Chapter 5 Integumentary System

Integument

Is the skin that covers human body also knon cutaneous membrane

Intergumentary System

Is the skin and It’s derivatives (nails, hair, ang glands)

The skin has 3 types

Epidermis, Dermis, Hypodermis] (fatty tissue)

Keratinized stratifieed squamous epithelium

The epithelium of the epidermis is

Avascular

Without blood vessel in epidermis

Strata

manyy layers

Stratum

One layer

Epidermis layers from superficial to deep

•Stratum corneum.

•Stratum Lucidum (found only in thick skin).

•Stratum Granulosum.

•Stratum Spinosum.

•Stratum Basale.

Thick Skin

contains five layers in epidermis (includes stratum lucidum)

•Found in palms of hands and soles of feet.

•Epidermis is 0.4–0.6 mm thick.

•No hair follicles or sebaceous glands.

Thinn skin

•lacks stratum lucidum—has four layers in epidermis.

•Covers most of body.

•Epidermis is 0.075–0.150 mm thick.

Hemoglobin

blood pigment; red in color

Melanin

pigment produced by melanocytes.

•Increases with exposure to ultraviolet radiation.

•All people have about same number of melanocytes.

Carotene

yellow-orange pigment from foods such as carrots; it builds up in the skin

Melanocytes

are special cells in your skin that produce melanin, the pigment that gives your skin, hair, and eyes their color.

Albinism

Hair is white, skin is pale, irises of eyes are pink

Bronzing

Skin appears golden-brown, copper, or bronze in color.

Cyanosis

•Skin appears bluish because of oxygen deficiency in circulating blood.

Erythema

Skin appears abnormally red.

Hematoma

A bruise (visible pool of clotted blood) is observable through the skin.

Jaundice

Skin and sclera (white of the eyes) appear yellowish.

Pallor

Skin appears pale due to white collagen fibers housed within the dermis.

Dermis

•Lies deep to the epidermis.

•Composed of areolar and dense irregular connective tissues.

Two layers of dermis

Papillary layer and reticular layer

Papillary layer

is the superficial region of the dermis directly adjacent to the epidermis.

composed of areolar connective tissue

Areolar Connective Tissue

is a type of loose connective tissue that acts like a soft, flexible “packing material” in your body

Dermal Papillae

are projections of the dedrmis toward the epidermis

contain capillaries that supply nutrients to the epidermis and  contain sensory receptors

Reticular layer

is the deeper region of the dermis that forms most of its thickness.

•Comprised mainly of dense irregular connective tissue.

•Large collagen bundles project in all directions.

•Includes many blood vessels, glands, hair follicles, and nerves.

Nerve fibers

are extensively dispersed in dermis

Innervation

hen nerves go to tissue or organ and control it.

i.Monitor sensory receptors.

ii.Control blood flow.

iii.Control glandular secretion.

Dermal Blood vessel

Help control body temperature and blood pressure

Vasoconstriction

(narrowed diameter of vessels) reduces blood flow to skin, helps conserve heat.

Vasodilation

(widening diameter of vessels) increases blood flow to skin, helps release heat.

Hypodermis (GK)

Below the skin

Subcutaneous (Latin)

Below the skin also called superficial fascia

Fascia

•band, in anatomy sheet of areolar connective tissue and adipose cells

Hypodermis

Storing energy.

Connecting the dermis layer of skin to muscles and bones.

Insulating and protecting body from harm. 

Different pattern of accumulation (male & female) and as age hypodermis decreases in size, and skin starts to sag.

Structures that are epidermal derivatives include:

Nails, Hair, Exocrine glands of the skin

Nails

Scalelike modifications of the stratum corneum

Nail plate

has a whitish free edge

Nail body

a pinkish

Nail root

Covered by the skin

Nail bed

nail body covers a layer of epidermis called the

Nail matrix

thickened growing part of the nail bed.

Lunula

white semilunar proximal area of nail body caused by thickened underlying stratum Basale obscuring capillaries in dermis.

Nail folds

overlap the lateral and proximal edges.

Eponychium (cuticle)

•is a narrow band of epidermis that extends from the margin of the nail onto the nail body.

hyponychium

is a region of thickened stratum corneum over which the free edge of the nail projects.

3 Types of hair

Lanugo, vellus, terminal hair

Lanugo

Found on fetus

Vellus

Fine and non pigmented, on most of the body

Terminal hair

Coarse and pigmented, thick adult hair

Pilus

consists of keratinocytes growing from follicles deep in dermis (often projecting to subcutaneous layer).

Keratinocytes

produce keratin and form the skin’s protective outer layer

Folliles

Small structure in the dermis that produces and support the growth hair

Hair bulb

deep swelling of epithelial cells where hair originates.

Hair root

portion that is deep to skin surface.

Hair shaft

portion that extends beyond skin surface.

skin contains two types of exocrine glands

Sweat (sudoriferous) glands and Oil (Sebaceous Glands)

Sweat sudoriferous glands has two types:

Merocine and apocrine

Sweat Glands

•Have coiled, tubular secretory portion in reticular layer of dermis or in subcutaneous layer.

•Produce watery solution.

Sebaceous Glands

•Holocrine glands that secrete oily sebum into hair follicles or directly onto skin surface.

Lubricaion

prevents drying of hair and skin.

Relatively inactive during childhood; sex hormones at puberty cause secretions to increase significantly