Integument System

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Integument System

• Pasterik

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• The Integument
• ?? The skin that covers your body.
• Skin is also known as the cutaneous
• membrane.
• ?? Integumentary system consists of the
• skin and its derivativesnails, hair,
• sweat glands, and sebaceous glands.

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• The Integument
• Is the bodys largest organ.
• Its surface is covered by an epithelium that
  protects
• underlying body layers.
• The connective tissues contain blood vessels that
• provide nutrients and provide strength and
  resilience
• to the skin.
• Smooth muscle controls both blood vessel diameter
• and hair position.
• Neural tissue supports and monitors sensory
• receptors in the skin

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• 2 Distinct Layers
• A layer of stratified squamous epithelium called
  the
• epidermis.
• A deeper layer of dense irregular connective
  tissue called the
• dermis.
• -deep to the dermis is a layer of areolar
  and adipose
• connective tissue called the subcutaneous
  layer, or
• hypodermis.

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• Thick Skin
• Thick epidermis is found on the palms
• of the hands, the soles of the feet, and
• corresponding surfaces of the fingers
• and toes.
• All five epidermal strata occur in thick
• skin.

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• Thin Skin
• Thin epidermis covers most of the body.
• Lacks the stratum lucidum
• Has only four specific layers.
• Contains the following accessories
• hair follicles, sebaceous glands, and sweat
• glands.

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• Functions of Skin
• protection
• prevention of water loss
• temperature regulation
• metabolic regulation
• immune defense
• sensory reception
• excretion

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• Skin Color
• Hemoglobin is an oxygen-binding protein
• present in red blood cells. Upon binding with
• oxygen, hemoglobin exhibits a bright red
• color.
• Melanin is a pigment produced and stored in
• cells called melanocytes.
• the two types of melanin occur in various
• yellow, reddish, tan, brown, and black
  shades.
• Carotene comes primarily from diet.

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• Friction Ridges
• Found on the fingers, palms, soles, and toes.
• Formed from large folds and valleys of both
• dermal and epidermal tissue.
• Help us grasp objects, and they
• Increase friction so that items do not slip
• easily from our hands.
• Our feet do not slip on the floor when we
• walk.

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• Friction Ridges
• Friction ridges can leave noticeable
• prints on touched surfaces.
• Each individual has a unique pattern of
• friction ridges.
• Fingerprints have become a valuable
• tool for law enforcement in identifying
• individuals.

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• Skin Markings
• Nevus (mole)
• Freckles
• Hemangioma
• capillary hemangiomas
• (strawberrycolored birthmarks)
• cavernous hemangiomas (port-wine stains)

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• Layers of the Dermis
• Composed of cells of the connective
• tissue proper and primarily of collagen
• fibers, although both elastic and
• reticular fibers are also present.
• Other components of the dermis are
• blood vessels, sweat glands, sebaceous
• glands, hair follicles, nail roots, sensory
• nerve endings, and muscular tissue.

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• 2 Major Regions of Dermis
• Superficial papillary layer
• Deeper reticular layer

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• Lines of Cleavage
• Tension lines in the skin identify the
• predominant orientation of collagen
• fiber bundles.
• Clinically and surgically significant
• because cuts can result in slow
• healing and increased scarring.

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• Innervation and Blood Supply
• The dermis has extensive innervation.
• Monitor sensory receptors in the dermis and
• epidermis, and control both blood flow and
  gland
• secretion rates.
• Tactile corpuscles and tactile (Merkel) cells
  perceive
• touch sensations, and work with a variety of
  other
• sensory nerve endings in the skin.
• This rich innervation allows us to be very aware
  of
• our surroundings and to differentiate among
  the
• different kinds of sensory signals from
  receptors in
• the skin.

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• Nails
• Scalelike modifications of the epidermis that
  form on
• the dorsal surfaces of the tips of the fingers
  
• and toes.
• Protect the exposed distal tips and prevent
  damage
• or distortion during jumping, kicking,
  catching, or
• grasping.
• Hard derivatives formed from the stratum corneum
  
• layer of the epidermis.

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• Hair
• Found almost everywhere on the body except the
• palms of the hands, the sides and soles of
  the feet, the
• lips, the sides of the fingers and toes, and
  portions of
• the external genitalia.
• Most of the hairs on the human body are on the
• general body surface rather than the head.

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• 3 Kinds of Hair
• During our lives, we produce
• three kinds of hair
• - lanugo
• - vellus
• - terminal hair

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• Functions of Hair
• Protection
• Heat retention
• Prevents the loss of conducted heat
• from the scalp to the surrounding air
• Facial expression
• Sensory reception
• Visual identification
• Chemical signal dispersal

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• Hair Color
• Result of the synthesis of melanin in the
• matrix adjacent to the papillae.
• Variations in hair color reflect genetically
• determined differences in the structure of
  the melanin.
• Environmental and hormonal factors
• Age
• Gray hair

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• Hair Growth and Replacement
• Sometimes hair loss may be temporary as a result
  of
• one or more of the following factors
  exposure to drugs,
• dietary factors, radiation, high fever, or
  stress.
• Thinning of the hair, called alopecia can occur
  in both
• sexes, usually as a result of aging.

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• Exocrine Glands of the Skin
• Sweat (sudoriferous) glands produce a watery
• solution that performs several specific
  functions.
• merocrine (eccrine) sweat glands
• apocrine sweat glands
• Sebaceous glands produce an oily material that
  coats
• hair shafts and the epidermal surface.

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• Other Integumentary Glands
• Ceruminous glands
• Mammary glands
• modified apocrine sweat glands

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• Burns
• Major cause of accidental death, primarily as
• a result of their effects on the skin.
• Usually caused by heat, radiation, harmful
• chemicals, sunlight, or electrical shock.
• The immediate threat to life results primarily
• from fluid loss, infection, and the effects
  of
• burned, dead tissue.
• Burns are classified according to the depth of
• tissue involvement.

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• Classification of Burns
• First- and second-degree burns are called
  partial-
• thickness burns.
• Third-degree burns are called fullthickness
  burns.
• First-degree burns involve only the epidermis
  and are
• characterized by redness, pain, and slight
  edema
• an example is sunburn

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• Classification of Burns
• Second-degree burns involve the epidermis and
  part
• of the dermis.
• The skin appears red, tan, or white, and is
  blistered
• and painful.
• An example is a scald.

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• Classification of Burns
• Third-degree burns involve the epidermis,
  dermis,
• and subcutaneous layer, which are often
  destroyed.
• Regeneration may occur from the edge only, due
  to
• the absence of dermis.
• Skin grafting is required to prevent abnormal
• connective tissue fibrosis and disfigurement.
• Dehydration is a major concern because the
  entire
• portion of skin has been lost, and water
  cannot be
• retained.
• Must be aggressively treated for dehydration.

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• Aging of the Integument
• Skin repair processes take longer due to reduced
  
• number and activity of stem cells.
• Skin forms wrinkles and becomes less resilient.
• Skins immune responsiveness is diminished.
• Skin becomes drier due to decreased sebaceous
  gland
• activity.
• Altered skin and hair pigmentation.

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• Aging of the Integument
• Sweat production diminishes.
• Blood supply to the dermis is reduced leading to
  impaired
• thermoregulation.
• Hair thinning and loss.
• Integumentary production of vitamin D3
  diminishes.
• Development of skin cancers.

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• Skin Cancer
• The most common type of cancer.
• The greatest risk factor is exposure to
• UV rays of the sun.
• The highest incidence is in people who
• have had severe sunburns, especially as
• children.