Transcript Function#2

Integumentary System- L2
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General structure: composed of
epidermis , dermis, separated by a
basement membrane and a
subcutaneous layer underneath
Has at least 8 functions!
Function #1: Protective
barrier against
1.
2.
3.
4.
5.
Loss of body fluids
Infection
Damage from physical injury
Heat/UV light
Physical stress
Function#2: Thermal
regulation
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1. Sweat from sweat glands
2. Controls blood supply to warm/cool
body
3. insulation: barrier against outside
4. Radiation of heat (#1 way to cool
body) and evaporation also a close #2
Function #3 Sensory
receptors in skin react to
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1. changes in temp
2. touch-pressure-pain
Function #4: Excretion of
Wastes
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1. Since it self-renews it can get rid of
nitrogen, salt, urea
Function #5 -#8:
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vitamin D production
energy storage (fat)
fingers and toes provide a gripping
surface
Blood reservoir. (skin has about 8-10%
of one's blood.)
First layer: Epidermis
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Has 5 layers of avascular stratified
squamous tissue
Has cells called keratinocytes and
melanocytes
Keratinocytes produce the protein keratin.
It makes up skin surface, hair and nails
Keratin helps waterproof and protect.
Second layer: Dermis (primarily
connective tissue) with the
following
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1. Has many nerves and blood vessels
going through it.
2. The cells of the dermis are primarily
fibroblasts.
3. The intercellular material is largely
collagen and elastin laid down in all
directions by the fibroblasts.
4. Adipose cells are also common
Third Layer: Subcutaneous
Layer (hypodermis)
- primarily connective tissue, adipocyte
cells are more predominant. This layer
contains blood vessels that supply the
skin.
Cells called: Melanocytes
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1. Melanocytes are in the basal layer of
epidermis
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A. Make black pigment called melanin
B. this coloration protects against UV light
C. Native Americans and Asians have
variations of melanin to have yellowish
color to skin
Melanocytes & Tanning
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Prolonged exposure to ultraviolet light
stimulates melanocyte activity &
melanin secretion in epidermis.
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This results in darker skin; the melanin
protects the DNA of cells from UV damage
by absorbing UV light.
Too much exposure to UV light may
overwhelm the protective function of
melanin and result in sunburn.
Fingerprints
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Specialized structure: Dermal papillae
Uneven ridges formed during fetal
development
NO TWO sets are exactly alike!
Hair and follicle
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1. Hair - made by epidermal keratin forming
cells.
a. Color = various levels of melanin and
carotene. Gray is due to air spaces in the
hair.
b. Function?
c. Growth is always from base. A new hair
starts and pushes the old one out. Hair goes
through growth-rest stages.
Sebacious gland: usually
connected to hair
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A. glands that secrete sebum,
B. Functions to keep skin and hair soft
and waterproof
C. Especially active during puberty. Can
clog with dead cells/sebum→pimple
Sebacious Gland, cont.
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D. Smooth muscle that lifts the hair is
called the arrector pili.
E. Nerve (sensory)
F. Dermal Papillae: fingerprints.
Projections extending into epidermis
from dermis. Helps increase friction to
help pick up things.
Sweat glands: 3000/sq.
inch
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1. # 1 Function- to cool the body
2. Excretes wastes
3. Regulated by nerves
4. A modified form secretes more
organic materials in arm pits/pubic
area. Bacteria break it down and cause
odor.
Nails:
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-protective covers on the ends of
fingers and toes
-undergo keratinization
1st degree burn
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Epidermis
ONLY
affected
Redness
and
burning
EX:
sunburn
Epidermal (1st degree) burn
2nd degree burn
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Damage to
both the
epidermis
and dermis
Damage
not
enough to
PREVENT
healing
Dermal (2nd degree) burn
Deep dermal (2nd degree)
burn
3rd Degree burn
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ENTIRE
epidermis,
dermis,
and
accessory
organs
destroyed
Tissue
death
Sub-dermal (3rd degree) burn
Skin graft
Common disorders of the Feet
Athlete's Foot
(right down)
Skin disorders of the feet
such as Callus, Athlete's foot
and Plantar Warts
Tinea pedis- Athlete’s Foot
Acne
Contact dermatitis
Moles are harmless skin growths that
may be flat or protruding. They vary in
color from pink flesh tones to dark brown
or black.
Pediculosis- lice
Decubitus ulcer (Bed sore)
Where do pressure ulcers
form?
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Where bone causes the greatest force
on the skin and tissue.
For bedridden persons, most pressure
ulcers form on the lower back below the
waist (sacrum), the hip bone
(trochanter), and heels.
Diabetic Ulcer
Pathophysiology: diabetic foot
ulceration
Neuropathy
Motor
Sensory
Autonomic
Abnormal foot
biomechanics
Loss of
protective
sensation
Reduced skin
compliance and
lubrication
Ulceration
Vascular
insufficiency
Infection
Eczema
Quick Quiz: 2 pts each
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1. Name 3 of the, at least 8 fx’s of
integ. system
2 . List and describe the 3 layers of the
skin
3. Name/describe top 2 ways we lose
body heat
4. Describe keratin and keratinocytes
5. Describe the relationship between
skin color and melanin
Quick Quiz: cont
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6. Describe what a sebacious gland
is/does
7. Describe what a sweat gland is/does
8. What does Vit D have to do with skin?
9 . Discuss the differences in 1st,2nd, 3rd
degree burns
10. Discuss two factors that can influence
diabetic ulcers and pressure ulcers