Ch05 Integumentary

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Human Anatomy, First EditionMcKinley & O'Loughlin

Chapter 5 Lecture Outline:

Integumentary System


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The Integument The skin that covers your body.

Skin is also known as the cutaneousmembrane.

Integumentary system consists of theskin 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 resilienceto the skin.

Smooth muscle controls both blood vessel diameterand hair position.

Neural tissue supports and monitors sensoryreceptors in the skin


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2 Distinct LayersA layer of stratified squamous

epithelium called the epidermis.

A deeper layer of dense irregularconnective tissue called the dermis.

deep to the dermis is a layer of areolar and

adipose connective tissue called thesubcutaneous 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 fingersand 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: hairfollicles, 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 redcolor.

Melanin is a pigment produced and stored incells 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 offriction ridges.

Fingerprints have become a valuable

tool for law enforcement in identifyingindividuals.


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Skin Markings Nevus (mole)

Freckles

Hemangioma

capillary hemangiomas (strawberry-colored birthmarks)

cavernous hemangiomas (port-winestains)


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Layers of the Dermis Composed of cells of the connective

tissue proper and primarily of collagen

fibers, although both elastic andreticular fibers are also present.

Other components of the dermis are

blood vessels, sweat glands, sebaceousglands, hair follicles, nail roots, sensorynerve 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 thepredominant orientation of collagen fiber

bundles. Clinically and surgically significant because

cuts can result in slow healing and increasedscarring.


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Innervation and Blood Supply

The dermis has extensive innervation.

Monitor sensory receptors in the dermis andepidermis, and control both blood flow and gland

secretion rates. Tactile corpuscles and tactile (Merkel) cells perceive

touch sensations, and work with a variety of othersensory nerve endings in the skin.

This rich innervation allows us to be very aware ofour surroundings and to differentiate among thedifferent kinds of sensory signals from receptors inthe skin.


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Nails

Scalelike modifications of the epidermisthat form on the dorsal surfaces of the

tips of the fingers and toes. Protect the exposed distal tips and

prevent damage or distortion duringjumping, kicking, catching, or grasping.

Hard derivatives formed from thestratum corneum layer of the epidermis.


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Hair

Found almost everywhere on the bodyexcept the palms of the hands, the

sides and soles of the feet, the lips, thesides of the fingers and toes, andportions of the external genitalia.

Most of the hairs on the human bodyare on the general body surface ratherthan the head.


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3 Kinds of Hair

During our lives, we produce threekinds of hair:

lanugo

vellus

terminal hair


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Functions of Hair

Protection

Heat retention

Prevents the loss of conducted heat from thescalp 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 thematrix adjacent to the papillae.

Variations in hair color reflect geneticallydetermined differences in the structure of themelanin.

Environmental and hormonal factors

Age Gray hair


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Hair Growth and Replacement

Sometimes hair loss may be temporaryas a result of one or more of the

following factors: exposure to drugs,dietary factors, radiation, high fever, orstress.

Thinning of the hair, called alopecia canoccur in both sexes, usually as a resultof aging.


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Exocrine Glands of the Skin

Sweat (sudoriferous) glands produce awatery 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 epidermalsurface.


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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 asa result of their effects on the skin.

Usually caused by heat, radiation, harmfulchemicals, sunlight, or electrical shock.

The immediate threat to life results primarilyfrom 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 arecalled partial-thickness burns.

Third-degree burns are called full-thickness burns. first-degree burns involve only the

epidermis and are characterized byredness, pain, and slight edema an example is sunburn


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Second-degree burns involve theepidermis and part of the dermis.

The skin appears red, tan, or white, andis blistered and painful.An example is a scald.


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Third-degree burns involve the epidermis, dermis,and subcutaneous layer, which are often destroyed.

Regeneration may occur from the edge only, due tothe absence of dermis.

Skin grafting is required to prevent abnormalconnective tissue fibrosis and disfigurement.

Dehydration is a major concern because the entireportion of skin has been lost, and water cannot beretained.

Must be aggressively treated for dehydration.


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Aging of the Integument

Skin repair processes take longer due toreduced number and activity of stem cells.

Skin forms wrinkles and becomes lessresilient.

Skins immune responsiveness is diminished.

Skin becomes drier due to decreasedsebaceous 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 D3diminishes.

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 whohave had severe sunburns, especially as

children.

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Ch05 Integumentary