Post on 28-Dec-2015
transcript
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