Journal #1: How is the integumentary
system (skin) like an onion?
1.
2.
3.
4.
5.
6.
7.
8.
Vocabulary
Integument
Epidermis
Dermis
Subcutaneous layer
Basal Cells
Keratin
Carotene
Melanin

Objective:
 List the components of
the integumentary
system and their
relationship to each
other
 Specify the functions of
the integumentary
system
Ch.5 Integumentary
System
Part 1: Layers
Pages 153-164
Components of the Integument

Cutaneous Membrane
 Epidermis
 Dermis

Accessory Structures
 Hair,

Nails, & Glands
Subcutaneous layer
 Hypodermis
 Superficial
Fascia/connective
tissue

Function
 Protection
 Excretion
 Maintenance
of
Homeostasis
 Synthesis of Vitamin D
 Storage of Lipids
 Detection/ Receptors
The Epidermis



Stratified Squamous
Epithelium
No Blood vessels
Many Keratinocytes



Cells that contain keratin
Thin Skin- most surfaces
Thick Skin- palms of
hands/soles of feet
Layers (Strata) of the Epidermis

From Deepest to
most Superficial
 Stratum
Germinativum
 Stratum Spinosum
 Stratum Granulosum
 Stratum Lucidum
 Stratum Corneum
Stratum Germinativum


Hemidesmosomes attach cells to basal lamina
Form epidermal ridges and dermal papillae
 Increase
surface area
 Genetically determined patterns are unique

Cells
 Basal
or Germinative Cells (stem cells)
 Merkel Cells (touch receptors)
 Melanocytes (skin pigmentation)
Stratum spinosum
“Spiny Layer” of 8-10 rows of
keratinocytes
 Results from one of the daughter cells
from stem cell division being pushed up
from the stratum germinativum
 Langerhans cells

 Stimulate
immune response to
microorganisms and cancer
Stratum Granulosum
“Grainy Layer” of 3-5 layers of
keratinocytes
 Lots of Keratin (tough protein) &
Keratohyaline (promotes dehydration)
 Thin flat cells with decreased permeability

Stratum Lucidum
In thick skin of palms and soles only
 Clear layer that covers the stratum
granulosum
 Flat, dense, and filled with keratin

Stratum corneum
Exposed surface of skin
 15-30 layers of keratinized (dead) cells
 Takes 15-30 days for the cell to move
from stratum germinativum to the
stratum corneum (2 weeks before it is
shed)
 Water resistant,
not waterproof
 Perspiration

Journal #2: Give the layers of the
epidermis from the most superficial to
the deepest.
Vocabulary
9. UV Radiation
10. Cyanosis
11. Vitamin D
12. Epidermal Growth
Factor
13. Papillary Layer
14. Reticular Layer
15. Hypodermis

Objective:
 List the components of
the integumentary
system and their
relationship to each
other
 Specify the functions of
the integumentary
system
Skin Color

Pigmentation
 Carotene
 Orange yellow pigment in epidermal cells
 Can convert to Vitamin A (needed in the growth of epidermal
cells)
 Melanin
 Brown, yellow, or black pigment
 Melanocytes produce it in the stratum germinativum and
store in vesicles called melanosomes
 Dark skinned people have larger melanosomes
 Synthesis increases with UV exposure

Dermal Circulation
 Red tones produced by hemoglobin
 Cyanosis- blue tone to skin
in RBC’s
Other Roles of the Epidermis

Steroid Production

UV Radiation in epidermal
cells in the stratum spinosum
and germinativum convert a
steroid into cholecalciferol or
Vitamin D
 Helps in bone development
and maintenance (Ricketsabnormal bone development
due to lack of Vitamin D

Epidermal Growth Factor

Made by salivary glands and
the glands of the duodenum
 Functions




Promotes cell division in
stratum germinativum and
spinosum
Speeds up production of
keratin in keratinocytes
Stimulates skin repair and
development
Stimulates activity and
secretion in epithelial glands
The Dermis

Components

Papillary Layer


Areolar tissue with
capillaries, lymph, and
sensory neurons
Reticular Layer


Irregular connective tissue
w/collagen fibers
extending to
subcutaneous layer
Blood vessels, lymph, and
nerve fibers
Characteristics of the Dermis

Strength and Elasticity



Lines of Cleavage (pattern fibers make)



Cut parallel will heal with little scarring
Cut at a right angle will have greater scarring
Blood Supply


Collagen & elastic fibers
Water content
Arteries to subcutaneous and border reticular layer called
cutaneous plexus
Innervation

Sensory reception


Light touch: tactile (Meisners’s) corpuscles
Deep pressure & vibration: lamellated (Pacinian) corpuscles
Subcutaneous Layer

Hypodermis
 Stabilizes
skin in relation to muscles and
other organs
 Areolar and adipose (baby fat) tissue
 Venous circulation contains a great amount of
blood

Subcutaneous injection effective