Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
59 Cards in this Set
- Front
- Back
The skin consists of three major regions:
|
1. Epidermis-outermost superficial region
2. Dermis-middle region 3. Hypodermis-deepest region |
|
Epidermis is composed of
|
keratinized stratified squamous epithelium, consisting of 4 distinct cell types and 4-5 layers
|
|
Epidermis cell types include:
|
Keratinocytes, Melanocytes, Merkel Cells, and Langerhans Cells
|
|
Keratinocytes produce
|
the fibrous protein keratin
|
|
Melanocytes produce
|
prothe brown pigment melanin
|
|
Merkel Cells function as
|
touch receptors in association with sensory nerve endings
|
|
Langerhans Cells
|
Epidernal macrophages that help activate the immune system
|
|
What are the layers of the Epidermis
|
1. Stratum Corneum
2.Stratum Granulosum 3.Stratum Spinosum 4. Stratum Basale 5. Dermis |
|
Stratum Corneum
|
* 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 |
|
Stratum Granulosum
|
*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 |
|
Stratum Spinosum
|
*Prickly Layer
-Cells contain a weblike system of intermediate filaments attached to desmosomes -Melanin granules and Langerhans' cells are abundant in this later |
|
Stratum Basale
|
-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 |
|
Stratum Lucidum
|
*Clear Layer
-Thin, transparent band superficial to the stratum granulosum -Consists of a few rows of flat, dead keratinocytes -Present only in thick skin |
|
Dermis
|
-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 |
|
Papillary Layer
|
-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 |
|
Reticular Layer
|
-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 |
|
Hypodermis
|
-Subcutaneous layer deep to the skin
-Composed of adipose and areolar c.t. |
|
What three pigments contribute to skin color?
|
Melanin
Carotene Hemoglobin |
|
Melanin
|
-yellow to reddish-brown to black pigment, responsible for dark skin colors
*Freckles and pigment moles result from local accumulations of melanin. |
|
Carotene
|
Yellow to orange pigment, most obvious in the palms and soles of the feet
|
|
Hemoglobin
|
reddish pigment responsible for the pinkish hue of the skin
|
|
Different types of these prevent overheating of the body and secrete ceremun and milk
|
Sweat Glands
|
|
Eccrine Sweat Glands are found in
|
palms, soles of the feet, and forehead
|
|
Apocrine Sweat Glands are found in
|
axillary and anogenital areas
|
|
Ceruminous Glands
|
Modified apocrine glands in external ear canal that secrete cerumen
|
|
Mammary Glands
|
Specialized sweat glands that Secrete milk
|
|
Sebaceous Glands
|
-Simple alveolar glands found all over the body
-Soften skin when stimulated by hormones -Secrete an oily secretion called sebum. |
|
Sebum
|
Oily secretion of sebaceous glands.
|
|
Hair
|
-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 |
|
Hair is pigmented by __________ at the base of the hair
|
melanocytes
|
|
Hair consists of a core called the ____a______, a ____b___, and an outermost ___c______.
|
a. medulla
b. cortex c. cuticle |
|
Hair is made up of
|
The shaft projecting from the skin, and the root embedded in the skin.
|
|
Hair Functions
|
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 |
|
Hair is distributed over the entire skin surface except:
|
-Palms, soles, and lips
-Nipples and portions of the external genitalia |
|
Hair Follicle
|
-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 |
|
Bending a hair stimulates _________ _________ _______, hence our hairs act as sensitive touch receptors.
|
Sensory nerve endings
|
|
Two types of hair
|
1. Vellus
2. Terminal |
|
Vellus
|
-Type of hair
-Pale, fine body hair found in children and the adult female |
|
Terminal
|
-Type of hair
-coarse, long hair of eyebrows, scalp, axillary, and pubic regions |
|
Alopecia
|
Hair thinning in both sexes
|
|
Male pattern baldness is caused by
|
follicular response to DHT
|
|
Structure of a nail
|
-Scalelike modification of the epidermis on the distal surface of fingers and toes
|
|
Functions of the Integument Sytsem
|
1. Protection
2.Body Temp Regulation 3.Cutaneous Sensation 4. Metabolic Functons 5. Blood Resevoir 6. Excretion |
|
Protection
|
-Function of the Integument System
-chemical, physical, and mechanical barrier |
|
Body Temp Regulation
|
-Function of the Integument System
-Accomplished by Dilation (cooling) and constriction (warming) of dermal vessels -Increasing sweat gland secretions to cool the body |
|
Cutaneous Sensation
|
-Function of the Integument System
-exoreceptors sense touch and pain |
|
Metabolic Functions
|
-Function of the Integument System
-Synthesis of vitamin d in dermal blood vessels |
|
Blood Resevoir
|
-Function of the Integument System
-skin blood vessels store up to 5% of the bodys blood volume |
|
Excretion
|
-Function of the Integument System
-limited amounts of nitrogenous wastes are eliminated from the body in sweat |
|
Most skin cancers are ______and do not metastasize
|
Benign
|
|
Three major types of skin cancer
|
1. Basal cell carcinoma
2. Squamous cell carcinoma 3.Melanoma |
|
Basal cell carcinoma
|
-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 |
|
Squamous cell carcinoma
|
-Arises from keratinocytes of stratum spinosum
|
|
Melanoma
|
Cancer of melanocytes is the most dangerous type of skin cancer because it is highly metastatic and resistant to chemotherapy
|
|
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) |
|
How is melanoma treated?
|
By wide surgical excision accompanied by immunotherapy
*chance of survival is poor if the lesion is over 4 mm thick |
|
1st Degree Burns
|
-only the epidermis is damaged
-symptoms include localized redness, swelling and pain |
|
Second Degree Burns
|
-epidermis and upper regions of dermis are damaged
-symptoms mimic 1st degree burns, but blisters also appear |
|
Third Degree Burns
|
Entire thickness of the skin is damaged.
|