Derm Flashcards
What are the layers of the skin?
Epidermis, Dermis, Subcutaneous layer or hypodermis
What is the epidermis?
It is avascular, keratinized cells that slough off
What are the layers of the epidermis? What do they do?
- Stratum corneum: topmost layer, dry flakey skin, dead skin sloths off
- Stratum lucidum: thick skin, feet and hands, wristband friction
- Stratum granulosum: cells start to die, barrier to water loss
- Stratum spinosum: thickest layer, lots of keratinocytes
- Stratum basale: stem cells and nutrients
What is the dermis?
Vascular, anchors and connects the epidermis. Has collagen, elastin, and immune cells. The dermis feeds up into the stratum basale
What are the layers of the dermis?
- Papillary dermis: areolar connective tissue
- Reticular dermis: dense irregular connective tissue
- Dermal papillae: anchoring
What is the subcutaneous layer or hypodermis?
Technically not part of the skin, has lots of fat insulation, and is a shock absorber.
How do you know when someone needs stitches?
If they won’t stop bleeding, you have most likley cut into the dermis and it will need stitiches
Why do cancer patients get thin skin?
Chemo attacks rapidly dividing cells. It attacks many different cells
What is keratinosis?
Cells slowly dehydrate and die and as they get closer to the surface, they sloth off.
What are melanocytes?
Made up of melanin that gives skin color differences due to the amount and form of melanin. Freckles and pigmented moles are accumulations of melanin. In response to sun exposure, melanocyte-stimulating hormone is released by the thalamus (the basis of tanning-body produces more of this) and melanin is produced and shared with the keratinocyte to shield the keratinocyte’s nuclei from UV light and sun exposure
What are Merkel cells?
Tactile/sensory cells that sense light touch.
What are keratinocytes?
Keratin-fibrous protein cells that makes up the epidermis.
What is carotene?
Yellow to orange pigment of skin due to Vitamin A, which also helps with eyesight and the growth of the epidermis
What gives translucent skin its color?
Hemoglobin gives skin a reddish color that you can see.
What is cyanosis?
Bluing of the skin. Low oxygenation of hemoglobin.
What is pallor?
Anemia, low blood pressure.
What is jaundice?
Elevated bilirubin, liver disorders.
What is vitiligo?
Uneven dispersal of melanin with melanocytes or the lack of melanin production.
What is ecchymosis?
Bruising, clotted blood beneath the skin.
What is erythema?
Redness, fever, hypertension, inflammation, allergy.
What are brown/black necklaces?
Acanthosis nigricans, hyperpigmented dark areas especially in the axilla and around the neck, may be a sign of insulin resistance (T2D) and elevated blood glucose levels. “Necklace of darker pigmented skin” and in armpits
What kinds of structures are in the extracellular matrix?
- Hyaluronic acid: naturally occurring, hydration
- Basal lamina: connects the epidermis and papillary dermis and allows for the flow of nutrients. Dermis feeds epidermis through this structure
Recticular layer
3. Collagen: tensile strength in the papillary layer and gives some flexibility
4. Fibroblasts
5. Water, Sugar, Glycoproteins
6. Elastic fibers for flexibility and less rigidity
Thicker collagen fibers are aranged in a what?
recticulum
What is turgor?
Skin with decreased turgor remains elevated after being pulled up and released. This is a physical exam finding and is a sign of dehydration.
What is pitting edema?
Fluid fills up a space and when pressed leaves a pit.
What are friction ridges?
Consist of epidermal ridges that lie on top of dermal ridges. sweat duct openings along the crest of friction ridges help make fingerprints. The capillary dermis or areas of thick skin. Occurs in utero.
What are cleavage lines?
Represent separation between underlying collagen fiber bundles in the reticular dermis. Run circularly around the trunk and longitudinally in the limbs. Surgical incisions parallel to cleavage lines heal better than those made across them. Reduce scarring tension.
What are flexure lines?
From where the dermis is closely attached to the underlying structures. The epidermis folds a little bit
What are striae?
Extreme stretching of skin can cause dermal tears, leaving silvery white scars. Comes from the dermal layer
Define blister.
Acute, short-term traumas to skin can cause blisters, fluid-filled pockets that separate epidermal and dermal layers
Define skin cancer.
Rapidly dividing cells. Risk factors include overexposure to UV radiation, frequent irritation of skin.
What happens with lanugo and fetal skin?
Well formed after the fourth month in utero, downy hairs. We don’t really understand the purpose, but perhaps it is for thorough my regulation, and it fades and goes away.
What is vernix caseosa?
Covers babies’ skin during their time in the womb. It comprises shed skin cells incubation secretions from the epidermis. It protects the fetuses fragile skin from the amniotic fluid. Caseosa means cheese in German.
Define middle to old age and some defining factors.
Wrinkles: deficiency of elastin and sebum in aging skin. There are many theories like free radicals in the environment, vitamin E/C, cellular changes in mitochondria and telomeres (shorten over time), genetic changes. Sweat and sebaceous glands decrease, thinning of hair, repeated UV exposure, epidermal thinning with age can lead to skin tearing, loss of body fat, increased risk of cancer
What are some accessory structures of the skin?
Hair shaft, skin appendages, sebaceous oil glands, eccrine sweat glands.
Describe the structures of the hair.
Hair shaft- hair
Arrector pili muscle
Sebaceous gland
Hair root
Hair bulb or follicle: where all the live cells are. Melanocytes give is the color of our hair and decrease over time and air bubble here cause dry and gray hair
Root hair plexus: close to the bulb and helps sense movement of hair
What is vellus hair?
Pale, fine body hair of children and adult females.
What is terminal hair?
Coarse, long hair (scalp/eyebrows) and in axilla, pubic regions, male face (during puberty) hormones-androgens
What is the hair growth cycle?
- Anagen (growth phase)- nourishment of hair follicle via blood supply enables hair growth. Active and is rapid
- Catagen (transition phase)- hair follicle detaches from nourishing blood supply. Shrinks and will stay attached but no more growth.
- Telogen (resting phase)- without nourishment, the hair dies and falls out
Define hirsutism.
Overproduction of male sex hormone in women causing excessive hairiness.
Define alopecia.
Immune system attacks hair follicle to cause hair loss.
Define male pattern baldness.
Follicular response to dihydrotestosterone (DHT is formed from testosterone)
Define baldness.
Genetically determined and sex-influenced condition (more common in men0
Define telogen effluvium.
Abrupt hair thinning caused by an abundance of hair follicles entering the resting phase at the same time and is often stress-induced (hormonal changes such as pregnancy, surgery, severe emotional trauma, crash dieting)
What are other causes of hair loss?
Chemotherapy, hypothyroidism, low protein diets.
Eccrine vs. Apocrine sweat glands?
- Eccrine- exit, skin surface most of these, salt, water, antibodies. Temp control, hypotonic filtrate of blood plasma at skin surface located everywhere but especially in palms, soles, forehead
- Apocrine- appear after puberty and may act as sexual scent glands. Filtrate of blood plasma with added protiens and fatty substances. Usually the upper part of the hair follicle, rarely, the skin surface. Most axillary and anogenital regions. Secrete a milky substance and when broken down causes a smell.
What are sebaceous glands?
Oil glands, sebum (an oily secretion that minimizes bacteria getting into skin), inactive until puberty. Lubricate skin and hair, help prevent water loss, antibacterial properties. Usually the upper part of the hair follicle, sometimes the skin surface. Everywhere except palms and soles.
What are some modified apocrine glands?
Ceruminous glands, mammary glands.
Define acne.
Inflammation of the sebaceous glands that cause pustules/cysts.
What is seborrhea or cradle cap in newborns?
Overactive sebaceous glands that cause pink, raised lesions that become yellow/brown and begin to slough off oily scales. Dandruff shampoos
What are the structures of the nail?
Nail matrix, nail bed, nail plate.
What’s important about the nail matrix?
Rapid replication of cells pushes out the nail. Naile appears pink due to underlying hemoglobin and can be used to assess capillary refill (press on the nail and let it become white and let go to assess refill and circulation)
What do yellow tinged nails indicate?
May indicate respiratory or thyroid gland disorder.
What is onychomycosis?
Thickened yellow nails due to fungal infection.
What is koilonchya?
aka “spoon nail” An outward concavity of nail may signal iron deficiency.
What are Beau’s lines?
Horizontal lines across nails may indicate severe illnesses such as uncontrolled diabetes, heart attack, and cancer
What are the functions of the skin?
Protection: cushions organs and protects form bumps, chemicals, water loss, UV radiation. Specifically epidermis. What kinds of things enter into skin? lipid/fat soluble. Fentanyl patches, transdermal medications and posion ivy
Regulation of body temp
Blood reservoir
Excretion of waste: urea, salts, and water lost through sweat
Production of vitamin D
Sensory receptors: keep us aware of conditions at the body’s surface
What is the chemical barrier of the skin?
Sweat and sebum, which contains antimicrobial proteins. Cells also secrete antimicrobial (natural antibiotics) defensin. Acid mantle: low ph of the skin slows bacterial multiplication. Melanin provides a chemical barrier against UV radiation damage.
What is the biological barrier?
Epidermis: contains phagocytes- dendritic (Langerhans) cells
Dermis contains macrophages
What types of regulation of body temp are there?
Epidermis: contains phagocytes- dendritic (Langerhans) cells
Dermis contains macrophages
Why do body structures regualte temp?
through a negative feedback loop
What is the role of Vitamin D?
The sun gives off UVB radiation and causes the Vitamin D precursor in your skin, which is fat soluble, to your liver which then helps with the reabsorption of calcium and phosphorus which are both needed to build bone.
What are Merkel cells?
Tactile epithelial cells that aid in touch.
What are Meissner’s corpuscles?
Tactile cells that aid in texture and slow vibration.
What are Ruffini endings?
Cells in the skin that sense sustained pressure.
What are Pacinian corpuscles?
Lamellar cells that sense coarse touch like sandpaper and deep pressure.
What are free nerve endings?
Bottom of hair, hair bulbs, thoughout skin, Sense painful stimuli.
What are Krause end bulbs?
Temp sensory and thermosensory.
What are the reasons for hair?
Warn off insects, guard against physical trauma, protect from heat loss, shield skin from sunlight
What is the difference between a full-thickness wound and a split-thickness wound?
Full: goes down through entire dermis. Split: hits just the top of the dermis.
What is erosion of the skin?
The loss of superficial epidermis only, with no involvement of the dermis. This wont bleed. What are some examples: superficial burns, stage I pressure ulcers, abrasions (road rash). Doesn’t normally scar because epidermal replacement is a local inflammatory response
What is partial thickness skin loss?
The loss of the epidermis and part of the dermis. Extends a little bit more into the dermis- split thickness wound. This will bleed some. Some examples are: stage II pressure ulcers, skin tears, and deep abrasions
What is full thickness skin loss?
The loss of the epidermis and dermis, extending into the subcutaneous tissue or hypodermis Ex: surgical incisions, stage 3 and 4 pressure ulcers. Will need debridement. Full thickness skin loss with involvement of muscle, bone, and tendon.
What is primary wound closure?
Use sutures and close wound.
What is delayed primary wound closure?
Clean wounds, tell them to come back in a few days.
What is secondary intent in regards to wound healing?
Packing a wound, because it is too risky to close. This is where a would vac applies
What is tertiary intent in regards to wound closure?
The wound was once closed, now it is open. so we let it heal on its own. Dihiscence: splits back open
What are the different phases of wound healing?
Schematic for wounds that extend into the dermis
Coagulation phase- clotting, releasing of growth factors, chemotaxis where inflammatory cells are (proinflammatory) this also relates to fibrin. Main cells involved are platelets
Inflammatory phase- cells involved: platelets, macrophages, neutrophils (first line of defense). VEGF- vascular endothelial growth factor.
Migratory/proliferation phase- cells involved: macrophages, fibroblasts, epithelial cells, and endothelial cells. Fibroblasts- collagen contract or shrink wound and pull it closer together.
Remodeling phase- fibroblasts and myofibroblasts deal with scarring and scaffolding
What is Pyoderma Gangrenosum?
Overactivation in the inflammatory phase. underlying autoimmune diseases are common.
Define wound repair.
Scrap wound, the biofilm impairs wound healing. ake dead tissues off (debridement). Can be done at bedside. In chronic wounds-no moisture- bleeds due to bacteria. Acute- moisture may be helpful. Venous inflammatory-lack of blood leaving the area
What are pressure ulcers and their staging?
Follicle injuries, poor nutrition and bed bound contributes. coccyx and heels are the most common places.
What are the burn types?
1st degree: superficial partial thickness. Epidermis affected only. Localized redness, edema, and pain (generally heals in 2-3 days). Common causes: sunburn
2nd degree: deep partial thickness. Epidermis and upper dermis. Blisters and causes the most discomfort. Common causes: contact with hot liquids. Flash burns due to intense light, electric current, or heat.
3rd degree: full thickness, epidermis and all of the dermis. Gray-white color, cherry red or blackened skin. No edema or pain (nerve endings are destroyed, indicator) skin graft is often necessary and hospitalization. Common causes: fire, electricity or lightning. Prolonged exposure to hot liquids/ objects
4th degree: burns that extend to the fat
5th degree: burns that extend into the muscle
6th degree: burns that extend into the bone
What is the rule of 9s critical values ?
Critical values: >25%= 2 degree or >10%= 3rd degree or face, hands, or feet = 3rd degree. At greatest risk of dehydration. Electrocution- cant see, but causes deep tissue damage, contact time vital to know, there is always an exit area.
What is a 3rd degree burn?
A full thickness burn affecting the epidermis and all of the dermis, characterized by gray-white color, cherry red, or blackened skin. There is no edema or pain due to destroyed nerve endings. Skin graft is often necessary, and hospitalization is required. Common causes include fire, electricity, or lightning, as well as prolonged exposure to hot liquids or objects.
What is a 4th degree burn?
Burns that extend to the fat.
What is a 5th degree burn?
Burns that extend into the muscle.
What is a 6th degree burn?
Burns that extend into the bone.
What is the rule of 9s?
A method used to estimate the total body surface area affected by burns.
What are critical values for burn assessment?
> 25% = 2nd degree burns or >10% = 3rd degree burns, or burns on the face, hands, or feet = 3rd degree. Patients are at greatest risk of dehydration.
What is electrocution in the context of burns?
A condition that cannot be seen but causes deep tissue damage. Contact time is vital to know, and there is always an exit area.
