Structure of Hair and Hair Growth Cycle

1. PRESENTED BY:
LIPANJALI BADHEI
REGD NO: 2061611004
DEPARTMENT OF
SUBJECT : COSMETICS & COSMECEUTICALS
TOPIC : STRUCTURE OF HAIR & HAIR
GROWTH CYCLE
School of pharmaceutical sciences
Siksha ‘O’ Anusandhan
(Deemed to be University)

2. CONTENT
1. INTRODUCTION
2. STRUCTURE OF HAIR
3. HAIR GROWTH CYCLE
4. LITERATURE RIVEW
5. REFRENCES

3. INTRODUCTION
 Hair is a simple structure that is made up of protein
filaments called keratin .
 This is of exactly the same protein from which the nail
and outer skin layer is comprised.
 Hair act as a barrier to foreign particle .
 It is a important part of appearance and creates gender
identity .
 Hair is the only body structure that can completely
renew itself .

4. Hair structure can be divided into two parts:
1. Hair Root
2. Hair Shaft
Structure Of Hair
1. Hair Root:[1]
A. Hair Follicle:
 This is the living part of the hair.
 The hair follicle is the Sac or tube that surrounds the hair root and extends into the
dermis.
 The follicle is surrounded by an inner and outer sheath that protects and molds the
growing hair shaft.

5. B. Hair Bulb:
 It is the lowest part of your hair strand, which lies inside
the follicle.
 The club-shape of the hair bulb helps it to get locked by
the dermal papilla.
C. Dermal Papilla:
 It is the cone-shaped elevation which is present at the base
of your hair follicle.
 It fits into the hair bulb and holds it. Dermal papilla is
connected with the blood vessels.
D. Melanocyte Cells:
 Melanocyte cells are located in the germinal matrix.
 It produce the pigment that gives colour to the hair.
 Hair is formed by cells in germinal matrix which undergo mitosis
or cell division.

6. E. Arrector Pili Muscle:
 It is an involuntary muscle present at the base of the hair follicle.
 We get goosebumps when arrector pili contracts.
F. Sebaceous Glands:
 These are the oil glands that are connected to the hair follicles.
 Sebaceous glands secrete sebum for your hair.
2. Hair Shaft:[1]
A. Cuticle:
 It is the outermost layer of your hair strand.
 It acts as a protecting layer to the inner hair structure.
 A strong and integrated cuticle layer imparts shine and smoothness to your hair.

7. B. Cortex:
 It is the middle layer of the hair strand.
 The protein present in the cortex is responsible for the
elasticity and colour of your hair.
C. Medulla:
 It is the innermost layer in the hair strand.
 In general, it exists only in thick and coarse hairs.
 The purpose of medulla has not been identified yet.

8. HAIR GROWTH CYCLE
1 . T H E A N A G E N P H A S E : [ 2 ]
 The Anagen phase is the period of growth. The cells in the hair bulb divide rapidly
creating new hair growth.
 Hair actively grows from the roots for an average of 2-7 years before hair follicles
becomes dormant. In this time, hair can grow anywhere between 18-30 inches.
 The length of this phase is dependent on your maximum hair length, which varies
between people due to genetics, age, health and many more factors.

9. 2 . T H E C A T A G E N P H A S E : [ 2 ]
 The second phase of hair growth cycle is Catagen.
 This period is short, lasting only 2-3 weeks on average.
 In this transitional phase, hair stops growing and detaches itself from the blood
supply and is then named a club hair.
3 . T H E T E L O G E N P H A S E : [ 2 ]
 Finally, hair enters it’s third and final stage called the Telogen phase.
 This phase begins with a resting period, where club hairs rest in the root while
new hair begins to grow beneath it.
 This phase lasts for around 3 months.
 After this time, the resting club hairs will fall out to allow the new hair to come
through the hair follicle.

10.  This is nothing to be alarmed about and is a natural process that should go completely
unnoticed.
 Each follicle is independent and goes through the growth cycle at different times so you
don’t lose patches of hair all at once and only shed 50-100 hairs each day.
4. THE EXOGEN PHASE: [2]
 This is part of the resting phase where the old hair sheds and a new hair
continues to grow.
 Approximately 50 to 150 hairs can fall out daily, this is considered to be normal
hair shedding

11. LITERATURE REVIEW
ARTICLE:- 1
HUMAN HAIR GROWTH IN-VITRO
BY M.P.PHILPOTT (1990) et al [3]
 Human anagen hair follicles were isolated by microdissection from human scalp skin.
 Isolation of the hair follicles was achieved by cutting the follicle at the dermo-subcutaneous fat interface
using a scalpel blade. Intact hair follicles were then removed from the fat using ‘watchmakers’ forceps.
 Isolated hair follicles maintained free-floating in supplemented Williams E medium in individual wells
of 24-well multiwell plates showed a significant increase in length over 4 days.
 The increase in length was seen to be attributed to the production of a keratinized hair shaft, and was
not associated with the loss of hair follicle morphology.
 [methyl-3H]thymidine autoradiography confirmed that in vitro the in vivo pattern of DNA synthesis
was maintained; furthermore, [35S]methionine labelling of keratins showed that their patter

12.  Light micrographs taken under an
inverted microscope showing the
sequential growth of the same hair
follicle in culture over 96 h.
 Graph showing the effects of growth factors and
mitogens on isolated human hair follicles
maintained in vitro over 5 days in the presence of 1
% FCS, EGF (lOngmP1), IGF- 1 OOngmr^/rGF-
zSl (lOngml-1) and TPA (lOO/igmP1).
CONCLUSION:The importance of this model to hair follicle biology is further demonstrated by the observations
that TGF-/51 has a negative growth-regulatory effect on hair follicles in vitro and that EGF mimics the in vivo
depilatory effects that have been reported in sheep and mice.
 Graph showing the effects of
Minoxidil on isolated human hair
follicles maintained in vitro over
5 days.

13. ARTICLE:- 2
NANOPARTICLES – AN EFFICIENT CARRIER FOR DRUG DELIVERY INTO THE HAIR FOLLICLE
BY J. LADEMANN (2007) et al [4]
 The penetration and storage behavior of dye-containing nanoparticles (diameter 320 nm) into the hair
follicles was investigated.
 In the first part of the experiments, the penetration of the dye into the hair follicles was investigated in vitro
on porcine skin, which is an appropriate model for human tissue.
 It was found that the nanoparticles penetrate much deeper into the hair follicles than the dye in the non-
particle form, if a massage had been applied. Without massage, similar results were obtained for both
formulations.
 Subsequently, the storage behavior of both formulations in the hair follicles was analyzed in vivo on human
skin by differential stripping. Using the same application protocol, the nanoparticles were stored in the hair
follicles up to 10 days, while the non-particle form could be detected only up to 4 days.

14. Fig - 1
(A) Dye in particle form.(B) Dye in non-particle form
Fig - 2
(A) Dye in particle form.(B) Dye in non-particle form
Without Massage
With Massage
 Semi-quantitative determination
of the fluorescent dye in the hair
follicle infundibula by
cyanoacrylate skin surface
biopsy at different time points
after application.
CONCLUSION:
 The surface structure of
the hair follicles was
assumed that the
movement of the hairs
may act as a pumping
mechanism pushing the
nanoparticles deep into
the hair follicles.

15. ACTIVE HAIR GROWTH (ANAGEN) IS ASSOCIATED WITH ANGIOGENESIS
BY L. MECKLENBURG (2000) et al [5]
ARTICLE:- 3
 After the completion of skin development, angiogenesis, i.e., the growth of new capillaries
from pre-existing blood vessels, is held to occur in the skin only under pathologic conditions.
 This study uses quantative histomorphometry and double-immunohistology detection
techniques for the demarcation of proliferating endothelial cell.
 Angiogenesis is a physiologic event in normal postnatal murine skin, apparently is dictated by
the hair follicle, and appears to be required for normal anagen development.

16. Inhibition of angiogenesis retards
induced anagen development
Treatment with TNP-470 over 6 d retards anagen
development.
Treatment with TNP-470 over 8 d retards anagen
development.
CONCLUSION:
 We show that synchronized hair follicle cycling in mice is associated with a
substantial remodelling of the perifollicular and interfollicular cutaneous
microvasculature, that anagen development is associated with angiogenesis, and
that inhibiting angiogenesis lead to a retardation of anagen development.

17. 1. M.R. Harkey, Anatomy and physiology of Hair, Forensic Science International, 63, 9-18 , 1990 .
2. A. Vogi, K.J. Mcelwee, V. Blume-Peytavi, Biology of Hair Follicle, Hair Growth and Discorders,
Chapter 1, 1-12, 2008 .
3. M.P. Philpott, M.R. Green, T. Kealey, Human Hair Growth In-Vitro, Journal of Cell Science , 97,
463-471, 1990.
4. J. Lademann, H, Richter, A. Techmann, N. Otbery, U. Blume-peytavi, J. Luengo, U.F. Schaefer, R.
Wepf, W. Sterry, Nanoparticles-An efficient Carrier for Drug Delivery into the Hair Follicles,
European Journal of Pharmaceutics and Biopharmaceutics,66, 159-164, 2007 .
5. L. Mecklenburg, D.J. Tobin, S. Miller-Rover, B. Handjiski, G. Wendt, E.M.J. Peters, S, Pohl, I.
Moll, R. Paus, Actie Hair Growth(Anagen) is Associated with Angiogenesis, The Journal of
Investigative Dermatology,114, 909-916, 2000 .
REFERENCES