Anatomical basis of
cutaneous
structure & function
Speaker - Dr. Dibbendhu Khanra
Chairperson – Dr./ Prof. D. Bandopadhyay
Bob Marley died of malignant melanoma
Paris
Hilton
has
atopic
dermatitis,
suffered
from
recurrent herpes labialis.
An american reporter had heat
stroke while he was covering
news in Sub-Saharan Africa
Painful leg ulcer in a DM patient
Young epileptic on valproate
developed TEN
What is the
function of

SKIN?

Preservation and
reproduction of DNA

What are the requirements of skin for the
protection...
 Skin is the largest organ in the body
 In a 70-kg individual, the skin weighs over 5 kg
 Covers a surface area approac...
Beauty may be skin–deep but skin has 4 layers
Epidermis is not dead
Protein rich
corneocytes

Cells of epidermis:
1. Keratinocytes
2. Langerhan’s cells
3. Mast cells
4....
Membrane proteins:
- Plakins

Granulocyte precursor:
- Loricrin
- Profilaggrin

Cytosolic precursors:
-Involucrin
- Small ...
Dermo-epidermal junction
Vascularized dermis provides
structural and nutritional support

-Vessels
- ECM
- Receptors and nerves
- Erector pili musc...
Extracellular matrix
Elastin
-Elasticity
-Resilience

Collagen
-tensile strength,
-protects against trauma

Proteoglycan/g...
Pilosebaceous
Unit
1.Terminal on the scalp and beard
2.Vellus on the majority of skin
3. Sebaceous on the chest, back and ...
‘Barrier’ function of skin

TEWL

Noxous
agent

 Intact stratum
corneum
 Lipid-rich
(Polar molecules
envelope
Can get th...
Skin: An immunological unit

Innate immunity
1.
2.
3.
4.

Complements
Toll Like Receptors (TLR)
Antimicrobial peptides (AM...
TLRs have emerged as a major class of
pattern recognition receptors in skin
AMPs
•
•
•
•
•

Cathelicidins
β-defensins
Adrenomedullin
Cystatin
Secretory protease inhibitor

• Alarmins

- Broad spectr...
Langerhan’s cells –
Survey the epidermal environment
Antigen presentation to T-cells
Dendrite surveillance
extension and r...
Immune Response

Effector cells
1.
2.
3.
4.
5.
6.
7.

Th1, Th2 cells (CD4)
Tc CELLS (CD8)
Treg cells
NK cells (UV-induced ...
Circulation
2-way haematogenous system

1. Nutritional support
2. Delivery of leucocytes
3. Thermoregulation
1-way lymphat...
Interfacing with External and Internal Environments:
Skin is a Communicating Organ
‘Wired’ communication
Autonomic system ...
Skin: conveyer of beauty & physical attraction;
server of socio-sexual communication

The skin, by virtue of its visual ap...
Pheromones – myth or reality?
•

Musky odour composed of 3-olcompound degraded by bacteria

•

Kalogeraki & Beiber - Boys ...
Skin is so busy that sometimes it fails!

Skin failure
‘A loss of normal temperature control with inability to maintain th...
Bioengineering and the skin
•
•
•
•
•
•
•

TEWL measurement is used to assess the barrier function of skin
Transcutaneous ...
What we have learned today?
Immunological
function

Sensory
unit

Absorption

Sociosexual
communication

Endocrine unit

W...
DNA
damage by
UV ray

Compromised
chemical and
immune
barrier

Loss of
thermoregulation

Vascular
damage

Problems revisit...
Thank you

What spirit is so empty and blind, that it
cannot recognize the fact that the foot is more
noble than the shoe,...
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Anatomical basis of cutaneous structure and function, presented at CMC, kol on april, 2013

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Anatomical basis of cutaneous structure and function, presented at CMC, kol on april, 2013

  1. 1. Anatomical basis of cutaneous structure & function Speaker - Dr. Dibbendhu Khanra Chairperson – Dr./ Prof. D. Bandopadhyay
  2. 2. Bob Marley died of malignant melanoma
  3. 3. Paris Hilton has atopic dermatitis, suffered from recurrent herpes labialis.
  4. 4. An american reporter had heat stroke while he was covering news in Sub-Saharan Africa
  5. 5. Painful leg ulcer in a DM patient
  6. 6. Young epileptic on valproate developed TEN
  7. 7. What is the function of SKIN? Preservation and reproduction of DNA What are the requirements of skin for the protection and duplication of DNA?
  8. 8.  Skin is the largest organ in the body  In a 70-kg individual, the skin weighs over 5 kg  Covers a surface area approaching 2 m2
  9. 9. Beauty may be skin–deep but skin has 4 layers
  10. 10. Epidermis is not dead Protein rich corneocytes Cells of epidermis: 1. Keratinocytes 2. Langerhan’s cells 3. Mast cells 4. Melanaocytes 5. Markel cells Lipid rich lamellar bodies
  11. 11. Membrane proteins: - Plakins Granulocyte precursor: - Loricrin - Profilaggrin Cytosolic precursors: -Involucrin - Small prolin rich protein Calcium Envelope proteins Lamellar body: Ceramide Fatty acid Cholestreol Cholesterol esters Corneocyte Glutamyl lysyl isodipeptidase bond Transglutaminase (TG 1-5) Protein-rich corneocytes are embedded within a continuous lipid-rich matrix
  12. 12. Dermo-epidermal junction
  13. 13. Vascularized dermis provides structural and nutritional support -Vessels - ECM - Receptors and nerves - Erector pili muscle - Pilosebaceous unit - Hair
  14. 14. Extracellular matrix Elastin -Elasticity -Resilience Collagen -tensile strength, -protects against trauma Proteoglycan/glycosaminoglycan - hydration Non-collagenous glycoproteins - facilitate cell-matrix interactions
  15. 15. Pilosebaceous Unit 1.Terminal on the scalp and beard 2.Vellus on the majority of skin 3. Sebaceous on the chest, back and face 4. Apopilosebaceous in axilla and groin Glands of skin Eccrine galnd: Sweating • Insensible and active • Thermal and mental • Sole, forehead and palm Apocrine glands: Pheromones • • • • • • Axilla Nipples Pubic/genital/circum-anal area Lips and circumoral Eyelids Outer ear
  16. 16. ‘Barrier’ function of skin TEWL Noxous agent  Intact stratum corneum  Lipid-rich (Polar molecules envelope Can get thru lipid layer)  Keratin  Keratin  Sebum  Immunity Stretching  ECM Trauma  Subcutaneous fat (80% of fat is in the subcutis) Light/ UV Ray  Thickened epidermis Stratum corneum  Melanin (-brown/black =eumelanin -yellow/red =phaeomelanin)
  17. 17. Skin: An immunological unit Innate immunity 1. 2. 3. 4. Complements Toll Like Receptors (TLR) Antimicrobial peptides (AMP) Macrophages Adaptive immunity 1. Antigen presenting cells (LC, DC) 2. Lymphocytes 3. Cytokines & Immunoglobulins
  18. 18. TLRs have emerged as a major class of pattern recognition receptors in skin
  19. 19. AMPs • • • • • Cathelicidins β-defensins Adrenomedullin Cystatin Secretory protease inhibitor • Alarmins - Broad spectrum of antimicrobial activity - Chemotactic for inflammatory cells - Promoting histamine release from mast cells - Adjuvant in enhancing antibody production - Increases the expression of TNF-α and IL-1 - Barrier repair and wound healing
  20. 20. Langerhan’s cells – Survey the epidermal environment Antigen presentation to T-cells Dendrite surveillance extension and retraction cycling habitude (dSEARCH) allows an efficient antigen sampling  Short-term LCs developed from Gr1hi monocytes under inflammatory conditions  Long-term LCs arose from bone marrow in steady state and depend on Id2  LC reconstitution occurs in two waves: - Initial fast and transient wave of short-term LCs - Second wave of long-term LCs.
  21. 21. Immune Response Effector cells 1. 2. 3. 4. 5. 6. 7. Th1, Th2 cells (CD4) Tc CELLS (CD8) Treg cells NK cells (UV-induced immunosuppression ) γ/δT cells (Leprosy, leishmnaiasis) DETCs (protect keratinocytes) B cells and Ig
  22. 22. Circulation 2-way haematogenous system 1. Nutritional support 2. Delivery of leucocytes 3. Thermoregulation 1-way lymphatic system - Adaptive immunity  Extensive subcutaneous venous plexus hold large quantities of blood dissipate heat from the surface of the skin  Arteriovenous anastomoses prominent in areas exposed to maximal cooling volar surfaces of the hands, feet, lips, nose, ears
  23. 23. Interfacing with External and Internal Environments: Skin is a Communicating Organ ‘Wired’ communication Autonomic system (cholinergic) 1. Vasomotor functions 2. Pilomotor activity 3. Eccrine sweat gland secretion Sensory system  Mechanoreceptors for touch • Skin: Rapidly adapting - Meissner’s corpuscle - Slowly adapting - Merkel’s receptor • Subcutaneous tissue : Rapidly adapting - Pacinian corpuscle, Slowly adapting - Ruffini’s corpuscle,  Thermoreceptor Cold receptors Warmth receptors  Nociceptors ‘Wire-less’ communication Cellular communication - APC - Lymphocytes - Mast cells Communication via hormones - ACTH in skin pigmentation - Vit D3 from epidermis - Pheromones from apocrine glands - MSH in appetite - Leptin from subcutaneous adipocytes Communication via cytokines - Keratinocytes produce IL-1, IL-8, TGF-β - Mast cells produce TNF - Vascular endothelial cells produce IL-1β, IL-6
  24. 24. Skin: conveyer of beauty & physical attraction; server of socio-sexual communication The skin, by virtue of its visual appeal, smell and feel, has an important role in social and sexual communication in humans On Beauty: Evolution, Psychological consideration and surgical enhancement: Allan & Dover
  25. 25. Pheromones – myth or reality? • Musky odour composed of 3-olcompound degraded by bacteria • Kalogeraki & Beiber - Boys show aversion to the odor of fathers but feels attraction to the odor of mothers (Oedipaus complex) • Russel – Babies suck on only to mother’s breast. Mother unconsciously marks her baby with a distinctive smell (Russel effect)
  26. 26. Skin is so busy that sometimes it fails! Skin failure ‘A loss of normal temperature control with inability to maintain the core temperature, failure to prevent percutaneous loss of fluid, electrolytes and protein with resulting imbalance and failure of the mechanical barrier to penetration of foreign materials’ Examples • Thermal Burns • Stevens–johnson Syndrome, • Toxic Epidermal Necrolysis, • Graft-versus-host Disease
  27. 27. Bioengineering and the skin • • • • • • • TEWL measurement is used to assess the barrier function of skin Transcutaneous oxygen tension (tcPo2) measurement to assess skin perfusion Botox injection: decrease facial lines and sweating in disabling hyperhydrosis Skin grafting Finger-printing Stem cells can be collected from skin LC and DC capture protein antigens: Possible targets for vaccination
  28. 28. What we have learned today? Immunological function Sensory unit Absorption Sociosexual communication Endocrine unit Waterproofing Excretion of waste 1. Structural organization 2. Skin: Multitasking unit 3. Skin immunity 4. Skin failure 5. Skin bio-engineering Mechanical barrier Pigmentory unit Temperature regulation Elastic function
  29. 29. DNA damage by UV ray Compromised chemical and immune barrier Loss of thermoregulation Vascular damage Problems revisited Skin failure with massive TEWL
  30. 30. Thank you What spirit is so empty and blind, that it cannot recognize the fact that the foot is more noble than the shoe, and skin more beautiful than the garment with which it is clothed Michalangelo

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