Week 3: Skin, Hair and Nails Flashcards
Skin
Body’s largest organ
Three layers of skin
Epidermis, dermis, subcutaneous
Epidermis
Outer layer of the skin
- Thin but tough, cells bound tightly for form protective barrier
- Avascular, nourished from blood vessels in the skin below
Consists of inner Basal Cell Layer (keratin and melanin) and outer Horny Cell Layer (dead skin cells)
Dermis
The middle, supportive layer of the skin
Consists mostly of collagen (connective tissue); resists tearing, elasticity to stretch with movement
Contains:
- Nerves, sensory receptors, blood vessels, lymphatic vessels
- Hair follicles, sebaceous glands, sweat gland
Subcutaneous
Innermost layer of the skin,
Consists of adipose/fatty layer
Function:
- Stores fat for energy and insulation (temp control)
- Aids in protection (cushioning effect)
- Gives skin mobility over structures beneath
Basal Cell Layer
Inner layer of the epidermis, consists of keratin (new cells) and melanin (pigmentation)
Horny Cell Layer
Outer layer of the epidermis, consists of dead skin cells
Sebum
- lipid substance secreted by the sebaceous glands in the hair follicle
- lubricates hair and skin
- prevents water loss
Eccrine glands
Sweat glands right on the skin for thermoregulation
Apocrine glands
vestigial glands secreting milky substances that produces body odour when interacting with bacteria in the axillae and peri areas
Epidermal Appendages (4)
Hair
Sebaceous glands
Sweat glands
Nails
Functions of the skin (10)
- Protection
- Guards the body from microorganisms
- Prevents water loss
- Sensory/perception (pressure, touch)
- Temperature regulation (sweating, heat storage)
- Identification
- Communication (emotions on skin)
- Wound repair
- Absorption and excretion
- Production of vitamin D (by absorbing UV light and converting cholesterol)
Lanugo
fuzzy hair over infant body at birth, lasts a few weeks
Vernix
white substance covering the newborn, protects skin in amniotic fluid
Milia
baby acne (excess sebum, little white dots)
Integumentary considerations for infants
Eccrine glands not fully functional for first few months and subcutaneous layer is insufficient at insulation in newborns, so thermoregulation is really tough for first few months
Integumentary considerations for adolescents (3)
- Increased secretion from apocrine glands (BO)
- Sebaceous glands more active (acne)
- Subcutaneous fat deposits increase (weight gain)
Integumentary considerations for pregnant people (3)
Linea nigra (line down the midline from extra hormones in body)
Cholasma: hyperpigmentation in the face, can remain post-partum
Striae gravidarum: stretch marks
Integumentary considerations for older people (5)
- Decrease elasticity, subcutaneous fat and muscle tones
- Decrease in sweat and sebaceous glands in number and function
- Drier, thinner, more lax skin as a result, and wrinkles
- Decreased melanocytes, hair starts to grey
- Hair distribution changes
Skin Mobility
The ease with which skin can be pulled (decreases with swelling)
Turgor
How quickly the skin returns to its normal position (decreases with age)
Lesion
any unexpected finding in the skin tissue
ABCDE
Danger signs in pigmented lesions
- Asymmetry
- Border irregularity (evenness is good)
- Colour variation(two or more shades is bad)
- Diameter greater than 6mm
- Elevation and evolution
Annular lesion
Circular
Confluent lesion
lesions that look like they are running or growing together (hives)
Discrete lesion
lesions are distinct and remain separate
Grouped lesion
clustered lesions (e.g., contact dermatitis)