The document describes the structure and function of the integumentary system. It discusses the different layers of the skin (epidermis and dermis), the cells found in each layer and their roles in protection, sensation, and regulation. It also describes skin appendages like hair, nails, sweat and sebaceous glands. The document outlines the types, layers and functions of fascia beneath the skin, and modifications like septa and sheaths. Finally, it discusses skin color changes that can provide diagnostic clues for medical conditions.

1. Integumentary System
AN 4.1 Describe different types of skin
& dermatomes in body AN 4.2 Describe structure and
function of skin with its appendages
AN 4.3 Describe superficial fascia
along with fat distribution in body
AN 4.4 Describe modifications of
deep fascia with its functions
AN4.5 Explain principles of skin incisions

3. Integumentary system
• Integumentum
– Covering
• Skin
– Largest organ
– 1/6th (16%) of body weight
– 18 Sq. ft. - surface area

4. Function of skin
 Protection
 Sensation
 Heat regulation
 Excretion
 Secretion
 Absorption

5. Types of skin
• 2 types
– Based on thickness of
epidermis
• Thick
– Otherwise - Glaberous skin
• Has thick stratum corneum
• No hairs
• Location
– Palm and sole
• Thin
– Epidermis is thin
– Loctation
• Except Palm and sole

6. Structure
• Formed by 2 layers
• Epidermis
• Dermis

7. Epidermis
• Superficial layer
• Avascular
• Stratified squamous epithelium
• Gives rise to
– Hair, nail sweat and sebaceous
glands

8. Cells of epidermis (4)
• 2 types of cells
• Keratinocytes (85-90%)
• Non-keratinocytes
– Melanocytes (8%)
– Dendritic cell of Langerhans
– Cells of Merkel

9. Keratinocytes
• 90 % of epidermis cells
• Environmental barrier
– via keratinization
• Regenerative (25-45 days)
• Protective
– Pathogens / Fungi /
parasites / Viruses
– Heat / UV radiation
– Water loss

10. Melanocyte

12. Merkel cells
• Location
– Stratum basale
– Abundant in
• Fingertips, lips, face
• Function
– Contact with a disc like
sensory nerve ending (in
dermis)
– Mechanoreceptors (low
pressure)

13. Dendritic cells of Langerhans
• Specialized Monocytes
• Location
– Stratum spinosum
• Origin
– Mesoderm (bone marrow)
• Function
– Antigen presenting cells
– Phagocytic
• Easily damaged by
– UV light

14. Layers of epidermis

15. Stratum basale
• Deepest layer of epidermis
• Consists of
– Single layer of cuboidal
cells
• These divide and give
keratinocytes (cells of
skin)
• So this layer is known as
– Stratum germinativum

16. Stratum spinosum
• Several layers of cells
• Polygonal cells
• Cells have the capacity
of mitosis

17. Stratum granulosum
• Consists of
– 1 – 3 cell thick layer of
keratinocytes
• Contains
– Granules of keratohyalin
protein

18. Stratum lucidum
(Clear)
• Present only in thick skin

19. Stratum corneum
• Superficial layer
• Cells are nonnucleated,
flat, scale like cells
• Cells are filled with keratin

20. Dermis
 Lies deep to Epidermis
 Contains:
 Blood vessels
 Sensory nerve endings
 Sudoriferous glands -
sweat
 Sebaceous glands - oil
 Hair follicles
 Arrector pili muscles
 Two layers
 Reticular layer(deeper
layer)
 Papillary layer (superfial)

21. Papillary layer
• Superficial layer of dermis
• Composed of loose areolar
connective tissue
• Has fingerlike projections
called papillae
• Provide the dermis a
"bumpy" surface that
interdigitates with the
epidermis
– Strengthening the connection
between the two layers of
skin
– Has thin collagen fibres

22. • Inner, thicker layer
• Composed of
– Dense irregular connective tissue
– Collagen / Reticular / Elastic fibres
– Langer lines
– Orientation of collagen fibres
– Surgery incisions made parallel
Reticular layer

23. Langer's lines /
Tension lines /
Cleavage lines
• Correspond to the
natural orientation
of collagen fibers in
the dermis

24. Stretch marks in skin
• Damage to the collagen
fibers in dermis due to
over stretching as in
pregnancy or abdominal
enlargement
– Striae gravidarum

25. Flexure lines
• Found in the vicinity of
synovial joints
• Here the skin is attached
strongly to underlying deep
fascia
• Prominent on the flexor
surfaces of palms, soles and
digits
• Skin lines don't necessarily
coincide with the underlying
joint line

26. Wrinkles
• If fibres loose their
tense wrinkles formed

27. Meissners corpuscles
• Rapidly adapting
Mechanoreceptor
• Lie in dermal papilla
• To detect light touch

28. Pacinian corpuscles
• Large structure
• Lies deep part of dermis
• Detect pressure and
vibration

29. Free nerve ending
• Lies in stratum granulosum
• Detect hot, cold

30. Dermatome
• Area of skin supplied by
a single nerve root

31. Skin appendages
• Epidermis gives this
appendages
• Hair follicle, hair
• Nail
• Sebaceous glands
• Sweat glands
– Apocrine
– Eccrine

32. Hair
• Shaft-portion that
project above skin
surface
• Root-embedded in skin,
penetrates into dermis
or subQ
• Hair Follicle- surrounds
the root
• Bulb-base of hair
follicle

33. Hair root
• Surrounded by hair
follicle

34. Sebaceous Glands
• Secrete an oily/waxy
matter, called sebum
• To lubricate and waterproof
the skin and hair
• Abundance on face and
scalp

35. Sebaceous Glands Diseases
• Acne
– Excess oil production
– Hair follicles clogged by
oil and dead skin cells
– Bacteria
– Excess activity of a type
of hormone (androgens)
• Sebaceous cysts
– Gland or its duct becomes
damaged or blocked

36. Sweat glands
• Produce sweat
• Helps to cool the body
• Two types
• Eccrine (sudoriferous)
– Opens on the surface of skin
through a duct
– Most numerous (3-4 million)
– Numerous on palms, sole of feet
and forehead
• Apocrine
– Empty into hair follicles
– Lies in armpits and genital areas

37. Sweat Glands Diseases
• Hyperhidrosis -
Excessive sweating
• Hypohidrosis -
diminished or absent
perspiration

38. Superficial fascia
• Mixture of adipose and loose
areolar tissues
• Unites the skin to the
underlying structures
• Most distinct
– Lower part of abdomen
– Perineum and limbs
• Very thin
– Eyelids, auricle, scrotum
(devoid of adipose tissue)
• Very dense
– Scalp, palm & sole
• Function
– Facilitate movements of skin
– Bad conductor of heat

39. Superficial fascia
• Flat sheets of muscles- in
some regions
• Skeletal muscle
– Platysma
– Palmaris brevis
• Smooth muscle
– Subareolar muscle of the
nipple
– Dartos
– Corrugator cutis ani
• Functions
– Facilitates movement of skin
over underlying structures
– Passage for cutaneous vessels,
nerves
– Protects the body against heat
loss

40. Deep fascia
• Beneath superficial
fascia
• Devoid of fat
• Inelastic & tough
• Either invests or bind
structures

41. Modifications of deep fascia
• Intermuscular septa
• Retiinaculum
• Epimysium, Perimysium
and endomysium
• Epineurium, perineurium
and endoneurium
• Sheath

42. Intradermal Injections
• Injection of the substance
into the dermis
• Indications
– Identify skin allergy to any
drugs
• Tuberculin injection
• Allergy sensitivity tests
• Local anesthesia
• BCG vaccine
• Angle- 10-15 degree
• Sites
– Forearm

43. Subcutaneous injection

44. • Cyanotic (cyan = blue)
– Who has stopped breathing
• Because the hemoglobin is
depleted of oxygen
• Jaundice (jaund = yellow)
– Build up of bilirubin (yellow
pigment) in the blood
• Erythema (ery = red)
– Engorgement of capillaries in
the dermis
• Skin injury, infection, heat
exposure, inflammation,
allergies, emotional state,
hypertension
• Pallor - paleness
– Emotional state, anemia, low
blood pressure
Skin color as diagnostic clues
for medical conditions