Integumentary Flashcards
Epidermis
- Keratinized Stratified Squamous
- Composed of:
- Langerhan’s Cells
- Melanocytes
- Keratinocytes
Langerhan’s Cells
- Type of dendritic cells
- Cytoplasmic extensions
- Take in foreign antigen
- Stimulates other immune system cells to respond to antigen
Melanocytes
- Irregular shape
- Long cytoplasmic extensions between keratinocytes of Stratum Basale and Stratum Spinosum
- Golgi package melanocytes into melanosomes
- Protection from UV light
- Determine skin/hair color
- Pigment - melanin
Keratinocytes
□ Produce keratin ◊ Protein molecular structure ◊ Gives structural strength ◊ Waterproof ◊ Antibacterial □ Keratinization ◊ Keratin % increases to surface of the epithelium □ Desquamate ◊ Loss of keratinized cells from the free surface
Epidermis Layers
Stratum Basale
Stratum Spinosum
Stratum Granulosum
Stratum Corneum
Stratum Basale
□ Against basement membrane □ Basal cells □ Hemidesmosomes ◊ Anchor to basement membrane □ Mitosis on average every 19 days □ Desquamate on average in 45 days
Stratum Spinosum
□ 8-10 layers □ More desmosomes □ Increase in keratin % □ Some mitosis occurs in layers □ Spinosum and Basale together are called Stratum Germinativum
Stratum Granulosum
□ 2-5 layers
□ More flattened
□ Keratohyalin protein granules accumulate in cytoplasm
□ Lamellar bodies of Stratum Spinosum move to cell surface and release lipids between cells
□ Nucleus and organelles degenerate
Stratum Corneum
□ Many layers thick normally to hundreds of layers in callus regions
□ Dead cornified cells
□ Highest % of keratin
□ Lipids from lamellar bodies offer some water resistance
□ This layer thickest in callus areas
Thick Skin
□ Also have Stratum Lucidum ◊ Several layers ◊ This layer absent on thin skin areas ◊ Cells appear transparent ◊ Dead cells ◊ Keratohyalin granules dispersed □ Found in areas of high pressure and resistance □ No hair
Dermis
Papillary Dermis (loose aerolar connective tissue) Reticular Dermis (dense irregular connective tissue) Collagen is primary fiber in matrix
Papillary Dermis
□ Directly underneath pigmented epithelium
□ Papillae (means nipple) extend toward epithelium
□ More cells and fewer fibers
□ Larger number of blood vessels
□ Supply blood to basal cells in epidermis
Reticular Dermis
□ Deeper
□ Main fibrous layer/strongest
□ Cleavage lines (collagen fiber direction)
◊ Cutting against will slow healing, increase scar formation
◊ Cutting with speeds healing, decrease scar formation
Hypodermis
Subcutaneous
Loose connective tissue
Yellow adipose tissue
Attaches dermis to underlying tissue
Hypodermis Cells
□ Fibroblasts/fibrocytes □ Mast cells (heparin (anticoagulant) + histamine) ◊ Look similar to basophils ◊ Stain all purple ◊ Nucleus is unilobe, central and lighter (sunny side up eggs) ◊ Mast cells have coarser granules □ Adipocytes □ Macrophages (phagocytosis)
Hair Follicle
Shaft Root Bulb Dermal Root Sheath Epithelial Root Sheath Matrix
Shaft
Above the skin surface
Root
Below the skin surface
Bulb
□ The expanded base of the root □ Both hair shaft and root are composed of: ® Medulla ◊ 2-3 layers of soft keratin ◊ Internal layer ® Cortex ◊ Many layers of hard keratin containing cells ◊ Forms the major part of the hair ® Cuticle ◊ Single layer of cells ◊ Forms the hair surface ◊ Hard keratin ◊ Cuticle cells overlap ◊ Varying amounts of melanin is in cells ◊ Determines hair color
Dermal Root Sheath
Part of the dermis surrounding the follicle and epithelial root sheath
Epithelial Root Sheath
□ Internal
◊ As raised edges that mesh with the cuticle of the hair
◊ Hold hair in place
□ External
◊ Has all the layers present in thin skin
◊ Layers will decrease to the hair bulb where only the Stratum Germanitivum is present
◊ Stratum Germanitivum on the bulb is the source of the hair
Matrix
□ Enlarged knob at the end of the hair bulb
□ Epithelial cells from the Stratum Germanitivum
□ Source of the hair and internal epithelial root sheath
Arrector Pili Muscle
Smooth muscle
Around sebaceous glands
Gives rise to goosebumps
Merocrine (Eccrine) Glands
Sweat glands found throughout the body
Apocrine Glands
Sweat glands found in axillary region. Much bigger than merocrine, responsible for body odor
Sebaceous Glands
Secrete oil, around hair follicle
Nails
Keratinized cells of Stratum Corneum Nail body Free edge Eponychium (cuticle) Nail root Nail bed Lunula Hyponychium Nail groove Nail fold
Nail Body
Majority of nail
Free Edge
Part you clip
Eponychium (cuticle)
Right under the nail body
Nail Root
Proximal to cuticle, where the nail body originates
Nail Bed
Layer deep to the nail body
Lunula
Small, white, crescent at the base of the nail
Hyponychium
Region under the free edge
Nail Groove
Depression between nail body and skin
Nail Fold
Ridge above the groove
