Chapter 3: Integumentary System

3 types of fibers in the dermis

collagen fibers elastin fibers reticular fibers

What is the proximal nail fold that projects over the nail body called?

cuticle

hair bulb

deep end of follicle which is expanded

nail bed

deep layers of the epidermis that extend beneath the nail

flexure lines

dermal folds occurring at or near joints where dermis is secured - skin does not slide so skin creases form

2 types of sweat glands

eccrine apocrine

Cleavage lines

* collagen fibers that run parallel to the skin surface * run circular around the trunk & longitudinally in the limbs * surgical incisions are made parallel to these lines - less chance of scarring

Merkel cellls

* found at the epidermal-dermal junction * attached to a sensory nerve ending

dermal papillae

* nipple-like projections formed by superior surface of papillary layer

what is the purpose of the dermal papillae

* produce epidermal ridges that increase friction and enhance gripping * sweat pores opening in crest, films of sweat referred to as fingerprints can be left

keratinocytes

* produce keratin * arise from basal layer of epidermis * when they reach the apical surface, they are dead cells that are totally keratin * totally new epidermis every 25-45 days

melanocytes

*synthesize the pigment melanin * are found in the basal layer of the epidermis * have branching processes that touch all the keratinocytes * keratinocytes ingest the melanin pigment - it accumulates on the sunny side of the keratinocyte nucleus forming a shield that protects the DNA in the nucleus from UV radiation

sweat glands

- also known as sudoriferous glands - this type of gland is a merocrine gland (they secrete sweat by exocytosis without damage to the gland itself)

squamous cell carcinoma

- arise from keratinocytes of stratum spinosum - grows rapidly and can metastasize, spreading to lymph nodes

malignant melanoma

- cancer of the melanocytes - most dangerous skin cancer - begins wherever there is pigment

sebaceous (oil) glands

- holocrine gland (inner cells fill with lipids and cell fragments until they rupture) - found all over the body except on palms & soles - secrete sebum, which softens & lubricates hair & skin - stimulated by hormones during puberty

basal cell carcinoma

- least malignant form of skin cancer - most common form of skin cancer - occurs in stratum basale - grows slowly and seldom metastasizes

eccrine sweat glands

- primary function is thermoregulation - 99% water solution that contains few salts - secreted on to skin surface via pores - cause heat-induced & emotionally-induced sweating

melanin

- produced by melanocytes - racial differences reflect the kind & amount of this pigment that is made - local accumulations form freckles & moles

apocrine sweat glands

- secretion similar to eccrine but contains proteins and fatty substances on which bacteria thrive - begin to function at puberty because of hormones - activated by stress and sexual foreplay

hemoglobin

- this oxygenated pigment gives pinkish hue to fair skin - fair skin only contains small amounts of melanin thus allowing this pigment's color to show through

carotene

- yellow to orange pigment found in plant products such as carrots - accumulates in the stratum corneum and hypodermis - most obvious in the palms and soles - can be intense when large amounts of carotene-rich foods are eaten

ABCD rule

Asymmetry Border irregularity Color Diameter

melanin air bubbles

Gray or white hair has decreased ____ production and replacement of melanin by ______.

melanocytes

Hair pigment is produced by ______ at the base of the hair follicle.

Hair follicles

_____ ______ extend from the epidermal surface into the dermis.

Burns pose an immediate threat to life because of loss of ____ _____.

body fluid

3 parts of a hair follicle

bulb root hair plexus arrector pili muscle

The stratum basale is also called the stratum germinativum, a name that refers tot he major function of this cell layer. What is that function?

cells germinate in this layer

where is vellus hair found?

child & female body hair

alopecia

coarse terminal hairs replaced by vellus (less dramatic in women)

third degree burns

entire thickness of skin is damaged burned area may appear blackened - not painful because of no nerve endings

second degree burns

epidermis & upper region of the dermis is damaged redness, swelling, pain, blisters

first degree burns

epidermis is damaged redness, swelling, and pain occur most sunburns

3 major layers of the skin

epidermis, dermis, hypodermis

Hair follicles, oil, and sweat glands are derived from _______ tissue but reside in the dermis.

epithelial

where is thin skin found in the body?

everywhere except for palms, fingertips, and soles of feet

where is terminal hair found?

eyebrows, scalp, axillary, pubic, male body hair

4 cell types in the dermis

fibroblasts macrophages mast cells white blood cells

where does heat-induced sweating begin?

forehead and spreads

hard

hair consists largely of dead keratinized cells containing _____ keratin

hair & nails contain ____ keratin

hard

Rule of Nines

in adults, the volume of fluid lost can be estimated by computing the percentage of body surface burned - this method divides the body into 11 areas, each accounting for 9% of total body area with additional 1% of body surface area around genitals

After initial crisis of a burn has passed, then ______ becomes the main threat.

infection

Langerhans cells

macrophages that help to activate the immune system

3 concentric layers of keratinized cells

medulla - central core cortex - layer surrounding medulla cuticle - outermost layer

3 pigments that contribute to skin color

melanin carotene hemoglobin

The dermis is richly supplies with what 3 things?

nerve fibers blood vessels lymphatic vessels

sweat glands are found over the entire skin except with 2 locations?

nipples external genitalia

sebaceous glands are not found in thick skin. why is their absence in those body regions desirable?

no slipping or dropping stuff

2 factors that affect hair growth

nutrition hormones

what causes seborrhea (cradle cap)?

overactive oil glands

where is thick skin found in the body?

palms, fingertips, soles of feet

where does emotionally-induced sweating begin?

palms, soles, axillary areas & spreads

2 major layers of the dermis

papillary reticular

root

part of hair imbedded in the skin shape of shaft determines whether hair is straight or curly

shaft

part of hair that projects from skin

keratin

protein that has protective properties

nail folds

proximal and lateral borders of the nail

nail matrix

proximal portion of the nail bed responsible for nail growth

what is the role of the arrector pili muscle?

pulls hair upright?

Cleavage lines, striae, blisters, and flexure lines occur in the ______ layer of the dermis.

reticular

which cutaneous glands are associated with hair follicles?

sebaceous

root hair plexus

sensory nerve ending that wraps around each hair bulb

Merkel disc

sensory receptor for touch composed of Merkel cell + sensory nerve ending

blister

separation of the epidermal and dermal layers by fluid filled pockets

2 main regions of hair

shaft root

List the parts of the integumentary system.

skin, hair, nails, sweat & oil glands

arrector pili muscle

smooth muscle cells that contract & pull the hair follicle into an upright position and dimples skin surface

The cuticle wears away allowing the cortex and medulla to frizz, creating what?

split ends

the epidermis is composed of ________ tissue

stratified squamous epithelium

Striae

stretch marks caused by tearing of the dermis

define hypodermis and its 2 functions

subcutaneous tissue deep to the skin which is composed of adipose tissue Functions: 1. stores fat, 2. anchors the skin to the underlying structure

free edge

tip of nail

male pattern baldness

true baldness, genetically determined and sex-influenced

2 types of hair

vellus terminal

(nail) body

visible attached portion of the nail

lunula

white crescent region that lies over the nail matrix - nails normally appear pink because of underlying capillaries

3 types of skin cancer

1. basal cell carcinoma 2. squamous cell carcinoma 3. malignant melanoma

3 major components that form the dermis

1. cells 2. matrix 3. fibers

4 cell types in the epidermis

1. keratinocyte 2. melanocyte 3. Langerhans cells 4. Merkel cells

2 advantages of hard keratin over soft keratin

1. more durable 2. individual cells do not flake off

4 layers of the epidermis in thin skin (superficial to deep)

1. stratum corneum 2. stratum granulosum 3. stratum spinosum 4. stratum basale (germanitivum)

5 layers of the epidermis in thick skin (superficial to deep)

1. stratum corneum 2. stratum lucidum 3. stratum granulosum 4. stratum spinosum 5. stratum basale (germanitivum)

3 burn classifications

1st degree 2nd degree 3rd degree

papillary layer composes ___% of dermis and reticular layer composes ____%.

20% 80%