Integumentary System

• 1.Epidermis
• 2.Dermis
• 3.Hypodermis

• 1.Epithelium
• 2.Superficial, thin
• 3.4 cell types:
• a.Keratinocytes (make, fill themselves with
• keratin)
• b.Melanocytes – melanin pigments (protect
• from UV rays)
• c.Merkel cells-sensory cell (receptor)
• d.Langerhans (epidermal dendritic) cells;
• phagocytesà
• present to immune system

• a)Basal – deepest, carcinoma (mitosis
• happens here, forms skin cells; 1 cells layer thick) 
• b)Spinosum – 2nd
• deepest (cells begin to flatten out; squamous cell carcinoma)
• c)Granulosum – flat cells, most superficial
• live layer
• d)Corneum – thickest, dead cells (keratin
• and lipid) 

4.Basal lamina

• 1. Papillary: Loose (areolar) connective tissue
• 2.Reticular: Dense (irregular) connective tissue

• 1.Barriers
• •Chemical
• •Physical
• •Biological

• 2.Temperature Regulation (always sweat a
• little-variess
• amount due to body temp; changing blood flow)

3.Sensation – cutaneous sensory receptors

4.Metabolism – vitamin D production

• 5.Blood Reservoir – skin can handle low
• levels of blood flow for some time

6.Excretion – small amount of N compounds

• A.Superficial fascia = hypodermis
• 1.Movement
• 2.Fat store
• 3.Anchor skin
• 4.Hypodermic injections

a.Epithelial cells in follicle

1.Sensory receptors at base (nerves)

• 2.smooth muscle (controls position of hair)
•     -sympathetic
• autonomic nervous system (ANS)

• 2 types
• 1.“apocrine” –few, large
• •Location:axillary and groin regions
• •Fatty substances and protein + water
• •Do not produce odor, odor comes from bacteria

• 2.merocrine –many, 99% H2O
• •Thermoregulation
• •Salt
• and waste exretion
• •Controlled by sympathetic ANS

• Sebaceous
• Sweat
• Mammary
• Ceruminous-ear wax

• –oily lipids, lubricate  
• -most around  
• -hormones controls these glands

• •Produce milk
• •Modified sweat glands
• •secretion controlled by oxytocin from hypothalamus of brain