Chapter 5: Integumentary System Flashcards
What are the two main parts of the skin?
Epidermis and dermis
What is the epidermis composed of?
Keratinized stratified squamous epithelium containing four main types of cells:
Keratinocytes
Melanocytes
Intraepidermal macrophages
Tactile epithelial cells
What is the dermis composed of?
Dense, irregular connective tissue containing collagen and elastic fibers
Where are lamellar granules located, and what is their function?
They are located in keratinocytes
They release lipid-rich secretions acting as a sealant, preventing the loss of body fluids and entry of foreign materials
What are the layers of the epidermis?
Four strata or layers:
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum corneum
What is the function of stratum spinosum?
It provides strength and flexibility
What is the function of stratum granulosum?
This is where keratinocytes undergo apoptosis
What is the stratum lucidum?
This is the fifth layer of skin in thick skin (on palms and soles). It is located between the granulosum and the corneum
Describe the superficial part of the dermis?
Makes up 1/5 of the thickness of the layer
Made of areolar connective tissue containing fine elastic fibers
Surface area is increased by dermal papillae, touch receptors, and free nerve endings
What is another term for touch receptors?
Meissner corpuscles
Describe the deeper part of the dermis
Attached to subcutaneous layer
Made of dense irregular connective tissue containing bundles of collagen and coarse elastic fibers
Adipose cells, hair follicles, nerves, oil glands, and sweat glands are found between the fibers.
What are striae?
These are permanent stretch marks that are visible at the skin surface
Created from extreme stretching that causes tears in course elastic fibers in the deep layer of the dermis
What is vitiligo?
This is a loss of melanocytes in a skin region and leads to patches of lighter or pale skin
Where does tattooing deposit pigmentation?
Pigment is deposited into the dermis with a needle. Because the dermis is stable, tattoos are permanent
Describe the layering of a hair follicle
It has an internal and external layer of epidermal cells, and then together are surrounded by a connective tissue sheath
What are hair root plexuses?
These are nerve ending surrounding each hair follicle that are sensitive to touch
What is the hair bulb?
This is the base of each hair follicle.
it contains the papilla of the hair, which are the blood vessels that provide nourishment for growing hair
What are arrector pili?
These are bundles of smooth muscle associated with hairs that contract under stress like cold or fright that make the hairs stand perpendicularly
What stimulates hair growth during puberty?
Androgens
What is Hirsutism?
This is the excessive hair growth due to androgens
What is androgenic alopecia?
This is genetically inhibited growth of scalp hair
What are ceruminous glands?
These are glands in the outer ear canal and produce a yellowish secretion called cerumen or earwax
What are sebaceous glands?
These are glands that secrete sebum (oily substance) that keeps hair from drying out, prevents excessive evaporation, softens skin, and inhibits certain bacteria
What are the two types of sudoriferous glands?
Apocrine sweat glands
Eccrine sweat glands
What are apocrine sweat glands?
These are found mainly in the skin of the axilla (armpit), groin, areolae of the breasts, and bearded regions of the face
What are eccrine sweat glands?
Most prevalent sweat glands found throughout most of the body - especially in forehead, palms, and soles
What are nails made of?
Hard, dead, keratinized epidermal cells
What are the main parts of a nail?
Nail body, free edge, nail root, lunula, cuticle, and nail matrix
What are the major functions of the skin?
Body temp regulation
Protection
Cutaneous sensations
Excretion and absorption
Synthesis of vit. D
How does the skin regulate body temperature?
Liberates sweat at skin surface
Adjusting blood flow in dermis
How is the skin involved in protection?
Keratin in skin protects underlying tissues from microbes, abrasion, heat, and chemicals.
Lipids from lamellar granules inhibit evaporation of water from the skin surface to protect from dehydration.
acidic pH of perspiration prevents some microbial growth
Melanin helps protect against UV light
Hair and nails have some protective functions
Intraepidermal macrophages alert immune system about potentially harmful microbial invaders
How is the skin involved in cutaneous sensations?
These arise in the skin and include tactile sensations and thermal sensations. Pain is also a cutaneous sensation, usually indicating tissue damage
How is the skin involved in vitamin D synthesis?
UV radiation exposure of the skin activates vitamin D. It is converted to its active form called calcitriol, and helps with absorption of calcium and phosphorus from the GIT into the blood.
What is transdermal drug administration?
This is when a drug is contained in an adhesive skin patch, and moves across the epidermis into the blood vessels of the dermis. Drug release is continuous and controlled over one to several days.
What is epidermal wound healing?
This is when a wound affects only the epidermis. Stratum basale cells move over to fill the void and create new epidermal layers. When migrating cells meet in the middle, they stop moving, grow, and build new strata to complete wound repair.
What is deep wound healing?
This is when a deep wound that extends to the dermis and potentially subcutaneous layer. Blood vessels are damaged, and scar tissue forms, and the tissue loses some of its functions. Once blood clots form, various cells move in and repair damage by removing damaged tissue and microbes, building the connective extracellular matrix, and making new epidermal cells.
What protein changes occur in the dermis during normal age-related changes?
Collagen fibers decrease in number, stiffen, break apart, and disorganize into a shapeless, matted tangle
Elastic fibers lose elasticity, thicken into clumps, and fray (accelerated in smokers’ skin)
Fibroblasts decrease in number (cells are responsible for collagen and elastic fiber production)
This leads to wrinkles
Why does the skin’s immune responsiveness decrease with age?
Intraepidermal macrophages decrease in number and become less-efficient phagocytes.
Skin becomes more dry and broken due to decreased sebaceous gland size.
What is the result of decreased functioning melanocytes with older age?
Increase in gray hair and atypical skin pigmentation
How does the integumentary system help maintain homeostasis of the skeletal system?
Helps activate vitamin D which is needed for absorption of dietary calcium and phosphorus to build and maintain bones
How does the integumentary system help maintain homeostasis of the muscular system?
Helps provide calcium ions which are key for muscle contraction
How does the integumentary system help maintain homeostasis of the nervous system?
Nerve endings in the skin and subcutaneous tissue provide sensory input for tactile, thermal, and pain sensations
How does the integumentary system help maintain homeostasis of the endocrine system?
Keratinocytes in skin help to activate vit. D to calcitriol, which is a hormone
How does the integumentary system help maintain homeostasis of the cardiovascular system?
Chemical changes in the dermis cause widening and narrowing of skin blood vessels that help adjust blood flow to the skin
How does the integumentary system help maintain homeostasis of the lymphatic/immune system?
Skin is first line of defense as it is a mechanical barrier and has chemical secretions to discourage growth of microbes
Intraepidermal macrophages participate in immune responses by recognizing foreign antigens
Macrophages in dermis phagocytize microbes that penetrate skin surface
How does the integumentary system help maintain homeostasis of the respiratory system?
Hairs in the nose filter dust particles from inhaled air
Stimulation of pain nerve endings in the skin may alter breathing rate
How does the integumentary system help maintain homeostasis of the digestive system?
The skin helps to activate vit. D to calcitriol, which is involved in absorption of dietary calcium and phosphorus in the small intestine
How does the integumentary system help maintain homeostasis of the urinary system?
kidney cells receive partially activated vit D from the skin and convert it to calcitriol
Some waste products are excreted from body in sweat, contributing to excretion by urinary system.
How does the integumentary system help maintain homeostasis of the Reproductive system?
Nerve endings in skin and subcutaneous tissue respond to erotic stimuli, contributing to sexual pleasure
Suckling of baby stimulates nerve endings in skin, causing milk ejection
Mammary glands are modified sweat glands that produce milk
Skin stretches during pregnancy as the fetus enlarges
How does the integumentary system help maintain homeostasis of the entire body?
skin and hair provide barriers protecting internal organs from damaging external agents.
Sweat glands and skin blood vessels regulate body temp, which is key for other body systems.
What are the three common forms of skin cancer?
Basal cell carcinomas
Squamous cell carcinomas
Malignant melanoma
Describe basal cell carcinomas
These account for about 78% of all skin cancels. Tumors arise from cells in the stratum basale of the epidermis and rarely metastasize.
Describe squamous cell carcinomas
These account for about 20% of all skin cancers, and arise from stratum spinosum of the epidermis
They have a variable tendency to metastasize.
What is a non-melanoma skin cancer?
This is a type of skin cancer that encapsulates both basal and squamous cell carcinomas
What are malignant melanomas?
These come from melanocytes and account for about 2% of all skin cancers. They are the most prevalent, life threatening cancer in young women.
What is the ABCDE acronym used to identify malignant melanomas?
A - asymmetry
B - border
C - colour
D - diameter
E - evolving
What are the risk factors for skin cancer?
Skin type - lighter skin who burn but not tan are at high risk
Sun exposure - higher sunlight per year and altitude are at higher risk. More exposure is higher risk
Family history - skin cancer rates are higher in some families than others
Age - Older people are more prone to skin cancer due to longer total exposure
Immunological status - Those who are immunosuppressed have higher incidence of skin cancer
How does UVA affect the skin?
These are longer wavelength ultraviolet A rays that make up 95% of the ultraviolet radiation that reaches the earth. They are not absorbed by the ozone layer, and penetrate the furthest into the skin, where they are absorbed by melanocytes and involved in sun tanning.
They depress the immune system
Thought to cause skin cancer
How does UVB affect the skin?
These are shorter-wavelength ultraviolet B rays that are partially absorbed by the ozone layer and don’t penetrate the skin as deeply as UVA. They cause sunburn and are responsible for most tissue damage due to the production of oxygen free radicals that disrupt collagen and elastic fibers, leading to wrinkling, aging of the skin, and cataract formation.
Thought to cause skin cancer
What is the result of long-term overexposure to sunlight?
dilated blood vessels, age spots, freckles, and changes in skin texture.
What is photosensitivity?
This is a heightened reaction of the skin after consumption of certain medications or contact with certain substances. It is characterized by redness, itching, blistering, peeling, hives, and shock. Exposure to UV radiation may cause this.
Substances that may cause a reaction include tetracycline, NSAIDs, Saint-John’s wort, some birth control pills, some high blood pressure medications, some antihistamines, some artificial sweeteners, perfumes, aftershaves, lotions, detergents, and medicated cosmetics
How do sunless tanners or self-tanning lotions work?
These are topically applied substances that have a colour additive to create the tanned appearance by interacting with skin proteins
How does sunscreen work?
This is topically applied and contain chemical agents that absorb UVB rays but let most of the UVA rays pass through
How does sunblock work?
These are topically applied and contain substances like zinc oxide that reflect and scatter both UVA and UVB rays
What is a burn?
This is tissue damage caused by excessive heat, electricity, radioactivity, or corrosive chemicals that denature the proteins in the skin cells.
How do burns affect the skin’s contributions to homeostasis?
It destroys protection against microbial invasion and dehydration, and disrupts regulation of body temperature.
What is a first-degree burn?
This is a burn involving only the epidermis. It is characterized by mild pain and redness (erythema), but no blisters. Skin functions remain intact, and immediate flushing with cold water can help lessen pain and damage.
Healing will generally occur in 3-6 days and is accompanied by flaking or peeling.
Eg. mild sunburn
What is a second-degree burn?
This is a burn involving the epidermis and part of the dermis. Some skin functions are lost.
Redness, blister formation, edema, and pain result
Associated structures like the hair follicles, sebaceous glands, and sweat glands are usually uninjured.
Without infection, these will heal without skin grafting in about 3-4 weeks, but may lead to scarring
What is a blister?
This is when the epidermis separates from the dermis due to accumulation of tissue fluid between them
What is a partial-thickness burn?
This is a term referring to first- and second-degree burns
What is a third-degree burn?
aka full thickness burn
Destroys epidermis, dermis, and subcutaneous layer
Most skin functions are lost
Vary in appearance from marble-white to mahogany coloured to charred, dry wounds.
Marked edema, and burned region is numb due to destruction of sensory nerve endings
Regeneration is slow, and granulation tissue forms before being covered by epithelium. Skin grafting may be required to promote healing and minimize scarring
What is the local effect of a burn?
This is the injury to the skin tissues directly in contact with the damaging agent
What can be included in the systemic effects of a burn?
Large loss of water, plasma, and plasma proteins leading to shock
Bacterial infection
Reduced circulation of blood
Decreased production of urine
Diminished immune responsesH
How is the seriousness of a burn determined?
Depth and extent of area involved
Age and general health of person
What is considered a major burn?
3rd degree burn over 10% of body surface area
2nd degree burn over 25% of body surface area
3rd degree burns of face, hands, feet, or perineum which includes anal and urogenital regions
What is the rule of nines for estimating surface area affected by a burn in an adult?
9% if both anterior and posterior surfaces of the head and neck are affected
9% for both anterior and posterior surfaces of each upper limb (18% for both upper limbs)
4x9 or 36% for both anterior and posterior surfaces of the trunk, including the buttocks
9% for each of the anterior and posterior surfaces of both the lower limbs up to the buttocks (total of 35% for both limbs)
1% for perineum
What is the mortality rate of burn victims with 70% burn area?
More than half die
How does hot smoke affect the body?
Damages the trachea (windpipe) causing its lining to swell
Airflow into lungs is thus obstructed
Small airways in the lungs can also narrow, causing wheezing or shortness of breath
What are pressure ulcers?
Aka decubitus ulcers or bedsores
Caused by constant deficiency of blood flow to tissues
Affected tissues are usually over bony projections subjected to prolonged pressure against an object like a bed, cast, or splint.
What is suggestive of redness from pressure ulcer?
Pressure has been relieved within a few hours and no lasting tissue damage is expected
What is suggestive of reddish-blue from pressure ulcer?
This may indicate deep tissue damage
What is suggestive of blistering from pressure ulcer?
This may indicated superficial damage
What is the result of a pressure ulcer?
Prolonged pressure causes small breaks in the epidermis, leading to infection. Sensitive subcutaneous layer and deeper tissues are damaged eventually causing tissue death.
What is a cold sore?
A lesion usually in the oral mucous membrane due to type 1 herpes simplex virus (HSV) transmitted by oral or respiratory routes.
Remains dormant until triggered by UV light, hormonal changes, or emotional stress. AKA a fever blister
What is contact dermatitus
Inflammation of the skin characterized by redness, itching, and swelling and caused by exposure of the skin to chemicals that bring about an allergic reaction, such as poison ivy toxin.
What is a hemangioma?
a localized tumor of the skin and subcutaneous layer that results from an abnormal increase in blood vessels. One type is a port‐wine stain, a flat pink, red, or purple lesion present at birth, usually at the nape of the neck.
What is impetigo?
This is a superficial skin infection caused by Staphylococcus bacteria; most common in children
What is a keloid?
This is an elevated, irregular darkened area of excess scar tissue caused by collagen formation during healing. It extends beyond the original injury and is tender and frequently painful. It occurs in the dermis and underlying subcutaneous tissue, usually after trauma, surgery, a burn, or severe acne; more common in people of African descent.
What is keratosis?
This is the formation of a hardened growth of epidermal tissue like a solar keratosis which is a premalignant lesion of the sun-exposed skin of the hands and face
What is pruritus?
It is itching - one of the most common dermatological disorders. It can be caused by skin disorders like infections, systemic disorders like cancer and kidney failure, psychogenic factors like stress, or allergic reactions.
What is a wart?
This is a mass produced by uncontrolled growth of epithelial skin cells, caused by papillomavirus. Most warts are noncancerous
