Chapter 5 Flashcards
What are the two parts of the skin?
Epidermis and dermis
What kind of tissue is the epidermis?
Epithelial Tissue
What type of tissue is the dermis?
Connective tissue (supplies nutrients to the epidermis)
What kind of cells are found in the epidermis?
Keratinized stratified squamous epithelium
What is another name for the hypodermis?
Superficial fascia
Where is the hypodermis located?
deep to the skin
NOT part of the skin
What kind of tissue is found in the hypodermis?
Adipose tissue
What does the hypodermis do for the skin?
It anchors the skin to underlying structures such as muscle
It acts a shock absorber an insulator (adipose-fat)
What are the 4 types of cells found in the skin?
Keratinocytes
Melanocytes
Dendritic (Langerhans) cells
Tactile (Merkel) cells
What do keratinocytes do for the skin?
Produce fibrous (structural) keratin
What connects keratinocytes in the epidermis and why is this important?
Desmosomes (tightly connected) Allows stretch (velcro) Keeps moisture in to avoid dehydration
What do melanocytes do for the cell?
Produce pigment melanin (protect against UV)
Why are dendritic cells important in the skin and what is an example of one?
Macrophages
Important for warding off infections
What do tactile cells for the skin?
Allow sensations of touch (Merkel)
There are deep and light touches
What is apoptosis?
Controlled cellular suicide
What are the 5 layers of the epidermis and what layer is only found in thickened skin like the palms and heels?
Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum Basale
Lucidum is only in tough areas (think lucid=white/clear and the heals and calyces are white)
What is the deepest layer of the epidermis and what does it do?
Stratum basale
Site of mitosis (production of new live cells - it is closest to the nourishment)
Think of a basement= basale and basements are the lowest part of the house
What layer of the epidermis has the highest concentration of dendritic cells?
Stratum spinosum
(spiny looking layers- spin/spine)
Dendritic cells help with immune protection
Also has melanosomes as well
What layer in the epidermis do cells start to change and become more tough and flat?
Stratum granulosum (contains keratinocytes and keratin is important for the tough structure of the skin)
What layer of the epidermis contains many rows dead keratinocytes?
The stratum corneum
(this layer is important for the first line of defense against assaults and is important for keeping the deeper layers from loosing water)
What is the dermis made up of?
Connective tissue
Fibroblasts,macrophages, and other immune cells
Nerve fibers
Blood and lymphatic vessels
Epidermal hair follicles, oil and sweat glands
What are the two layers of the dermis?
Papillary and reticular
What layer of the dermis gives rise to fingerprints?
The thin papillary layer (dermal papillae to be specific)
What kind of connective tissue is found in the papillary layer?
Areolar connective tissue with collagen and elastic fibers and blood vessels
(Allows for stretch and recoil while also having structure and strength and is vascularized so nourished)
What does the dermal papillae allow for in the fingers and toes?
Friction ridges
Enhance grip, contribute to sense of touch (Merkel cells)
What layer of the dermis accounts for 80% of its thickness?
The reticular layer
What connective tissue is the reticular layer made up of?
Dense fibrous connective tissue (elastic and collagen -strength and stretch/recoil)
What are cleavage lines and what are they formed by?
Formed by collagen fibers that run parallel to the skin surface (surgeons use these lines so that the person heals faster)
What skin marking is formed by dermal folds at or near joints (like palm reading lines)
Flexure lines (where there is alot of range of motion)
What skin marking is referred to as stretch marks?
Striae (silvery-white scars)
What skin marking is a fluid filled pocket that separates the epidermal and dermal layer and what might cause this?
Blisters (2nd degree burn/ when your sunburn bubbles up)
What are the three pigments that contribute to skin color?
Melanin (brown hue or reddish yellow hue)
Carotene (orange hue)
Hemoglobin (red hue)
Where is melanin formed?
In melanocytes
What marking is formed by local accumulations of melanin?
freckles or moles
What stimulates melanin production?
Sun exposure
What are fungal infections that look like white dots on the skin?
Sunspots (tinea versicolor- not related to melanin production)
What are the two forms of melanin?
Reddish-yellow
Brownish-black
What pigment does carotene cause?
Yellow to orange pigment (carrots and carotene)
What can carotene be converted into and what is this used for?
Vitamin A - vision and epidermal health
What hue is given off from hemoglobin and in what type of skin?
Pinkish hue of fair skin
What diagnosis can come from cyanosis?
Hypoxia/ low oxygenation of hemoglobin
Blue hue of skin
What causes erythema?
Redness of skin
Fever, high blood pressure (hypertension), inflammation, allergy (histamines)
What diagnosis can cause pallor?
Blanching of skin is usually caused by anemia, low blood pressure, fear, anger
You see a patient that has jaundice. What organ may be failing?
Liver (hepato diseases/ alcoholism- bilirubin(what makes our urine yellow) has increased in the blood)
Your friend never goes out in the sun but always has a bronze tint to her skin. What disease may she have?
Addison’s disease (underproduction of steroid hormones by the adrenal glands)
What causes bruising of the skin?
Clotted blood under the skin
What are the 4 appendages of the skin?
Hair and hair follicles
Nails
Sweat glands (sudoriferous)
Sebaceous (oil) glands
What is hair consisted of?
Dead keratinized cells
Where is hair absent on the body?
Palms, soles, lips, nipples, portions of external genitalia
What are the functions of the hair?
Warn of trauma (touch/merkel cells)
Heat loss
What causes red hair?
Trichosiderin
Why would someone get grey hair?
A decrease in melanin production
What are the main parts of the hair follicle?
Hair bulb (expanded deep end with sensory nerve endings) Arrector pili (smooth muscle attached to the follicle -goosebumps) Hair papilla (blood supply/dermal tissue)
Is the hair follicle part of the dermis or epidermis?
Both (hair matrix is in the epidermis)
How would you describe vellus hair?
Pale, fine body hair of children and adult females
What type of hair is course and long and is usually found in the hair of the eyebrows and scalp?
Terminal hair
Also found in the pubic region and axillary region once one hits puberty
What two things effect hair growth?
Nutrients and hormones
What is alopecia?
Thinning of the hair
What is true (frank) baldness determined by?
Genetics and sex
What causes male pattern baldness?
follicular response to dihydrotestosterone
A patient comes in and is balding. He asks you what can he use to treat this and get his luscious locks back. What do you recommend?
Minoxidil (rogaine)
Finasteride (propecia)
What are nails?
Scale-like modifications of epidermis
What do nails contain?
Hard keratin (protective covering)
What supports nail growth (what part of the nail)?
Nail matrix
What is another name for sweat glands?
Sudoriferous glands
What parts of the body do not have sweat glands?
Nipples and parts of external genetalia
What are the two main types of sweat glands?
Eccrine (merocrine- found everywhere except armpit and anal region)
Apocrine (anal area and armpits- think AAA)
What kind of cells are found in the sweat glands?
Myoepithelial (muscle cells to contract and force sweat into ducts/ exocrine glands)
Where are eccrine sweat glands most abundant?
Palms, soles, and forehead
ducts connect to pores
What is the function of eccrine sweat glands?
Thermoregulation
What is sweat made up of?
Mainly water Salts (decrease pH to kill bacteria) Vitamin C Microbe-killing peptides Metabolic wastes
A patient has B.O. and wishes he could stop sweating. Is the sweat actually causing the smell?
No the bacterial contact with the sweat is
Where do the ducts form apocrine sweat glands lead into to?
Hair follicles
What are found in apocrine sweat?
Proteins and fatty substances
What are the two modified apocrine glands?
Ceruminous glands- external ear canal -earwax
Mammary glands - secrete milk
Where are sebaceous oil glands located?
Not in palms or soles
Near hair follicle
What do sebaceous glands secrete?
Sebum (bactericidal/ softens hair and skin)
What stimulates sebaceous oil gland?
Hormones (estrogens and androgens)
What are the main functions of the integumentary system?
Protection (from external environment)
Body temperature regulation (muscle contractions and eccrine sweat glands)
Cutaneous sensations (sensory receptors)
Metabolic functions (eliminate metabolic wastes)
Blood reservoir
Excretion
What are the three types of barriers for protection?
Chemical
Physical (piercing skin)
Biological (bacteria and microbes)
What are the two chemical barriers of the skin and what do they do?
Skin secretions (low pH to destroy microbes- sebum and defensins) Melanin (UV radiation)
What physical barriers block most water and water-soluble substances from skin?
Keratin and glycolipids
What substances have limited penetration of skin?
Lipid-soluble substances Plant oleoresin Organic solvents Salts of heavy metals Some drugs
What are the biological barriers of the skin?
Dendritic cells of epidermis and macrophages of the dermis (present foreign antigens to white blood cells)
DNA (absorb UV radiation and convert it to heat)
What happens in the skin when we have elevated body temperature?
Dilation of dermal vessels (redness) and increased sweat gland activity (sensible perspiration) to cool the body
What happens to the skin when in a cold environment?
The dermal blood vessels constrict and skin temperature drops to slow the passive heat loss (think heat escapes to cold so if we lower the skin temperature then we lose less heat to the environment)
What do cutaneous sensory receptors respond to ?
Temperature (thermoreceptors), touch (Merkel), pain (nocioreceptors)
What to exteroceptors do?
respond to external stimuli
What are the two types of touch receptors and describe the differences?
Tactile (Meissner’s) corpuscles - in dermal papillae and detect light touch
Lamellar (pacinian) corpuscles - deeper in dermis and hypodermis and detect deep pressure
What are the two ways the skin participates in metabolic functions?
Synthesis of Vitamin D precursor and collagenase (helps gut resorb calcium)
Chemical conversion of carcinogens and activate some hormones
What does the skin excrete?
Nitrogenous wastes and salt in sweat
What are the risk factors to getting skin cancer?
Overexposure of UV
Frequent irritation of the skin
What are the three types of skin cancer?
Basal cell carcinoma
Squamous cell carcinoma
Melanoma (bad one)
What kind of skin cancer is the least malignant and most common? Where does this cancer happen?
Basal cell carcinoma
Stratum basale in the epidermis (where cell mitosis occurs- dead cells go down instead of to apical surface)
How would you cure basal cell carcinoma?
Surgical removal
What is involved in squamous cell carcinoma? Does this metastisize?
Karatinocytes of stratum spinosum
Yes
What can you do to treat squamous cell carcinoma?
Radiation therapy or surgical removal
What is melanoma?
Cancer of melanocytes - most dangerous
How can you treat melanoma?
Wide surgical excision and immunotherapy (immune to radiotherapy)
What is the ABCD rule for skin cancer?
Asymmetry
Border irregularities
Color (black, brown, red/ sometimes tan)
Diameter (larger than the size of a pencil eraser
What are the two partial thickness burns and what is the difference?
First degree burn (epidermal damage only- redness, edema, pain)
Second degree burn (epidermal and upper dermal damage - blisters)
What is a full thickness burn?
Third degree burn
Entire thickness of skin, not painful because burned the nerve endings
Usually need skin grafting
What are the treatments for burns?
Debridement of burned skin (removal)
Antibiotics
Skin grafts
Temporary covering
