EXAM 2 (ch. 5-8) - Dr. Jones

epidermis

outermost protective shield of body

epidermis

which layer of the skin consists of epithelial and is avascular?

dermis

underlies epidermis and makes up the bulk of the skin (middle section)

-Recticular layer - dense irregular connective tissue

dermis

which skin layer is mostly dense connective tissue and vascular

subcutaneous tissue

layer that is also called hypodermis or superficial fascia with mostly fat tissue and some areolar connective tissue

subcutaneous tissue

loosely anchors skin to underlying structures, mostly mucles

-act as shock absorption and insulation

keratinocytes, melanocytes, dendritic cells/ langerhans cells, tactile epithelial cells/ merkel cell

what are the 4 cell types of the epidermis?

keratinocyte

produce fibrous protein in keratin (strong, flexible)

-protein found abundantly in outermost layer of epidermal cells

melanocyte

produce brown pigment (melanin)

dendritic cell / langerhan cell

epidermal macrophages that help activate immune system (eg. the local cop); patrol deep epidermis

tactile epithelial cells / merkel cells

function as touch receptors (nerve endings), located at epidermal-dermal junction

stratum corneum, stratum granulosum, stratum spinosum, stratum basale

what are the 4 thin layers of the epidermis? (start from top to bottom)

stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale

what are the 5 thick layers of the epidermis? (start from top to bottom)

stratum lucidum

what is the main layer difference between thin and thick epidermis?

stratum corneum

which layer are dead skin cells laid at?

stratum corneum

which epidermal layer protects from abrasion and penetration, acting as a barrier against biological, chemical, and physical assaults? (thickest of epidermal layer)

stratum granulosum

what epidermal layer does keratinization begin?

(also known as point of no return… above this layer cells die)

stratum spinosum

known as the prickly/spiny layer which allows skin to resist tension and pulling

stratum spinosum

which layer are langerhan’s cells (dendritic cell) staying at?

stratum basale

deepest of all epidermal layers, consisting of a single row of stem cells which actively divide

stratum basale

what is the stratum basale layer also known as becaus of active mitosis?

stratum corneum

“horny layer”, outermost layer of keratinized cells

papillary layer

20% in dermis layer of skin. areolar connective tissue with collagen + elastic fiber, convoluted layer to hold tightly together

dermal papillae

superficial region of dermis that sends fingerlike projections up into the epidermis so dermis and epidermis connects

dermal papillae

contain capillary loops, Meisner corpuscle (touch nerves) and free nerve endings

free nerve ending

temperature, and pain receptors. used as a warning system. contain meisener’s corpuscle touch cell

friction ridges, cleavage lines, flexure lines

what are the 3 dermal modifications?

friction ridges

occur in thick skin, dermal papillae lie on top of dermal ridges (which give rise to epidermal ridges)

friction ridges

-enhance grip ability
-contribute to sense of touch
-sweat pores in ridges leave unique finger print

reticular dermis

makes up of dermal thickness; consists of coarse, dense irregular tissue

-elastic fibers provide stretch-recoil properties

-collagen fibers provide strength and resiliency

-bind water, keeping skin hydrated

dermal vascular plexus

organization of blood vessels between reticular layer and subcutaneous tissue

cleavage (tension) lines

lies in reticular layer caused by many collage fibers running PARALLEL to skin surface.

-externally invisible

-important to surgeons b/c incisions parallel to these lines heal better

-cesarean section (C-SECTION)

flexure lines

in reticular layer are dermal folds at or near joints.

-dermis tightly secured to deeper structures

-visible on hand, wrists, fingers, soles, toes

-for easy movement

striae

dermal tears known as “stretch marks”

blisters

fluid-filled pockets that separate epidermal and dermal layers

melanin

made by melanocytes

-freckles and moles locally accumulate these

-protection from uv light

-reddish yellow to brownish black

carotene

-on palms and soles

-convert for vitamin A for vision and epidermal health
-accumulate at stratum corneum and hypodermis
-yellow orange pigment

hemoglobin

-pinkish hue of fair skin due to lower levels of melanin

-in Caucasians more transparent

-red blood cell

cyanosis

blue skin color; low oxygen of hemogoblin

pallor

blanching or pale color: anemia, low blood pressure… blood not following enough in specific area

erythema

redness, fever, hypertension, inflammation, allergy

juandice

yellow cast; liver disorder (protein bilirubin in liver accumulate in blood so you turn yellow)

hematoma

clotting of escaped blood from circulation (bruising)

hyperpigmentation

brown or black patches, thickened skin folds may be a sign of endocrine disorder

hair root

Embedded into skin

hair shaft

sticks up and out that you can see

hair

consists of dead, keratinized cells; none located on palms, soles, lips, nipples, and portions of external genitalia

arrector pili

smooth muscle attached to follicle; responsible for “goosebumps”

vellus

hair type:
pale, fine body hair usually found on females and children

terminal

hair type:
coarse long hair of eyebrows, scalp, axillary, pubic regions

(nutritions and hormones can affect hair growth)

nails

act as protective covers for tips of fingers and toes

sweat glands / sudoriferous glands

control body temperature

eccrine (merocrine) gland

what is the sweat gland?

Function: temp ctrl, antibacteral property, slightly acidic
secretion exit to skin surface

eccrine (merocrine) gland

what is the sweat gland?

Location: everywhere but especially on palms, soles, forehead

apocrine gland

what is the sweat gland?
Function: act as sexual scent gland, secretes viscous milky or yellowish sweat that contains fatty substances and proteins.

-bacteria breaks down fat in the sweat

apocrine gland

what is the sweat gland?

Location: most axillary and anogenital regions

ceruminous gland

modify apocrine glands in external ear canal that secrete cerumen (earwax)

mammary glands

specialized sweat gland that secrete milk

sebaceous glands / oil glands

gland found where you have hair; secretes sebum that has bacteria-killing properties

protection, body temp regulation, cutaneous sensations, metabolic functions, blood reservoir, excretion

functions of the skin

chemical barriers of skin

-sweat (antimicrobial proteins)

-sebum and defensins (kill bacteria)

-acid mantle (low pH slows bacterial multiplication)

-melanin (provide barrier against UV radiation)

physical barriers of skin

-flat, dead keratinized cells surrounded by glycolipids block most water and water-soluble substances

-some chemicals have limited penetration of skin though..

• lipid soluble substances

• plant oleoresins (poison ivy)

• organic solvents

• salts of heavy metals

• some drugs (nicotine patch)

biological barriers of skin

-dendritic cells (patrol layers of the skin, engulfing foreign antigens)

-macrophages (activate immune system)

insensible perspiration

sweat body exerts throughout the day; if boy temp rises, dilation of dermal vessels increase sweat gland activity to cool body

sensible perspiration

in cold environments, dermal blood vessels constrict to slow passive heat loss

cutaneous sensory receptors

part of the nervous system

exteroreceptors

respond to stimuli outside the body

• touch (Meissner’s corpuscle)

• deep pressure (lamellar / pacinian corpuscles)

• hair movement (hair follicle receptors)

vasodilation

blood vessels increase in diameter (usually in hot environment)

vasoconstriction

blood vessels shrink or decrease in diameter, reducing blood flow (usually in cold environment)

tactile (Meissner’s) corpuscle

in dermal papillar and tactile epithelial cells associated with sensory nerve endings

lamellar (Pacinian) corpuscle

Intense pressure; feel pain

calcium absorption

why do you need skin to synthesize vitamin D from the sun?

excretion of skin

-skin can secrete limited amounts of nitrogenous wastes such as ammonia, urea, uric acid

-sweating can cause salt and water loss

blood reservoir

skin vessels constrict to shunt blood to other organs

benign

not cancerous

metastasize

cancer that spreads

basal cell carcinoma

skin cancer:
-least malignant most common skin cancer

-most benign

-slow growing, often not metasize

-cure: surgical excision

squamous cell carcinoma

skin cancer:
-arise from keratinocyte of stratum spinosum

-more aggressive

-arise most often on scalp, ear, lower lip
-treatment: radiation therapy or remove surgically

melanoma

skin cancer:

-cancer of melanocyte

-most dangerous type of skin cancer

-highly metastatic

-resistant to chemotherapy

asymmetry

ABCs:
(draw line in the middle)
benign moles - symmetrical

malignant moles - asymmetrical

border

ABCs:
benign moles: smooth, even border
malignant moles: tend to be uneven and edges scalloped or notched

color

ABCs:
benign moles: one color- often single shade of brown

malignant moles: variety of colors, some brown tan blac red white or blue mixed

diameter

ABCs:
benign mole: smaller diameter
malignant moles: larger in diameter than size of eraser on your pencil (may be smaller when first detected

evolving

ABCs:
benign moles: look the smae over time

malignant moles: change in size, shape, color, elevation, etc, or new symptoms like itching or crusting

1st degree burn

BURNS
-only epidermis is damaged

-symptoms: redness, swelling, pain

-eg. sunburn

burn

tissue damage caused by heat, electricity, radiation or certain chemicals; damage caused by denaturation of proteins which destroys cells

2nd degree burn

BURNS

-epidermis and upper regions of dermis are damaged

-blisters appear and mimics 1st degree

3rd degree burn

BURNS

-entire thickness of skin is damaged

-burn area appear gray-white, cherry red, or black; there is no initial edema or pain (NERVE ENDINGS DESTROYED)

-pt goes into shock

-25% of body has 2nd degree

-10% of body has 3rd degree

-3rd degree on face, hand,feet, chest

burns are critical if:

rule of nines

-anterior and posterior head and neck 9% (4.5)

-BOTH anterior and posterior upper limbs 18% (4.5 each arm)

-anterior and posterior trunk 36% (18)

-BOTH anterior and posterior lower limb 36% (9 each leg)

-perineum 1%

debridement

removal of burned skin

signs of aging skin

-epidermal replacement slows; skin becomes thin, dry, itchy

-elasticity decrease, cold intolerance, wrinkles

-hair thinning

dense irregular connective tissue

The dermis is primarily composed of which tissue type?

palms and soles

Sebaceous glands are located everywhere EXCEPT

loss of body fluids

What is the most immediate threat to life from a serious burn?

dendritic cell / langerhan cell

Which of the following cells is part of the immune system?

a) Merkel cell

b) Langerhans cell

c) melanocyte

d) keratinocyte

osteoprogenitor cells

Bone-forming cells originate from __. (bone stem cell)

skeletal cartilage

made of highly resilient, molded cartilage tissue that consists primarily of water; contain no blood vessels or nerves

perichondrium

dense connective tissue surrounding cartilage like a girdle

-helps cartilage resist outward expansion

-contain blood vessels for nutrient delivery to cartilage

chondrocytes

what cartilage is made up of; cells encased in small lacunae within jelly-like extracellular matrix