Skin-anatomy

Question 1

Epidermis & dermis are derived from?

Answer 1

Epidermis → ectoderm
Dermis → mesoderm

Question 2

Principle cells of epidermis?

Answer 2

Keratinocytes - 90% of epidermal cells

Question 3

Dermis contains which collagen?

Answer 3

Type 1 → 80%
& 3 → 10 -20%
Ratio of → 4:1

Question 4

Skin weight?

Answer 4

12 - 16% of total body weight

Question 5

Naive the layers of epidermis?

Answer 5

Corneum
Lucidum
Granulosum
Spinosum
Basale

Question 6

Stratum Malpighi?

Answer 6

Stratum battle & stratum spinosum

Question 7

Intracellular edema of keratinocytes in ?
Stratum basale?
Stratum spinosum?

Answer 7

St. Basale → ballooning
St. Spinosum → spongiosis → ch. Of eczema

Question 8

Layer absent in premature neonate?

Answer 8

St. Corneum

Question 9

Layer with highest concentration of free amino acids ?

Answer 9

Stratum corneum

Question 10

What is parakeratosis??

Answer 10

Retention of nuclei in stratum corneum

Question 11

Define hyper keratosis?

Answer 11

Thickening of stratum corneum

Question 12

Keratin is mostly synthesized in ?

Answer 12

Stratum spinosum

Question 13

Layer containing refractive droplets of eleidin?

Answer 13

Stratum lucidum

Question 14

What are rete ridges?

Answer 14

Downgrowths of epidermis folds into dermis

Question 15

Layers of dermis?

Answer 15

Papillary & reticular

Papillary → superficial layer → contains loose areolar tissue , superficial capillaries & nerve endings

Reticular → deep layer → contains collagen, elastic fibres, appendages, arterioles & venules

Question 16

Subcutaneous tissue?

Answer 16

Consists of fat
Attached to deep fascia
Thickest → in palms & soles
Thinnest → in eyelids

Question 17

Describe cells in epidermis?
Where are they derived from?

Answer 17

Local cells → keratinocytes → develop from ectoderm
Immigrant cells → melanocytes→ neural crest cells →→→ develop elsewhere & migrate to epidermis
→ Merkle calls → neural crest cells
→ langerhan cells → derived from mesenchyme

Question 18

Keratinocytes?

Answer 18

Proliferate (divide) → in basal layer
Differentiate in → stratum spinosum & stratum granulosum
Completely mature & die in → stratum corneum

Question 19

Melanocytes

Answer 19

Max number is in → skin of genitalia

Question 20

Langerhan cells

Answer 20

These are APC → in stratum spinosum
Reduced in » aging, bcc, SCC, sarcoidosis & aids
Increased in → oral lichen planus, langerhau cell histiocytosis, contact hypersensitivity

Question 21

Merkle cells

Answer 21

Slow adapting touch receptors
Present in basal layer