Ch04lecturepresentation 140913123323-phpapp01

© 2012 Pearson Education, Inc.
4
The Integumentary
System
PowerPoint®
Lecture Presentations prepared by
Steven Bassett
Southeast Community College
Lincoln, Nebraska

Introduction
• The integumentary system is composed of:
• Skin
• Hair
• Nails
• Sweat glands
• Oil glands
• Mammary glands

Introduction
• The skin is the most visible organ of the
body
• Clinicians can tell a lot about the overall
health of the body by examining the skin
• Skin is capable of repair even after serious
damage because of containing stem cells
persist both in epidermis and dermis.

Integumentary Structure and Function
• Cutaneous membrane
• Epidermis
• Dermis
• Accessory structures
• Hair follicles
• Exocrine glands
• Nails

Figure 4.1 Functional Organization of the Integumentary System
Integumentary
System
Cutaneous
Membrane
Accessory
Structures
Epidermis
Dermis
Hair Follicles
Exocrine Glands
Nails
• Physical protection from
environmental hazards
• Synthesis and storage
of lipid reserves
• Coordination of immune
response to pathogens
and cancers in skin
• Thermoregulation
• Excretion
• Synthesis of vitamin D3
• Sensory information
• Protects dermis from trauma,chemicals
• Controls skin permeability, prevents water loss
• Prevents entry of pathogens
• Synthesizes vitamin D3
• Sensory receptors detect touch, pressure, pain, and temperature
• Coordinates immune response to pathogens and skin cancers
• Nourishes and
supports
epidermis
• Restricts spread of pathogens penetrating
epidermis
Papillary Layer Reticular Layer
• Stores lipid reserves
• Attaches skin to deeper tissues
• Sensory receptors detect touch, pressure,
pain, vibration, and temperature
• Blood vessels assist in thermoregulation
• Produce hairs that protect skull
• Produce hairs that provide delicate touch
sensations on general body surface
• Assist in thermoregulation
• Excrete wastes
• Lubricate epidermis
• Protect and support tips of fingers and toes

Figure 4.1 Functional Organization of the Integumentary System (Part 1 of 2)
Cutaneous
Membrane
Epidermis
Dermis
• Protects dermis from trauma,chemicals
• Controls skin permeability, prevents water loss
• Prevents entry of pathogens
• Synthesizes vitamin D3
• Sensory receptors detect touch, pressure, pain, and temperature
• Coordinates immune response to pathogens and skin cancers
• Nourishes and
supports
epidermis
• Restricts spread of pathogens penetrating
epidermis
Papillary Layer Reticular Layer
• Stores lipid reserves
• Attaches skin to deeper tissues
• Sensory receptors detect touch, pressure,
paid, vibration, and temperature
• Blood vessels assist in thermoregulation

Figure 4.1 Functional Organization of the Integumentary System (Part 2 of 2)
Accessory
Structures
Hair Follicles
Exocrine Glands
Nails
• Produce hairs that protect skull
• Produce hairs that provide delicate touch
sensations on general body surface
• Excrete wastes
• Protect and support tips of fingers and toes

• Functions include:
• Physical protection
• Regulation of body temperature
• Excretion of products (secretion)
• Synthesis of products (nutrition)
• Sensation
• Immune defense

• Skin (cutaneous membrane) is made of
two divisions
• Epidermis
• Dermis
• Hypodermis (subcutaneous layer) is deep to the
dermis. This layer separates the skin from deep
fasciae
• Accessory structures
• Hair, nails, exocrine glands

Figure 4.2 Components of the Integumentary System
Cutaneous Membrane
Accessory Structures
Dermis
Papillary layer
Epidermis
Reticular layer
Subcutaneous layer
(hypodermis)
Hair shaft
Pore of sweat
gland duct
Tactile corpuscle
Sebaceous gland
Arrector pili muscle
Sweat gland duct
Hair follicle
Lamellated corpuscle
Nerve fibers
Sweat gland
Fat
Artery
Vein
Cutaneous
plexus

The Epidermis
• There are four cell types found in the epidermis
• Keratinocytes
• Produces a tough protein called keratin
• the most abundant cells in the epidermis.
• Melanocytes
• Pigment cells located deep in the epidermis
• Produce melanin (skin color)
• Merkel cells
• Sensory cells
• They send their free nerve endings into the epidermis, which are
very sensitive to gentle touch.
• Langerhans cells
• Fixed macrophages

The Epidermis
• Layers of the Epidermis
• Stratum basale (stratum germinativum)
• Deepest layer
• Stratum spinosum
• Stratum granulosum
• Stratum lucidum
• Stratum corneum
• Most superficial layer

Surface
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
Basal lamina
Dermis
Epidermis of thick skin LM × 225
Figure 4.3 The Structure of the Epidermis

Table 4.1 Epidermal Layers

The Epidermis
• Epidermal ridges
• Stratum germinativum forms epidermal
ridges
• Ridges (dermal papillae) extend into the
dermis
• Creates ridges we call fingerprints

Figure 4.4ab Thin and Thick Skin
Epidermis
Epidermal
ridge
Dermal
papilla
Dermis
Stratum
corneum
Basal
lamina
Dermis
Thin skin covers most of
the exposed body surface.
(During sectioning the
stratum corneum has
pulled away from the rest
of the epidermis.)
The basic organization of the
epidermis. The thickness of the
epidermis, especially the thickness
of the stratum corneum, changes
radically depending on the
location sampled.
LM × 240

Figure 4.5 The Epidermal Ridges of Thick Skin
Pores of sweat
gland ducts
Epidermal
ridge
SEM × 25

The Epidermis
• Skin color
• Due to:
• Dermal blood supply
• Thickness of stratum corneum
• Various concentrations of carotene and melanin

Figure 4.6 Melanocytes
Thin skin LM × 600
Melanocytes
in stratum
basale
Melanin
pigment
Basal lamina
Melanosome
Keratinocyte
Melanin
pigment
Melanocyte
Basal
lamina
Melanocytes produce and store melanin.
This micrograph indicates the
location and orientation of
melanocytes in the stratum
basale of a dark-skinned person.

The Dermis
• The dermis consists of two layers
• Papillary layer
• Superficial dermis
• Reticular layer
• Deep dermis

The Dermis
• Papillary layer (details)
• Consists of:
• Dermal papillae
• Capillaries
• Nerve axons

The Dermis
• Reticular layer (details)
• Consists of:
• Interwoven network of dense irregular connective
tissue
• Hair follicles
• Sweat glands
• Sebaceous glands

Figure 4.7a The Structure of the Dermis and the Subcutaneous Layer
Dermal papillae
Papillary layer
Reticular layer
Cutaneous plexus
Adipocytes
Papillary
plexus
Epidermal
ridges
Papillary layer of dermis SEM × 649
The papillary layer of the dermis consists
of loose connective tissue that contains
numerous blood vessels (not visible),
fibers (Fi), and macrophages (not visible).
Open spaces, such as those marked by
asterisks, would be filled with fluid
ground substance
Fi

Figure 4.7b The Structure of the Dermis and the Subcutaneous Layer
Dermal papillae
Papillary layer
Reticular layer
Cutaneous plexus
Adipocytes
Papillary
plexus
Epidermal
ridges
SEM × 1340Reticular layer of dermis
The reticular layer of the dermis contains
dense, irregular connective tissue.

• Hair
• Made of keratin
 98% of the 5 million hairs on the body are not
on the head.
 The fine hairs grown on the fetus body is
called Lanugo.
• Hair follicles
 Hair follicles are the organs that form the
hairs.

Figure 4.9a Accessory Structures of the Skin
A diagrammatic view of a
single hair follicle
Hair papilla
Hair bulb
Connective
tissue
sheath
Arrector
pili muscle
Sebaceous
gland
Hair shaft
Boundary
between hair
shaft and
hair root
Hair
root
Exposed shaft
of hair

Figure 4.9b Accessory Structures of the Skin
A light micrograph showing the sectional appearance
of the skin of the scalp. Note the abundance of hair
follicles and the way they extend into the dermis.
Subcutaneous
adipose tissue
Epidermis
Dermis
Medulla
Papilla
Scalp, sectional view LM × 66
Hair bulb
Cortex
Connective tissue sheath
of hair follicle
External root sheath
Glassy membrane
Hair
Hair follicle, cross section
Hair shaft
Sebaceous gland
Arrector pili muscle

• Glands in the skin
• Eccrine glands or Merocrine glands:
• The most abundant and widely distributed
sweat glands that regulate body temperature.
• Sebaceous glands:
• Often associated with hair follicles. This is
true also with Apocrine sweat glands that
connect to the hair follicle to access to the
surface of the skin.

Figure 4.12 A Classification of Exocrine Glands in the Skin
Exocrine Glands
Sebaceous Glands Sweat Glands
Typical Sebaceous Glands Sebaceous Follicles Apocrine Sweat Glands Merocrine Sweat Glands
Ceruminous Glands Mammary Glands
• Excrete wastes
• Secrete oily lipid (sebum) that
coats hair shaft and epidermis
• Provide lubrication and
antibacterial action
types
consist of
Secrete into hair follicles Secrete onto skin surface
• Produce watery solution by
merocrine secretion
• Flush epidermal surface
• Perform other special functions
types
• Limited distribution
(axillae, groin,
nipples)
• Produce a viscous
secretion of complex
composition
• Possible function in
communication
• Strongly influenced
by hormones
• Widespread
• Produce thin secretions,
mostly water
• Merocrine secretion
mechanism
• Controlled primarily by
nervous system
• Important in
thermoregulation and
excretion
• Some antibacterial action
special apocrine glands
Secrete waxy cerumen
into external ear canal
Apocrine glands
specialized for milk
production

Figure 4.13 Sebaceous Glands and Follicles
Epidermis
Dermis
Subcutaneous
layer
Sebaceous
follicle
Sebaceous
gland
Lumen (hair
removed)
Wall of
hair follicle
Basal lamina
Discharge of
sebum
Lumen
Breakdown of
cell walls
Mitosis and
growth
Germinative
cellsSebaceous gland LM × 150

• Sweat glands
• Mammary glands
• A special type of apocrine gland
• Produce milk under the control of hormones from
the pituitary gland
• Ceruminous glands
• A special type of apocrine gland
• Found only in the ear canal
• Produce cerumen (ear wax)
• Provide minimal protection associated with the ear

Figure 4.15c Structure of a Nail
Phalanx
Proximal nail fold
Nail root Lunula
Nail
body Hyponychium
DermisEpidermis
Longitudinal section
Eponychium

Aging and the Integumentary System
• Epidermis becomes thinner
• Dermis becomes thinner
• Number of Langerhans’ cells decreases
• Vitamin D production declines
• Melanocyte activity declines
• Glandular activity declines
• Hair follicles stop functioning
• Skin repair slows down
 Mechanical stress can trigger stem cell divisions resulting in calluses.
 Regeneration occurs after damage.
 The inability to completely heal after severe damage may result in acellular
scar tissue.

Figure 4.16 The Skin during the Aging Process
Fewer Melanocytes Fewer Active
Follicles
Thinner, sparse
hairs
• Pale skin
• Reduced tolerance
for sun exposure
Skin repairs proceed
more slowly.
Reduced Skin Repair Decreased Immunity
Thin Epidermis
Reduced Sweat
Gland Activity
The number of dendritic cells
decreases to about 50 percent of levels
seen at maturity (roughly age 21).
• Decreased vitamin
D production
• Reduced number
of Langerhans cells
• Slow repairs
Tendency to
overheat
Thin DermisReduced Blood SupplyDry EpidermisChanges in Distribution of
Fat and Hair
Due to reductions in
sex hormone levels
Reduction in
sebaceous and
sweat gland activity
• Slow healing
• Reduced ability to lose
heat
Sagging and
wrinkling due to
fiber loss

Ch04lecturepresentation 140913123323-phpapp01

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