Module 5 - Integumentary System Flashcards
Skin Functions
Thermoregulation
Protection – physical, chemical, and biological – barrier
Excretion and absorption
Synthesis of vitamin D
Cutaneous sensations
Cutaneous sensations
Cutaneous sensations
Touch pressure
Vibration
Tickle
Heat
Cold
Pain
Principal Cells of Epidermis
4 principal cells
Keratinocytes
Melanocytes
Langerhans
Merkel
Keratinocytes
Keratinocytes – protein keratin – protect skin and tissue from heart, microbes, and chemicals – produces lamellar granules (water proof) – replacement = keratinization, 2-4 weeks
Melanocytes
Melanocytes – pigment – skin colour – absorbs damaging UV light
Langerhans
Langerhans – immune response
Merkel
Merkel – sensory touch – tactile merkel disc
Layers of Epidermis
Layers – Deepest to surface
Stratum Basale
Stratum Spinosum
Stratum Granulosum
Stratum Lucidum
Stratum Corneum
Stratum Basale
Stratum Basale – stem cells to divide – stratum germinativum – forms new cells – makes melanin – colour = amount of melanin produced - 1st layer
Stratum Spinosum
Stratum Spinosum – provides strength and flex - 2nd layer
Stratum Granulosum
Stratum Granulosum – transition b/w deeper – water-repellent to protect lower metabolically active strata - 3rd layer
Stratum Lucidum
Stratum Lucidum – ONLY present on fingers, palms, and soles – clear layer to reduce friction - 4th layer
Stratum Corneum
Stratum Corneum – superficial – dead cells – lamellar granules are water-repellent – friction = callus (abnormal thickening) - 5th layer
Dermis
Dermis
Deeper layer
Dense irregular connective tissue
Collagen and elastic fibres
Blood vessels, hair follicles, sweat glands
2 layers
Papillary layer
Reticular layer
Epidermal ridges
3 pigments in dermis
Papillary layer
Papillary layer – areolar connective tissue – Meissner corpuscles (touch) – nerve ends for heat, cold, pain, tickle, and itch – finger prints here – fine elastic fibres
Reticular layer
Reticular layer (deeper) – collagen – irregular connective - some elastic fibres
Epidermal ridges
Epidermal ridges – finger prints – contours of underlying dermis – help grasping
Pigments in dermis
3 pigments in dermis – melanin, carotene, and hemoglobin (blood in capillaries)
Subcutaneous – Hypodermis
Subcutaneous – Hypodermis
Deepest
Areolar and adipose tissue
Fat storage
Blood vessel passage
Pressure nerve endings
Areolar tissue
Areolar tissue – loose connective – provides support, protects organs and muscles – binds skin together
Hair
Hair
Shaft
Root
Hair bulb
Hair papilla
Hair matrix
Arrector pili
Hair Functions
Functions – protection, thermal insulation, and sensing light touch
Parts of shaft and roots
Shaft and root are continuous
Outer cuticle
Inner medulla
Innermost cortex
Hair bulb
Hair bulb – protective layer
Arrector pili
Arrector pili – muscle controls hair standing or not
Hair Matrix
Hair matrix – mitotically active – new hair
Hair papilla
Hair papilla – blood vessels
Hair Root
Root – penetrates dermis and subQ – living
Hair Shaft
Shaft – surface of skin – non-living
Sebaceous Glands
Sebaceous – oil – connected to hair follicles – none in palms and soles
Sebum
Sebum
Sebum – moistens hair, waterproofs and softens skin, inhibits bacteria
Sudoriferous Glands
Sudoriferous – sweat
Eccrine
Apocrine
Eccrine Glands
Eccrine – regulate temp – eliminates waste
Apocrine Glands
Apocrine – skin of axilla, pubis, and areolae – ducts open onto follicles
Ceruminous glands
Ceruminous glands – modified sudoriferous - cerumen
Cerumen
Cerumen – external auditory meatus
