Skin appendages
Hair, sebaceous gland, nail, eccrine and apocrine glands
Hair: *hair germ
* hair papilla
* hair bulb: Matrix cells and melanocytes
* hair shaft: Medulla, cortex and cuticle
Types of hair
• Lanugo hair: fine and long. Shed before birth
• Vellus hair: fine and short. Replace lanugo
• Terminal hair: long course. Scalp, mustache
---Arrector pili : smooth muscle attach to the hair shaft, its contraction
results in goose flesh.
Hair cycle
Anagen: grow- 3 years
Catagen: involution- 3 weeks
Telogen: resting- 3 months
Sebaceous gland
Multilobed, associated with hair.
* Ectopic sebaceous glands (not associated with hair follicles)
Meibomian gl.---eyelid
Tyson’s gl.----prepuce
Fordyce spots----buccal mucosa
Montgomery's gl.---- areola
• Sebum( TG, ch.esters, phos. Lip. and squalene)
Lubricant, bacterio and fungistatic
Nail
• Nail plate- hard keratin
• Nail folds
• Nail matrix
• Cuticle
• Nail bed
Eccrine gland
• Coiled secretary portion and duct
• Cholinergic stimulation
• Thermoregulation
• 3 types of sweating
1- Thermal: due to hot environment, fever, exercise. It is
generalized sweating.
2- Emotional: due to fear and anxiety. Usually affects the palms and
soles.
3- Gustatory: due to spicy food. Usually affects the face.
• Sweat: Na, KCL, lactate, urea, ammonia
Apocrine gland
• Coiled sec. portion and duct
• Axilla, nipple, periumbilical and genitalia
• Adrenergic stimuli
• Unknown function
• Protein, CHO, lipid and ammonia
Primary skin lesions
• Macule: flat discoloration <0.5 cm ex. Freckle
• Patch: flat discoloration >0.5 cm ex. Vitiligo
• Papule: superficial elevation <0.5cm ex. Wart
• Plaque: superficial elevation >0.5cm ex. Psor.
• Nodule: circumscribed elevation with depth ex. leishmaniasis
• Vesicle: circum. elevation contain fluid<0.5 cm ex. Herpes
• Bulla: circum. elevation contain fluid >0.5cm-B.pemph.
• Wheal: evanescent edematous elevation<24 h—urticaria
• Petechiae: pinhead size blood depsits
• Purpura: larger macules and papulues of blood
• Pustules: small elevation contain pus-- folliculitis
Secondary skin lesions
• Scales: excess dead epidermal cells.—psoriasis.
• Crust: dried blood or tissue fluid—impetigo
• Erosion: loss of epidermis, heals without scar
• Ulcer: loss of epidermis and part of dermis, heals with scar.
• Excoriation: scratch marks
• Scar: new connective tissue
• Atrophy: thinning of epidermis, dermis or fat.
• Lichenification: thickening and hyperpigmentaion of skin, with
accentuation of skin markings.
Pathological terms
• Acanthosis: hyperplasia of prickle.—psor.
• Hyperkeratosis: thickening of stratum corneum
• Hypergranulosis: thickening of granular Layer—lichen planus
• Acantholysis: loss of cohesion between Keratinocyes resulting in
Intraepidermal vesicle.---pemphigus
• Parakeratosis: retention of nuclei in stratum corneum– psoriasis
• Spongiosis: intercellu. Edema---dermatitis
• Dyskeratosis: premature keratinization ---Squamous cell carcinoma
• Exocytosis: migration of inflammatory cells from the dermal vessels
to the epidermis.
• Liquefaction degeneration: degeneration of the basal layer
• Balloon degeneration: swelling of keratinocytes with loss of bridges
between the cells and vesicle formation. Ex . herpes