Skin Layers Reading

University:
The University Of Western Ontario
Course:
ANAT 2200B | Systemic Anatomy of the Human Body
Academic year:

2022
Views:

185

Pages:

3
Author:

Kyuwon J.

Skin layer ● Largest organ in the body ○ Barrier ○ Thermoregulation ○ Sensory interface ● Three main layers ○ Epidermis ○ Dermis ○ Hypodermis Epidermis ● Stratified squamous keratinized epithelium ○ Avascular = nourished in diffusion of dermis ○ Thickness may vary ■ Thinnest in eyelids (0.05mm) ■ Thickest in palm+Sole (1.5mm) ● Sublayers ○ Stratum basale ■ Germinativum ● Single basal keratinocytes ● Attached through basement membrane by hemidesmosomes ● Melanocytes ● Merkel cells (touch receptors) ○ ○ ○ ○ ■ Mitosis takes place Stratum spinosum ■ Prickle cell layer ● Keratinocytes are linked by desmosomes ● Tensile strength d ● Langerhans cell ○ Immunity and surveillance Stratum granulosus ■ 3-5 layers in flatted cell ■ Keratoyalin granules ● Keratin precursors ■ Lamellar body will release in lipids => creates water barriers Stratum lucidum ■ Clear layer by dead keratinocytes ● Filled with eleidin Stratum corneum ■ Dead flatten keratinocytes ● Corenocytes ■ Barriers in mechanical chemical against water loss Layer Key Features Function Epidermis Keratinized squamous epithelium; avascular Protective barrier – Basale Stem cells, melanocytes, Merkel cells Cell renewal, pigment, sensation – Spinosum Desmosomes, “prickle cells” Strength, flexibility – Granulosum Keratohyalin granules, lipids Waterproofing, barrier formation – Lucidum* Clear layer (thick skin only) Extra protection (palms/soles) – Corneum Dead, keratinized cells Outer barrier, prevents water loss Dermis Connective tissue, vascularized Strength, elasticity, support – Papillary Loose CT, capillaries, Meissner corpuscles Nourishes epidermis, light touch – Reticular Dense CT, glands, follicles, Pacinian corpuscles Strength, pressure detection Hypodermis Loose CT + adipose Insulation, cushion, energy store Dermis ● Connective tissue layer under epidermis ● Strength elasticity + thermoregulations ● Have vascular supply ● 0.6mm ● Hair follicles + sweat glands Hypodermis ● Not part of skin but have associations ● Connective tissue + adipose tissue ● Used for E storage ● Thermal insulation ● Shock absorptions ● Anchors skin to muscles and fascia