Download The Integumentary System

The Integumentary System
Beauty is only skin deep
and most of what you see is dead…
Your skin…
1) is as thick as a paper towel- 1.5-4 mm
2) covers about 1.2-2.2 square meters
3) weighs 9-11 lbs.
4) makes up about 7% of body weight
5) renews the outer region every 25-45 days
6) can develop over 100 skin
diseases/disorders- dermatology
The Functions of the Skin
The skin exhibits numerous functions.
These include
Regulation of body temperature
Protection
Sensation
Excretion
Immunity
Synthesis of Vitamin D
Organization
Atoms Molecules  Cells  Tissues
Organs System
The Skin has two Regions:
EPIDERMIS = epithelial tissue, made of
layers of cells
Tissue= group of cells that work
together to perform a function.
Epithelial tissue covers….
Connective tissue connects…
DERMIS= Connective Tissues (connects skin
to muscles, usually)
Lower subcutaneous layer of fat
Why are Layers of Flat Cells suitable for
the Epidermis?
The Epidermis has 4 types of
cells:
Keratinocytes-make keratin protein
Melanocytes- make melanin
Langerhans' cells- immune function
against microbes and cancer cells
Merkel cells- sensory/touch
The Epidermis is organized into five
distinct layers:
STRATUM CORNEUM-outermost, dead
STRATUM SPINOSUM-has Langerhans
cells
STRATUM GRANULOSUM-dehydrating
STRATUM LUCIDUM- soles, palms only
STRATUM BASALE-innermost, mitotic
As cells are produced in the stratum basale
layer, cells are pushed upwards, begin to
produce keratin, and become flatter
The Dermis is your Hide.
It is made of Connective Tissue that
connects it to the layer beneath and makes it
tough and leathery.
Connective tissue has blood vessels and
nerves
The Dermis has two distinct subregions:
1. PAPILLARY REGION- loose, connective
tissue w/ collagen and elastic fibers;
Fingerprints
2. RETICULAR LAYER- dense, irregular
connective tissue w/ lots of collagen and
elastic fibers.
DERMATOMES-collagen fibers run horizontally on
head and limbs, circularly around neck and trunk*surgery and healing.
Flexure lines- on palms, wrists, fingers- deep folds
in dermis allow for joint movement
Skin Color is due to 2 Pigments:
1) MELANIN- made of tyrosine (aa) polymer,
in melanocytes; stratum germinativum
All humans have same no. of melanocytes; more
melanin=darker skin, but also due to larger
melanosomes deposited in stratum granulosum
3 variations- yellow, brown, black
Accumulates on ‘sunny’ side to protect cells
Do tans fade?
Sun damage= clumpy elastin fibers-> leathery
skin, weaker immune system, DNA damagesome medicines make skin sun sensitive!
Skin Pigment
2) CAROTENEaccumulates in epidermis
yellow, orange
Yes- you can turn orange if you eat lots of
carrots and are fair skinned
HEMOGLOBIN gives fair skinned
people their color
Albinism is due to a gene
mutation
There are several
types of albinism
One type is due to a
gene mutation where
amino acid Tyrosine
cannot be converted to
Melanin
Three Types of Glands in the
Skin
Sebaceous Glands- secrete
oilsoft skin
Sweat or Sudoriferous
Merocrine- secrete
water and salts
Apocrine- axillary and
external genitaliasecrete water, salts,
fatty acids, proteins
Ceruminous Glands- make
ear wax
HOMEOSTATIC IMBALANCE!
BLUE SKIN- cyanosis- not enough O2- heart
failure, respiratory distress
RED SKIN- fever, high blood pressure,
Polycythemia, emotions, inflammation, allergy
WHITE SKIN- emotional stress, anemia, low BP
YELLOW-Jaundice- liver disorder
BRONZE- Addison’s Disease- pituitary secretes
too much ACTH
BLACK & BLUE- hematoma- bruise
Homeostasis Interrupted!
Stretch Marks- dermal tearing- striae
Blisters- temporary separation of
epidermis from dermis, becomes fluid
filled
Burns- later…
BURNS are classified by severity
and surface area
First Degree-epidermis
• Red, painful, swelling
Second Degree-epidermis and
some dermis
Red, swelling, blisters
Third Degree
Both layers destroyed as
well as subcutaneous
White or charred, no
swelling, no pain (nerves
destroyed)
Fluid loss and infection
Fourth Degree Burn
• Burn reaches bone/muscle
BURNS
Causes: heat, chemicals, electricity, radiation
Most serious threats to survival-fluid and
electrolyte loss
Burned skin is easily invaded by bacteria
Fluid lost in burn is protein rich and actually
‘feeds’ bacteria
Immune system is exhausted within 2-3 days
Burns are classified by the
“Rule of Nines”
Anterior+Posterior head= 9%
Anterior+Posterior Trunk= 36%
Anterior+Posterior Thighs=18%
Perineum=1%
Anterior+ Posterior Lower
Limbs=36%
Basal Cell Carcinoma
Open sores that bleed,
ooze, or crust for more
than 3 weeks
Acne
Increased hormone
activity turns on
sebaceous glands
Sebum and dead skin
cells block hair
follicles and
accumulate until
follicle ruptures
Malignant Melanoma
Cancer of the
melanocytes, is a
particularly serious skin
cancer.
ABCD=
asymmetryBorders-uneven
Coloration-uneven
Diameter->6mm
Squamous Cell Carcinoma
2nd most common skin
cancer
Most are not serious
but can spread
Red, patch that itches
or hurts
In Class Assignment: How does the
integumentary system interact with:
Skeletal System- support, movement, Ca+
regulation
Muscle System-movement, heat regulation
Respiratory System- gas exchange, pH reg.
Digestive System- digest food, absorb Ca+
Urinary System- Excrete wastes, pH reg.
Reproductive System- produce offspring, reg
reproductive cycles
Nervous System-respond to environment,
regulation
Cardiovascular System-move blood around body
Endocrine System-regulation
Lymphatic System-defense against microbes
Accessory Organs of The Skin:
HAIR, GLANDS, NAILS
1. HAIR =Dead, keratinized cells
(hard keratin)
Each hair has a:
SHAFT and a ROOT.
HAIR FOLLICLE surrounds the root and is
composed of two layers of epidermal tissue.
Cuticle-single layer of cells around hair, keeps
hairs apart- hair conditioners smooth out cuticles;
split ends= worn cuticles
HAIR COLOR
Melanocytes at base of follicle- yellow,
brown, black (Red Hair has iron containing
cpd)
White hair- melanin replaced by air bubbles
Why don’t your eyebrow hairs grow as
long as the hair on your head?
Follicles on your scalp are active for 4yrs,
then rest
Follicles in your eyebrows are active for 3-4
months- (except Andy Rooney)
HAIR LOSS = ALOPECIA
due to fever, vit A overdose, some
antidepressants, chemo, protein deficiency,
lactation, or genetics (sex influenced trait)
Minoxidil- used to treat blood pressure, but
also stimulates hair follicles
Nails are keratinized, epidermal
cells on fingers and toes
Parts of nails include:
free edge,
nail body-stratum basale grows under nail
body to form nail bed
nail root-covered
Lunula-white part