Lecture 8 Flashcards
The Integumentary system
Skin=
Accessory Structures=
-epidermis
-dermis
-hypodermis
-hair
-nails
-glands
Cells of the Epidermis
Five epidermal cell types
1.
2.
3.
4.
5.
- stem cells
- Keratinocytes
- Melanocytes
- Tactile cells
- Dendritic cells
Stem cells
-undifferentiated cells that give rise to keratinocytes
-in deepest layer of epidermis (stratum basal)
-going through mitotic division
Keratinocytes
great majority of epidermal cells; synthesize keratin
Melanocytes
synthesize pigment melanin; shields DNA ultraviolet radiation
Tactile cells
touch receptor cells associated with dermal nerve fibers
Dendritic cells
macrophages originating in bone marrow that guard against pathogens
Layers of the Epidermis
Thin skins contains ______ strata; thick skin contains ______ strata
5 layers include:
1.
2.
3.
4.
5.
four; five
1. Stratum corneum (surface layer)
2. Stratum lucidum
3. Stratum granulosum
4. Stratum spinous
5. Stratum basale
Stratum corneum:
several layers (up to ___) of dead, scaly, ________ cells
-resists ________, __________, and ________
30; keratinized
-abrasion; penetration; water loss
Stratum lucidum
Thin, pale layer found only in _____ skin
-keratinocytes packed with clear protein _______
-only found in……
thick
-eleidin
-palms of hands, soles of feet
Stratum granulosum
_____ to _____ layers of flat keratinocytes
- cells contain dark-staining ________ granules
three; five
-keratohyalin
Stratum spinosum
several layers of keratinocytes joined by ________ and __________________
-names of appearance of cells after histological preparation (spiny)
-also contains some _______ cells
desmosomes; tight junctions
-dendritic
Stratum basale (deepest epidermal layer)
-single layer of ____ cells and keratinocytes
-also contains a few _________ and _______ cells
-stem
-melanocytes; tactile
The Dermis
-ranges from 0.2 mm (eyelids) to 4 mm (palms, soles)
-composed mainly of _____
-Well supplies with blood vessels, sweat glands, sebaceous glands, and nerve endings
-houses _____ follicles and ______ roots
-________ of facial expression attach to dermis
-wavy, conspicuous boundary between dermis and epidermis
-Dermal ________
-Epidermal ______
-collagen
-hair; nail
-muscles
-papillae
-ridges
Dermal papillae
upward, finger-like extensions of dermis
Epidermal ridges
downward waves of epidermis
The dermis consists of two layers
1.
2.
Papillary layer
Reticular layer
Papillary layer
-Thin zone of _______ tissue in and near the dermal papilla
-allows for mobility of ______ and other defense cells
-rich in ______ blood vessels
-areolar
-leukocytes
-small
Reticular layer
-thicker layer of ______________ connective tissue
-Stretch marks (striae)
-tears in the ________ fibers caused by stretching of the skin due to pregnancy or obesity
-dense irregular
-collagen
Skin Color
-dark and light skin individuals have the same number of ____________ but different types of ______
melanocytes; melanin
Darker skin= more _________
-melanocytes produce ______ quantities of melanin
-melanin breaks down more slowly
-melanin granules more ___________ in keratinocytes
-melanized cells seen throughout the epidermis
eumelanin
-greater
-spread out
Lighter skin= more ____________
-melanin clumped near keratinocyte nucleus
-little melanin seen beyond stratum _____
pheomelanin
-basale
Cyanosis
blueness due to oxygen deficiency
Erythema
redness due to increased blood flow to skin
