Chapter 5.1: Integumentary

System

Cutaneous Membrane—Skin Made up of epidermis and dermis Accessory Structures Hypodermis—subcutaneous layer

Functions

Figure 5.1

Protection Temperature Maintenance Synthesis and storage of nutrients Makes Vitamin D Stores Lipids Sensory Reception Touch, Pressure, Pain Excretion and Secretion Excrete salts, water and wastes Secrete milk

Functions cont…

Stratified squamous epithelium Thick skin—palms and soles of feet 5 layers thick Thin skin—rest of body (4 layers thick) Strata—cell layers

Epidermis

Figure 5.1

Deepest layer Attached to basement membrane Forms fingerprints Stem cells Divide and grow into new skin Melanocytes—receptors for touch Make melanin Brown, Yellow/brown or black pigment Gives us skin color

Stratum germinativum

Figure 5.2

Figure 5.3

Adds to thickness of epidermis

Stratum spinosum

Figure 5.2

Produces keratin Protein Durable and water resistant Forms hair, calluses and nails

Stratum granulosum

Figure 5.2

Only on palms and soles

Stratum lucidum

Figure 5.2

15-30 layers of dead cellsShed in large groups or sheets

Stratum corneum

Figure 5.2

Pigmentation Carotene Orange/Yellow pigment Found in orange veggies Gets converted to vitamin A Keeps epidermis healthy

Skin Color

Melanocytes—produce and store melanin Increases in sunlight Freckles—small, pigmented spots Greater than average melanin production

Skin color cont…

Figure 5.3

Good—stimulates synthesis of vitamin D3 Bad—mild to severe burns Melanin absorbs UV rays Protects our DNA Long-term exposure Alterations to connective tissue—wrinkles Chromosomal damage—Skin cancer Prevention—sunscreen with at least SPF 15

UV Rays

Figure 5.4

Due to how much melanin is made Ex: Albinism Have melanocytes Cannot produce melanin

Different Skin Color

Blood is red Gives skin reddish tint Blood vessels dialated—more red color Blood vessels constricted—pale Cyanosis—bluish tint Due to lack of oxygen in blood

Dermal Circulation