The document is a comprehensive presentation on the integumentary system, detailing skin anatomy, physiology, and pathology, including the layers of skin, accessory organs like hair and nails, and functions such as protection, temperature regulation, and sensation. It also covers common skin diseases and their clinical implications, diagnostic techniques, and interactions with other bodily systems. The presentation emphasizes the importance of skin health and understanding its complex structure for effective medical examination and treatment.

1. Integumentary system
PRESENTER: DR SOUMYA P
2ND YEAR PG SCHOLAR
DEPARTMENT : KAYACHIKITSA

2. Contents
 Intoduction
 Skin anatomy
 Anatomy of accessory organs
 Skin physiology
 Interaction with other system
 Skin pathology
 Classification of skin diseases
 History taking and examinations
 Laboratory investigations

3. Introduction
 Skin = integument
 Skin+ accessory organs = integumentary system.
 The integumentary system comprises the skin and its appendages acting to
protect the body from various kinds of damage, such as loss of water or damages
from outside.
 It includes hair, glands and nails.
 It has a variety of additional functions; it may serve to waterproof, and protect the
deeper tissues, excrete wastes, and regulate body temperature, and is the
attachment site for sensory receptors to detect pain, sensation, pressure, and
temperature,vitamin D synthesis.

4. Skin and its layers
• Largest organ in the body
• Constitutes of 15% of body weight
• Surface area – 1.5 to 2.0 square
meters
1. Epidermis
2. Dermis
3. Hypodermis ( subcutaneous
layer)

5. Epidermis
 Most superficial layer of the skin
 Approx 10 to 30 cells thick ( epithelial)
 Cell types
Keratinocytes -90%
Melanocytes
Merkel cells 10%
Langerhens
CLINICAL APPLICATION : KERATINIZATION - PSORIASIS

6. Stratum Basale
Anatomy
 Stratum germinativum
 Deepest epidermal layer
 Attaches to basal lamina
 Cells bond to dermis via
collagen fibres
 Finger like projection called
dermal papillae in dermis
 Helps in stronger connection
 Cells- cuboidal shaped
keratinocytes
 Grows constantly ,mitosis
 Pushed up old cells
Applied aspect
 Cells – merkel cell – function as receptor- stimulating
sensory nerve fibres
 Found in hairless skin.
 Abundant on surface of hand and feet.
 Melanocytes- produces pigment melanin
 - gives hair and skin its color
 -protect from u rays
 Note: skin color influenced by ,melanin and carotene –
carrot, oxygenated haemoglobin
 Fingerprints-epidermal ridges

7. Stratum spinosum
ANATOMY
 Spiny in appearance
 Desmosomsis protruding cell
 Interlock between cells
 Composed of 8to 10 layers of
keratinocytes
APPLIED ASPECT
 Langerhans cell –as a macrophage by
engulfing bacteria and foreign body and
damaged cell.
 Keratinocytes synthesise keratin and
prevent water loss

8. Stratum granulosum
 Has a grainy appearance
 Cells become flattened,and cell membrane thicken, and generate large amount of
protein keratin and keratohyalin
 After cell dies , keratin ,keratohyalin and cell membrane forms stratum lucidum
 And accessory structures of hair and nail

9. Stratum lucidum
 Smooth translucent layer
 It is found only in thick skin of palms ,soles,digits
 Cells are densely packed with eleidin , a clear protein rich in lipids,
 Transparent appearance

10. Stratum corneum
ANATOMY
 Most superficial layer of epidermis
 The increased keratinization of cell
 It has 15 to 30 layers of cells
 Water is lost from skin in 2 ways
 Insensible perspiration
water diffuses from stratum corneum and evaporates
from skin
-500 ml per day
 Sensible perspiration
 Water excreted by sweat glands.
APPLIED ASPECT
 Helps prevent penetration of microbes and
dehydration of underlying tissue
 Provides mechanical protection against abrasion
 Entire layer is replaced during a period of about 4
weeks.
 Cosmetic procedures , microdermabrasion help
remove some of the dry upper layer and looks fresh
and healthy.

11. Clinical application
Some medications are toxic if swallowed, but safe if used topically (applied to surface of
skin)
• Certain topical antibiotics are fairly toxic if taken by mouth, butcan be applied to skin with
minimal risk of systemic absorption;they are polar molecules that cannot pass through
epidermis toreach blood vessels in dermis; allows for local effect only
• Nonpolar substances cross epidermis much more easily;provides a convenient route of
administration for certainmedications such as hormones in birth control patches
• Unfortunately, many poisons and toxins (like thallium, a heavymetal) are also nonpolar;
cross epidermis with same ease;therefore always good idea to wear gloves when handling
chemicals

12. Dermis
 Dermis – highly vascular layer deep to epidermis
Functions:
Provides blood supply for epidermis
Contains sensory receptors
Anchors epidermis in place
 Cells
Fibroblasts
Macrophages
Adipocytes

13. Papillary layer
 Loose areolar connective tissue
 Collagen + elastin
 Contains capillaries, lymphatics vessels and sensory neurons
 Dermal papillae
 capillaries Allow oxygen and nutrientsto diffuse into extracellular
fluid of dermis; then into cells of avascular epidermis
 Tactile (Meissner) corpuscles – also found in dermal papillae; sensory
receptors that respond to light touch stimuli; more numerous in
regions of body where sensation is a primary function; skin of
fingertips, lips, face, and external genitalia .

14. Reticular layer
 Dense irregular connective tissue
 Contains collagen and elastic fibres
• Collagen bundles strengthen dermis and prevent traumatic injuries from damaging
deeper tissues
• Elastic fibers allow dermis to return to its original shape and size after stretching
 Rich in proteoglycans that draw water into ground substance; keeps skin firm and
hydrated
 • Lamellated (Pacinian) corpuscles – found embedded within reticular layer; sensory
receptors that respond mainly to changes in pressure and vibration associated with
skin
 • Blood vessels, sweat glands, hairs, sebaceous glands, and adipose tissue are found in
reticular layer

15. Applied aspect
 Dermal strength and elasticity
 Elastic fibres permit stretching and then recoil to original length
 Provide flexibility
 Fibres and water provide flexibility and resilience- known as skin turgor.
 Clinical Application:
The patch drug delivery system. The transdermal patch is an increasingly popular drug
delivery system. These patches are designed so that the drug molecules diffuse through
the epidermis to the blood vessels in the dermis layer. A typical patch works well for small
lipid-soluble molecules (for example, estrogen, nitroglycerin, and nicotine) that can make
their way between epidermal cells.

16. Subcutaneous layer
 Deepest part of skin
 Connective tissue
 Adipose tissue(fat storage )
 Site of subcutaneous injections using hypodermic needles

17. Dermal blood supply
 Cutaneous plexus
 Sub papillary plexus
 Applied aspect:
 Contusions / bruise

18. Nerve supply
 Control blood flow
 Adjust gland secretion rates
 Monitor sensory receptors
- light touch – Meissner corpuscles-dermal papillae
- deep pressure and vibration – lamellar (Pacinian)corpuscle-reticular layer.

19. Hair
 Types of hair- lanugo , vellus,terminal
 Protect and insulate
 Guard openings from particles and insects
 Serve as sensory receptors.
 Parts of hair
Medulla
Cortex
cuticle
 Hair follicle:
root
Shaft
Hair bulb matrix
Arrector pili muscle:
 Involantary smooth muscle
 Contraction causes hair to stand up – goose bumps.

20. Glands
 Sweat glands
Found al over the body and ducts directly open on to the skin surface.
Sweat is derived from blood plasma and is a dilute solution of NaCl and urea.
 Eccrine (Mecocrine glands) – 99% water , to cool the skin ( thermore gulation
) palms, soles, and forehead
 Apocrine glands contains fatty acids , found near hair follicles ,responds to
stress.
 Develop during early to mid puberty seen in armpits and genitalia.
Bromhydrosis – body odour due to action of bacteria on fatty acids of sweat.
 Sebaceous glands- open into the hair follicle and release secretion called
sebum , which softens the dead keratinocytes.
 The activity of the sebaceous glands increases during puberty because of
.heightened levels of androgens

21. Nail
 The structure we know of as the nail is divided
into six specificparts - the root, nail bed, nail plate,
eponychium (cuticle), perionychium, and
hyponychium
 It serves as a protective plate and enhances
sensation of the fingertip.

22. FUNCTIONS OF THE
INTEGUMENTARY SYSTEM
Function of skin Structures involved
Protection- chemical and
mechanical trauma -
uv rays
-antigens
- microbes
Stratum corneum
Melanocytes
Langerhans
Mast cells
Fluid balance Stratum corneum
Shock absorber Dermis
Subcutaneous fat
Sensation Sensory receptors
Vitamin D synthesis Keratinocytes
Temperature regulation Eccrine sweat glands
Blod vessels
Immunity Phagoctyes

23. Protective barrier
Protection
Microorganism Uvrays mechanical trauma fluid balance
Sebaceous gland melanocytes keratinized hydrophobic lipid
Acidic ph secrets melanin flexible surface repel covalent
Molecule like salt an water
Inhibits pathogens protects from uv rays protect from trauma maintain water balance

25. Thermoregulation

26. Sensation

27.  Sensory Receptors of the Skin
 a) Free Nerve Endings are the tips of neuron processes that are sensitive to pain (nociceptors) or change
in temperature (hot and cold). Commonly found in epithelia and connective tissue.
 b) Merkel’s (tactile) Endings are free nerve endings associated with a Merkel’s cell. This is a sensitive
mechanoreceptor for sensing textures, edges and shapes. Encapsulated Nerve Endings:
 c) Pacinian (Lamellated) Corpuscles sense deep pressure, stretch, and vibration. Nerve ending is wrapped
in a capsule of many layers of Schwann cells. Found in dermis of hands, feet, breasts and genitals.
 d) Krause’s End Bulbs are similar to Merkel’s disks, but are found in mucus membranes of the mouth and
are cold temperature receptors.
 e) Meissner’s Corpuscles sense light touch and texture. Located in dermal papillae and are abundant in
the lips.
 f) Ruffini’s Corpuscles are sensitive to stretch or compression of skin.

28. Vitamin D synthesis
Insufficient Vit D3 causes rickets.
essential for absorption of calcium and phosphate ions by small intestine.
-liver and kidney together convert vitamin D3 into calcitriol
it is released into blood
Coverted into cholecalciferol - ( UV radiation )
Convetrs this inactive precussor to active form
Precussor ( modified cholesterol molecule )
Epidermal cells consist of vitamin D precussor

30.  Keratinocytes
 They act as the first line of innate immune defence against infection. They express Toll-like receptors (TLRs), which are pattern-recognition
receptors (PRRs) that detect conserved molecules on pathogens and trigger an inflammatory
 Neutrophils are the first cells to respond to infection. They directly attack microorganisms by phagocytosis and by degranulation of toxic
substances.
 Dendritic cells
 Dendritic cells possess TLRs that can be activated by microbial components
 Plasmacytoid dendritic cells (pDCs) produce large amounts of interferon-γ (IFN-γ) in response to viral infection.
 NK cells are cytotoxic lymphocytes that can eliminate virally infected cells and cancer cells without antigen presentation or priming.
 NK cells are activated by interferons or other cytokines released from macrophages. NK cells express inhibitor receptors that recognise MHC–I
and prevent undesirable attacks on self. They can kill target cells through the perforin-granzyme pathway, which induces apoptosis (programmed
cell death).
 Mast cells
 Mast cells are activated in response to allergic reactions and produce cytoplasmic granules filled with pre-formed inflammatory mediators, such
as histamine. They release these granules when their high-affinity immunoglobulin E (IgE) receptor (FcεRI) on the mast cell surface reacts upon
contact with stimuli such as allergens, venoms, IgE antibodies, and medications.
 These mediators can result in pruritic weals due to increased vascular permeability (urticaria). In rare cases, mast cell activation can lead to
anaphylaxis, characterised by bronchoconstriction, dizziness, and syncope.

31. Skin pigmentation
Normal skin color
 Melanin
 Haemoglobin
 carotene
Abnormal Skin Colors
 • Albinism is a genetic lack of
melanin.
 • Vitiligo is a patterned albinism
thought to be caused by an
autoimmune disorder that kills
melanocytes in specific regions of
the skin.
 • Hematoma is a bruise caused by
clotted blood that escaped into the
connective tissue of the dermis and
hypodermis.

32. Skin markings / finger prints
Skin markings – small visible lines in epidermis created by interaction between dermis and
epidermis; best seen in thick skin of palmar surfaces of hands and fingers and plantar
surface of feet and toes
• Dermal ridges – found in areas where dermal papillae are more prominent due to
presence of thick collagen bundles
• Dermal ridges indent overlying epidermisto create epidermal ridges; enhance gripping
ability of hands and feet:
Epidermal ridges occur in characteristic patterns; loops, arches, and whorls; genetically
determined and unique to each person
Sweat pores open along these ridges and leave a thin film or fingerprint on things
touched with fingers

33. Tension lines
 Tension lines / clevage lines
 Produced by parallel bundle of collagen
and elastin fibres in the dermis
 Resist force applied to the skin
 During surgery it plays an important role.

34. Interactions with other body sytem
Systems Its effects on skin
Endocrine Thyroid function affects growth and texture of skin hair and nail.
Hormones stimulate sebaceous glands.
Adrenal hormones affect dermal blood supply.
Renal Kidney remove swaste and mainatain normal ph .
Respiratory Colour of skin nad nails are affected by changes in respiratory system
Digestive Supply nutrients to skin
Skeletal Provides a framework for skin
Muscular Gives shape and support to skin
Reproductive Provides sensory receptors for sexual stimulation

35. Pathology

36. Route of infection

46. ACNE
 Acne vulgaris – affects 96% of adolescents and young adults to some degree
• Cause – accumulation of sebum and dead cells within sebaceous glands; produces a
comedone (blackhead); occasionally becomes infected by Propionibacterium acnes,
resulting in inflammation and formation of a pustule (pimple)
• May be severe and cause permanent scarring in some individuals • Male sex
hormones (like testosterone) are primary cause; tends to be more pronounced in
males entering puberty; decreases and may disappear by age 20 25; may persist
much longer in some individuals.

47. Skin Cancers
• Skin cancer can be induced by UV rays of the sun and is most common in fair-
skinned and elderly people.
• Basal Cell Carcinoma – arises from keratinocyes in the stratum basale that transform
and invade the dermis – treated by surgical removal and/or radiation
• squamous cell carcinoma – arises from keratinocytes in the stratum spinosum –
metastasis to the lymph nodes can be lethal
• melanoma (most deadly skin cancer) – arises from melanocytes –
ABCD: asymmetry, border irregular, color mixed, diameter over 6 mm

48. Integumentary examination /History taking

49. Continued…

50. Physical examination
• Inspection
• Around the bedside
• The patient
• Basics of rash description
• Site; shape; size; symmetry
• Colour
• Border
• Specifics
• Excoriation
• Ulcer/erosion
• Weeping
• Crusting, hyperkeratosis or scale
• visibility of blood vessels
• Odour
• Palpation
• Tenderness (ask the patient first!)
• Surface texture
• Elevation
• Skin thickness
• Blanching
• Tissue loss
• Tethering
• Associated signs
• Temperature
• Oedema
• Crepitus

51. Types of lesion
Lesion Description Example
Primary Lesions
Macule <0.5cm, flat, circumscribed area of
altered skin colour
Vitiligo (small)
Patch ≥0.5cm, flat, circumscribed area of
altered skin colour
Vitiligo (large)
Papule <0.5cm, circumscribed elevation of
skin
Molluscum contagiosum
Plaque ≥0.5cm, circumscribed elevation of
skin
Psoriasis
Weal Transient, smooth, slightly raised
lesion, characteristically with a pale
centre and a pink margin
Urticaria
Vesicle (blister) <0.5cm, circumscribed, fluid-
containing elevation
Acute eczema e.g. pompylox

52. Bulla (blister) ≥0.5cm, circumscribed, fluid-
containing elevation
Burn, friction
Pustule Visible collection of pus Staphylococcal folliculitis
Abscess Localised collection of pus in a cavity Bacterial infection
Erythema Redness, blanching Erythema nodosum
Purpura Redness, non-blanching, secondary to
collections of red blood cells
Vasculitis, platelet or clotting defect
Telangiectasis Dilated capillaries visible on the skin
surface
Side-effect of topical steroids
Secondary Lesions
Scale Thickened, loose, readily detached
fragments of stratum corneum
Psoriasis

55. Examination aids / diagnostic aids
 Ruler
 Lighting
 Penlight
 Gloves
 Magnifying glass
 Woods lamp

56. Ruler
 Accurately records the size of a lesion on
successive examination.
 Measure in longest axis first and then in
the perpendicular axis.

57. Dermatoscopy
 Distinguish benign from malignant
tumors.
 Melanoma , basal cell carcinoma..

58. penlight

59. Diascopy
 Vascular - blanches
 non vascular or haemorrhagic – no
blanching
Ex : nevus, petechia

60. Woods lamp
 Tinea capitis
 Pityriasis versicolor
 Vitiligo
 melasma

61. Skin biopsy
 Skin biopsy
 Biopsy may be used to provide a histopathological specimen to aid diagnosis and
guide further management. Always provide relevant history, description and
differential diagnosis to assist the histopathologist.
 Histology may not be able to differentiate between some cases of dysplastic naevi
and melanoma so that any case of incompletely excised 'dysplastic naevus' should
be referred for a further excision.

62. Patch test
 A patch test is a diagnostic method used
to determine which specific substances
cause allergic inflammation of a patient's
skin. Patch testing helps identify which
substances may be causing a delayed-
type allergic reaction in a patient, and may
identify allergens not identified by blood
testing or skin prick testing.

63. Skin prick test
 Skin prick testing is an allergy test used to
identify allergens responsible for triggering
symptoms in allergic diseases
 skin prick testing is useful in the diagnosis
of other allergies such
as aeroallergens causing hay fever, food
allergy, latex allergy, drug allergy, and bee
and wasp venom allergy.

64. Laboratory investigation