3. THE HAIR
Hairs are elastic keratinized threads, vary in
thickness
Derived from an invagination of the epidermis
Consist of two portions: Shaft & Root
The shaft projects above the skin surface
The root is embedded in the skin
Hair root is surrounded by Hair Follicle
Hair follicle consist of epidermal (epithelial) & dermal
(connective tissue) elements
Deep end of hair follicle expanded to form Hair bulb
4.
5.
6. • Hair follicle is associated with:
• Sebaceous glands
• Arrector pili muscle (smooth muscle) goose
flesh
• Growth of hair, average rate 2 mm per week
• The production & growth depends upon the hair
follicle that surrounds the root of the hair
• Color of the hair depends on the quantity of
melanin pigment & amount of air in the hair
substance
7. • Hair shaft consist of
epithelial cells arranged
in three regions
• Medulla (moderately
keratinized cuboidal
cells)
• Cortex (main bulk,
heavily keratinized cells)
• Cuticle (single layer of
flattened keratinized
cells)
8. NAILS
• Hard, translucent, roughly
rectangular plates
• Highly keratinized
epithelium
• Covers the dorsal aspect
of terminal phalanges
• Nail plate consist of: Body,
Free Edge & Root
• Lunula (crescent-shaped
whitish area)
• Each nail plate rests on a
nail bed (skin under the
nail)
9. • Nail bed consist of stratum basale
• Epidermis (stratum basale) of nail bed is
very thick proximally and is called Nail
Matrix
• Nail matrix is responsible for the growth of
nail, exhibit high rate of cell division
• Growth of fingernails is 0.5 mm per week &
growth of toenails is 1 mm per month
• Nail keratin is hard keratin do not
desquamate
10. SEBACEOUS GLANDS
• Sebaceous
glands are usually
associated with
hair
• Located between
a hair follicle and
its arrector pili
muscle in the
dermis.
11. • There are mitotically active cells giving rise
to the larger sebum-producing cells in the
center of the gland accumulate fat
ultimately breakdown to produce sebum
• Most abundant in the face and scalp,
completely absent in the skin of palm and
soles
• Function maintenance of proper skin
texture & hair flexibility. In addition, sebum
may possess weak antifungal &
antibacterial properties
12. Sweat glands
• Classified into two types
• Eccrine sweat glands
• Apocrine sweat glands
• Eccrine sweat glands
are distributed over
whole body
• Apocrine sweat glands
are limited to certain
specific regions of the
body e.g. axilla
13. ECCRINE SWEAT GLANDS
• Simple tubular glands
• Abundant in the skin of palms and soles
• Terminal secretory portion of sweat gland is
coiled and lie in dermis
• Sweat pore
• Lined by simple cuboidal epithelium
• Secretion is produced in response to heat
and nervous strain
14. • Sweat is a clear liquid, derived from blood
capillaries and consist of water, potassium,
sodium, chloride, urea, ammonia, uric acid
& lactic acid
• Functions:
• Temperature regulation
• Source of excretion of waste products like
ammonia, urea and uric acid
15.
16. • Which of the following is composed of
loose connective tissue?
•
a. Epidermis
b. Reticular layer of dermis
c. Hypodermis
d. Both a and b
e. Both b and c
17. • A new miracle skin cream recently hit the
beauty counters which is suppose to
stimulate collagen production. Which cell is
it supposedly stimulating?
a. Langerhans cell
b. Keratinocyte
c. Melanocyte
d. Merkel cell
e. Fibroblast
18. • What is the growing part of the nail?
•
a. Lunula
b. Eponychium
c. Matrix
d. Nail bed
e. Root
19. • Which cell is the most abundant cell in the
epidermis?
•
a. Langerhans cell
b. Keratinocyte
c. Melanocyte
d. Merkel cell
e. Fibroblast
20. • Which cell is a mechanoreceptors?
•
a. Langerhans cell
b. Keratinocyte
c. Melanocyte
d. Merkel cell
e. Fibroblast
21. • Which layer of the epidermis is also called
the stratum germinativum?
•
a. Stratum basale
b. Stratum spinosum
c. Stratum granulosum
d. Stratum lucidum
e. Stratum corneum
