Mark Robertson Professor of Biology

Delta College

THE INTEGUMENT

MEMBRANE TYPESConsist of 2 Tissues (basal areolar connective tissue & apical epithelium) Classes Recognized

Cutaneous (stratified squamous keratinized with areolar and dense irregular fibrous CT) Mucous (stratified squamous nonkeratinized, simple columnar, or pseudostratified columnar with areolar CT) Serous (simple squamous with areolar CT) Synovial (areolar connective with degraded simple squamous remnants)

FUNCTIONAL USES Protection (against microbes, abrasion, punctures, etc.) Maintain Water Balance (holds in moisture using keratinized dead outer cells)

Thermoregulation (adipocytes to hold in heat and sweat glands for heat loss)

Vitamin D Production (which allows calcium absorption in our intestinal tract lining)

Blood Reservoir (provides 5% of our total) Sensory Apparatus (creates parts for all 5 senses)

EPIDERMAL STRATA

3 Main Divisions Epidermis (above dermis)

4-5 layers: stratum corneum, lucidum, granulosum, spinosum, and basale Forms outer skin, hair, and nails

Dermis Papillary Region (tightly attached with folds and full of stretchy areolar tissue) Reticular Region (stiffer protective area with dense irregular fibrous tissue)

Hypodermis Dominated by adipose tissue, blood vessels, and nerves

EPIDERMAL STRATAStratum Basale

25% melanocytes/75% Keratinocytes; forms all upper layers; expandable

Stratum Spinosum Adds tensile strength to skin

Stratum Granulosum Makes subcomponents of keratin

Stratum Lucidum Assembles subcomponents to form keratin; creates thick skin in palmar/plantar regions

Stratum Corneum Dead layer; waterproofs the body

CLG

S

B

GLANDULAR SECRETIONSMerocrine (or Eccrine) Sweat Glands

sudoriferous glands with thin sweat; hairless areas: forehead, back, chest evaporation for cooling the body

Apocrine Sweat Glands sudoriferous glands with thick sweat; axillae and perineal modified products like cerumen in ears, milk in mammaries, and pheremones (volatile sex attractants)

Holocrine Oil Glands sebaceous glands; hairy areas only; provides lubricants with hair follicles

EPIDERMAL AND DERMAL FEATURES

Lines of Cleavage (cut lines; dense fibrous masses in dermis) Lines Of Flexure (permanent fold lines in epidermis; thinner area) Dermal Papillae (fingerprints and toeprints; increase gripping ability on digits) Tactile Sensory Structures

Meissner’s Corpuscles (superficial, detect light touch) Pacinian Corpuscles (detect deeper, heavy pressure and vibrations)

POSSIBLE JOURNAL CRITIQUE TOPICS?

Melanomas and Carcinomas? Male-Pattern Baldness? Scleroderma? Third Degree Burn Treatment? Sweat Gland Disorders? Albinism? Chalazian