallery/images/humansmall

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