Mss 08: Dermis And Subcutaneous Tissue

Front 1

What is the middle layer of the skin? What is it derived from?

Back 1

Dermis - mesoderm

Front 2

What is the function of the dermis?

Back 2

- Structure and flexibility
- Vascular support
- Immunologic protection
- Nerve sensation
- Adnexal structures: hair follicles, eccrine (sweat) glands, sebaceous (oil) glands

Front 3

What are the layers of the Dermis?

Back 3

- Papillary dermis (superficial)
- Reticular Dermis (deep)

Front 4

What is the difference between Papillary Dermis vs. Reticular Dermis?

Back 4

- Papillary - more superficial, more cells, fine / loosely woven collagen, interdigitates w/ rete ridges of epidermis
- Reticular - deeper, fewer cells, coarse / tightly packed collagen

Front 5

What is the main component of the dermis? Function?

Back 5

Extracellular Matrix
- Scaffold that gives dermis its structure and function
- Regulates cell functions such as adhesion, migration, division, and apoptosis
- Important for development, wound healing, tumorigenesis, and inflammation

Front 6

What are the components of the Extracellular Matrix in the dermis?

Back 6

- Collagen
- Elastic fibers
- Extrafibrillar matrix

Front 7

What amount of the overall skin volume is collagen? What amount of the dry weight of the skin is collagen?

Back 7

- Overall: 20%
- Dry weight: 75%

Front 8

What produces the collagen in the dermis?

Back 8

Dermal fibroblasts

Front 9

How many types of collagen are in the skin?

Back 9

12 of 28:
- Type 1 - most abundant (80-90%)
- Type 3 - second most abundant, increases during embryogenesis and wound healing
- Types 4, 7, and 17 (aka BP180) found in BM zone

Front 10

What are the properties of collagen in the skin?

Back 10

- Very strong
- Stretches very little

Front 11

What are the function and structure of elastic fibers int he dermis?

Back 11

- Give skin elasticity
- Made of microfibrils (fibrillin and amorphous elastin)

Front 12

What is the ground substance made of in the ECM?

Back 12

AKA extrafibrillar matrix:
- Water
- Electrolytes
- Plasma proteins
- Proteoglycans, glycoproteins, hyaluronic acid

Front 13

What are the types of cells in the dermis?

Back 13

- Fibroblasts (predominant cells of dermis)
- Macrophages, mast cells, other immune cells
- Endothelial cells
- Nervous tissue

Front 14

What are fibroblasts derived from? What do they do?

Back 14

- Derived from mesoderm
- Synthesize ECM components: collagen, elastic fibers, ground substance

Front 15

What is the blood vessel organization in the dermis? Functions?

Back 15

- Superficial plexus in papillary dermis
- Deep plexus in reticular dermis
- Capillaries emanate from these structures to supply the dermis
- Nutrition/circulation, temperature regulation, leukocyte trafficking, and wound healing

Front 16

Where do nerves run in the dermis? Functions?

Back 16

- Course along the superficial and deep vascular plexuses
- Autonomic motor nerves innervate endothelial cells to control tone, smooth muscles of hair follicle to control pilomotor response, and eccrine glands to mediate sweating
- Somatic sensory nerves detect light touch, discriminative touch, pressure, temperature, pain, itch, vibration, and proprioception

Front 17

What are the touch and pressure receptors we need to know?

Back 17

- Pacinian corpuscles - weight-bearing surfaces, as well as lips, nipples, penis, and clitoris (deep dermis and subcutaneous tissue) = Detect Pressure
- Meissner's corpuscles - located below epidermis in dermal papillae, concentrated in palms and soles = Detect Light Touch

Front 18

What are the diseases of the dermis?

Back 18

- Marfan Syndrome
- Ehlers-Danlos Syndrome
- Morphea (localized scleroderma)
- Systemic Sclerosis

Front 19

How is Marfan Syndrome acquired? What is the cause?

Back 19

- Autosomal dominant
- Mutation in fibrillin
- Variable expression

Front 20

What are the common features of Marfan Syndrome?

Back 20

- Tall and thin body type
- Long limbs and fingers
- Scoliosis
- Flexible joints
- Striae (stretch marks)
- Nearsightedness (myopia)
- Ectopia lentis (dislocation of lens of eye)
- Aortic dilation or aneurysm
- Mitral valve prolapse

Front 21

How is Ehlers-Danlos Syndrome acquired? What is the cause?

Back 21

- Inherited connective tissue disorder (variable inheritance)
- Abnormality in collagen structure, production, processing, or assembly

Front 22

What are the common features of Ehlers-Danlos Syndrome?

Back 22

- Fragile skin (very elastic and prone to scarring)
- Extremely flexible joints - may cause joint dislocations or early arthritis
- Severe scoliosis - curvature of spine may affect breathing
- Rupture of blood vessels, intestines and uterus in some types

Front 23

How is Morphea (localized scleroderma) acquired? What is the cause?

Back 23

- Acquired autoimmune disease
- Thickening of collagen (sclerosis)
- Children and adults, females > males

Front 24

What are the common features of Morphea?

Back 24

- Sclerosis
- Erythematous and indurated plaques that slowly expand (violaceous plaques and sclerotic plaques)
- Fibrotic or atrophic scars
- Joint and neurologic complications (not as bad internal organ involvement) - may not be able to move joints d/t sclerosis

Front 25

How is Systemic Sclerosis acquired? What is the cause?

Back 25

- Autoimmune disease
- Affects middle-aged women especially
- Widespread sclerosis

Front 26

What are the two types of Systemic Sclerosis?

Back 26

- Limited Systemic Sclerosis (formerly called CREST syndrome)
- Diffuse Systemic Sclerosis

Front 27

What are the common features of Limited Systemic Sclerosis?

Back 27

CREST Syndrome:
- Calcinosis cutis - calcium deposits in skin
- Raynaud phenomenon - fingers turn white d/t lack of blood flow, then blue as vessels dilate, then red as flood flow returns (white-blue-red)
- Esophageal dysmotility
- Sclerodactyly (thickening and tightening of skin of fingers)
- Telangiectasia of face (small broken capillaries on skin surface)
(also microstomia - pinched mouth in some)

Front 28

What is the subcutaneous fat derived from? What are its functions?

Back 28

- Derived from mesoderm
- Energy storage, insulation, and shock absorption

Front 29

What are the main cells of the subcutaneous fat? Functions?

Back 29

Adipocytes - synthesize and store lipids in cytoplasm

Front 30

How are adipocytes arranged?

Back 30

- Adipocytes aggregate in lobules
- Fibrous bands called septae or trabeculae separate the lobules
- Septae contain blood vessels and nerves

Front 31

What are the disorders of the subcutaneous fat?

Back 31

- Inflammation = Panniculitis
- Erythema Nodosum

Front 32

What is panniculitis?

Back 32

Inflammation of the subcutaneous fat

Front 33

What is the most common type of panniculitis (inflamed subcutaneous fat)? Who is most likely to get this?

Back 33

Erythema Nodosum (EN)
- More common in young women (maybe d/t contraception)
- Can affect people of any age, sex, or race

Front 34

What commonly causes Erythema Nodosum?

Back 34

- Reactive process that can be triggered by a variety of factors
- Most times idiopathic
- Infectious causes most common (especially upper respiratory streptococcal infection)
- Medications (especially oral contraceptives), sarcoidosis, inflammatory bowel disease, and malignancy can also trigger

Front 35

What are the common features of Erythema Nodosum?

Back 35

- Tender, red nodules that arise on shins
- May arise in crops, then slowly involute over course of a few days or weeks

Front 36

What disease is characterized by the following symptoms?
- Tall and thin body type w/ long thin limbs and fingers
- Flexible joints
- Scoliosis
- Striae (stretch marks)
- Nearsightedness and ectopia lentis (dislocation of lens)
- Aortic dilation or aneurysm
- Mitral Valve prolapse

What is the cause?

Back 36

- Marfan Syndrome
- Autosomal dominant d/t mutations in fibrillin --> connective tissue disorder

Front 37

What disease is characterized by the following symptoms?
- Extremely flexible joints
- Fragile skin
- Joint dislocations and early arthritis
- Severe scoliosis
- Rupture of blood vessels, intestines, and uterus possible

What is the cause?

Back 37

- Ehlers-Danlos Syndrome
- Mutations in structure, production, processing, or assembly of collagen

Front 38

What disease is characterized by the following symptoms?
- Thickening of collagen
- Erythematous indurated plaques that slowly expand
- Even w/ treatment may leave fibrotic or atrophic scars
- Some joint and neurologic complications
What is the cause?

Back 38

- Morphea (localized scleroderma)
- Acquired autoimmune disease

Front 39

What disease is characterized by the following symptoms?
- CREST syndrome
- Calcinosis cutis
- Raynaud phenomenon
- Esophageal dysmotility
- Sclerodactyly
- Telangiectasia
- Pulmonary fibrosis, renal failure, GI disease, and cardiac disease

What is the cause?

Back 39

Systemic Sclerosis (specifically limited type)
- Acquired autoimmune disease

Front 40

What disease is characterized by the following symptoms?
- Tender red nodules on shins
- May arise in crops that involute over the course of a few days to weeks

What is the cause?

Back 40

Erythema Nodosum
- Acquired disorder
- Triggered most commonly by upper respiratory streptococcal infection
- Other triggers: meds (oral contraceptives), sarcoidosis, IBD, and malignancy