Transcript Integumentary System

Integumentary System
Cover & Protect
Functions of the Skin
1. PROTECTS - from injury, chemicals,
temperature, & bacteria
2. PREVENTS water loss by producing keratin – a
water proofing protein
3. REGULATES body temperature
4. EXCRETES excess wastes
5. PRODUCES Vitamin D
6. PROVIDE information about our environment
Epidermis - the outer layers of
the skin
made up of stratified
squamous epithelium that is
capable of keratinizing
Dermis - deep layer of the
skin; composed of dense,
irregular connective tissue.
subcutaneous tissue, or
hypodermis - adipose tissue
anchor the skin to underlying
organs
Structures of the Epidermis
• STRATUM BASALE
- deepest cell layer of the epidermis
- connected to dermis along a wavy
borderline that resembles corrugated cardboard
- contains epidermal cells that receive the
most adequate nourishment
- millions of new cells are produced daily
Structures of the Epidermis
• STRATUM SPINOSUM & STRATUM
GRANULOSUM
- Cells become increasingly flat and full of
keratin – water-proofing protein
• STRATUM LUCIDUM
– Layer in which cells die- only found where skin is
hairless and extra thick - the palms of the hands
and soles of the feet
Structures of the Epidermis
• STRATUM CORNEUM (outermost layer)
– 20 to 30 cell layers thick
– Cells are completely filled with keratin
– Creates hard layer that protects cells underneath
– Average person loses 18 kg (40 lb) of this layer in
their lifetime
– Replaced by cells of stratum basale every 25 to 45
days
MELANOCYTES
• a cell that produces melanin
• Melanin - dark pigment responsible for skin
color
Structures of the Dermis
• PAPILLARY LAYER
– Upper dermal region that is uneven
– Has projections called dermal papillae which
indent the epidermis above
– Papillae of hands and feet are arranged in definite
patterns – these form looped and whorled ridges
– Layer that houses touch (Meissner’s corpuscles)
and pain receptors (free nerve endings)
Structures of the Dermis
• RETICULAR LAYER
– Deepest skin layer
– Contains blood vessels, sweat and oil glands
– Has deep pressure receptors called Pacinian
corpuscles
– Contains collagen fibers which gives the skin its
strength
– Contains elastic fibers which give skin elasticity
when we are young
SKIN PIGMENTS
• Amount and kind of melanin – ranges from
yellow to brown to black
• Amount of carotene – a yellow-orange
pigment found in foods like carrots – the body
deposits it in stratum corneum and
subcutaneous layer
• Amount of oxygen-rich hemoglobin – blood
pigment that shows through from the dermal
capillaries
SKIN APPENDAGES
• SEBACEOUS GLANDS
– Produces oils (sebum) that keep skin moist and
soft
– Prevents hair from becoming brittle
– Sebum contains chemicals that kill bacteria
SKIN APPENDAGES
• SWEAT (SUDORIFEROUS) GLANDS
– ECCRINE - numerous and are found all over the
body; produce sweat; important and highly
efficient part of the body’s heat-regulating
equipment
– APOCRINE - confined to the axillary and genital
areas of the body; usually larger; ducts empty into
hair follicles
SKIN APPENDAGES
• HAIR
– Produced by an epithelial structure called the hair
follicle
– Composed of three layers: medulla (inner layer),
cortex (middle layer) & cuticle (outer layer)
– The cuticle is formed by highly keratinized, dead
epithelial cells
– The arrector pili muscle attached to the hair
follicle are the cause of “goose bumps”
SKIN APPENDAGES
• NAILS
– Modifications in the epidermis having free edge,
nody (visible attached portion) and root
(embedded in skin)
– Heavily keratinized and colorless – appear pink
because of blood supply below
– Grows from the nail bed or matrix
BURNS
• BURN – damage or cell death caused by
intense heat
– 1st Degree - only the epidermis is damaged; area is
red and swollen; generally heal in two to three
days; Sunburn
– 2nd Degree - injury to the epidermis and the upper
region of the dermis; skin is red and painful, and
blisters appear
– 3rd Degree - destroy the entire thickness of the
skin; blanched (gray-white) or blackened
SKIN DISORDERS
• ATHLETE’S FOOT – itchy, red, peeling condition
between toes – caused by a fungus
• COLD SORES – fluid filled blisters that itch &
sting – caused by herpes simplex infectionactivated by upset, fever or UV light
• PSORIASIS – chronic condition producing too
many skin cells – believed to be an
autoimmune disorder in which the immune
system attacks a person’s own tissues
SKIN DISORDERS
• ACNE – condition caused by the
overproduction in the hair follicles – prevalent
in teens because of hormonal changes
• Basal Cell Carcinoma – most common skin
cancer – appear as lesions in areas that have
been exposed to a lot of sun – relatively slow
growing
SKIN DISORDERS
• Squamous Cell Carcinoma – appears as a red,
scaley lesion – eventually forms an ulcer on
the surface of the skin – appear most often on
scalp, ears, dorsum of the hands, and lower
lip- also believed to be sun-induced
• Melignant Melanoma – begins wherever there
is pigment – appears spontaneously or where
there is existing pigment
DIAGNOSIS - ABCs
A) Asymmetry- sides of the pigmented spot or
mole do not match
B) Border irregularity - borders of the lesion are
not smooth but exhibit indentations.
C) Color - pigmented spot contains areas of
different colors (blacks, browns, tans, and
sometimes blues and reds).
D) Diameter - spot is larger than 6 millimeters
(mm) in diameter (the size of a pencil eraser).
E)Elevation – above skin surface