Integumentary System

1. Lab Exercise 5
INTEGUMENTARY SYSTEM

2. The Integumentary
System
 Consist of the skin and associated
structures like the hair, nails, and glands
 The skin is the largest organ in the
body
 Protects against water loss,
entrance of microorganisms, and
regulates temperature
 Primarily made up of cutaneous membrane
composed of an epidermis and a dermis
 Under the dermis is the hypodermis
which anchors the integument to
deeper structures

3. Epidermis, Dermis and Hypodermis
Epidermis: most superficial
layer. Consist of epithelial cells
Dermis: inferior to the
epidermis. Consist primarily of
collagenous fibers
Hypodermis or subcutaneous
layer: is not a layer of the
integument but a structure
anchoring the integument to
underlying bone or muscle

4. Epidermis
 Composed of keratinized stratified squamous epithelium
 Thick or thin skin
 5 layers:
 Stratum Corneum
 Stratum Lucidum
 Stratum Granulosum
 Stratum Spinosum
 Stratum Basale
Epidermis

5. Layers: Superficial
to Deep
Come – Stratum corneum
Lets - Stratum Lucidum
Get – Stratum Granulosum
Some – Stratum Spinosum
Beers – Stratum Basale

6. Stratum Corneum
 Most superficial layer
 Consist of dead cells that are
flattened on the surface
 Cells have been hardened
keratinization process
 Keratinized stratified
squamous epithelium
Stratum Lucidum
 Appears translucent
 Only in palms and soles (Thick
skin only)
Stratum Granulosum
 Granules which are precursors
keratin

7. Stratum Spinosum
 Made up of numerous cells
Stratum Basale
 Deepest layer
 Attached to the dermis by the
basement layer
 Divide rapidly and push old cell
toward surface
 Melanocytes are found here
 Cells that produce brown
pigment known as melanin.

8. Dermis
 Structural integrity of the integumentary
system
 Composed primarily of closely apposed fibers
along with blood vessels, nerves, sensory
receptors, hair follicles, and gland
 Two major regions
 Superficial
 papillary layer
 Deep
 Reticular layer
 Blood vessels are found here and brings
nutrients to the dermis and epidermis (by
diffusion)
 Temperature regulation
 Many nerves
 Light touch, temp change, and the feeling
of pain

9. Two Regions
 Papillary layer: Superficial
 Named for the papillae that
interlock with the epidermis
 Provides good adhesion between
the two layers
 Reticular layer: Deep
 Is the largest layer of the dermis
 Composed of irregularly arranged
collagenous fibers along with
some elastic and reticular fibers
 Majority or collagenous fibers
 Provide strength and flexibility

10. Integumentary Glands
Found in the Dermis and Hypodermis
 Many glands including
 Sudoriferous (sweat) glands
 Lactiferous (Milk) glands
 Sebaceous (Oil) glands
 Ceruminous (earwax) glands
 Only look at Sweat and Oil in lab

11. Sweat Glands
 Composed of simple cuboidal
epithelium
 Two different types
 Merocrine sweat glands
 Most common (superficial)
 Sensitive to temp
 Produce normal body
perspiration
 Apocrine sweat glands
 Secrete water
 Higher concentration of
organic acid
 Organic acids + bacterial
components = body odor
 Found in axilla and groin area
associated with hair follicles
Merocrine

13. Sebaceous Glands
 Associated with hair follicles
 Larger sweat glands
 Might not see the hair follicle
 Secrete oily material known as sebum
 Helps lubricate the hair and decreases the wetting action of
water on the skin

14. Hair
 Considered an accessory structure
of the integumentary system
 Consist of keratinized cells that are
produced in hair follicles
 Follicle: encloses the hair the
same way a bud vase encloses
the stem of a rose
 Composed of an outer
dermal layer of connective
tissues and an inner
epithelial layer
 These form the root
sheath
 Projections of the epidermis
layers into the dermis
 Thus can be an epidermis
derivative

15. Parts of the Hair
 Parts of the hair
 Shaft
 The portion that erupts
from the skin surface
 Root
 Is enclosed by the follicle
 Bulb
 Is the actively growing
portion of the hair
 At the center there is a
structure called dermal
papilla
 Blood vessels and
nerves found here

16. Types of Hair
 Two types of hair
 Determinate Hair
 Grows to a specific length then stops
 Found in many places
 Axilla, groin, arms, legs, eye lashes and eyebrows
 Indeterminate Hair
 Continues to grow with out regards to length
 Found on scalp and in beards

17. Piloerector
(Arrector pili)
Muscle
 When the hair ”stands on end” it
contracts the arrector pili muscle
 Composed of a cluster of parallel
smooth muscle fibers that connect
the hair follicle to the upper region of
the dermis
 In a response to cold conditions the
arrector pili muscle contracts
producing goose bumps
 In a frightened situation the arrector
pili muscle contract as well

18. Cross Section of the Hair
 Central portion is known as Medulla
 Medulla is enclosed by an outer cortex
 Cortex contains pigment which give us
different hair colors
 Superficial layer of the cortex is known as
the cuticle

19. Nails
Not on lab examination!!
 Modification of the epidermis on
the distal dorsal surface of the
finger tips
 Parts:
 Nail body
 Free edge
 Cuticle or eponychium
 Nail root
 Nail bed
 Nail body
 Lunula
 Nail matrix
 Hyponychium
 Nail groove
 Nail fold

20. Review for Lab Exercise
 Slide 10
 Slide 11
 Hair/Skin model
 Lab files