Functions of integumentary system & cell types & layers of epidermis

pages 13-15 in notes packet; 5pt quiz on 10/15

functions of integumentary system (6 of them)

• protection

• body temperature regulation

• cutaneous sensations

• vitamin D synthesis

• reservoir

• excretion

4 cell types of the epidermis

1. Keratinocytes

2. Melanocytes

3. Langerhans’ cells

4. Merkel cells

Layer from deep to superficial in thick skin (5 layers)

1. Stratum Basale

2. Stratum Spinosum

3. Stratum Granulosum

4. Stratum Lucidum

5. Stratum Corneum

Protection

• Chemical: skin secretions, acid mantle, natural antibiotic

• Physical: keratinized cells = hardness, waterproofing lipids

• Biological: langerhan’s cells communicate to immune system, macrophages are antigen presenters, DNA converts UV radiation to harmless heat

Body temperature regulation

• blood vessels in dermis dialate to release heat

• sweat glands secrete water that evaporates to cool body

Cutaneous sensations

• skin contains sensory receptors

• Controls: light touch, deep pressure, hair follicle receptors, pain

Vitamin D synthesis

• Cholesterol in skin is changed to vitamin D

• vitamin D helps intestine absorb calcium (makes bone tissue)

Reservoir

• dermis is vascular so stores blood

• dermis contains areolar tissue which stores water and salts

Execretion

• sweat contains small amounts of nitrogen containing wastes

• extreme sweating is important for water and salt loss

Keratinocytes

produce keratin which gives the epidermis its protective properties

Melanocytes

produce melanin

Langerhans’ cells

macrophages that help activate the immune system

Merkel cells

function as touch receptors in association with sensory nerve endings