Skin appendages Hair, sebaceous gland, nail, eccrine and apocrine glands Hair

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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 plate- hard keratin

  • Nail folds

  • Nail matrix

  • Cuticle

  • Nail bed

Eccrine gland

  • Coiled secretary portion and duct

  • Cholinergic stimulation

  • Thermoregulation

  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

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