Lecture 5.2: Integumentary System
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Lecture 5.2: Integumentary System
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Lecture 5.2: Integumentary System. Epidermis and Vitamin D3. UV rays cause cholesterol-like steroid to change to vitamin D3 Decreased Vitamin D leads to abnormal bone growth. Skin Cancer. Most common cancer Most people survive Treatment = removal of tumor Melanomas—extremely dangerous - PowerPoint PPT Presentation
Transcript of Lecture 5.2: Integumentary System
Lecture 5.2: Integumentary
System
UV rays cause cholesterol-like steroid to change to vitamin D3
Decreased Vitamin D leads to abnormal bone growth
Epidermis and Vitamin D3
Most common cancer Most people survive Treatment = removal of tumor Melanomas—extremely dangerous Usually begin as mole Grow rapidly Spread via lymphatic system
Skin Cancer
Figure 5.4
Papillary Layer Supports and nourishes epidermis Capillaries and nerves for skin surface are
here Reticular Layer Elastic fibers for elasticity Collagen fibers limit elasticity for protection
Dermis—Layers
Figure 5.2
Hair Follicles Sweat Glands
Other Dermal Components
Figure 5.1
Increased adipose cells Decreased heat loss in infants Energy reserve Shock absorber
Subcutaneous Layer
Figure 5.1
Everywhere except: Sides and soles of feet Palms Sides of fingers/toes Lips Parts of genitalia
Hair
Hair follicles—where hair is produced Hair papillae—where vessels and nerves are Hair root—anchors hair into skin Hair shaft—what we see Cuticle—surface layer of hair Grows about 0.3 mm/day May become inactive for awhile
Hair cont…
Figure 5.5b
Round hairs = straight hair Flattened hairs = curly hair Functions Protect from UV rays Cushion light blows Insulate Prevent entry of pathogens
Hair cont…
Sensory nerve fiber at base Arrector pili—bundle of smooth muscle Causes hair to stand up “Goosebumps”
Hair cont…
Figure 5.5b
Due to amounts of pigment produced by melanocytes
Due to genetics Pigment production decreases with age No pigment = white hair
Hair Color
Average about 50 hairs/day More than 100 hairs/day = hair loss Temporarily due to: Drugs Diet Radiation High Fever Stress Pregnancy
Hair Loss
AKA: Oil Glands Secrete into hair follicle Sometimes onto skin Secreted through arrector pili Sebum—secretion of oil Lubricates hair and skin Inhibits bacteria High amounts at puberty Acne—sebaceous duct blocked Secretions accumulate Causes pimples
Sebaceous Glands
Figure 5.7
Apocrine Glands Secrete into armpits, nipples and groin Sticky, cloudy, odorous secretion Starts at puberty Odorous when bacteria feed on sweat
Sweat Glands
Figure 5.7
