Download Chapter 5 Integumentary System

PowerPoint® Lecture Slides
prepared by Vince Austin,
Bluegrass Technical
and Community College
CHAPTER
Elaine N. Marieb
Katja Hoehn
Human
Anatomy
& Physiology
SEVENTH EDITION
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
5
The
Integumentary
System
Functions of the Integument

1.
protects us from bacterial invasion

2. protects us from dessication

3. protects us from heat loss

4. protects us from UV radiation
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Skin (Integument)

Consists of three major regions



Epidermis – outermost superficial
region
Dermis – middle region
Hypodermis (superficial fascia) –
deepest region
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Hair shaft
Pore
Dermal papillae
(papillary layer
of dermis)
Epidermis
Meissner's corpuscle
Free nerve ending
Reticular layer of dermis
Sebaceous (oil) gland
Arrector pili muscle
Dermis
Sensory nerve fiber
Eccrine sweat gland
Pacinian corpuscle
Artery
Hypodermis
(superficial
fascia)
Hair root
Hair follicle
Eccrine sweat
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gland
Vein
Adipose tissue
Hair follicle receptor
(root hair plexus)
Figure 5.1
Epidermis

a.
b.
4 major types of cells in the epidermis:
Keratinocytes – produce keratin which protects
the skin
Melanocytes – protects the cell nuclei from UV
radiation – gives us skin color
c.
Langerhans cells – ingest foreign substances
d.
Merkel cells – sensory receptor for touch
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Layers of the Epidermis
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Figure 5.2b
Layers of the Epidermis

Stratum Basale – deepest layer
next to dermis
a. continual mitosis
b. produces new keratinocytes
and melanocytes
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Layers of the Epidermis

Stratum Spinosum
a.
Have filaments that function to
resist tension and attach to the
desmosomes
b.
Have Langerhans cells and
melanin granules and spiky
kerantinocytes
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Layers of the Epidermis

Stratum Granulosum
a.
Keratinocytes change to flattened shape
b.
Organelles disintegrate
c.
Granules which form keratin
d.
Granules which form a glycolipid waterproofing
contained in extracellular space to slow water
loss from epidermis
e.
No capillarity above this layer
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Layers of the Epidermis

Stratum Lucidum
a.
Clear flat dead keratinocytes
b.
Visible only in thick skin area of the body
c.
No present in think skin areas of the body
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Layers of the Epidermis

Stratum Corneum
a.
Outermost layer
b.
Protect against penetration and abrasion
c.
Consists of dead cells (dead skin and dandruff)
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Dermis

Contains fibroblasts (produces fibers);
macrophages (destroy bacteria and worn cells);
mast cells (detect foreign substances and initiate
the inflammatory response); white blood cells
(take part of the immune response)

Supplied with nerve, blood, and lymphatic vessels

Contain hair follicle, oil and sweat glands
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Dermis


Second major skin region containing
strong, flexible connective tissue
Composed of two layers –

papillary

reticular
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Layers of the Dermis: Papillary Layer

Touch receptors

Fingerprints

Gripping of hands and feet


Contain Meissner’s corpuscles
(touch)
Contain Pacinian corpuscles (pain)
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Layers of the Dermis: Reticular Layer

80% of the thickness of the skin

Collagen fibers in this layer add
strength and resiliency to the skin

Elastin fibers provide stretch-recoil
properties

Nourished by cutaneous plexus
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Hypodermis

Subcutaneous layer deep to
the skin

Composed of adipose and
areolar connective tissue
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Skin Color

Three pigments contribute to skin color

Melanin – yellow to reddish-brown to black
pigment, responsible for dark skin colors



Freckles and pigmented moles – result from local
accumulations of melanin
Carotene – yellow to orange pigment, most
obvious in the palms and soles of the feet
Hemoglobin – reddish pigment responsible for the
pinkish hue of the skin
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Sweat Glands (sudoriferous glands)

prevent overheating of the body

secrete cerumen and milk




Eccrine – found in palms, soles of the feet, and
forehead
Apocrine – found in axillary and anogenital areas
Ceruminous glands – modified apocrine glands in
external ear canal that secrete cerumen
Mammary glands – specialized sweat glands that
secrete milk
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Sebaceous Glands

Soften skin when stimulated by
hormones

Secrete an oily secretion called
sebum

Whitehead, blackhead, seborrhea
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Hair (Pili)

dead keratinized cells produced by hair
follicles

Regions are shaft and root

Contains hard keratin

Consists of a core called the medulla, a
cortex, and an outermost cuticle

Pigmented by melanocytes at the base of
the hair
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Shaft of Hair (Go to Microscope)

If shaft is flat and ribbon like (kinky)

If shaft is oval (silky and wavy)

If shaft is round (straight)

Locate medulla, cortex, cuticle

Look at the slides with beard hair (note the shape
of the tip ends)

Pull a hair out by the root (observe the root tip)
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Hair Function and Distribution

Functions of hair include:

Helping to maintain warmth

Alerting the body to presence of
insects on the skin

Guarding the scalp against physical
trauma, heat loss, and sunlight
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Hair Follicle
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Figure 5.5c
Types of Hair


Vellus – pale, fine body hair
found in children and the adult
female
Terminal – coarse, long hair of
eyebrows, scalp, axillary, and
pubic regions
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Structure of a Nail

Scalelike modification of the epidermis on the
distal, dorsal surface of fingers and toes
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Figure 5.6
Functions of the Integumentary System

Protection

Body temperature regulation

Cutaneous sensation - touch and
pain
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Protection- Physical Barriers
Prevents bacterial invasion
Provides waterproofing with glycolipids
Does allow penetration of:
a.
O, CO2, Vitamins A,D,E,K and steroids
b.
Oleoresins (poison oak/ivy)
c.
Organic solvents (paint thinner, acetone)
d.
Salts and heavy metals (Pb,Hg)
e.
Drug agents
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Protection - Biological
a.
Langerhans cells – detect foreign
substances
b.
Macrophages – viruses and bacteria
c.
DNA-conversion of radiation to heat
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Body Temperature Regulation

Constant secretion of sweat

Dilation of blood vessels and increased sweat
production during excessive heat

Evaporation

Constriction of blood vessels and heat loss is
slowed
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Metabolic Functions

Synthesis of vitamin D in dermal
blood vessels – aids in Ca absorption
from digestive system

Makes chemicals to aid liver function

Makes enzymes that deter wrinkles
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Functions of Skin

Blood reservoir – 5% of blood volume

Excretion – sweat (amonia, urea, uric acid)
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Skin Cancer

Most skin tumors are benign and do not
metastasize

A crucial risk factor for nonmelanoma skin cancers
is the disabling of the p53 gene

Newly developed skin lotions can fix damaged
DNA
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Skin Cancer – 3 types
1. Basal cell carcinoma – least
malignant and most common-stratum
basale
2.Squamous cell carcinoma -stratum
spinosum-most head,hands,can
metastasize
3. Melanoma – cancer of melanocytsmost dangerous
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Skin Cancers
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Figure 5.7a–c
Melanoma – ABCD rule

A: Asymmetry; the two sides of the
pigmented area do not match

B: Border is irregular and exhibits
indentations

C: Color (pigmented area) is black,
brown, tan, and sometimes red or blue

D: Diameter is larger than 6 mm (size
of a pencil eraser)
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Rule of Nines - Burns

Burns considered critical if:

Over 25% of the body has second-degree burns

Over 10% of the body has third-degree burns

There are third-degree burns on face, hands, or feet
Volume of fluid lost extimated by percentage of
body surface burned
11 body areas – each 9%
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Rule of Nines
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Figure 5.8a
Developmental Aspects of the Integument:
Fetal

Epidermis develops from ectoderm

Dermis and hypodermis develop from mesoderm


Lanugo – downy coat of delicate hairs covering the
fetus
Vernix caseosa – substance produced by sebaceous
glands that protects the skin of the fetus in the
amnion
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