Chapter 6 part 2 Flashcards
Hypodermis
superficial fascia = subcutaneous layer (= subQ layer)
Areolar & adipose CT that is continuous w/ organs
Site of injections due to network of blood supply
Skin color
originates from all 3 layers
- Melanin
- Carotene
- Hemoglobin
Melanin
brown pigment)
Formed by keratinocytes in epidermis
Amount depends on genetics & UV exposure
Nevus or mole is localized overgrowth of melanin-producing cells
Carotene
orange lipid soluble pigment)
Converted to vit A for vision & free radical protection
Stored in S. corneum & hypodermis
Hemoglobin
(red to blue)
Blood vessels of dermis & hypodermis
Structures derived from epidermis
Nails and Hair
Nails
Hard flat modified stratum corneum (keratin) that reinforces fingers & toes & help w/ grasping.
Color indicates blood supply in area
Texture is window to nutrition
Hair
Thin strands of hardened keratin produced by hair follicles. Hair is shaft (above epidermal surface), root (from surface to bulb) & bulb.
Bulb
has living epi cells but shaft & root are dead epi cells. Bulb is swollen area surrounding hair papilla which contains nerve, blood vessels & CT. Bulb cells mitotically divide, produce keratin, are pigmented by melanocytes of hair papilla, & push older cells towards shaft
Hair Follicles
are layers of epi & CT that wrap bulb & dermal root & anchor to hypodermis. Arrector pili anchor to follicle & position hair
Hair functions
include protection from sunburn & injury, heat retention, sensory reception, pheromone dispersal, & visual identification.
Glands
Sebaceous (oil) glands
Sweat (sudoriferous) glands
Sebaceous (oil) glands
are everywhere, but also vent to hair follicle to soften skin & hair.
Secretion is sebum (oil & cell fragments) via holocrine method. Large volumes produced during puberty when steroid hormones are fluctuating are cause of acne.
Sweat (sudoriferous) glands
- Eccrine sweat glands
* Apocrine sweat glands
Eccrine sweat glands
are found in palms, soles & forehead. Secrete a watery salty sweat via merocrine methods
Apocrine sweat glands
are found around nipples & in axillary & anogenital areas. Secrete a viscous & cloudy solution with lipids & proteins that bacteria love
Repair of Integument
- Damage
- Coagulation
- Granulation
- Regeneration
Damage
Initial cut or damage thru epidermis & dermis causing bleeding
Coagulation
Blood vessel damage “calls” army to clot, clean & pull wound together. Internal to clot PMNs & macrophages remove debris.
Granulation
new blood vessels grow into wound & fibroblasts quickly secrete collagen & form granulation tissue. Deep clot removed
Regeneration
epithelium migrates under scab & displaces it. CT fibrosis continues until complete repair or scar is formed.
Skin Cancer
Basal Cell Carcinoma
Squamous Cell Carcinoma
Melanoma is a killer!
Basal Cell Carcinoma
is the least malignant & most common. Origin is S. basale then BCC grows into dermis & hypodermis. Slow, non-metastatic growth & so surgical removal is usually adequate
Squamous Cell Carcinoma
grows quickly & is metastatic. Origin is S. spinosum, then it metastasizes to deeper layers. Scalp, ears, & lower lip are common sites. Radiation +/- surgery are treatment. In mouth, sun exposure is not a risk factor but alcohol multiples risk for oral tobacco users (snuff…).
Melanoma is a killer
Origin is melanocytes in epidermis which are more mitotically active w/ high UV exposures. It is locally invasive & quickly metastasizes. Wide surgical margins, removal of lymph nodes, & combined therapies are treatments.
ABCDE rule
A: Asymmetry B: Border– irregular & indented C: Color—black, brown, tan, red or blue D: Diameter > 6 mm E: Elevation (survival poor if > 4 mm thick)
