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59 Cards in this Set
- Front
- Back
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The skin consists of three major regions:
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1. Epidermis-outermost superficial region
2. Dermis-middle region 3. Hypodermis-deepest region |
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Epidermis is composed of
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keratinized stratified squamous epithelium, consisting of 4 distinct cell types and 4-5 layers
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Epidermis cell types include:
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Keratinocytes, Melanocytes, Merkel Cells, and Langerhans Cells
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Keratinocytes produce
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the fibrous protein keratin
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Melanocytes produce
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prothe brown pigment melanin
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Merkel Cells function as
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touch receptors in association with sensory nerve endings
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Langerhans Cells
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Epidernal macrophages that help activate the immune system
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What are the layers of the Epidermis
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1. Stratum Corneum
2.Stratum Granulosum 3.Stratum Spinosum 4. Stratum Basale 5. Dermis |
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Stratum Corneum
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* Horny Layer
-Outermost layer of keratinized cells -Accounts for 3 quarters of the epidermal thickness -Functions include: waterproofing, protection from abrasion and penetration, rendering the body relatively insensitive to biological, chemical, and physical assaults |
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Stratum Granulosum
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*Granular Layer
-Thin; 3-5 cell layers in which drastic changes in keratinocyte appearance occurs -Keratohyaline and lamellated granules accumulate in the cells of this layer |
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Stratum Spinosum
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*Prickly Layer
-Cells contain a weblike system of intermediate filaments attached to desmosomes -Melanin granules and Langerhans' cells are abundant in this later |
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Stratum Basale
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-Deepest epidermal layer firmly attached to the dermis
-Consists of a single row of the youngest keratinocytes -Cells undergo rapid division, hence its alternate name, stratum germinativum |
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Stratum Lucidum
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*Clear Layer
-Thin, transparent band superficial to the stratum granulosum -Consists of a few rows of flat, dead keratinocytes -Present only in thick skin |
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Dermis
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-Second major skin region containing strong, flexible c.t.
-Cell types include firboblasts, macrophages and occasionally mast cells and white blood cells -composed of 2 layers, papillary and reticular |
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Papillary Layer
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-Areolar c.t. with collagen and elastic fibers
-Its superior surface contains peglike projections called dermal papillae -Dermal papillae contain capillary loops, Meissner's Corpuscles, and free nerve endings |
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Reticular Layer
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-Accounts for approx. 80% of the thickness of the skin
-Collagen fibers in this layer add strength and resiliency to the skin -Elastin fibers provide stretch-recoil properties |
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Hypodermis
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-Subcutaneous layer deep to the skin
-Composed of adipose and areolar c.t. |
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What three pigments contribute to skin color?
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Melanin
Carotene Hemoglobin |
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Melanin
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-yellow to reddish-brown to black pigment, responsible for dark skin colors
*Freckles and pigment moles result from local accumulations of melanin. |
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Carotene
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Yellow to orange pigment, most obvious in the palms and soles of the feet
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Hemoglobin
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reddish pigment responsible for the pinkish hue of the skin
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Different types of these prevent overheating of the body and secrete ceremun and milk
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Sweat Glands
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Eccrine Sweat Glands are found in
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palms, soles of the feet, and forehead
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Apocrine Sweat Glands are found in
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axillary and anogenital areas
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Ceruminous Glands
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Modified apocrine glands in external ear canal that secrete cerumen
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Mammary Glands
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Specialized sweat glands that Secrete milk
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Sebaceous Glands
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-Simple alveolar glands found all over the body
-Soften skin when stimulated by hormones -Secrete an oily secretion called sebum. |
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Sebum
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Oily secretion of sebaceous glands.
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Hair
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-Filamentous strands of dead keratinized cells produced by hair follicles
-Contains hard keratin which is tougher and more durable than soft keratin of the skin |
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Hair is pigmented by __________ at the base of the hair
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melanocytes
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Hair consists of a core called the ____a______, a ____b___, and an outermost ___c______.
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a. medulla
b. cortex c. cuticle |
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Hair is made up of
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The shaft projecting from the skin, and the root embedded in the skin.
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Hair Functions
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1. Helping to maintain warmth
2. Alerting the body to presence of insects on the skin 3. Guarding the scalp against physical trauma, heat loss, and sunlight |
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Hair is distributed over the entire skin surface except:
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-Palms, soles, and lips
-Nipples and portions of the external genitalia |
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Hair Follicle
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-Root sheath extending from the epidermal surface into the dermis
-Deep end is expanded forming a hair bulb -A knot of sensory nerve endings (a root hair plexus) wraps around each hair bulb |
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Bending a hair stimulates _________ _________ _______, hence our hairs act as sensitive touch receptors.
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Sensory nerve endings
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Two types of hair
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1. Vellus
2. Terminal |
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Vellus
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-Type of hair
-Pale, fine body hair found in children and the adult female |
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Terminal
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-Type of hair
-coarse, long hair of eyebrows, scalp, axillary, and pubic regions |
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Alopecia
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Hair thinning in both sexes
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Male pattern baldness is caused by
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follicular response to DHT
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Structure of a nail
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-Scalelike modification of the epidermis on the distal surface of fingers and toes
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Functions of the Integument Sytsem
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1. Protection
2.Body Temp Regulation 3.Cutaneous Sensation 4. Metabolic Functons 5. Blood Resevoir 6. Excretion |
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Protection
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-Function of the Integument System
-chemical, physical, and mechanical barrier |
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Body Temp Regulation
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-Function of the Integument System
-Accomplished by Dilation (cooling) and constriction (warming) of dermal vessels -Increasing sweat gland secretions to cool the body |
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Cutaneous Sensation
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-Function of the Integument System
-exoreceptors sense touch and pain |
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Metabolic Functions
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-Function of the Integument System
-Synthesis of vitamin d in dermal blood vessels |
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Blood Resevoir
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-Function of the Integument System
-skin blood vessels store up to 5% of the bodys blood volume |
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Excretion
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-Function of the Integument System
-limited amounts of nitrogenous wastes are eliminated from the body in sweat |
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Most skin cancers are ______and do not metastasize
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Benign
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Three major types of skin cancer
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1. Basal cell carcinoma
2. Squamous cell carcinoma 3.Melanoma |
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Basal cell carcinoma
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-Most common skin cancer
-Least Malignant -Slow growing and often doesnt metastasize -Can be cured by surgical excision in 99% of the cases -Stratum Basale cells proliferate and invade the dermis and hypodermis |
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Squamous cell carcinoma
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-Arises from keratinocytes of stratum spinosum
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Melanoma
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Cancer of melanocytes is the most dangerous type of skin cancer because it is highly metastatic and resistant to chemotherapy
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Characteristics of Melanoma
(ABCD Rule) |
A: Asymmetry; the 2 sides of the pigmented area do not match
B: Border is irregular and exhibits indentations C: Color (pigmented area) is black, brown, tan, and sometimes red or blue D: Diameter is larger than 6 mm(size of a pencil eraser) |
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How is melanoma treated?
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By wide surgical excision accompanied by immunotherapy
*chance of survival is poor if the lesion is over 4 mm thick |
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1st Degree Burns
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-only the epidermis is damaged
-symptoms include localized redness, swelling and pain |
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Second Degree Burns
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-epidermis and upper regions of dermis are damaged
-symptoms mimic 1st degree burns, but blisters also appear |
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Third Degree Burns
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Entire thickness of the skin is damaged.
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