Chapter 5: Integumentary Flashcards
What are the major organs of the Integumentary System?
- Hair
- Skin
- Nails
- Sweat Glands
- Oil Glands
What are the 2 distinct regions of the skin?
- Epidermis
- Dermis
(3. Hyperdermis)
Epidermis
Superficial Region; consists of epithelial tissue and is avascular
Dermis
Underlies epidermis; Mostly fibrous connective tissue, vascular
Hyperdermis
Superficial fascia; shares some skin functions
- Mostly adipose tissue that absorbs shock and insulates
- Anchors skin to underlying structures: mostly muscles
What are the 4 types of cells found in the Epidermis?
- Keratinocytes
- Melanocytes
- Dendritic (Langerhans) cells
- Tactile (Merkel) cells
Keratinocytes
Produce fibrous keratin (protein that gives skin it’s protective properties)
Melanocytes
Produce pigment melanin, which protects the skin from UV radiation
Dendritic (Langerhans) cells
Macrophages that patrols deep epidermis
Tactile (Merkel) cells
Sensory receptors that sense touch
What are the 5 layers of the Epidermis?
4-5 distinct layers
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum (only in thick skin)
- Stratum corneum
Stratum Basale (basal layer)
Layer is firmly attached to dermis
- Consists of a single row of stem cells that actively divide
Stratum spinosum (prickly layer)
Several cell layers thick
Weblike system of intermediate prekeratin filaments
to resist tension and pulling
- Keratinocytes in this layer appear spikey
Stratum granulosum (granular layer)
4-6 cells thick, but cells are flattened, so layer is thin
- Cells die cause they’re too far from connective tissue to get nutrients
- *cells flatten, nuclei and organelles disintegrate**
- Keratinization begins
Stratum lucidum (clear layer)
Thick skin
- Made of thin, translucent band of 2 to 3 of clear, flat, dead keratinocytes
Stratum corneum (horny layer)
20-30 rows of flat, anucleated, keratinized dead cells
** 3/4 of epidermal thickness**
Dead cells give protection
Dermis
Strong, flexible connective tissue
- Contains nerves, blood vessels, and lymphatic vessels
- Contains epidermal hair follicles, oil glands and sweat glands
Has 2 layers
What are the 2 layers of the dermis?
- Papillary
2. Reticular
Papillary
Areolar connective tissue loosely packed to allow phagocytes to patrol for microorganisms
Reticular
Contains many elastic fibers and collagen fibers allowing for strength and stretch; contains lines of cleavage
Cleavage (tension) lines
In reticular layer are caused by many collagen fibers running parallel to skin surface
- Externally invisible
What are the 3 pigments that contribute to skin color?
- Melanin
- Carotene
- Hemoglobin
Melanin
Red or brownish black
- Freckles and pigmented moles are local accumulations of melanin
- *Sun exposure stimulates melanin production**
Carotene
Yellow to orange pigment
Hemoglobin
Pinkish hues in fair skin
What can excessive exposure to sun do to the skin?
- Elastic fibers clump
- Depress immune system
- Alterations to DNA (skin cancer)
- UV light destroys folic acid
- Photosensitivity is increased reaction to sun
What alterations in skin color can indicate disease?
- Cyanosis
- Erythema
- Pallor
- Jaundice
Cyanosis
Blue skin color- low oxygenation of hemoglobin
Erythema
Redness- fever, hypertension, inflammation, allergy
Pallor
Pale color- Anemia, low blood pressure, fear, anger
Jaundice
Yellow- Liver disorder
Hairs
Flexible strands of dead, keratinized cells
- Produced by hair follicles
- Hard keratin
Shaft
Area that extends above scalp, where keratinization is complete
Root
Area within scalp, where keratinization is still going on
Nails
Scale-like modifications of epidermis that contain hard keratin
- Consists of free edge, nail plate and root
Nail matrix
Thickened portions of bed responsible for nail growth
