CHAPTER 4
INTEGUMENTARY
SYSTEM
Erica O. Ababa, MD
MC 1. Anatomy and Physiology Lecturer
OUTLINE
1
Functions of Integumentary
System
2
Skin
3
Subcutaneous Tissue
4
Accessory Skin Structures
OUTLINE
5
Physiology of the Integumentary
System
6
Integumentary System as a
Diagnostic Aid
7
Burns
OUTLINE
1
Functions of Integumentary
System
2
Skin
3
Subcutaneous Tissue
4
Accessory Skin Structures
1
FUNCTIONS OF INTEGUMENTARY SYSTEM
INTEGUMENTARY SYSTEM
consists of skin and accessory structures
hair
glands
nails
1
FUNCTIONS OF INTEGUMENTARY SYSTEM
INTEGUMENTARY SYSTEM
Integument — “covering”
covers outside of the body
easily observed
appearance can indicate physiologic imbalances
1
FUNCTIONS OF INTEGUMENTARY SYSTEM
FUNCTIONS
Protection
against abrasion and UV light
prevents microbes from entering the body
reduces water loss
1
FUNCTIONS OF INTEGUMENTARY SYSTEM
FUNCTIONS
Sensation
(+) sensory receptors
detect heat, cold, touch,
pressure and pain
1
FUNCTIONS OF INTEGUMENTARY SYSTEM
FUNCTIONS
Vitamin D production
production of molecules
converted into vitamin D
important for Calcium
homeostasis
1
FUNCTIONS OF INTEGUMENTARY SYSTEM
FUNCTIONS
Temperature regulation
amount of blood flow
beneath the skin’s surface
activity of sweat glands
1
FUNCTIONS OF INTEGUMENTARY SYSTEM
FUNCTIONS
Excretion
skin glands remove small amounts of waste products
OUTLINE
1
Functions of Integumentary
System
2
Skin
3
Subcutaneous Tissue
4
Accessory Skin Structures
SKIN
2
MAJOR LAYERS
Epidermis
most superficial skin layer
epithelial tissue
Dermis
dense connective tissue
2
SKIN
EPIDERMIS
stratified squamous epithelium
divided into 5 strata
with distinct cellular characteristics
2
SKIN
2
SKIN
C
Come
Corneum
L
Let’s
Lucidum
G
Get
Granulosum
S
Sun
Spinosum
B
Burned
Basale
2
SKIN
Stratum basale
cuboidal or columnar cells
undergo mitotic divisions
2
SKIN
Stratum spinosum
flattened appearance
accumulate lamellar bodies
2
SKIN
Stratum granulosum
flat and diamond shaped cells
grainly appearance
2
SKIN
Stratum lucidum
thin, clear zone
cells stain more lightly
no nuclei and organelles
absent in thin skin
2
SKIN
Stratum corneum
most superficial stratum
dead squamous cells
keratin-filled, surrounded by lipids
2
SKIN
EPIDERMIS
Keratinization
transformation of
stratum basale cells into
stratum corneum
SKIN
2
DERMIS
dense collagenous connective tissue
fibroblasts, adipocytes, and macrophages
provides structural support:
collagen fiber
elastic fiber
SKIN
2
DERMIS
Cleavage lines
tension lines
important for sugeons
2
SKIN
SKIN COLOR
Factors that determine skin color:
pigments in the skin
blood circulating through the skin
thickness of the stratum corneum
SKIN
2
SKIN COLOR
Melanin
produced by melanocytes
irregularly shaped cells
between stratum basale
and stratum spinosum
SKIN
2
SKIN COLOR
Melanin
genetically determined
more melanin = darker skin
SKIN
2
SKIN COLOR
Melanin
modified by UV light
increased melanin
production
SKIN
2
SKIN COLOR
Melanin
modified by hormones
estrogen
melanocyte-stimulating
hormone
SKIN
2
SKIN COLOR
Carotene
plant pigment
source of vitamin A
causes skin to appear
yellowish
2
SKIN
SKIN COLOR
Blood flowing through the skin
increased blood flow = red
decreased blood flow = pale
decreased blood O2 = cyanosis
OUTLINE
1
Functions of Integumentary
System
2
Skin
3
Subcutaneous Tissue
4
Accessory Skin Structures
3
SUBCUTANEOUS TISSUE
SUBCUTANEOUS TISSUE
loose connective tissue
not part of the skin
attaches the skin to
underlying tissues
where 1/2 of body’s
lipids are stored
OUTLINE
1
Functions of Integumentary
System
2
Skin
3
Subcutaneous Tissue
4
Accessory Skin Structures
4
ACCESSORY SKIN STRUCTURES
HAIR
found everywhere on the skin, except on:
palms and soles
parts of genitalia
lips
distal segment of fingers and toes
nipples
4
ACCESSORY SKIN STRUCTURES
HAIR
columns of dead, keratinized
epithelial cells
hair follicle
4
ACCESSORY SKIN STRUCTURES
HAIR
shaft — above the skin
root — below the skin
hair bulb
site of hair cell formation
4
ACCESSORY SKIN STRUCTURES
HAIR
2 phases:
Growth phase
within the hair bulb
Resting phase
held in the hair follicle
4
ACCESSORY SKIN STRUCTURES
HAIR
goose bumps
caused by contraction
of arrector pili muscle
hair “stands on end”
4
ACCESSORY SKIN STRUCTURES
GLANDS
Sebaceous glands
produce sebum
oils the hair and surface
of the skin
4
ACCESSORY SKIN STRUCTURES
GLANDS
Eccrine sweat glands
produce sweat
cools the body
4
ACCESSORY SKIN STRUCTURES
GLANDS
Apocrine sweat glands
produce organic secretion
causes body odor
4
ACCESSORY SKIN STRUCTURES
REVIEW:
Sebaceous glands produce
Eccrine sweat glands produce
Apocrine sweat glands produce
sebum
4
ACCESSORY SKIN STRUCTURES
REVIEW:
Sebaceous glands produce
sebum
Eccrine sweat glands produce
sweat
Apocrine sweat glands produce
4
ACCESSORY SKIN STRUCTURES
REVIEW:
Sebaceous glands produce
sebum
Eccrine sweat glands produce
sweat
Apocrine sweat glands produce
organic secretion
4
ACCESSORY SKIN STRUCTURES
NAILS
thin plate
dead stratum corneum cells
very hard type of keratin
4
ACCESSORY SKIN STRUCTURES
NAILS
consists of nail body and nail root
4
ACCESSORY SKIN STRUCTURES
NAILS
nail matrix
produces the nail
contains hard keratin
4
ACCESSORY SKIN STRUCTURES
NAILS
lunula
whitish, crescent-shaped
base of the nail
4
ACCESSORY SKIN STRUCTURES
NAILS
cuticle
eponychium
stratum corneum
extends onto the nail body
OUTLINE
5
Physiology of the Integumentary
System
6
Integumentary System as a
Diagnostic Aid
7
Burns
5
PHYSIOLOGY OF INTEGUMENTARY SYSTEM
PROTECTION
Skin
reduces water loss
prevents entry of microorganisms
provides protection against abrasion and UV light
5
PHYSIOLOGY OF INTEGUMENTARY SYSTEM
PROTECTION
Hair and nails
also perform protective functions
hair on the head as heat insulator
eyebrows keep sweat out of the eyes
5
PHYSIOLOGY OF INTEGUMENTARY SYSTEM
SENSATION
Skin
contains sensory receptors
pain
cold
heat
pressure
5
PHYSIOLOGY OF INTEGUMENTARY SYSTEM
VITAMIN D PRODUCTION
Skin
UV light stimulates the
production of 7dehydrocholesterol
modified by the liver and
kidneys into vitamin D
5
PHYSIOLOGY OF INTEGUMENTARY SYSTEM
VITAMIN D PRODUCTION
Reference: Bedaso et al. (2019)
5
PHYSIOLOGY OF INTEGUMENTARY SYSTEM
TEMPERATURE REGULATION
Skin
controls heat loss from the body
through dilation and constriction of blood vessels
evaporation of sweat cools the body
5
PHYSIOLOGY OF INTEGUMENTARY SYSTEM
EXCRETION
Skin glands
remove small amounts of waste products
OUTLINE
5
Physiology of the Integumentary
System
6
Integumentary System as a
Diagnostic Aid
7
Burns
6
AS DIAGNOSTIC AID
DIAGNOSTIC AID
Integumentary system is easily observed
often reflects events occuring in other parts of the body
cyanosis
jaundice
rashes
6
AS DIAGNOSTIC AID
DIAGNOSTIC AID
6
AS DIAGNOSTIC AID
DIAGNOSTIC AID
Acanthosis nigricans
hyperpigmentation
Polycystic Ovarian Syndrome
6
AS DIAGNOSTIC AID
DIAGNOSTIC AID
6
AS DIAGNOSTIC AID
DIAGNOSTIC AID
impaired circulatory or respiratory
function
Tetralogy of Fallot
decreased blood O2
6
AS DIAGNOSTIC AID
DIAGNOSTIC AID
6
AS DIAGNOSTIC AID
DIAGNOSTIC AID
Insufficient Iron stores
Iron deficiency Anemia
6
AS DIAGNOSTIC AID
DIAGNOSTIC AID
6
AS DIAGNOSTIC AID
DIAGNOSTIC AID
Skin rashes
viral infection (e.g. German
measles)
allergic reaction (e.g. Contact
dermatitis)
6
AS DIAGNOSTIC AID
DIAGNOSTIC AID
Impaired liver function
Viral Hepatitis
OUTLINE
5
Physiology of the Integumentary
System
6
Integumentary System as a
Diagnostic Aid
7
Burns
BURNS
6
BURN
injury to a tissue caused by:
heat and cold
electricity
friction
radiation
chemicals
classified according to their depth
partial-thickness burn
full-thickness burn
6
BURNS
PARTIAL-THICKNESS BURNS
first-degree burn
epidermis only
second-degree burn
epidermis + dermis
6
BURNS
FULL-THICKNESS BURNS
third-degree burn
epidermis + dermis
+ underlying tissues
6
BURNS
FULL-THICKNESS BURNS
fourth-degree burn
epidermis + dermis
+ underlying tissues
+ muscle and bone
6
BURNS
Epidermis only
First degree burn
Second degree burn
Third degree burn
Fourth degree burn
Dermis
Underlying
tissues
Muscle and
Bone
REFERENCES
VanPutte, C.L., Regan, J.L., Russo, A.F., Seeley, R.R., Stephens, T. and Tate, P.
(2017). Seeley’s Anatomy and Physiology. 11th edition. McGraw-Hill Education.
Bedaso, A., Gebrie, M., Deribe, B. et al. Knowledge and practice on adequate
sunlight exposure of infants among mothers attending EPI unit of Aleta Wondo
Health Center, SNNPR, Ethiopia. BMC Res Notes 12, 183 (2019).
END OF LECTURE
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