CH 6 Flashcards
Accessory organs of the integumentary system
Hair, nails, cutaneous glands
Skin makes up what % of body weight?
8% , largest and heaviest organ of the body
What does thick skin have? What is it lacking?
It has sweat glands but lacks hair follicles and sebaceous glands
Where is thick skin found?
Palms of hands and soles of feet
Integumentary System Functions:
thermoregulation, sensory reception, Vitamin D production
Hypodermis
Connective tissue layer that lies between the skin and the deeper muscle or other tissue
What classifies skin as thick or thin?
the thickness of stratum corneum
Where is thin skin found?
Everywhere except the palms of hands, soles of the feet, fingertips, and toes
What is impaired in burn patients?
Vitamin D production
Region with the fewest sensory receptors in the skin
The back
What inhibits bacterial growth on skin?
Dryness of the skin and the acid mantle
Method of preserving body heat
Vasoconstriction of blood vessels in the skin
Stem Cells
undifferentiated cells that divide and give rise to Keratinocytes in skin
Keratinocytes
epidermal cells that produce keratin
Melanocytes
cells that produce dark pigments that act as a UV shiled
Tactile cells
sensory receptors for touch
Dendritic Cells
Immune cells that guard against pathogens that penetrate into the skin
5 cell types found in Epidermis
Keratinocytes, melanocytes, stem cells, dendritic cells, tactile cells
Epidermal layers from deepest to most superficial
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
Thickest layer in thin skin
stratum spinosum
Thickest layer in thick skin
stratum corneum
Stratum Granulosum
cells contain coarse, dark staining Keratohyalin granules
Dendritic cells origin
originate in the bone marrow and migrate to the skin
Stratum Lucidum
contains the clear protein eledin and is visible only in thick skin
Life cycle of Keratinocyte
1) Stem cells divide to produce new keratinocytes
2) Mitosis ceases as epidermal cells are pushed upward
3) Keratinocytes flatten and produce waterproof bundles of keratin filaments
4) Keratinocytes dies
5) Dead keratinocytes flake off surface of the skin
Dander
dead keratinocytes that flake off of the skin
Dandruff
dander mixed with sebum, usually found on scalp
What aids with water retention in skin?
there is a lipid layer between stratum spinosum and stratum granulosum
Where is the dermis the thickest?
In the palms and soles
Tissue found in papillary layer of the dermis
Areolar connective tissue
Why are injections administered in the hypodermis?
because the subcutaneous tissue is highly vascular and therefore produces a big immune response
What is the papillary layer rich in?
Blood vessels
2 layers of the Dermis
Papillary (superior) and reticular layers (inferior)
Primary tissue of hypodermis
Adipose tissue
What gives normal healthy skin a pink color?
Hemoglobin
Carotene
yellow pigment that can become concentrated to various degrees in the stratum corneum and subcutaneous fat
Cyanosis
blueness of the skin resulting from a deficiency of oxygen circulating in the blood
Eumelanin
form of melanin that has a brownish-black color
Erythema
abnormal redness of the skin
Pallor
pale or ashen color that occurs when there is so little blood flow through the skin that the white of the dermal collagen shows through
Albinism
genetic lack of melanin that results in milky white hair and skin and blue-gray eyes
Hematoma
aka a bruise, is a mass of clotted blood showing through the skin
Friction Ridges
enhance sensitivity to texture by vibrating and stimulating lamellar corpuscles in the skin when fingertips stroke uneven surfaces
Flexion lines
the creases found on the surfaces of the hands
Juandice
yellowing of the skin caused by accumulating bilirubin that is excreted by the liver
Freckles and Moles
aggregations of melanized Keratinocytes
Skin markings
flexion creases, friction ridges, and patches of pigmentation
Hemangiomas
Birthmarks, patches of skin discolored by benign tumors of the blood capillaries
Capillary Hemangiomas
strawberry birthmarks
Cavernous Hemangiomas
Flatter and duller in color
Port-wine Stain
flat and pinkish to dark purple in color, typically does not regress or fade with age
Thinnest (softest) hair to thickest (coarsest) hair
Lanugo, vellus, terminal hair
Individual hair is also known as
a Pilus
Vellus hair characteristics and abundance in females and males
Fine, pale hair. Constitutes about 2/3 of hair in women and 1/10 of hair in men
Lanugo Hair
fine hair found on a fetus in the last 3 months of development
Terminal Hair
predominant form of hair found on scalp
Shaft
the part of the hair that projects from the surface of the skin
What nourishes hair cells?
Dermal papillae
Hair matrix
the region of actively mitotic cells above the papilla
Layers of hair from outermost to innermost
Cuticle, Cortex, Medulla
Epithelial Root Sheath
an extension of the epidermis that lies adjacent to the hair root
Root
all parts of the hair below the surface
What is an extension of the vascular system into the hair bulb?
the dermal papilla
2 main layers of hair follicle
epithelial root sheath and connective tissue root sheath
Bulge of the hair follicle
Functions as a source of stem cells for follicle growth
What causes goosebumps?
Piloerector contractions
Wavy Hair
oval cross section shape
Straight Hair
round cross section shape
Tight curly hair
flat round section shape
Gray and White hair
caused by absence of melanin in the cortex of the hair and presence of air in the medulla
3 phases of hair cycle
Anagen, Catagen, Telogen
Anagen
stem cells in hair bulge multiply, follicle deepens, and hair grows in length. Lasts about 6 to 8 years
Catagen
mitosis ceases, follicle shrinks, and hair dies and loses its anchorage. Lasts about 2 to 3 weeks
Telogen
follicle rests for 1 to 3 months and begins hair cycle again
What influences pattern baldness expression?
Testosterone levels which is why it is seen more in men and menopausal women
Hirsutism
excessive or unwanted hairiness in areas that are not usually hairy, especially in women and children. Caused by hormone inbalances
Why would a bald man feel cold air on his scalp?
Scalp lacks an insulating fat layer. Also dense hair on scalp helps insulate warm air near scalp
Alopecia
Thinning of the hair or baldness
Vibrissae
Guard hairs, guard the nostrils and ear canals preventing particles from entering
Pattern baldness
loss of hair in specific areas of the scalp
Fingernails and Toenails
derivatives of the stratum corneum
Hyponychium
epidermis of the nail bed
Nail bed
skin underlying the nail plate (hyponychium)
Lunule
white crescent area located over the nail matrix
Eponychium
cuticle, narrow zone of dead skin that commonly overlays proximal end of the nail
Flat or concave nails
Iron deficiency
Nail body
portion of fingernail or or toenail that is attached to the finger or toe
Apocrine sweat glands
occur in the groin, anal region, axilla, areola, and beard area. Produce sweat that contains fatty acids
Clubbed fingertips
sign of longterm hypoxemia (deficiency of oxygen in the blood)
Bromhidrosis
clinical term for disagreeable body odor
Merocrine sweat glands
aka eccrine sweat glands. Relatively narrow lumen and duct that opens by way of a pore on the skin surface. Especially abundant on palms, soles, and the forehead. Primary function is to cool the body
Myoepithelial cells
cells found in apocrine and merocrine sweat glands that have contractile properties similar to smooth muscle
Diaphoresis
sweat is produced causing noticeably wet skin during exercise or circulatory shock
Sebum
secreted by sebaceous glands and functions as a lubricant for the hair and skin
Ceruminous Glands
secrete substance that combines with sebum to keep eardrum protected
Sebaceous Glands
flask shaped glands with short ducts, usually open into a hair follicle or directly onto skin
Mammary Glands
Modified apocrine sweat glands. usually only active in pregnant and lactating females
Polythelia
the presence of additional nipples
Basal Cell carcinoma
most common type of skin cancer, least deadly. Arises from stratum basale and eventually invades the dermis. On the surface, first appears as small, shiny bumpy. As it enlarges, often developes a central depression.
BRAF in men
Oncogene that causes about 2/3 of cases of melanoma in men
BRAF in women
oncogene that is linked to melanoma and breast cancer in women
How are the 3 types of skin cancer distinguished from each other?
by their lesions and zones of tissue injury
Electrodesiccation
destruction of the cancer lesion by heat
Eschar
burned, dead tissue
Debridement
removal of eschar
What is principle cause of death in burn patients?
Circulatory shock due to fluid loss
Allografts or homografts
skin grafts from different individuals
Isografts
tissue transplant between identical twins
Autograft
Skin taken from one part of your own body, and grafted onto another
Xenograft
Skin graft from different species like a pig
Nocireceptors
respond to potentially damaging stimuli and trigger sensation of pain
Mechanoreceptors
Respond to mechanical stimuli like touch and vibration
How are melanin granules distributed in light and dark skin?
melanin granules in keratinocytes are tighter in light skin and more spread out in darker skin
Brown and Black hair are rich in what?
Eumelanin
Red hair
little bit of eumelanin but high concentration of pheomelanin
Blonde Hair
Intermediate amount of pheomelanin but very little eumelanin
