What does the integument system consist of?
Skin Accessory Organs (Hair, Nails, & Cutaneous glands)
What are the 3 layers of the skin?
What type of tissue is the epidermis made of?
What type of tissue is the dermis made of?
Thick Skin (3)
- on palms and soles (corresponding areas)
- has sweat glands, but no hair follicles or sebaceous glands
- has 5 layers
Thin Skin (3)
- covers the rest of the body
- has sweat glands, sebaceous glands, & hair follicles
- has 4 layers
What are the functions of the skin? (6)
- resistance to trauma & infection
- other barriers (waterproof)
- Vitamin D synthesis
- Nonverbal communication
What organs help complete Vitamin D synthesis?
Skin, Liver & Kidneys
Characteristics of the epidermis? (3)
- no blood vessels
- depends on the diffusion of nutrients from underlying tissue
- contains dead cells (keratin)
What are the layers of the skin?
Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale
What cells are found in the stratum basale? (4)
Where does mitosis take place?
stratum basale & deepest cells of stratum spinosum
What happens in the stratum spinosum?
more and more keratin filaments are produced which cause the cells to flatten
Characteristics of stratum spinosum? (4)
- dendritic cells found throughout
- named after spiny appearance
- thickest layer in thin skin
- deepest cells capable of mitosis
Characteristics of stratum granulosum?
- contains coarse dark staining granules
- waterproofing layer
- 3-5 layers of keratinocytes
Characteristics of stratum lucidum? (3)
- seen only in thick skin
- cells have no nucleus or organelles
- thin translucent zone (no granulation)
Characterisitcs of stratum corneum? (2)
- 30 layers of dead keratinized cells
- resistant to abrasion, penetration, & water loss
5 types of cells found in the epidermis
- tactile cells
- dendritic cells
- stem cells
Stem cells (2)
- undifferentiated cells that give rise to keratinocytes
- found in stratum basale
- synthesize keratin w/ greatest majority found in epidermal cells
- produced by stem cells
- occur only in stratum basale
- synthesize pigment melanin
- branched process spread among keratinocytes
tactile (merkel) cells (2)
- in basal layer of epidermis
- touch receptors associated w/dermal nerve fibers
dendritic cells (3)
- found in stratum spinosum & granulosum
- stand guard against toxins, microbes, etc
What does mitosis require?
abundant supply of oxygen & nutrients that are acquired from blood vessels
As keratinocytes are pushed up they _________
Effects on keratinocytes production (2)
- slower in old age
- faster in injury or stressed skin
What do the keratinocytes produce?
lipid filled membrane coating vesicles (lamellar granules)
What are the 3 important developments that occur in stratum granulosum?
- keratinocytes nucleus & organelles degenerate (cells die)
- granules release a protein filaggrin
- vesicles release lipid mixture that spreads & waterproofs
The water barrier is produced by which layers?
stratum granulosum & stratum spinosum
Fingerprints come from?
Characteristics of dermis (3)
- beneath the epidermis
- composed mainly of collagen (reticular, elastic) & fibroblast
- contains blood vessels, sweat glands, oil glands, and nerve endings
What are embedded in the dermis?
hair follicles & roots
What portion of the dermis leave the fingerprints?
What are the 2 layers of the dermis?
- papillary layer
- reticular layer
Papillary layer (dermis) (4)
- superficial zone of dermis
- thin zone of areolar tissue
- allows for mobility of leukocytes
- rich in small blood vessels
Reticular layer (dermis) (3)
- deeper & much thicker layer of dermis
- consists of dense, irregular connective tissue
- stretch marks caused by tears in collagen fibers
- subcutaneous tissue
- more areolar & adipose tissue
- binds skin to underlying tissue
- good for injections due to being highly vascular
Importants of melanin?
absorbs ultraviolet radiation
Why do people have different skin color?
they have the same number of melanocytes, but different quantities of melanin
Dark skin vs. Light skin
Dark Skin: melanin breaks down slowly;melanin granules more spread out
Light Skin: melanin breaks down fast;melanin granules tightly clumped
- results from combination of evolutionary selection pressures
- differences in exposure to ultraviolet radiation
markings on the fingertips that leave oily fingerprints on surfaces we touch
- lines on the flexor surfaces of the digits, palms, wrist,elbows
- marks sites where the skin folds during flexion of the joints
What are freckles & moles?
aggregations of melanocytes
-patches of discolored skin caused by benign tumors of dermal capillaries
What are hair & nails composed mostly of?
hard dead keratinized cells
pilus vs pili
____ of hair does not differ much from person to person or between sexes. What are the differences due to?
number; texture & pigmentation of hair
3 kinds of hair
- fine, downy, unpigmented hair
- appears on the fetus in the last 3 months of development
- fine, pale hair that replaces lanugo after birth
- 2/3 of the hair in women; 1/3 of the hair in men
terminal hair (3)
- longer, coarser, and usually heavily pigmented
- after puberty (forms axillary & public hair)
- facial hair of males and some of the hair on the trunks
3 zones that hair is divisible
swelling at the base where hair originates in dermis or hypodermis (ONLY living hair near this area)
remainder of the hair in the follicle
the portion above the skin surface
bud of vascular connective tissue encased by bulb that provides nutrients to the hair
immediately above the papilla where cells are actively undergoing mitosis
3 layers of the hair (inside to out)
medulla (core)->cortex(bulk)->cuticle(fly away hairs)
epithelial root sheath (2)
- extension of epidermis
- lies immediately adjacent to hair root
connective tissue root sheath (2)
- derived from dermis
- surrounds epithelial root sheath
Hair receptors (2)
- nerve fibers that entwine each follicle
- respond to hair movement
Piloerector muscle (2)
- bundles of smooth muscle cells
- goose bumps
Textures of the hair?straight?wavy?curly?
related to dif in cross sectional shape
3 stages of hair growth
anagen, catagen, and telogen
resting stage when papilla reaches the bulge
- degenerative stage
- mitosis ceases and sheath cells below the bulge die
- follicle shrinks & dermal papilla is moved up
- base keratinizes into a hard club hair (leaves anchorage)
- growth stage (most of scalp follicles)
- dermal papilla pushed deeper into skin form epithelial root sheath
hard derivatives of stratum cornenum?
fingernails & toenails
what makes up the nail plate? (3)
overhangs the fingernail
visible attached part of the nail
not visible; extends proximally under overlying skin
When does club hair fall out?
during catagen or telogen
surrounding skin rising a bit above the nail
separates nail fold from nail plate
skin underlying nail plate
hyponychium vs eponychium
hypo: epidermis of the nail bed (alive)
epon: narrow zone of skin (cuticle:dead)
growth zone of thickened stratum basale
an opaque white crescent at proximal end of end
what are the 5 types of glands found in the skin?
merocrine sweat glands aprocrine sweat glands ceruminous glands (ear wax) mammary glands sebaceous glands
merocrine glands (2)
- most numerous skin gland that helps cool the body
- sweat is watery
aprocrine gland (4)
- ducts lead to hair follicles
- sweat is thicker, milky & contains fatty acids
- respond to sexual and stress stimulation
- found in groin, anal, and axilla areas
disagreeable body odor produced by bacterial action of fatty acids
begins as a protein-free filtrate of blood plasma produced by deep secretory portion of gland
secretion consists of broken down cells
which gland keeps the skin & hair from becoming dry, brittle, and cracked
ceruminous gland (3)
- only found in external ear canal
- keeps eardrum pliable
- waterproofs the canal
milk producing glands that develop only during pregnancy and lactation
3 types of skin cancer?
- basal cell carcinoma
- malignant melanoma
- squamous cell carcinoma
basal cell carcinoma (3)
- most common type
- least dangerous & seldom metastasizes
- forms from stratum basale cells
squamous cell carcinoma (3)
- from keratinocytes in stratum spinosum
- tends to metastasizes to lymph nodes & may become lethal
- have scaly apperances
malignant melanoma (4)
- arises from melanocytes (moles)
- most deadly form although rare
- metastasizes rapidly
- unresponsive to chemotherapy
why do deaths occur from burns?
result primarily from fluid loss & infection
What is the leading cause of accidental death?
1st degree burn (2)
- partial thickness burn; involves only epidermis
- redness & pain (sunburn)
2nd degree burn (2)
- partial thickness burn; involves epidermis & part of the dermis
- blistered & very painful
3rd degree burn (3)
- full thickness burn; involves the epidermis & all of the dermis
- some tissue damage is observed
- require skin graft
tissue taken from another location on the same person’s body
from identical twin