Integumentary System (Exam 1) Flashcards
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Epidermis
Outermost
Stratified squamous epithelium
Most cells produce keratin
The skin
Largest organ of the body
Composed of epidermis and dermis
Stratum corneum
Top layer of epidermis
Hard layer
20-30 layers of dead cells filled with keratin
Water proofing glycolipids
Stratum lucidum
Clear layer
2nd layer
2-3 layers of dead cells filled with keratin
Only found in hard skin (soles, palms)
Stratum granulosum
Granular layer
3rd layer
3-5 layers of cells that are alive but dying
Keratinacyte
Produce granules of keratohyaline
Which secrete keratin
Lamellar bodies
Produce lamellated granules
Which secrete the glycolipids
Stratum spinosum
Spiny layer 4th layer 5-7 layers of living cells Has melanin granules Has langerhan's cells
Langerhan’s cells
Cells of the immune system that have migrated from the bone marrow
Stratum basalt
Basal layer 5th layer One layer of rapidly dividing cells Has melanacytes Has merkel discs
Melanacyte
Produces melanin granules
Merkel discs
Touch receptors
Dermis
Dense irregular connective tissue Has: Blood vessels Nerve endings Hair follicles Glands Smooth muscle
Papillary layer
1st layer of dermis
Immediately below that stratum basale
Areolar connective tissue with collagen and elastin
Dermal papillae on palms form fingerprints
Reticular layer
2nd layer of dermis
80% of the dermis
Dense irregular connective tissue with large bundles of collagen and elastin
Hypodermis
Below the dermis
Functions:
Stores fat for insulation and shock absorption
Anchors the skin to underlying bone and muscle
Pathway for blood vessels and nerves to reach upper layers
Merocrine/eccrine
Sweat glands
Most common
Secretory portion is coiled deep in the dermis
Releasing duct extends to the surface of the epidermis
Secretes sweat made of H2O and salt
Apocrine
Larger sweat glands Releasing duct opens into hair follicles Found in the Axillary and pubic region Not active till puberty Organic substances in secretions: Odorless when first released Odiferous when bacteria begin breaking down organic constituents
Sebaceous gland
Present everywhere except palms and soles
Secretes sebrum
Softens and lubricates hair and skin
Hair shaft
Extends above the skins surface
Hair root
Embedded in the skin
Inside of follicle
Medulla
Central axis of hair made of soft keratin
Cortex
The bulk of the hair
Cuticle
Outermost layer of hard keratin
Hair follicle
Wraps around the root
Deep end extends into the hair bulb
Hair bulb
Contains the matrix
Mitosis epithelial cells that produce new hair
Arrector pili muscle
Smooth muscle cells that stand up the follicle
Nail
Scale like modification of the epidermis
Nail root
Proximal end covered by skin
Nail body
Visible portion
Nail fold
Skin covering the lateral ends of the nail
Nail groove
Holds the edge of the nail in place
Free edge
Portion of the nail extending past the finger tip
Eponychium (cuticle)
Stratum corneum of nail fold that has grown over the nail body
Lunula
Crescent shaped area above the cuticle
Nail bed
Deeper layers of the epidermis extending beneath the nail
Nail matrix
The proximal portion of the nail be
Meissner’s corpuscles
Touch receptor in dermis
Nociceptors
Pain receptor in dermis
Thermoceptors
Temperature receptors in Deimos
Pacinian corpuscles
Pressure receptors in dermis
Integumentary system functions
Protection
Body temperature regulation
Sensation
Protection
Chemical barrier
Physical barrier
Biological barrier
Basal cell carcinoma
Least malignant
Most common
Begins in the stratum basale
Tissue destruction produces an ulcer
Surgical removal or radiation therapy
Squamous cell carcinoma
Cells in the stratum spinosum continue unregulated cell growth
Rarely the tumor migrates from the epidermis to the dermis and can metastasize
Malignant melanoma
Least common
Arises from melanocytes
Develops as a large, flat, spreading sore, or a lump under the skin
Metastasis is common, usually fatal
1st degree burn
Only on the epidermis
Red and painful
Heals in a week without scarring
2nd degree burn
Epidermis and dermis are damaged Red and painful Edema (swelling) usually develops Blisters develop Heal in 1-2 weeks, scarring depends on extent of dermal damage
3rd degree burn
Epidermis and dermis are completely destroyed
Skin can only regenerate from the edges
Skin grafts are often necessary
