Integumentary Flashcards
(36 cards)
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
