Transcript INTEGUMENTARY SYSTEM

INTEGUMENTARY SYSTEM
ANATOMY AND PHYSIOLOGY
INTRODUCTION
• All living things are made of cells
• Cells join together to make tissues
• Tissues join together to form organs
Skin
• Skin is the principal organ of the
integumentary system
• Skin is one of a group of anatomically
simple but functionally important
sheetlike structures called membranes
Membranes
Membranes
• A membrane is a thin, sheetlike
structure with many important
functions in the body
• Membranes cover and protect the body
surface, line body cavities, and cover
the inner surfaces of the hollow organs.
Two major categories of
membranes
• Epithelial – composed of epithelial
tissue and an underlying layer of
specialized connective tissue
• Connective tissue membranes –
composed exclusively of various
types of connective tissue
Three types of epithelial
membranes
– Cutaneous
– Serous
– Mucous
Cutaneous Membrane
Cutaneous Membrane
• Commonly called the skin
• One of the largest and more
versatile organs of the body
Functions of Cutaneous
Membrane
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Protective covering
Regulates body temperature
Prevents water loss
Houses sensory receptors
Synthesizes various biochemical
Excretes small qualities of waste
Serous Membranes
Serous Membranes
• Found only on surfaces within closed
cavities
• Composed of 2 layers of tissue – the
epithelial sheet and a thin layer of
connective tissue
• Secrete serous fluid- watery fluid
which lubricates the membranes
surface
Serous Membranes
• Two types:
– Parietal – lines the walls of a body cavity
– Visceral – covers the surface of organs
found in the body cavities
Serous Membranes
• Pleura
– Serous membranes that line the thoracic
cavity
• Peritoneum
– Serous membranes that line the
abdominal cavity
Mucous Membranes
Mucous Membranes
• Lines cavities and tubes that are open
to the outside
• Consist of epithelial overlying a layer
of loose connective tissue
• Specialized cells within a mucous
membrane secrete mucus
Mucous Membrane
• Examples – linings of:
– Respiratory
– Digestive
– Urinary, and
– Reproductive tracts
Mucocutanous Junction
Mucocutanous Junction
The transitional area that serves as a point of
“fusion” where the skin and mucous
membranes meet
Connective Tissue Membranes
• Also called synovial membranes
• Line the spaces between bones and
joints that move
• Slick, smooth membranes that secrete
synovial fluid, which lubricates the
ends of bones within the joint
• Reduce friction between bones
Cutaneous Membrane (Skin)
Composed of the following layers:
• Epidermis-outer layer of skin
• Dermis- middle layer of skin
• Subcutaneous-innermost layer of
skin – thick layer of loose
connective tissue and fat
Epidermis
• Tightly packed epithelial cells arranged in
layers
• Inner – stratum germinativum
• Outer – stratum corneum
Epidermis
• Inner layer – stratum germinativum – cells
specialize to increase their ability to protect the
tissues below them. This enables the skin to
repair itself if it is injured. As the cells approach
the surface, the cytoplasm is replaced by keratin,
a protein which is tough and waterproof and
protects the body
• Sometimes called the pigment layer because it is
responsible for melanin production
Epidermis
• Outer layer – stratum corneum
• Keratin-filled cells are constantly pushed to
the surface and “flake off”
• Millions of epithelial cells reproduce daily
to replace the millions shed
Melanin
• Melanocytes are the cells within the
pigment layer that produce melanin
• Melanin is a dark pigment that
provides skin color
Melanin
• Melanin absorbs light energy and protects
deeper cells from the ill effects of UV
light.
• Skin color is due largely to melanin
• Color is mostly genetically determined but
can also be modified by sunlight exposure
Skin Color Abnormalities
• Cyanosis - bluish discoloration of
the skin
• Jaundice - yellowish discoloration of
the skin
• Erythemia - reddish discoloration
Skin Color Abnormalities
• Vitiligo – patchy areas of light skin
resulting from the acquired loss of
epidermal melanocytes. Most cases are
genetic in origin.
• Albinism – hereditary condition,
characterized by a partial or total lack of
melanin. Affected individuals are prone
to eye damage and sunburn
Dermis
• Binds the epidermis to the
subcutaneous layer
• Contains blood vessels, hair follicles,
nerve endings, sweat glands and nerve
fibers
Dermis
• Upper region has parallel rows of peg
like projections called dermal papillae
• Form the dermal-epidermal junction
• Form groves and ridges that make
fingerprints
• The pattern of these are unique in
every person
Dermis, cont.
• Deeper area of dermis is collagen that
gives toughness to skin.
• Elastic fibers are present
• Makes skin stretchable and elastic
• Wrinkles form as skin loses elasticity
Appendages
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Hair
Receptors
Nails
Skin glands
Appendages-Hair
• Millions of small hairs cover the body
• Follicles - present at birth, required for hair
growth
• Newborns are covered with soft, fine hair called
lanugo
• Areas of body that are hairless are lips, palms of
hands and soles of feet
• Most visible on scalp, eyelids and eyebrows
Appendages-Hair
• Growth begins from a small cluster of cells
called the papilla.
• Cells grow down into the dermis forming a
small tube called the hair follicle
• The root is the part of the hair that we can’t
see (under the skin)
• The shaft is the part of the hair we can see
Appendages-Hair
• Alopecia is hair loss
• Arrector pili – involuntary muscle that
contracts when we are frightened or
cold, producing raised places called
“goose bumps” or “goose pimples.”
Appendages-Receptors
• Act as sense organs
• Relay messages such as touch, pain, temperature and
pressure
• Free nerve endings - respond to pain
• Meissner’s corpuscles - located near the surface and
detects light touch
• Ruffini’s corpuscles – located in dermal layer and
subcutaneous tissues of fingers, detect touch and
pressure
• Pacinian corpuscle- deep in dermis and capable of
detecting pressure
• Krause’s end bulb-responds to cold
Appendages-Nails
• Produced by cells in the epidermis
• Form when epidermal cells fill with
keratin and become hard and platelike
Appendages-Nails
• Nail body-visible part of the nail
• Root-lies in a groove
• Cuticle-groove and is hidden by a fold of
skin
• Lunula-”little moon”, near the root
• Nail bed- area beneath nail
• Color pink due to abundant supply of blood
vessels seen through translucent nail bodies
Appendages-Skin Glands
• Sweat or Sudoriferous
– Most numerous of skin glands
– Two types: Eccrine and Apocrine
• Sebaceous
– Oil-secreting glands
Appendages-Skin Glands
• Eccrine Sweat Glands
– Numerous and widespread throughout
the body
– Secrete watery liquid called perspiration
(sweat)
– Sweat assists in the elimination of waste
products such as ammonia and uric acid
Appendages-Skin Glands
• Apocrine Sweat Glands
– Found in axilla and in pigmented areas of
genitals
– Large, secrete milky secretions
– Produces odor that is caused by mixing
with skin bacteria
– Enlarge and begin functioning at puberty
Appendages-Skin Glands
• Sebaceous Glands
– Secrete oil for the hair and skin
– Grow where hair grows
– Tiny ducts open into hair follicles so that
their secretion, called sebum, can
lubricate hair and skin.
– Sebum darkens to form blackheads
– Acne vulgaris is the over secretion of
sebum
Disorders of Skin
• Dermatosis-any disorder of the skin
• Dermatitis-inflammation of the skin
• Lesion-measurable variation from the
normal structure of a tissue
– Distinguished by abnormal density, or
coloration
– Discoloration usually occurs
Skin Lesions
ELEVATED
• Papule
• Plaque
• Vesicle
• Pustule
• Crust
• Wheal
FLAT
• Macule
DEPRESSED
• Excoriation
• Ulcer
• Fissure
Skin Lesions
ELEVATED
• Papule - warts
• Plaque – can be caused by friction
• Vesicle – non-genital herpes
• Pustule – acne
• Crust - scab
• Wheal - hives
Skin Lesions
FLAT
• Macule - freckles
• Patch - vitiligo
DEPRESSED
• Excoriation – scratches
• Atrophy – stretch marks
• Ulcer - bedsore
• Fissure – athlete’s foot
Classification of Burns
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First-degree burns
Second-degree burns
Third-degree burns
Fourth-degree burns
• Third- and fourth-degree burns are
both called full-thickness burns
Burns-Classifications
• First-degree burns-causes minor
discomfort
– Example-sunburn
– Reddening of the skin
– No blistering
– Tissue damage is minimal
Burns-Classifications
• Second-Degree Burns
– Involves deep epidermal layers
– Causes injury to upper layers of dermis
– Damages sweat glands, hair follicles and
sebaceous glands
– Blisters, severe pain, generalized
swelling
– Scarring is common
Burns-Classifications
• Third-Degree Burns
– Complete destruction of the epidermis
and dermis
– Tissue death extends to subcutaneous
layer
– Insensitive to pain due to destruction of
nerve endings
– Increased fluid loss
Burns-Classifications
• Fourth-Degree Burns
– Full thickness burn that extends below the
subcutaneous layer to reach muscle or bone
– Often result from electrical burns or exposure
to intense heat over time
– Insensitive to pain due to destruction of nerve
endings
– Increased fluid loss
Burns-Classifications
• Serious burns result in over 50,000
hospital admissions each year.
• Circulatory shock, fluid loss,
respiratory injury, and infections are
common complications.
• May require skin grafting or
amputation of limbs
Estimating Body Surface Area
• “Rule of Nines”-body is divided into
11 areas of 9%
– Each arm is 9% for total of 18%
– Head is 9%
– Each leg is 18% for total of 36%
– Torso is 18%
– Back is 18%
– Perineal area is 1%
Skin Infections
Bacterial infections (streptococcal or
staphylococcal)
• Impetigo
• Boils
Skin Infections
Viral infections
• Warts
Skin Infections
Fungal infections
• Tinea – ringworm, jock itch,
athlete’s foot
Skin Infections
Arthropod infestations
• Scabies – caused by the itch
mite
Skin Infections
Other skin disorders
• Decubitus ulcers – bedsores
• Urticaria – hives (often caused by
allergic reaction)
• Scleroderma – autoimmune disease
affecting blood vessels and
connective tissues
• Psoriasis – plaques that remain on
the skin for a long time
• Eczema – inflammation, caused by
an underlying disease
Skin Cancers
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Squamous Cell Carcinoma
Basal Cell Carcinoma
Melanoma
Kaposi’s Sarcoma