BIO-50A Chapter 5

Integumentary system

1. Outer epidermis

2. Inner epidermis

Stratum Germinatium

1. innermost layer

2. New cells produce keratin then go up and die

Defensins

1. Antimicrobial peptides (Skin is injured)

Vitamin D

Cholesterol is changed in UV rays

Stratum Corneum

1. Outermost layer; prevent water loss/entry

2. Resists pathogens & Chemicals

Langerhans Cells

1. Phagocytize foreign material

2. Transports to lymph nodes

3. Stimulate immune response by lymphocytes

Melanocytes

1. Lower epidermis; produce melanin

Hair Follicles

1. Mitosis in hair root

2. Produce keratin - hair shaft

3. Insulates scalp, protects eyes and hair

Nail follicles

1. Ends of fingers & toes

2. Mitosis occurs

Receptors of skin

1. Detect changes; provides feedback

2. Sensitivity depends on receptors

Sebaceus gland

1. Secrete sebum

   1. Inhibits bacterial growth

2. Prevents drying

Cerminous gland

1. Secrete cerumen (earwax)

   1. Prevent dryness

Apocrine seat glands

1. Modified scent glands

   1. Axillae & Genital

2. From stress/emotions

Eccrine glands

1. Often on face, palms, & soles

2. High temp. or exercise

3. Sweat

Artioles

1. Vasoconstriction (Cold/stress)

   1. Reduce flow to organs

2. Vasodilation (warmth)

   1. Increase flow for warmth

Areolar tissue

1. Loose connective tissue

   1. Contains fluid and destroys pathogens

2. Master cells produce inflammation inducing cells

Adipose tissue

1. Store fat for potential energy

2. Cushions body prominences

3. Insulation