The Integumentary System BIOL 3310 Anatomy and Physiology Lecture Exam 1

Dermatology

medicinal study, diagnosis and treatment of the integumentary system

Cutaneous membrane

the skin

What is the function of the skin?

regulate body temperature, blood reservoir, protect (keratin), cutaneous sensations, diffusion, synthesis of vitamin D

Epidermis

outer, thinner layer of keratinized stratified squamous epithelial tissue

Dermis

inner, thicker layer of connective tissue, determines thickness of the skin

Hypodermis

subcutaneous layer, composed of adipose tissue, attaches dermis to underlying orans

Papillary region

upper layer of dermis, consists of areolar connective tissue, has dermal papillae with capillaries, corpuscles of touch, free nerve endings

Reticular region

lower layer of dermis, consists of dense irregular connective tissue with bundles of collagen and elastic fibers, adipocytes, hair follicles, nerves, sebaceous and sudioerous glands

Keratinocytes

90% of all cells, produce, keratin, tough fibrous proteins that provide protection

Melanocytes

produce melanin, protects DNA against UV damage, found in stratum basale

Langerhans (dendritic) cells

immune response from red bone marrow

Merkel cells

function in the sensation of touch along with the adjacent tactile discs

Stratum basale

houses melanocytes, tactile cells, stem cells, keratinocytes

stem cells of the sb divide and push cells towards surface

Stratum spinosum

consists of several layers of keratinocytes, thickest stratum, houses dendritic cells

deepest cells capable of mitosis, but cease dividing as pushed upwards, and begin to flatten

Stratum granulosum

3-5 layers of flat keratinocytes

produce lipid filled membrane coating vesicles, lamellar granules found throughout

Stratum lucidum

only in thick skin, dead cells

Stratum corneum

up to 30 layers of dead, scaly, keratinized cells

forms durable surface layer, cells flatten and exfoliate

Melanin

most significant factor of skin color

produced by melanocytes, accumulated in keratinocytes in basale and spinosum

pigments eumelanin and pheomelanin

everyone has same number of melanocytes

Dark skin

greater quantities of melanin

melanin spread out

breaks down slowly

Light skin

melanin clumped

breaks down quickly

not seen beyond basale

Hemogobin

red pigment in blood

Carotene

yellow pigment in egg yolks/carrots, can be deposited into corneum and subq fat, making skin appear orange

Cyanosis

blueness of the skin from lack of oxygen in circulating blood

Erythema

abnormal redness of the skin due to dilated cutaneous vessels

Pallor

pale or ashen color when there is little blood flow through the skin

Albinism

genetic lack of melanin that results in white hair, pale skin, pink eyes

Vitiligo

partial or full loss of melanocytes

Jaundice

yellowing of skin and sclera due to excess of bilirubin in blood

Cleavage/Tension lines

lines in dermis that indicate the predominant direction of collagen fibers

Epidermal regions

reflect contours of underlying dermal papillae and form basis for finger prints/foot prints

Flexion lines/creases

marks sites where the skin folds during flexion of the joints

Freckles

flat, melanized patches of dermis

Moles

raised melanized patches with hair

Hemangiomas

birthmarks, patches of discolored skin caused by benign tumors of the dermal blood capillaries

Sebaceous glands

oil/sebum glands, always connected to hair follicles

Sudoriferous glands

sweat glands, two kinds

Eccrine/merocrine glands

Major type, pores go straight to surface, secretes water/ions, aids in thermoregulation

Apocrine glands

Minor type, connected to hair follicles found with auxiliary hairs

Mammary glands

modified apocrine sweat glands, develop during pregnancy, triggered by hormones

Ceruminous glands

modified sweat glands in ear canal, combines sweat, oil, and dead skin cells, produce cerumen or earwax

Pilli

Hair, function to protect, reduce heat loss, sense light touch

made up of shaft and root

Lanugo hair

fine, downy, unpigmented hair on fetus in the last 3 months of development

Vellus hair

fine, pale hair replaces lanugo by time of birth. makes up 2/3 hair on females, 1/3 hair on males and all hair on children except eyelashes, eyebrows, scalp

Terminal hair

longer, coarser hair, typically more pigmented. forms eyelashes, eyebrows, scalp, auxiliary hair. androgen may turn vellus hair terminal in women

Bulb

swelling base where hair originates, either in dermis or hypodermis, only living aspect of hair

Root

remainder of hair follicle

Shaft

portion of hair above skin surface

Dermal papilla

bud of vascular connective tissue encased by bulb, provides hair with nutrition

Hair matrix

region of mitochondrially active cells immediately above papilla, hair growth center

Follicle

diagonal tube that dips deeply into the dermis and may extend into hypodermis

Epithelial root shaft

extension of shaft into the dermis, lies adjacent to hair root, towards deep end widens to be source of stem cells for follicular growth

Connective tissue root shaft

derived from dermis, surrounds epithelial root sheath, denser than adjacent connective tissue

Hair receptors

nerve fibers that entwine follicles, respond to hair movement

Piloerector muscles/arrector pili

bundles of smooth muscle cells that extend from dermal collagen to connective tissue

How is hair texture determined?

by the cross-sectional shape of the follicle

circular - straight hair

ovular - wavy hair

flat - curly hair

What pigments make up hair colors?

pigment found in cortex

Brown/black hair - rich in eumelanin

Blonde - medium amount of pheomelanin, little eumelanin

Red - some eumelanin, high pheomelanin

Gray/white - very little pigment, air in medulla

Anagen phase

growth phase, 90% of hair at one time is in this phase for 6-8 years, mitosis occurs pushing dead cells up out of dermis

Catagen phase

degenerate phase, mitosis in hair matrix ceases and sheath cells below bulge die, becoming club hair

Telogen phase

resting stage, club hair may fall out or be pushed out in next

Alopecia

thinning of hair or complete baldness, as body attacks hair follicles

Pattern baldness

condition where hair loss from specific region of scalp thin randomly

Hirsutism

excessive/undesirable hairiness in areas not usually hairy

Nails

keratinized epidermal cells located over dorsal surface of digits, grows from matrix

Epidermal wound healing

occurs when only superficial wounds occur, only cutting epidermis

cells of stratum basale multiply and migrate to fill wound, stop when they contact each other

Deep wound healing

clot formation begins, with inflammation

scab develops

proliferation of epithelium and deposition of new collagen

maturation, collagen fibers become organized and blood vessels connect

Fibrosis

scar tissue forms, dense collagen fibers, can be hypertrophic or keloid

Burns

leading cause of accidental death, death primarily occurs with fluid loss

Eschar

burned, dead tissue

Debridement

removal of eschar

1st degree burns

only damage epidermis, slight edema, redness and pain, but will heal in few days

2nd degree burns

damage epidermis and part of dermis, tissue can still repair itself, takes longer, blisters very painful

3rd degree burns

full thickness, beyond dermis, often require skin grafts and fluid replacement/infection control

Autograft

skin graft taken from own body

Split-skin graft

taking epidermis and part of dermis, from undamaged area

Isograft

graft from identical twin

Homograft/allograft

unrelated person, need to be on immunorepresant

Heterograft

different species, temporary

Aminon

from afterbirth

Artificial skin

combination of silicone and collagen

What are the types of UV light?

UVA - longer wavelength, penetrates deeper, triggers melanocytes

UVB - shorter wavelength, less penetration, more energy/damage

Both canerous

Basal cell carcinoma

most common form of skin cancer, least dangerous as it rarely metastasizes, forms from cells in stratum basale, lesion is small shiny bump with central depression

Squamous cell carcinoma

from keratinocytes in stratum spinosum, lesions typically on scalp, ears, lower lip, back of hand, raised reddened scaly appearance, may metastasize to lymphs, which may be lethal

Malignant melanoma

skin cancer from melanocytes, often in preexisting mole, less than 5% of skin cancers but most fatal, typically can only be treated surgically and metastasizes quickly

ABCD rule for malignancy

Asymmetric

Border irregularity

mix of Colors/Change of colors

larger than 6mm in Diameter