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113 Cards in this Set
- Front
- Back
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What percent of the body weight is skin?
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16%
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Some disease states can be seen on the skin. Name some.
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Jaundice
Cyanosis Measles Chicken pox |
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Name the five functions of skin.
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1. protection
2. sensory receptor 3. role in excretion 4. Vitamin D metabolism 5. Regulation of blood pressure and temperature |
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What are the two layers of skin?
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epidermis and dermis
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Where is the hypodermis located?
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beneath the dermis
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Dermal papillae and epidermal ridges form what structures?
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Fingerprints
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When do keratinocytes divide?
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At night
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What epithelium forms the epidermis?
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keratinized stratified squamous epithelium
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The epidermis is derived from what embryological layer?
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ectoderm
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How often is the epidermis regenerated?
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30 days
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What are the 5 layers of epidermis?
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Stratum:
1. basale 2. spinosum 3. granulosum 4. lucidum 5. corneum |
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What layer of the epidermis rests on the basement membrane?
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Stratum basele
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What three cell types can be found in the stratum basale layer?
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1. Keratinocytes
2. Merkel cells 3. Melanocytes |
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How does the cytokeratin concentration change as the cells move to the surface?
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Increase
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What layer of the epidermis is characterized by cytokeratin spiny processes?
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Stratum spinosum
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Which layers of the epidermis are mitotically active?
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Stratum basale and spinosum
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In which layer of skin will keratohyalin granules first produced?
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Stratum spinosum
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Which layer of epidermis has lamellar granules?
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Stratum spinosum and granulosum
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Which layers of the epidermis are known as Malpighian layer?
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Stratum basale and spinosum
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Describe the process of waterproofing that occurs in the granulosum layer.
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lamellar granules fuse with membranes to release GAGs
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What is the first step in keratinization?
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release of granules
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What type of skin has stratum lucidum
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Thick skin
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What type of skin is acidophilic?
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Thick skin
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Where can you find immature keratin (eleidin)?
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Stratum lucidum in thick skin
Stratum corneum in thin skin |
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What is the most superficial layer of the epidermis?
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Stratum corneum
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What causes psoriasis?
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Accelerate keratinocyte mitosis
thickening of the epidermis |
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What causes the psoriatic plaque formation?
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persistent hyperplasia and abnormal microcirculation
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What is unique about surface cells in psoriasis?
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Have nuclei
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What are the two types of nonkeratinocytes in the epidermis?
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Merkel's cells and Langerhans' cells
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Which nonkeratinocyte is derived from bone marrow?
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Langerhans
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Which cell have Birbeck granules?
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Langerhans
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Which nonkeratinocyte is antigen presenting?
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Langerhans
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Which nonkeratinocyte is part of the mononuclear phagocytic family?
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Langerhans
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Where are Merkel's cells found?
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Stratum basale
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Where are Langerhans cells found?
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Stratum spinosum
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What are Merkel's cells derived from?
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neural crest
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What is the function of Merkel's cells?
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mechanoreceptors (tactile)
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In what type of skin in Merkel's cells most numerous?
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Thick skin
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What synthesizes melanin?
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Melanocytes
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What are melanocytes derived from?
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Neural crest
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In what layer of the skin can you find melanocytes?
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Stratum basale
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What is different in light and dark skinned races?
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Melanin synthesis, accumulation, and degradation
NOT number of melanocytes |
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What is an epidermal-melanin unit?
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One melanocyte and about 36 keratinocytes, which as all connected through the melanocyte processes
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What is unique about melanocytes from other cells found in the stratum basale?
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no desmosomes
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What is the mechanism of secretion of melanin by melanocytes?
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Cytocrine secretion
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Which cells are melanin injected into and in what layer of the skin?
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Keratinocytes in the basale and spinosum
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In what cell type is most of the melanin found?
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Keratinocytes
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Where will melanin accumulate in the keratinocyte and why?
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Over the nucleus to block UV light and prevent damage to DNA
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What organelle degrades the melanin in keratinocytes? How often?
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lysosomes
Every few days |
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What function allows melanin to be protective against sunlight?
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1. Does absorb some light
2. Can absorb reactive radicals created by sunlight<-- most important |
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What is the only true benefit of sunlight?
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Production of active vitamin D
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When do we experience most of our sun exposure?
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50% prior to age 18
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What can cause enlargement, increase and movement of melanocytes in to more superficial levels of the epidermis?
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pathological sun damage
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What happens to keratinocytes with sun damage?
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flatten
lose register obtain nuclear inclusions |
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How are Langerhans' cells effected by sun exposure?
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Decreased antigen-presenting capabilities
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What happens to the T suppressor network with sun damage?
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Becomes activated
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What cells increase in number in the dermal layer as a result of sun damage?
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Mast cells
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What is the most common type of skin cancer?
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Basal carcinomas (75%)
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What skin cancers develop from the spinosum layer and have high chance of metastasis?
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Squamous cell carcinomas
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Which skin carcinomas have the highest cure rate?
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basal carcinomas
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Which skin carcinomas usually develop in elderly?
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Squamous cell carcinomas
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Which skin cancer is the least common?
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Melanoma (5%)
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What is the most common sites of appearance for melanomas?
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upper back for men
legs for women |
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What are the 4 points of diagnosis for melanoma?
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ABCD:
Asymmetry Border irregularity Color (Black/red/blue) Diameter (>6mm) |
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What is the most telling sign of metastasis of melanomas?
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Breslow depth (thickness)
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What is the embryological origin of dermis?
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mesoderm
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What layer of skin houses arteriovenous shunts for temperature regulation?
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dermis
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What is thicker dermis or epidermis?
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Dermis
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Where can you find Meissner's corpuscles?
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Pappillary layer of the dermis
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What is the function of Meissner's corpuscles?
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fine touch receptors
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What type of collagen and connective tissue can be found in the papillary layer of the dermis?
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Type III collagen
Elastic fibers Type VII anchoring fibers |
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What are the two layers of the dermis?
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Papillary and Reticular
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In which layer of dermis can you find follicles and glands?
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Reticular layer
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What type of connective tissue is found in the reticular layer of the dermis?
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Dense irregular connective tissue
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What type of collagen is found in the reticular layer of the dermis?
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Type I
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What is the function of the pacinian corpuscle?
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Pressure receptor
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What is the function of the Ruffini corpuscle?
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Temperature and pressure receptor
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What layer deep to the skin is composed of loose connective tissue and adipose?
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hypodermis
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What is really thick hypodermis called?
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panniculus adiposus
(Layer of fat) |
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Where can you find thick skin?
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Palms and soles
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Where can you find thin skin?
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Everywhere except palms and soles
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What layer of skin is absent in thin skin?
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Stratum lucidum
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What dermal component is absent in thick skin?
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Hair follicles
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Where can you find more sebaceous glands (thin or thick skin)?
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Thin
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Where can you find more eccrine sweat glands (thin or thick skin)?
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Thick
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What is the thickest layer of thick skin?
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Stratum corneum
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What layers of skin form the hair follicle?
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Epidermis and dermis
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When are hair follicles formed?
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Prior to birth
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What type of muscles are arrector pili muscles?
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smooth muscle
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What is the secretion mechanism of sebaceous glands?
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holocrine
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What do sebaceous glands produce?
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sebum
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What glands are responsible for acne?
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Sebaceous glands
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What skin glands become inactive at birth?
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Sebaceous glands
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When are sebaceous glands active?
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in utero and after puberty
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What hormone activates the sebaceous glands?
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Androgens
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What type of epithelium lines the sebaceous gland?
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stratified squamous epithelium
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What cells regenerate the sebaceous gland after holocrine secretory process?
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basal cells
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What class of gland is the eccrine sweat gland?
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simple coiled tubular gland
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What epithelium lines the ducts of the eccrine sweat gland?
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stratified cuboidal
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What is the secretion mechanism of eccrine sweat glands?
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merocrine
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What does the eccrine sweat gland respond to?
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Heat and nervous stress
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What autonomic system controls emotional sweating?
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sympathetic
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What is excessive sweating called?
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hyperhidrosis
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What is iontophoresis and how does it relate to sweat glands?
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removal of sweat glands via electric current
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What autonomic system controls thermoregulation?
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parasympathetic
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What is secreted by the dark cells of the eccrine sweat glands?
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glycoproteins
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What is secreted by the clear cells of the eccrine sweat glands?
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Water and electrolytes
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What are the three parts of the eccrine secretory unit?
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Dark cells
Clear cells Myoepithelial cells |
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What glands are vestigial scent glands?
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Apocrine glands
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When do apocrine glands begin to function?
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puberty
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What do apocrine glands respond to?
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hormones
emotions NOT heat |
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What is secretion mechanism for apocrine sweat glands?
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merocrine
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Where do the secretory ducts of apocrine glands open?
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Into the canal of the hair follicle
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