Exercise 7- The Integumentary System

The accessory organs of the skin

1. Cutaneous glands 2. Hair 3. Nails

Two distinct regions of the skin

1. Epidermis 2. Dermis

Two primary regions of hair

1. Hair shaft 2. Hair root

Two dermis regions

1. Papillary layer 2. Reticular layer

Two primary categories of cutaneous glands

1. Sebaceous (oil) glands 2. Sweat (sudoriferous) glands

Five layers of epidermis

1. Stratum Basale 2. Stratum Spinosum 3. Stratum Granulosum 4. Stratum Lucidum 5. Stratum Corneum

Hair bulb

A collection of well-nourished epithelial cells at the base of the hair follicles.

Keratin

A fibrous protein that gives the epidermis its durability and protective capabilities.

Epidermis

A keratinized stratified squamous epithelium consisting of four distinct cell types and four to five distinct layers.

Sebum

A mixture of oily substances and fragmented cells that acts as a lubricant to keep the skin soft and moist and keeps the hair from being brittle.

Stratum Basale (basal layer)

A single row of cells immediately above the dermis. Its cell are constantly undergoing mitosis to form new cells.

Hair Follicle

A structure formed from both epithelial and dermal cells.

Stratum Granulosum (granulosum layer)

A thin layer named for the abundant granules its cells contain.

Acne

Acne is an active infection of the sebaceous glands.

Blackheads

An accumulation of dried sebum bacteria, and melanin from epithelial cells in the oil duct.

(Eccrine/Apocrine) glands are found primarily in the genital and axillary areas

Apocrine

_________ is a yellow-orange pigment found in the stratum corneum and the hypodermic. A. Keratin B. Carotene C. Melanin D. Hemoglobin

B. Carotene

Melanin

Brown-to-black pigment; Provides a protective pigment umbrella over the other layers of the epidermis.

These cells produce a brown-to-black pigment that colors the skin and protects DNA from ultraviolet radiation damage. These cells are: A. Dendritic cells B. Keratinocytes C. Melanocytes D. Tactile cells

C. Melanocytes

The portion of a hair that projects from the scalp surface is known as the: A. Bulb B. Matrix C. Root D. Shaft

D. Shaft

All of the following are functions of the skin except: A. Excretion body wastes B. Insulation C. Protection from mechanical damage D. Site of vitamin A synthesis

D. Site of vitamin A synthesis

The most superficial layer of the epidermis is the: A. Stratum Basale B. Stratum Spinosum C. Stratum Granulosum D. Stratum Corneum

D. Stratum Corneum

Reticular Layer

Deepest layer of skin.

The skin has two distinct regions. The superficial layer is the _____________ and the underlying connective tissue is the ________________.

Epidermis; Dermis

Sweat (sudoriferous) glands

Exocrine glands that are widely distributed all over the skin; Outlet known as pores.

Nail bed

Extension of the stratum basle beneath the nail.

Dermal Papillae

Fingerlike projections from its superior surface which attach to the epidermis layer and produce fingerprints.

Thick skin of the epidermis contains _____ layers.

Five 1. Corneum 2. Lucidum 3. Granulosum 4. Spinosum 5. Basale

Sebaceous (oil) glands

Found nearly all over skin; Their ducts usually empty into a hair follicle, but some open directly on the skin surface; Produce sebum.

Apocrine sweat glands

Found predominantly in the axillary and genital area; Secrete the basic components of eccrine sweat plus proteins and fat-rich substances; Produce B.O.

Eccrine sweat glands

Gland that produce clear perspiration consisting primarily of water, salts, and urea; Heat-regulating apparatus

Nails

Hornlike derivatives of the epidermis.

Hypodermis (superficial fascia)

Immediately deep to the dermis; Not considered part of the skin; Primarily consists of adipose tissue.

Keratinocytes

Keratin cells; Most abundant epidermal cells; Main function is to produce keratin fibrils.

Hair matrix

Layer of actively dividing epithelial cells that is located on tip of the hair papilla.

Tactile (Merkel) cells

Occasionally spiky hemispheres that, in combination with sensory nerve endings, form sensitive touch receptors called Tactile of Merkel discs located at the epidermal-dermal junction.

Skin

Organ that insulates and cushions the underlying body tissues and protects the entire body from abrasion, exposure to harmful chemicals, temperature extremes, and bacterial invasion.

Stratum Lucidum (clear layer)

Present only in thick skin. A very thin transparent band of flattened, dead keratinocytes with indistinct boundaries.

Eponychium

Projection of the thick proximal nail fold commonly called the cuticle.

Hair shaft

Region of the hair projecting from the skin.

Hair root

Region of the hair that is beneath the surface of the skin and is embedded within the hair follicle.

The ducts of (sebaceous/sweat) glands usually empty into a hair follicle but may also open directly on the skin surface.

Sebaceous

Stratum Spinosum (spiny layer)

Several layers of cells that contain thick, weblike bundles of intermediate filaments made of a pre-keratin protein; Cells appear to be spiky

Nail folds

Skin folds that overlap the borders of the nail.

Arrestor pili muscle

Small band of smooth muscle cells connect each hair follicle to the papillary layer of the dermis; Causes goosebumps

Melanocytes

Spidery black cells that produce melanin.

Papillary layer

The more superficial dermal region composed of areolar connective tissue.

Stratum Corneum (horny layer)

The outermost layer consisting of 20-30 layers of dead, scalelike keratinocytes.

Nail root

The part that is embedded in the skin and adheres to an epithelial nail bed.

Free edge

The portion of the nail that grow out away from the body.

Lunule

The proximal region of the thickened nail matrix, which appears as a white crescent moon.

Hyponychium

The region beneath the free edge of the nail

Nail matrix

The thickened part of the nail bed containing germinal cells responsible for nail growth.

Nail body

The visible attached portion.

True/False. Nails originate from the epidermis.

True