Lecture 10 - Integumentary System Flashcards
2 Main Components of Integumentary System
Cutaneous Membrane
Accessory Structures
6 Functions of Integumentary System
Protection
Excretion
Maintenance of Body Temperature
Melanin/Keratin Production
Synthesis of Vitamin D
Sensation
3 Layers of Integumentary System
Epidermis
Dermis
Hypodermis
3 types of receptors in Integumentary System
Tactile Corpuscle - Touch
Lamellated Corpuscle - Pressure
Nerve Fibres - Pain
2 glands in Integumentary System
Sweat Gland
Sebaceous Gland
4 other structures in Integumentary System
Hair Shaft
Arrector Pili Muscle
Hair Follicle
Cutaneous Plexus - Artery/Vein
Epidermis Definition
Superficial layer of Skin
Epidermis Tissue Type
Stratified Squamous Epithelium
2 types of skin
Thin Skin - covers most of body
Thick Skin - covers palms and soles
Papilla definition
Projection in the Dermis that interlock with the Epidermal Ridge
Creates Large Surface Area
Keratinocytes Definition
Skin Cells
Mechanism of Skin Renewal
As Keratinocytes divide, daughter cells are pushed superficially
As they are filled with Keratin, they die as they get to the surface
Layers of Thick Skin
Surface
Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
Basement Membrane
Stratum Corneum Definition
Layers of Dead, flat keratinocytes lacking organelles
Stratum Lucidum Defintion
Layer of Flattened Clear Cells
Stratum Granulosum Definition
Layer of Cells where Keratin is produced
Apoptosis occurs
Stratum Spinosum Defintion
Layer of Shrunken Keratinocytes
Stratum Basale Definition
Layer of dividing Basal Keratinocytes
EGF Definition
Epidermal Growth Factor
EGF Function
Stimulates Cell Division, Keratin Production and Glandular Secretion
Location of Epidermal Ridges
Fingertips
Epidermal Ridges Function
Provides Friction
Location of Thick/Thin Skin
Thick - Fingertips/Palms/Soles
Thin - Everywhere
Epidermal Thickness of Thick/Thin Skin
Thick - 0.6-4.5mm
Thin - 0.1-0.15mm
Difference in Epidermal Strata in Thick/Thin Skin
Think - Thicker Lucidum/Spinosum/Corneum
Thin - No Lucidum/Thinner Spinosum/Corneum
Epidermal Ridges in Thick/Thin Skin
Thick - Present
Thin - Absent
Presence of Hair Follicles in Thick/Thin Skin
Thick - Absent
Thin - Present
Presence of Sweat Glands in Thick/Thin Skin
Thick - More Numerous
Thin - Fewer
Presence of Sensory Receptors in Thick/Thin Skin
Thick - More Numerous
Thin - Sparse
Melanocyte Definition
Melanin producing cell
Melanocyte Function
Secretes Melanin into Keratinocytes
Trend in Melanin concentration and skin colour
Less Melanin = Whiter Skin
Cause of Freckles
More active Melanocytes
2 types of Pigments in Skin
Carotene
Melanin
Carotene Features (
Yellowish
Gained from Vitamin A
Melanin Features
Brown
Protects from UV Radiation
Dermis Function
Supports Epidermis
Uses Collagen and Elastic Fibres
2 Layers of Dermis
Papillary Layer
Reticular Layer
Papillary Layer Definition
Areolar Tissue
Reticular Layer Definition
Fibrous Network
Hypodermis Features
Layer of Loose Connective Tissue
Interwoven with Reticular Layer of Dermis
2 Tissues in Hypodermis
Areolar Tissue
Adipose Tissue
Hair Follicle Functions
Protection
Insulation
Sensation
Hair Follicle Distribution
Thousands of Epithelial Cells : 1 Hair Follicle
Location of Hair Follicle
Deep in Dermis
3 Layers in Hair Structure
Medulla (Core) - Contains Soft Keratin
Cortex - Thick Layers of Hard Keratin
Cuticle - Thin Layer of Hard Keratin
4 Parts of Follicle Structure
Internal Root Sheath - Epithelial Cells surrounding Hair Root
External Root Sheath - More Epithelial Cells
Glassy Membrane - Thick Clear Layer Wrapped in Connective Tissue Sheath
Connective Tissue Sheath - Protective
Hair Loss in Chemotherapy Mechanism
Cell Division in Hair Follicle is quick
Chemotherapy targets fast dividing cells
Therefore, Hair Loss
7 Steps of Hair Growth Cycle
Basal Cells Divide
Daugther Cells are pushed superficially ~0.33mm/day
Increasingly more Keratinised
At End, Follicle becomes inactive
Connections between hair matrix and root break down
Old Hair Sheds
New Hair Produced
Sebaceous Gland Function
Secretion of Sebum onto hair shaft
2 Sebum Functions
Helps waterproof skin
Pathogen Protection - slightly acidic
Mode of Sebum Secretion
Holocrine
2 Functions of Fingernails
Protection
Limits Distortion
6 Parts of Outer Fingernail
Free Edge
Lateral Nail Fold
Nail Body
Lunula
Proximal Nail Fold
Eponychium - Cuticle
Component of Nail Body
Keratinised Epithelial Cells
Lunula Function
Maintains Nail Body Structure
Parts of Inner Fingernail
Nail Bed - Epidermis
Phalanx
Nail Root
Nail Root Function
Nail Production
2 types of Sweat Glands
Apocrine
Merocrine
Apocrine Sweat Glands Function
Secretes odorous fluid in armpits (axillary)
Causes Body Odour
Merocrine Sweat Glands Function
Discharge watery fluid onto skin surface
3 General Sweat Gland Functions
Skin surface cooling
Excretion
Protection
Cause of Skin Cancer
Uncontrolled Cell Replication
78% are basal cell carcinomas
2% are Malignant Melanoma (can metastasise)
3 types of Burns
First Degree
Second Degree
Third Degree
First Degree Burn Feature
Reddening of the Epidermis
Second Degree Burn Feature
Blisters
Third Degree Burn Feature
Sensory Nerve Destroyed
7 Steps of Skin Injury Repair
Bleeding
Clot forms
Cells migrate from stratum basale
Phagocytic Cells arrive
Mesh produced by fibroblasts
Clot breaks up
Epidermis is healed
Intrinsic Skin Aging
Reduction in cell activity, GF hormones etc
5 Intrinsic Skin Aging Characteristics
Dermal Thinning
Wrinkling
White Hair
Increased Infection Risk
Slower Healing
Extrinsic Skin Aging
Changes from Sunshine Exposure + Smoking
2 Extrinsic Skin Aging Characteristics
Increased Wrinkling
Increased Skin Cancer risk
