Clinical Integumentary

Question 1

what is the normal duration of skin renewal

Answer 1

• 2-4 weeks (on average)

Question 2

describe wound healing

Answer 2

• epidermal wound healing: occurs following wounds that affect only the epidermis
• deep wound healing: occurs following wounds that penetrate the dermis

Question 3

describe epidermal wound healing

Answer 3

• in response to an injury, the basal cells of the epidermis surrounding the wound, break contact with the basement membrane, enlarge and migrate across the wound
• epidermal growth factor stimulates basal stem cells to divide and replace the lost cells

Question 4

describe deep wound healing

Answer 4

• as the injury involves multiple tissue layers, healing process is more complex
• 4 phases:
  
  • inflammatory phase
  • migratory phase
  • proliferative phase
  • maturation phase

Question 5

describe the inflammatory phase of deep wound healing

Answer 5

• blood clot is formed and lossely attaches the cut edges
• vasodilation and increased permeability helps neutrophils and monocytes (which become macrophages) to enter the area and eliminate microbes, foreign material and dying tissue
• mesenchymal cells develop into fibroblasts

Question 6

describe the migratory phase of deep wound healing

Answer 6

• the clot becomes a scab, epithelial cells migrate beneath it to bridge the wound
• fibroblasts synthesize scar tissue (collagen and glycoprotein) and damaged vessels regrow
• this now constitutes the granulation tissue

Question 7

describe the proliferative phase of deep wound healing

Answer 7

• growth of the epithelial tissue at random
• continued growth of vessels

Question 8

describe the maturation phase of deep wound healing

Answer 8

• scab sloughs off
• epidermis restored to normal thickness
• collagen is more organized
• fibroblasts decrease and blood vessels stabilize
• the scar is called a fibrosis

Question 9

describe hyperkeratosis

Answer 9

• hyperplasia of the stratum corneum

Question 10

describe parakeratosis

Answer 10

• retention of nuclei in the stratum corneum of the skin
  
  • ex: psoriasis

Question 11

define acantholysis

Answer 11

• loss of intercellular connections resulting in loss of cohesion between keratinocytes
  
  • ex: pemphigus vulgaris

Question 12

define acanthosis

Answer 12

• epidermal hyperplasia (stratum spinosum)

Question 13

describe psoriasis

Answer 13

• disease is due to increased rate of proliferation of the mitotic cells thereby leading to thickened epidermis (acanthosis)
• leads to shedding of the epidermis constantly-resulting in scales seen as whitish patches

Question 14

describe bullous pemphigoid

Answer 14

• chronic autoimmune blistering disease
• presence of IgG antibodies specific to hemidesmosomes
• IgG bind to basement membrane and stimulate leukocytic infiltration
• eosinophils release proteases that degrade hemidesmosomes
• fluid accumulation –> blister formation

Question 15

describe pemphigus vulgaris

Answer 15

• rare autoimmune disorder affecting epidermis and mucosal epithelium
• antibodies target cadherins and desmoplakins in desmosomes
• separation of epidermal cells, especially in stratum spinosum
• atrophy of the prickle cell layer
• leads to blister formation (easy to rupture vs bollus pemphigoid blisters)

Question 16

describe albinism

Answer 16

• 2 types: ocular and oculocutaneous
• caused by inactivity of the tyrosinase enzyme
• tyrosine–>DOPA via tyrosinase enzyme
  
  • DOPA –> melanin

Question 17

describe vitiligo

Answer 17

• autoimmune condition that leads to destruction of melanocytes

Question 18

name the cancers arising from squamous cells, basal cells and melanocytes

Answer 18

• squamous cells = squamous cell carcinoma
• basal cell = basal cell carcinoma
• melanocytes = malignant melanoma
  
  • malignant because derived from the neural crest

Question 19

describe squamous cell carcinoma

Answer 19

• malignant tumor of keratinocytes
• hyperkeratosis and parakeratosis
• dermis deeply infiltrated by islands and sheets of malignant squamous cells
• the islands have undifferentiated cells, resembling basal cells, around the perimeter
• islands show squamous differentiation with formation of squamous pearls or swirls

Question 20

Answer 20

• Islands show squamous differentiation with formation of squamous pearls or swirls

Question 22

describe basal cell carcinoma

Answer 22

• involves the basal cells
• single arrangement of basal cells surrounding group of tumor cells (Palisade arrangement)

Question 23

describe malignant melanoma

Answer 23

• malignant transformation of melanocytes
• causes highest # of skin cancer related deaths in US
• increased number of melanocytes with large atypical morphology
  
  • arranged at the dermo-epidermal junction
• may invade the dermis-metastases