Week 5: Integumentary System Flashcards
***Integumentary System & General Function
- Skin: largest organ in body
- Accessory Organs:
- Hair
- Nails - Glands
Function: Serves to protect the viscera (internal organs) and regulate temperature
***Integumentary System Layers
3 Layers:
- Epidermis
- Dermis
- Hypodermis
***Epidermis: Location, Structure, and Function
Location:
Outermost layer of skin
Structure/ Function:
-Stratum Corneum – hard outermost layer of epidermis
Produces a protein called keratin
Keratinization causes hardening of dead skin cells, making skin waterproof.
Stratum Basale – produces new cells of epidermis
Contains Langerhans cells (for immunity) and melanocytes (make pigment to give skin color)
***Dermis: Location, Structure, and Function
Location: middle layer of skin
Structure:
Thick layer of connective tissue containing:
-Dermal papillae – ridges (epidermal waves) that cause fingerprints and provide gripping surface
-Collagen & elastic fibers – stretching & movement
-Blood vessels
-Sensory Nerves/ Nerve Endings
-Sebaceous Glands
-Hair Follicles
Function:
- stretching and movement (collagen/ elastic fibers)
- sensation
- gripping surface (dermal pappilae)
- nutrient exchange
- secretion/ absorption
Keratinization
causes hardening of dead skin cells, making skin waterproof & protective of foreign invaders
Hypodermis
Also known as the subcutaneous tissue
Location:
-Deepest layer of skin
Structure:
-Composed of loose connective tissue and adipose tissue (fat)
Function:
-Helps to store energy, insulate body, and provides protective padding
***Functions of Skin/ Integument
- Protection
- Regulates Water Loss
- Produces Vitamin D
- Gathers Sensory Information
- Regulates Body Temperature
- Nonverbal Communication
Function of skin: Protection
-Physical barrier to disease, dirt, and UV radiation
Bacteria and other invaders are prevented entry by the top dead layer of skin and the acidic, oily secretion from sebaceous glands (sebum).
Function of skin: Regulates Water Loss
-When the body is too hot, the skin will help to release heat to cool the body temperature back to 98.6°:
Sweat
Dilation of dermal blood vessels
-When the body is too cold, the skin will help to raise body temperature back to 98.6° by generating heat:
Shivering (muscle contraction)
Goosebumps (contraction of arector pili muscles attached to hair follicles) cause hair to trap heat
Constriction of dermal blood vessels
Lack of homeostasis in body temp:
- Hypothermia -Lower body temp. than normal interferes with the body’s normal functions and eventually ends in death
- Hyperthermia—Higher body temp. than normal results in dehydration (from excess sweating) and heat stroke.
Function of Skin: Gathers Sensory Information
Sensory receptors are linked to the nervous system Receptors specialize in sensing -Touch -Pressure -Pain -Temperature (hot & cold)
*Many receptors in the extremities ie hands
Function of Skin: Produces Vitamin D
- Melanocytes produce melanin to protect against harmful UV radiation from the sun and also to produce Vitamin D
- Vitamin D helps regulate the uptake of calcium by the digestive system.
- Calcium is needed for strong bones.
Function of Skin: Regulates Water Loss
- Keratinization of the dead skin outer layer also prevents water from entering or leaving the skin, even when immersed in water.
- Skin works with the urinary system to sweat off some excess water.
Skin Disorder Types:
- Chronic
- Infectious
- Burns
- Skin Cancers
Urticaria (Hives)
- Raised, often itchy, red welts on skin surface
- Usually due to an allergic reaction (to animal dander, insect bites, pollen, shellfish, nuts, eggs, milk)
- Also caused by stress, extreme cold or hot, or illness
Eczema
-Chronic skin disorder that involves scaly and itchy rashes
-Dry, flaky, blistering skin appears red and inflamed
Intense itching and burning sensations
-Can be triggered by allergic reactions to chemicals, fabrics, heat, dryness
Dandruff (Seborrheic dermatitis)
- Caused by a yeast
- White, flaky, inflammatory skin condition
- Often found on the scalp
- Not contagious
Psoraiasis
- Flaky, silver-white patches called scales
- Redness and irritation
- Genetic
- The body produces too many new skin cells.
- Normally skin cell turn around is ~30 days, but with psoraiasis, turn over is around one week.
Albinism
- Genetic disorder in which the body cannot produce melanin
- Symptoms: absence of color in hair, skin, or iris; light sensitivity; prone to sunburn & skin cancer
Impetigo
- Bacterial infection
- Highly contagious
- Causes blisters or sores on face and hands
- Common among kids
Acne
- Caused by an overproduction of sebum and oil, leading to clogging of the pores
- Clogged pores trap bacteria, dead skin cells, and pus (white blood cells)
- Inflammation and swelling form red bumps
- Pimples deep in the skin can form painful cysts
Other Causes Of Acne
- Genetics
- Hormonal changes due to menstrual cycles (females) or stress
- Greasy or oily cosmetic and hair products
- Certain drugs (such as steroids, testosterone, estrogen)
- High levels of humidity and sweating
- Diets high in refined sugars
Athlete’s Foot
- Fungal infection
- Very common on foot or other moist, warm areas of body
- Fungus infects the upper layers of the skin, causing itching, cracking, and pain
Ringworm
-Not a worm, caused by fungus
-Occurs in warm, moist areas with frequent wetness (such as from sweating) and minor injuries to your skin
Itchy, red, raised, scaly patches that may blister and ooze
MRSA
- MSRA = methicillin- resistant staphylococcus aureus
- Staph infections are caused by bacteria
- Staphylococcus bacteria normally lives on the skin with no problems
- MRSA is a strain that is resistant to antibiotics and therefore very dangerous or deadly
MSRA Stands For..
Methicillin-Resistant Staphylococcus aureus
MSRA: Signs & Symptoms
- People in hospitals are most likely to get MRSA
- Staph skin infections start as small red bumps that resemble pimples, boils or spider bites
- Quickly turn into deep, painful abscesses that must be surgically drained
- Sometimes the bacteria remain in the skin, but if it penetrates into the body, it can be life-threatening
Skin Burns: Attributes & Causes
-A burn is tissue damage which destroys cell proteins and cause cell death in the affected areas
-Caused by:
Heat
Radiation (sunlight, tanning beds)
Chemicals
Electricity
**Degress of burns:
1st Degree Burn
2nd Degree Burn
3rds Degree Burn
Are tanning beds safe ?
The salons say yes, but studies show tanning beds still increase the risk of cancer
***2nd Degree Burn
Burns occur in the epidermis and some of the dermis
Redness, Pain, & blistering
***1st Degree Burn
Burns only the epidermis (ex. Sunburn)
Redness & Pain, no blistering
***3rd Degree Burn
The epidermis, dermis, and hypodermis are destroyed
Damage to the nerve endings (ex. Exposure to direct fire)
Rule of Nines
Body is divided into 11 regions (each accounting for 9% of total body area)
Critical Burns
-Cover more than10% of the body’s surface area -Burns on face, genitals, or completely encircling the hands or feet
Critical Burn Complications
-Complications: Infection, hypothermia, dehydration
Crticial Burn Treatment
- Intense doses of intravenous fluids to replace electrolyte imbalance
- Warm and isolated environment to reduce risk of infection
- Skin graft can be done as soon as patient is stable
***Skin Cancer: Risk Factors
- Age (Older people)
- Light-skin
- Excessive sun exposure
- Genetics (family history)
- Chemical exposure
***Skin Cancer: When to see your doctor?
If you have any of the warning signs, are older, or have a family history of skin cancer
Cancer Definition
abnormal division of a cell that has undergone a DNA mutation
Tumor Definition
mass of mutated cells
Metastasis
the spread of cancer cells from one part of the body to another
***Skin Cancer Types
1) Non-Melanoma
Includes Basal cell carcinoma and Squamous cell carcinoma
2) Melanoma
***Basal Cell Carcinoma
-Most common skin cancer
-Occurs – in sun-exposed areas
-Appearance – pearly or waxy bump or a flat, flesh-colored or brown scar-like legion
-Treatment – cryosurgery, surgical removal
95% of patients easily cured,
but it may come back
***Squamous Cell Carcinoma
-Five times less common than basal cell carcinoma, but more likely to spread to nearby organs
-Occurs – on sun-exposed areas
-Appearance – firm, red nodule or a flat lesion with a scaly, crusted surface
-Treatment – cryosurgery,
surgical removal,
medication
***Melanoma
-Most dangerous skin cancer because it can metastasize (spread) and lead to death
-Occurs – anywhere on body’s skin
-Appearance – large brownish spot with darker speckles or a mole that changes in color, size or bleeds
Men – on trunk, head or neck
Women – lower legs
-Treatment – surgical removal, radiation, chemotherapy
Dermatology
branch of medicine specializing in care and treatment of the skin
Integument
Skin
***Stratum Corneum
- Consists of up to 30 layers of dead, scaly keratinized cells
- Hard outermost layer of epidermis - resistant to abrasion, penetration, and water loss
- Produces a protein called keratin
***Stratum Basale
- Deepest Layer of epidermis
- Mainly consists of single layer of cuboidal to low columnar stem cells and young keratinocytes (migrate towards the surface)
- Produces new cells of epidermis
Cells in the skins:
- Keratinocytes
- Stem Cells
- Melanocytes
- Tactile Cells
- Dendritic Cells
***Thick Epidermis Layers
- Stratum Basale
- Stratum Spinosum
- Stratum Granulosum
- Stratum Lucidum
- Stratum Corneum
***Stratum Spinosum
- Typically the thickest layer with the exception of palms & soles (Stratum corneum is thicker)
- Living Keratoncytes are firlmy attached to one another here (by demosomes- which create bridges)
***Stratum Granulosum
- Consists of 3-5 layers of flat keratinocytes (more in thick skin vs thin skin)
- Have dark-staining keratinhylain granules which give this layer its name
***Stratum Lucidum
- Thin Zone (superficial to the granulosum)
- Keratoncytes are densley packed with a clear protein named eledin
- No Nucleus in Keratoncytes
- Featureless Area
Subcutaneous Tissue
Hypodermis
Ambiguous boundary between the hypodermis and dermis; how can you tell between the two?
More adipose tissue in the hypodermis
***Drugs Injection and Hypodermis
Drugs are introduced into the hypodermis because the subcutaneous tissue is highly vascular and absorbs them quickly.
Infants & Elderly sensitivity to cold
Typically have less subcutaneous fat and are more sensitive to cold.. less thermoregulation
Skin Color Factors
- Melanin: More provide darker (eumelanin) or reddish pigment (theomelanin).
- Exposure to UV Light- darker skin tone
- Hemoglobin- reddish color
- Carotene- yellow pigment
- Cyanosis - blueness
- Erythema- abnormal redness of skin
- Pallor- pale or ashy color
- Albinism- milky white hair and skin
- Jaundice- yellowing of skin and whites of the eyes
- Hematoma (or bruise) - reddish/ purplish area
Melanin Types
- Eumelanin: brown black
2. Pheomelanin- reddish/ yellow sulfur containing pigment
Melanin Variations & Expressions
- people with different skin colors have essentially the same amount of melanocytes
- in dark skin, the melanocytes produce greater quantities of melanin- the melano granules in the keratinocytes are mostly spread out, than tightly clumped, and the melanin breaks down more slowly.
Accesory Organs of Skin
- Hair
- Nails
- Cutaneous Gland
Pilus
Hair
Hair Follicule
Oblique tube in skin where hair forms from
Shaft
Portion of hair above the skin
Root
Portion of hair beneath the skin
Bulb
End of hair within the hypodermis- dilated
-Only living cells of hair exist here
Dermal Papilla
Vascular Connective tissue- provides the hair with its sole source of nutrion
Alopecia
Thinning of hair or baldness
-Could be worsened by disease, poor nutrition, fever, emotional stress, raditation, chemotherapy
***Hair Growth Factors
Anagen- 90% of hair follicule develops during this time
Factors:
- Genetics
- Puberty
- Pregnancy
- Environmental Factors (nutrition, stress, health, etc)
***Why are eyebrows shorter than hair on head?
Have much shorter anagen phase than hair in the head- tighter window for growth; Important for them to be just long enough to protect eyes from catching debris, etc. Too long would block vision.
Hair Growth Cycle
- Anagen- hair growth
- Catagen- hault of growth- blood supply gets cut off
- Telogen- hair dies
***A light skinned person who is very cold may have a pale appearance, why?
the vessels that supply blood to the skin constrict or narrow in response to cold temperatures. This reaction, called “vasoconstriction,” decreases blood flow to the skin, which helps to minimize heat loss from the warm blood and therefore preserve a normal internal or “core” temperature.
**In warm temperatures, these same blood vessels dilate or widen, increasing the flow of blood to the skin surface, thus allowing heat to leave the body, and keeping the core body temperature from rising to a dangerous level.
***A light-skinned person may appear pink when they become over heated. Why?
In warm/ hot temperatures, these same blood vessels dilate or widen, increasing the flow of blood to the skin surface, thus allowing heat to leave the body, and keeping the core body temperature from rising to a dangerous level.
***A substance received or given off by your body will likely pass through which tissue type?
Epithelial Tissue
***Sebaceous Glands
Produce an oily secretion called sebum which keep the skin and hair from getting dry
***Skin Gland Types
- eccrine sweat gland
- apocrine sweat glands
- sebaceous glands
- ceruminous glands
- mammary glands
***Sweat Glands
- Two Types: Appocrine & Eccrine
- Sweat glands that produce prespiration needed to cool down the body or
***Apocrine Sweat Glands
Sweat Glands that function as scent glands. Found in armpits, pubic region, etc. Serves as a signal for sexual attraction- a reproduction adaptation.
***Eccrine
Sweat glands that function in evaporative cooling
***Ceruminous Glands
In the ear canal that form wax
***Mammary
Milk producing glands
***Adenoma
Non cancerous tumor that originates in the glandular tissue; can affect various organs
***Addison’s Disease
- Endocrine related/ autoimmune disease that occurs when the adrenal gland doesn’t produce enough corticosteroids
- Characterized by weight loss, muscle weakness, fatigue, low blood pressure, and sometimes darkening of the skin
***Which tissue type would likely function to hold the kidneys in place?
Connective Tissue ie. renal fascia
***Which tissue in the wall of the uterus is required for labor contractions?
Smooth muscle tissue ie. myometrium
Superficial Fascia
Hypodermis
Corpus Unguis
Nail Plate
What epidermal layer is not found in thin skin?
Straum Lucidum
**Pallor: Color/ Cause
- Pale or ashy color that occurs when there is so little blood flow through the skin that the white of the dermal collagen shows through.
- Can result from emotional stress, low blood pressure, circulatory shock, cold temperatures, or severe anemia.
**Melanin: Color/ Cause
- More provide darker (eumelanin) or reddish pigment (theomelanin).
- Produced by melanocytes and accumulates in the keratinocytes of the stratus basale and stratus spinosum BUT seen from stratum basale to stratum corneum
**Exposure to UV light: Color/ Cause
- Darker tone
- Stimulates melanin production- sun tans fade when melanin is degraded in older keratinoytes and migrate to surface and exfoliate.
***Hemoglobin: Color/ Cause
-cause reddish color in high capillary networked areas ie: lips
***Carotene: Color/ Cause
- yellow pigment acquired by yellow yolks and orange vegetables.
- Most expressed in heels and caluses of feet because this is where stratum corneum is thickest.
***Cyanosis
- blueness
- resulting from deficiency of oxygen
***Erythema
- Abnormal redness of skin
- Due to exercise, hot weather, sunburn, anger, embarrassment
- Caused by increased blood flow in dilated cutaneous blood vessels or from dermal pooling of red blood cells that have escaped from abnormally permeable capillaries, as in sunburn.
***Albinism
-genetic lack of melanin that results in milky white hair and skin, and blue gray eyes.
***Jaundice
- Yellowing of skin and whites of the eyes
- Result from high levels of bilirubin build up in the blood. Bilirubin is a byproduct of broken down hemoglobin
- Sick people with poorly functioning liver
***Hematoma (or bruise)
-reddish/ purplish area is a mass of clotted blood showing through the skin. Usually due to accidental trauma (blows to the skin)
What would happen if I decide to cut my pateint by cutting the integument parallel to the cleavage lines of the dermis (tension lines)?
- Faster healing of the skin and less scarring
- If the skin is disrupted parallel to the long axis of the fibers, the wound tends to reapproximate.
- If the wound crosses the long axis of the fibers perpendicularly, they are disrupted in a manner that causes the wound to gape open; therefore, greater tension is required to close the wound.
Skin Tension Lines
-Also known as Langer’s Lines or Lines of Cleavage
- linear clefts in the skin that indicate the direction of orientation of the underlying collagen fibers.
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***Thin Epidermal Layers
- Stratum Basale
- Stratum Spinosum
- Stratum Granulosum
- Stratum Corneum
Necrotizing Facitis
- Flesh Eating Disease
- Very Rare
- Necrosis (Death) of the subcuntaneous layer of the skin
