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142 Cards in this Set
- Front
- Back
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What are the most common skin diseases?
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Dermaphytosis
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What is dermaphytosis caused by?
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Small fungi
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What is an example of adermaphytosis disease?
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Athlete's foot
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What is the second most prevalent skin disease?
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Acne
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What are the two types of acne?
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Vulgaris and cystic
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How are most skin disease diagnoses made?
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Through visual examinations
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Which is the largest organ in the body?
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The skin
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What forms the outer layer of the skin surface?
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keratin
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What happens to the cells that produce keratin?
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They proliferate from the bottom to the top of the skin surface
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How does the blood supply to the skin vary?
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It varies to where the skin is in the body
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What is the most reactive component of the body in terms of blood supply?
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The face
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What is the dermis?
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A layer of dense connective tissue that is known as the dermis, in which there are numerous blood vessels
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What are melanocytes?
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They are at the base of every skin
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What are melanocytes derived from?
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The neural tube
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What is the ratio of melanocytes to keratinocytes?
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1 melanocyte to 36 keratinocytes
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What is a melanosome?
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The granule that melanocytes contain that has the pigment melanin
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Where is the melanin distributed?
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Into the keratinocytes from the melanocytes
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Does melanin vary amongst species?
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No. Its composition has remained highly conserved throughout evolution
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How is the distribution of melanin affected?
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It is genetically determined but can also be activated upon damage to the skin
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How do different pigmentations result?
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The process of melanin distribution has different activities in different people
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What are the function of Langerhans cells?
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They function to protect you and are the first cells that come into contact with foreign antigen
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Where are langerhans cells located?
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In the upper layers of the epidermis
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What type of granules do langerhans cells have?
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Birbeck granules
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What is the role of Merkel cells?
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They act as mechanoreceptors
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How do these merkel cells work?
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When you touch your skin, these cells are activated, which are in close proximity to a nerve terminal which sends a signal to the brain telling you the state of your skin
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What type of granules do Merkel cells have?
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Merkel granules
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How is the skin attached to us?
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Desmosomes w/ filaments
Junctions |
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How do blisters result?
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When the attachments of the skin are disrupted
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What are some causes of blisters?
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Burns, some cases of dermatitis, complex diseases
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What is pemphigus?
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A disease where there is a lack of formation or default in the adherence of the skin to the body
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Which glands in the skin secrete sweat?
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Eccrine glands
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What is the purpose of sweat?
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It keeps the body temperature low
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What is a hair shaft?
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The part of the hair that is constantly undergoing replacement
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What are apocrine glands?
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Components of the hair that secrete oil
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What are sebaceous glands?
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Components of the hair that secrete smell
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How is the epidermis attached to the dermis?
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Bumpiness of the epidermis= pegs
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What are the functions of the epidermis pegs?
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Increase epidermis adhesion to dermis
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What is in the dermis?
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nerves, hair, glands
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What is dermatitis?
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Inflammation of the skin
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What is acute dermatitis caused by?
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Somethins irritates the skin, such as a chemical, allergic reaction, insect bite
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What develops in acute dermatitis?
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Inflamation of the epidermis, spongiosis, blister
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Why is an itch produced in acute dermatitis?
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There is an inflammatory reaction beneath the skin that gives the area a red appearance and results in the release of a variety of cytokines and chemokines
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What are some changes that occur in chronic dermatitis?
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-Thickening of the epidermis, layer of keratin thickning, resulting in a plaque like structure
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Why do the plaques appear red in chronic dermatitis?
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There are numerous dilated blood vessels
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What can chronic dermatitis be caused by?
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An allergic reaction to a metal or poison ivy
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What is hypersenstitivity type I?
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An immunological disorder of the skin that is an unusual reaction to something that is not normally an antigen
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What is hypersenstivity type I reactions often caused by?
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A common food or househould allergy
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What happens in more developed cases of hypersensitivity type I reactions?
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There is the breakdown of the epidermis and bleeding. Blisters break, resulting in possible infections
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What is dermatitis herpetiformis?
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A gluten sensitive enteropathy
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What is a defect of the immune response in gluten sensitive enteropathies?
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There is immune complex deposition
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How does immune complex deposition occur in gluten sensitivity?
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Gluten enters through the gut and forms complexes which deposit in the ksin. These result in the release of chemotactic factors and the attraction of neutrophils
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How does the recruitment of neutrophils in immune complex deposition result in gluten sensitive enteropathies?
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THey release proteases in an attempt to eliminate the immune complexes which damage the surrounding skin
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What does contact dermitis cause?
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Increased cell mediated reactions
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What type of cells are activated in contact dermatitis?
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T cells are activated
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What are some antigens that can result in contact dermatitis?
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Poison oak, ivy, nickel, cheap jewelry, watchband, chemical, etc
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How does the immune response get triggered in contact dermatitis?
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The hapten is taken up by Langerhaans cells in the area of contact. These cells migrate to lymph nodes and sensitizes these cells to the hapten. The senstized skin has a very strong reaction the next time it comes into contact with the hapten
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What is a key difference between psoriasis and leprosy?
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Psoriasis is not contageous
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What is the main type of psoriasis?
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Psoriasis vulgaris
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How does sunlight affect psoriasis?
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It seems to have a beneficial affect
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What are some secondary components to psoriasis?
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-Arthritis
-Diabetes, cardiovascular disease, crohn's disease -Changes in fingers and toenails |
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How does changes in fingernails and toenails occur in psoriasis?
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The lesion often destroys the fingernail as it gets into the cuticle of the finger
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What are the age groups typically affected?
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16-20 yrs
40-60 yrs |
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What is the lesion in psoriasis characterized?
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Demarcated elevation in the skin characterized by whiteness and increased keratin
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What are some typical sites of psoriasis?
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Scalp, back, back of elbows, knees
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What type of bacterial infection sometimes leads to the development of psoriasis in children?
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Beta-hemolytic streptococcal infection
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What type of disease is psoriasis?
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An immune-mediated disease and the hyperkeratosis is secondary to the increased stimulation of the epidermis by the inflamatory reaction
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What is VEG-F?
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Vascular Endothelial Growth Factor
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What does VEG-F induce in psoriasis?
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Angiogenesis
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What leads to the proliferation of keratinocytes in psoriasis?
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T cell cytokines
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Why is the composition of keratin abnormal?
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Breakdown due to protease release
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What is the principle of the test for psoriasis?
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The fact that the vessels arereally clos to the skin surface and are thus easily traumatized
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Where do lesions typically occur in psoriasis?
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Near points of trauma (ex: elbow andknees)
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What does the trauma induce?
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The intiation of the inflammatory reaction and thus the production of a plaque
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How are the pegs changed in psoriasis?
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They elongate further into the dermis
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How is the scaly surface produced in psoriasis?
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The accumulation of abnormal keratinocytes
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How is the scaly surface produced in psoriasis?
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The accumulation of abnormal keratinocytes
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Where are the T cells located in psoriasis?
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In the area between the pegs
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Which cells have the CD45 RO antigen?
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T memory effector cells
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What is the major gene involved in the hereditary cases of psoriasis?
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Psor1
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Which TF is upregulated in psoriasis?
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Stat3
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What is an example of a systemic treatment for psoriasis?
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A decoy Stat3 oligonucleotide to block upregulation of Stat3
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What type of treatment is the most common?
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Topical, for instance, topical corticosteroids that suppress the production of keratin
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What affects the physiological changes in the fluid component of the body due to a burn?
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The degree and extent of the burn
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What are first degree burns?
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Superficial burns, there is an area of erythema
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What are second degree burns?
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The skin is burnt away to the dermis or muscle
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What are third degree burns?
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They are burnt almost to the bone
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What can burns lead to?
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Shock, septicemia, or even death
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Which component of the skin is involved in acne?
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The sebaceous gland
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What is the normal role of the sebaceous glnd?
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Produce an oil that covers the skin, keeps it soft, and possibly protects against UV light
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Where are sebaceous glands located?
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Adjacent to hair follicles
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Where are sebaceous gands particularly numerous?
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In the face, shoulders, and back (main areas of acne!)
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What is a blackhead?
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In acne, there is a keratin plug blocking the glands
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What does the plug lead to?
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Being extremely prone to infetion
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What hapens in acne?
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There is hyperkeratosis and increased production of melanin (leading to the black head)
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What is another term for blackhead?
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Closed comedo
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What happens when there is bacterial infection in this cavity in the blackhead?
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There is the release of chemotactic factors and high levels of inflammation and and absess forms
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What can happen if the absess ruptures?
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It can break, spreading to the adjacent skin, resulting in an extensive area of inflammation
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What is a whitehead?
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When the plug isnt completely closed and there is a small opening
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What is cystic acne?
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When the sebaceous gland rupturs leading to larger areas of inflammation, which can spread into the dermis
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What is isoretinoin?
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It removes keratin and has a beneficial effect on acne
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How can acne be treated?
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H2O2 or low dose antibiotics
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What can sun damage result in?
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Wrinkles, keratosis, and tumors
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What is the damaging component of sunlight?
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UV
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Which UV type gets prevented from entering our atmosphere?
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UVC
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What type of Uv light is the most damaging?
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UVB is more than UVA but both cause damage
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When is UV index the highest?
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At noon
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Where does UVB stop?
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At the epidermis/dermis boundary
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Where does UVA stop?
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At the dermis bottom
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Wjhat is a consequence of UV damage?
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Melanin is distributed amongst the epidermis
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What happens to the skin in UV sun damage in addition to change in pigmentation?
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The skin becomes thickend
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What happens to the dermis under UV damage?
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The dermis seems to replace the collagin with elastic fibers, resultin in more inflexible ridges and giving a wrinkled appearance, restricted movement of the skin
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Which immune component is expressed during sun damage?
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The RankL (RANK ligand)
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What does expression of RankL lead to?
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Activation of T reg cells, which causes a state of immunosuppresion
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What is telangiectasia?
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A disease that one gets with age that is characterized by dilatation and prolfieration of numerous blood vessels in the cheeks
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How do we get melanin?
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Melanocytes migrate from the neual crest to the bottom of the epidermis and produce melanosomes which are injected into the keratinocytes, providing proection
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What are the different types of melanin in mice?
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Eu-melanin and phaeco-melanin
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What is vitiligo?
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A disease in which the melanin disappears
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Why are type 1 at a highest risk for skin cancer?
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They have the least melanin distributed throughout the epidermis and therefore the lowest protection from the damaging effects of the sun
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What are the two types of DNA alterations that UV light induces?
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Thymine dimers or 6,4-photoproducts
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What are the three types of skin cancer?
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Melanoma
Basal cell carcinoma Squamous cell carcinoma |
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Which skin cancer is the most deadly?
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Melanoma
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Where do basal cell carcinoma and squamous cell carcinoma tend to occur?
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They remain localized and are at high risk on the face
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What is basal cell carcinoma?
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An area of induration on the skin
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What is the difference between squamous cell carcinoma and basal cell carcinoma?
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The lesion in squamous cell carcinom can become ulcerated
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Which types of skin cancer are more common?
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Basal cell and squamous cell
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What are the two forms of melanoma?
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Nevus and invasive
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What is the nevus form?
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The superficial spread
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What is solar letigo?
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How melanoma can beigin, it is an aarea of pigmentation that will gradually grow
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What are some warning signs of melanoma?
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Change in pigmentation, size, lumpy, bleeding
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What are the ABCD signs?
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Assymetry
Border Color Diameter |
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What is the prognosis of a malginant melanoma dependent on?
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The depth of the tumor within the skin
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How can UV light affect the eyes?
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It can cause cataracts in the eyes
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What is the most common cause of Athlete's foot (a type of dermatophyytosis)?
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Poor hygiene
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What does the name of a particular dermatophytosis depend on?
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Where the fungus localizes
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What are some symptoms of Athlete's foot?
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Hyperkeratosis, ucleration and pain
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Which viruses cause warts?
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Human Papilloma Virus
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What does HPV4 cause?
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Verruca vulgaris
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What does HPV3 cause?
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Verruca plana
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What does HPV1 and 2 cause?
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Verruca plantaris (HPV1 and 2)
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What does HPV6 and HPV16 cause?
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Condyloma acuminatum
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How does viral infection result in wart formation?
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They induce hyperplasia, resulting in an area of hyperkeratinosis and development of a wart
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What is koilocytosis?
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The formation of cytoplasmic vacuoles (induced by HPV during wart infection)
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