Dermis and subcutaneous tissue

Question 1

Layers of dermis:

Answer 1

Papillary: loose connective tissue beneath the epidermis.

Reticular: Dense dermal collagen.

Question 2

Functions of the dermis:

Answer 2

1. Structure and flexibility.
2. Vascular support.
3. Immunologic protection.
4. Nerve sensation.

Question 3

Function of ECM:

Answer 3

Supports cells of the dermis.

Question 4

Components of ECM:

Answer 4

1. Collagen
2. Elastic fibers
3. Extrafibrillar matrix

Question 5

Collagen produced by:

Answer 5

Dermal fibroblasts.

Question 6

Types of collagen:

Answer 6

Collagen I: most abundant.

Collagen III: Increased levels during embryogenesis, infancy, wound healing.

Collagen IV, VII, XVII are in the basement membrane.

Question 7

Structure of elastic fibers:

Answer 7

1. Microfibrils (mainly fibrillin)

2. Elastin

Question 8

Extrafibrillar matrix composition:

Answer 8

1. Water
2. Electrolytes
3. Plasma proteins
4. Proteoglycans

Question 9

Proteoglycan structure and function:

Answer 9

Structure: Protein core + glycosaminoglycan.

Function: bind large amounts of water.

Question 10

Fibroblasts:

Answer 10

Derived from mesoderm.

Synthesize ECM components:
Collagen
Elastic fibers
Ground substance

High metabolic activity.

Question 11

Meissner:

Pacinian:

Answer 11

Fine touch.

Deep pressure, vibration.

Question 12

Marfan syndrome:

Answer 12

Autosomal dominant.

Production of weak elastic tissue due to a defect in synthesizing fibrillin.

Variable expression:
Most often CV abnormalities dominate.
Dislocation of lens (suspensory ligament is elastic).
Pectus excavatum.
Striae.

Question 13

Ehlers-Danlos syndrome:

Answer 13

Abnormalities of collagen structure, production, processing, or assembly.

Hypermobile joints and really stretchy skin.

Question 14

Morphea:

Answer 14

Autoimmune disease, causes sclerosis.

Violaceous plaques, sclerotic plaques. Limb and joint complications. Neurologic involvement. En coup de sabre.

Women > men.

Question 15

Systemic sclerosis:

Answer 15

Autoimmune disease.

Multisystem disease characterized by vascular dysfunction, excessive production of collagen that primarily targets the skin and visceral organs, and immune dysfunction.

Middle-aged women, increased incidence in the black female population.

Clinical features: 
     Sclerosis of the skin (microstomia, sclerodactyly)
     Raynaud's phenomenon
     Telangiectasia
     Arthritis
     Internal organ involvement

Question 16

Functions of subcutis:

Answer 16

1. Energy storage
2. Insulation
3. Shock absorption

Question 17

Erythema nodosum:

Answer 17

Inflammatory lesion of subcutis (panniculitis)

Raised, erythematous, painful nodules usually located on the anterior portion of the skins.

More common in young women.