CHAPTER 4

SKIN

and

BODY MEMBRANES

CHAPTER 4 VOCABULARY 4A

body membranes pericardiumcutaneous membranes peritoneumdermis pleuraepidermis serous fluidepithelial membranes stratum basaleIntegument stratum corneumintegumentary system stratum lucidumkeratin subcutaneous tissue/hypodermismelanin synovial membranesmelanocytes

CHAPTER 4 VOCABULARY4B

acne medulla

apocrine glands Meissner's corpuscles

arrector pili nail

athlete's foot papillary layer

cold sores psoriasis

cuticle reticular layer

decubitus ulcers sebaceous glands

dermal papillae seborrhea

eccrine glands sebum

impetigo sudoriferous glands

Color Sheet Color Code-plate 104Stratum corneum – red shaft – light blue

Stratum lucidum – orange follicle – dark green

Stratum granulosum – yellowyellow bulb of follicle - tan

Stratum spinosum – light greenlight green matrix - lavendar

Stratum basale – blue dermal papilla - aquaaqua

Connective tissue – pinkpink arrector pili – dark pink

Papillae – purple sebaceous gland - goldgold

Nerve – gray sweat gland - green

Artery – dark blue superficial fascia –

Vein – orange peach/fleshpeach/flesh

Lymphatic vessel – brown

Color Code – Plate 105Epidermis – red

Dermis – pink

Superficial fascia – peach

Pain Free Nerve Endings – orange

Touch Merkel’s Discs Meissner’s Corpuscles Root Hair Plexuses – yellowyellow

Pressure Pacinian Corpuscles – green

Cold Krause Corpuscles – blue

Heat Ruffini Corpuscles - purple

I. Body Membranes

A. cover surfaces

line body cavities

form protective sheets around organs

B. classified into:

1. Epithelial membranes

2. Connective tissue membranes

II. Epithelial membranes

A. include:

cutaneous membrane (skin)

mucous membranes

serous membranes

B. Cutaneous Membrane

1. Superficial layer epidermis

2. Underlying(deep) layer dermis

C. Mucous Membranes

1. composed of epithelium resting on a loose conn. tiss. membrane called a

lamina propria

2. type of epithelium varies with the site

3. lines all body cavities that open to the exterior

4. lines hollow organs of the resp., dig., and reprod. tracts

D. Serous Membranes

1. simple squamous epithelium resting on a thin layer of areolar conn. tiss.

2. line body cavities that are closed to the exterior

3. occur in pairs:

a. parietal layer – lines a specific portion of the wall of the

ventral body cavity

b. visceral layer – covers the outside of the organs in that cavity

4. Specific name depends on location

a. peritoneum – lines abdominal cavity and covers its

organs

b. pleura – surround the lungs

c. pericardium – around the heart

5. Name examples:

a. parietal pleura – line the body cavity around the lungs

b. visceral pleura – covers the outside of the lungs

III. Integumentary System

A. skin, hair, nails, sweat & oil glands

B. cutaneous membranes skin

C. functions:

1. keeps H2O & other molecules in

2. keeps H2O & other things out (can swim and not get waterlogged)

The above is possible due to keratin

3. regulates heat loss from body surface (due to capillary network and sweat glands)

4. synthesizes vitamin D (modified cholesterol in skin is converted by sunlight)

D. structure of skin (pg. 112, 113)

1. composed outer epidermis firmly connected to underlying dermis

2. Subcutaneous tissue

a. also called hypodermis

b. deep to the dermis

c. serves as a shock absorber

E. Epidermis

1. avascular

2. layers: (from inner to outer)

a. stratum basale

*deepest cell layer

*where millions of new cells are

produced daily

*also called stratum germinativum

b. stratum spinosum – next layer

c. stratum granulosum – 3rd layer

d. stratum lucidum

*layer in wh/ cells b/c flatter, increasingly full of keratin

and finally die

*not seen in all skin regions (only where skin is hairless

and extra thick – palms and soles)

e. stratum corneum

*outermost layerA totally new epidermis occurs every 25-45 days

3. melanin

a. pigment in skin

b. ranges from yellow to brown to black

c. produced by melanocytes

(found in stratum basale)

d. a natural sunscreen

F. Dermis

1. makes up mj. portion of skin

2. made of dense (fibrous) c.t. consisting of 2 regions:

a. papillary

b. reticular

3. papillary layer

a. upper dermal region

b. has fingerlike proj. of dermis into the epidermis dermal papillae

c. many contain capillary loops

(furnish nutrients to epidermis)

d. house receptors:

*pain – free nerve endings

*touch – Meissner’s corpuscles

e. papillae form fingerprints

4. reticular layer

a. deepest skin layer

b. contains:

*blood vessels

*sweat glands

*oil glands

*deep pressure receptors

Pacinian corpuscles

G. skin appendages

1. sebaceous glands (oil glands) pg. 117

a. found all over the skin except palms and soles

b. product sebum (a lubricant)

*keeps skin soft & moist

*prevents hair from b/cing brittle

*contains chemicals that kill bacteria

c. b/c active when male sex hormones are prod. in increasing amts. (in both sexes)

2. sudoriferous glands(sweat glands) pg. 117

a. 2 types:

*eccrine glands

*apocrine glands

b. eccrine glands

*> #ous, found all over body

*produce sweat

*imp. & highly efficient part of body’s heat-regulating equipment (thermoregulators)

c. apocrine glands

*found in axillary & genital areas

*product fatty acids & proteins wh/ empty

i/t hair follicles

*minimal role in thermoregulation

3. hair (pg. 118, 119)

a. minor protective functions

b. composed primarily of dead keratinized cells

c. hair follicles

*produce hair

d. root

*part of hair enclosed in follicle

e. matrix

*÷ to form hair cells

f. layers of a hair

1) medulla

central core

2) cortex

surrounds medulla

3) cuticle

*outermost layer that encloses cortex

*single layer of overlapping cells (roof shingles)

*most heavily keratinized region

g. hair follicle structures

1) epidermal sheath

*inner part

2) dermal sheath

*outer part

3) arrector pili

*small bands of smooth muscle cells

*connect to ea. side of hair follicle

*contraction hair to be pulled upright forming “goose bumps”

(helps keep animals warm)

4. nails (pg. 120)

a. modification of epidermis

b. nail matrix

*thickened proximal area

*responsible for nail growth

c. transparent & colorless

(appear pink b/c of rich blood supply in underlying epidermis)

d. lunula

*area of thickened nail matrix

*appears as a white crescent

IV. Skin Conditions/Infections/Allergies

A. decubitus ulcers (pg. 116)

1. also called bedsores

2. occur in bedridden patients that are not turned regularly

3. weight of body puts pressure on skin

Decubitus ulcers (bedsores)

B. acne

active infection of the sebaceous glands accompanied by pimples

C. Seborrhea

1.overactivity of sebaceous glands

2.forms a yellow to brown crust that sloughs off as dandruff

D. athlete’s foot

fungal infection b/t toes

E. boils

inflammation of hair follicles and sebaceous glands

Boil

Carbuncle

Acne

Seborrhea

Athlete’s foot

F. cold sores (pg. 121 pic. A)

1.fluid-filled blisters, itch and sting 2.caused by herpes simplex infection

G. impetigo (pg. 121 pic. B)

1.H2O-filled lesions around nose & mouth

2.caused by staphylococcus infection

H. psoriasis (pg. 121 pic. C)

overprod. of skin cells dry, silvery scales

impetigo

psoriasisCold sores

I. Burns (pg. 122)

a. 2 life-threatening problems may occur:

1.dehydration & electrolyte imbalance

2. kidney shutdown & circulation shock

b. 1st degree burns

1. only epidermis is damaged

2. temporary discomfort, heals in 2-3 days

c. 2nd degree burns

1. damage to epidermis & upper dermis

2. red, painful, blisters appear

3. regrowth of epithelium can occur; usu. no permanent scars

1st & 2nd degree burns are partial-thickness burns

d. 3rd degree burns

1. destroy entire thickness of skin

2. full-thickness burns

3. since nerve endings are destroyed burned area is not painful

4. regeneration not possible skin grafting is necessary

1st degree burns

2nd degree burns

3rd degree burns

J. Skin Cancer

1. basal cell carcinoma (pg. 123 A)

a. < malignant, > most common

b. malignancy of the lowest epidermal layer

2. squamous cell carcinoma (pg.123B)

a. involves cells of stratum spinosum

b. believed to be sun-induced

3. malignant melanoma(pg. 123C)

a. cancer of melanocytes

4. ABCD rule for melanoma:

A-asymmetry

B-border irregularity

C-color (areas of diff. colors)

D-diameter (> 6mm)

Basal Cell Carcinoma

Squamous Cell Carcinoma

Melanoma

K. aging

1. amt. of subcut. tissue decreases

causes intolerance to cold

2. oil prod. decreases drier skin

3. thinning of skin > bruising

4. decrease in skin elasticity bags under eyes, sagging jowls

(sped up with smoking & sun)

5. reduction in # of hair follicles

hair thinning/balding (alopecia)