Derm Flashcards
What are the layers of the skin?
Epidermis, Dermis, Subcutaneous layer or hypodermis
What is the epidermis?
It is avascular.
What are the layers of the epidermis?
- 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, barrierto 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.
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.
Why do cancer patients get thin skin?
Chemo attacks rapidly dividing cells.
What is keratosis?
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 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?
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
- Collagen: tensile strength in the papillary layer and gives some flexibility
- Fibroblasts
- Water, Sugar, Glycoproteins
- Elastic fibers for flexibility and less rigidity
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.