Appendages (1) Cutaneous glands – all exocrine glands –Form in stratum basale and push down into...
-
Upload
sophia-osborne -
Category
Documents
-
view
215 -
download
0
Transcript of Appendages (1) Cutaneous glands – all exocrine glands –Form in stratum basale and push down into...
Appendages• (1) Cutaneous glands – all exocrine glands
– Form in stratum basale and push down into dermis
– (A) Sebaceous (oil) glands
• Everywhere but palms and soles
• Most ducts empty into hair follicles
• Produce sebum – oily substance and fragmented cells
– Keep skin moist
– Have chemicals to kill bacteria
– Production especially stimulated
by male sex hormones
– (B) Sweat glands (sudoriferous)
• More than 2.5 million
• 2 types
• Eccrine glands
–All over
–Produce sweat: water, salts, vitamin C, metabolic wastes, lactic acid
»Clear
»Acidic – pH 4-6 - inhibits bacteria
–Opening = pore – directly to surface
–Regulate body temp
–Stimulated by nerve endings
–May lose up to 7 liters on a hot day
• Apocrine glands–Axillary and genital areas–Ducts open into hair follicles–Secrete fatty acids, proteins, and all of
eccrine secretions –Milky/yellowish color–1st stimulated by sex hormones during
puberty–Activated by nerve endings
• (2) Hair/Hair follicles– Hair follicle produces hair
• Epidermal sheath – inner• Dermal sheath - outer
– Root – hair portion in follicle– Shaft – hair on surface
• Medulla – center• Cortex – intermediate• Cuticle - outer
– Highly keratinized dead cells– Color caused by melanocytes in bulb– Arrector pilli – smooth muscle – pulls hair
upright to add an insulating air layer
• (3) Nails– Scalelike modification of epidermis– Keratinized dead cells– Appear pink because of dermal blood supply– Parts
• Free edge• Body• Root• Nail folds – overlapping skin
– Proximal fold – cuticle
• Nail bed – nail matrix – proximal end = nail growth• Lunula – white crescent – over nail matrix
Infections & Allergies• Athlete’s foot – tinea pedis
– Itchy, red peeling – fungal infection
• Boils & carbuncles – inflammations of hair follicles and sebaceous glands
• Cold sores – fever blisters
– Caused by herpes infection
– Blisters itch and sting
– Activated by stress, fear UV radiation
• Contact dermatitis – caused by chemical exposure
– Ex. Poison ivy
• Impetigo– Caused by staph– Pink, water filled, raised lesions– Develop yellow crust and rupture
• Psoriasis – autoimmune disorder– Red lesions covered by dry, silvery scales– Overproduction of skin cells
Skin Cancer
• Benign – does not metastasize (spread)
• Malignant – metastasizes
• Most common cancer in humans (1 in 5)
• Types
• (1) Basal cell carcinoma
– Least malignant – slow growing
– Most comon
– Stratum basale cells invade dermis
– Form small dome shaped lesions w/ a central ulcer
– Common on face
• (2) Squamous cell carcinoma– Stratum spinosum– Scaly, reddened papule (elevation) – shallow
ulcer w/ raised border– Rapid growth – metastasizes to lymph nodes– Common on scalp, ears, hands, lower lip
• (3) Malignant melanoma– In melanocytes– 5% of skin cancers – 50% chance of survival– Spreading brown/black patch– Metastasizes to lymph nodes and blood
vessels
• ABCD Rule – to recognize melanoma– A – asymmetry– B – border
irregularity – not smooth
– C – color – does it contain different colors
– D – diameter – larger than 6mm
Burns• Caused by heat, electricity, UV radiation,
chemicals• Problems:• (1) Allow fluid to seep out (contains proteins and
electrolytes)– May lead to kidney shutdown and circulatory
shock– Must replace fluids
• (2) Infection – leading cause of death w/ burns– Bacteria and fungi may invade
• Determine extent of burns using “Rule of Nines”
– Body is divided into 11 areas (each 9% of body surface) and genital area (1%)
– Critical
• 25% of body w/ 2nd degree
• 10% w/ 3rd degree
• Face/hands/feet w/ 3rd degree
–If on face they may cause swelling and suffocation
• Classified by severity
• 1st degree – only epidermis
– Red, swollen
– Heal w/in 2-3 days
– Ex. Most sunburns
– Aka partial thickness burn
• 2nd degree – epidermis and upper dermis
– Red, blisters
– Regeneration can still occur
– Aka partial thickness burn
• 3rd degree – all of epidermis and dermis
– Not painful – destroys nerve endings
– Gray, white, or blackened
– No regeneration
– Aka full thickness burn
Development• Birth
– Lanugo – downy covering – infant sheds by birth
– Vernix caseosa – white substance produced by sebaceous glands
– Milia – accumulation
of vernix caseosa in
glands which can be
seen through skin
• Adolescence– Becomes oily– Acne
• 20’s – 30’s– Optimal appearance
• Old age– Hypodermis thins = cold intolerance– Thinning = easier bruising– Dries out– Hair – loses luster, graying
• # follicles decreases = thinning hair• Alopecia - baldness