Skin

Question 1

What are the 5 layers of the epidermis

Answer 1

-Stratum corneum -Stratum lucidum -Stratum granulosum -Stratum Spinosum -Stratum Basale

Question 2

What occurs in the Stratum corneum?

Answer 2

• 15-20 layers of squamous dead keratinized cells
• Continuous shedding at epidermal surface because the desmosomes break down

Question 3

What occurs in the Stratum lucidum?

Answer 3

• Only in thick skin
• Flattened keratinocytes
  
  • desmosomes still intact
  • no nuclei (dead)
  • No organelles
  • Packed keratin filaments
• ​“Sequential march of death”

Question 4

What occurs in the Stratum granulosum?

Answer 4

-Formation of a barier to penetration by most foreign materials via:

• Keratinization of dense keratohyaline granules
• Lamellar Granules which contain lipids, which are excreted as a barrier against water loss

Question 5

What occurs in the Stratum spinosum?

Answer 5

• Several layers of keratinocytes
• Production of tonofibrils, which terminate at the desmosome (gives spiney look after fixation of tissue)

Question 6

What occurs in the Stratum Basale?

Answer 6

-A single layer of stem cells tightly bound by desmosomes

Question 7

What is the difference between thick and thin skin?

Answer 7

-Thick skin has extra layer, stratum lucidum -Think skin has much thinner layer of Stratum corneum

Question 8

What are the 4 types of cells in the epidermis?

Answer 8

-Keratinocytes -Melanocytes -Langerhans cells -Merkel Cells

Question 9

Match.

Answer 9

A. Stratum Corneum

B. Stratum Lucidum

C. Stratum Granulosum

D. Stratum Spinosum

E. Stratum Basale

Question 10

Why do basal cell carcinoma’s rarely metastisize?

Answer 10

Because they are tightly bound to each other and the basal lamina via junctional complexes.

Question 11

What are Tonofibrils?

Answer 11

Assembled keratin filaments in the keratinocytes of the stratum spinosum. Attach at the desmosomes.

Question 12

In what layer of the skindo Langerhans cells reside?

Answer 12

The stratum spinosum

Question 13

What is the cause of Psoriasis

Answer 13

• Likely autoimmune
• keratinocytes are produced at accelerated rates

Question 14

What is the role of the dermis?

Answer 14

• Support of the epidermis
  
  • Contains all the neurovascular elements of skin
• Reinforces the dermal-epidermal junction with dermal papillae

Question 15

What structures are contained within the reticular layer of the dermis?

Answer 15

• Hair follicles
• Sebaceous Glands
• Sweat glands
• Nerves

Question 16

What are the two layers of the dermis?

Answer 16

1. Papillary layer
2. Reticular layer

Question 17

What is Bullous pemphigoid?

Answer 17

• An autoimmune dizease in which the body attacks the proteins of the hemidesmosome
• The epidermis lifts off from the basememt membrane, forming blisters

Question 18

What is Pemphigus?

Answer 18

• An autoimmune disease in which the body attacks desmosomal proteins
• ungluing of the keratinocytes
• Blisters form within the epidermis
  
  • break easily, forming crater

Question 19

What is the purpose of the Hypodermis?

Answer 19

• Binds skin to adjacent organs
• Facilitates skin sliding over underlying organs
• Highly vascularized
  
  • uptake of drugs

Question 20

What are the two layers of the stratum corneum?

Answer 20

1. Stratum Compactum
2. Stratum Disjunctum

Question 21

What anchors the dermis to the epidermis?

Answer 21

Type VII collagen inserts into the basal lamina layer of the basement membrane from the papillary layer

Question 22

What are the two major plexuses of the Dermis?

Answer 22

1. Subpapillary plexus
2. deep plexus

Question 23

Subpapillary Plexus

Answer 23

Between papillary and reticular layer. Capillaries extend up into the dermal papillae

Question 24

Deep Plexus

Answer 24

Interface of the dermis and hypodermis

Question 25

Where will blood be shunted in the dermis if a human is cold?

Answer 25

to the deep plexus

Question 26

Melanocyte

Answer 26

- Originate from neural crest - intermediate filament is vimentin - Live in the stratum basale - Produce black, brown, or red pigment

Question 27

Eumelanins

Answer 27

Black or brown pigment produced by melanocytes

Question 28

Pheomelanin

Answer 28

red pigment produced by melanocytes

Question 29

Epidermal-Melanin Unit

Answer 29

- Melanocyte + long irregular cytoplasmic projections - Terminates in invaginations in the keratinocytes of the stratum spinosum - Produces melanosomes which are transferred to the keratinocyte via fusion

Question 30

What is the structure which melanosomes accumulate into in the keratinocyte?

Answer 30

the supranuclear cap

Question 31

What is the function of a Langerhans Cell?

Answer 31

- Prevents microorganisms from penetrating the epidermis - Extend cytoplasmic projections between the keratinocytes of all layers

Question 32

Where do Langerhans Cells develop before migrating into the epithelium?

Answer 32

Bone marrow

Question 33

What happens to Langerhans Cells upon antigen capture?

Answer 33

They leave and travel to the lymph node where they initiate an immune response

Question 34

What are the three types of unencapsulated sensory receptors of the skin?

Answer 34

1. Merkel cells 2. Free nerve endings 3. Root hair plexus

Question 35

Where are merkel cells located? What do they do?

Answer 35

- The stratum basale of the epidermis - They sense light touch and texture

Question 36

Where do free nerve endings of the skin live?What do they sense?

Answer 36

- Papillary dermis layer - Temperature, pain, itching, touch

Question 37

Where does the root hair plexus live? What does it do?

Answer 37

- the Reticular dermis, surrounding base of hair follicles - Detects movement of hairs

Question 38

Where do merkel cells originate?

Answer 38

same stem cells as keratinocytes

Question 39

List the encapsulated sensory receptors of the skin.

Answer 39

- meissners corpuscles - Pacinian corpuscles - Krause end bulbs - Ruffini corpuscles

Question 40

Sebaceous release sebum with what type of secretion?

Answer 40

Holocrine secretion

Question 41

What is the purpose of sebaceous glands?

Answer 41

- to maintain the stratum corneum - Has antibacterial/fungal properties

Question 42

What is an eccrine gland?

Answer 42

sweat gland, widely distributed

Question 43

What are the three cell types of Eccrine Glands?

Answer 43

1. Clear cells 2. Dark cells 3. Myoepithelial cells

Question 44

What do the clear cells of the eccrine gland do?

Answer 44

produce sweat from interstitial fluid from the blood vessels in the dermis

Question 45

What do the dark cells of the eccrine gland do?

Answer 45

release a mixture of glycoproteins with antibacterial properties

Question 46

What to the myoepithelial cells of the eccrine gland do?

Answer 46

Contract to move watery secretion into the duct

Question 47

What is an apocrine gland?

Answer 47

A sweat gland located primarily in the axilla and perineal areas.

Question 48

Why are apocrine glands misnamed?

Answer 48

They actually use merocrine secretion

Question 49

Do melanocytes have desmosomes?

Answer 49

No

Question 50

What type of secretion do melanocytes perform?

Answer 50

Cytocrine secretion

Question 51

Why is melanoma so dangerous?

Answer 51

Melanocytes don't have desmosomes to prevent metastasis

Question 52

Where do Meissners corpuscles reside?

Answer 52

Dermal papillae of the fingertips, palms, and soles

Question 53

Where do krause end bulbs live?

Answer 53

Skin of penis and clitoris

Question 54

Where are pacinian corpuscles located?

Answer 54

Deep in reticular dermis and hypodermis