The integumentary system is the physical system that forms the barrier between the external environment and the internal systems of the body. In humans, this system consists of skin, hair, nails, and related glands. Altogether, the integumentary system forms the largest organ in the body. The main function of this system is to protect bones, organs, and other internal structures from harm. In addition, the integumentary system performs important immune functions, cell fluid maintenance, synthesis of Vitamin D, body temperature regulation, and detection of stimuli.

1. INTEGUMENTARY SYSTEM
PRESENTED BY:
MS. SHRADDHA MAHADEV PARAB
ASSISTANT PROFESSOR
YASHAWANTRAO BHONSALE COLLEGE OF PHARMACY, SAWANTWADI
Yashawantrao Bhonsale College of Pharmacy, Sawantwadi

2. CONTENTS
 Introduction
 Functions of skin
 Structure of skin
 Hair: Structure of hair
 Function of hair
 Nails
 Structure of nails

3. INTRODUCTION TO INTEGUMENTARY SYSTEM
 The skin is the largest organ of the human body
 Accessory structures include: - Hair, nails,
sebaceous glands, and sudoriferous
 Is composed of three layers:
1) Epidermis (Epi - above or outer)
2) Dermis
3) Subcutaneous layer (Sub - below)
 Impulses from the skin are interpreted in the
parietal lobe of the brain - Parietal refers to a layer
away from the organ

4. INTEGUMENTARY SYSTEM
The Integument
 Is the largest system of the body: 16% of body weight, 1.5 to 2m² in area,
 The integument comprises two parts:
1. Cutaneous membrane
a. Epidermis- Superficial epithelium
b. Dermis - underlying CT with blood supply
2. Accessory structures
a. Hair
b. Nails
c. Exocrine Glands

5. FUNCTIONS OF INTEGUMENTARY SYSTEM
Protection
Absorption
Regulation
Secretion
Sensation

6. PROTECTION
Intact skin serves as a protective
barrier to our body
1. First line of defense against
 Bacteria
 Viruses
2. Protects underlying structures
from Ultraviolet (UV) radiation
Dehydration
3. Vitamin D production: Needed
for calcium absorption

7. ABSORPTION
 The skin is a route by which substances
can enter the body.
 Transdermal absorption can administer
medications such as motion sickness
medications and hormonal therapies.
 Medication lotions are applied to the
skin for quick absorption and surface
treatment.
 Transdermal patches and medication
pastes have time-release properties
that allow medications to be absorbed
through the skin at a slower process
rate.

8. REGULATION
1. Body temperature regulation
 If too hot
 Dermal blood vessels dilate
 Vessels carry more blood to surface so heat can escape
 If too cold
 Dermal blood vessels constrict
 Prevents heat from escaping
2. Excretion
 Small amounts of waste products are lost through perspiration

9. SECRETION
 The skin contains millions of sudoriferous
glands that produce sweat and sebaceous
glands that produce oil for skin lubrication.
 Perspiration is a mixture of salt and water
with other chemical compounds.
 Accumulated sweat produces body odor and
bacteria.
 Sebaceous glands produce sebum, which
protects the body from dehydration.

10. SENSATION
 The skin has millions of microscopic nerve
endings that act as sensory receptors.
 Sensory reactions include responses to
pressure, traction, heat, cold, pain, and
other sensations.
 Nerve endings send information to the
brain for the appropriate response to
sensations.
 The integumentary and nervous systems
work together for the function of
sensation.

11. STRUCTURE OF SKIN
 The Epidermis Epithelial tissue
 Dermis Dense connective tissue
proper - irregular
 Hypodermis OR Subcutaneous
tissue- loose connective tissue
proper and adipose tissue

12. EPIDERMIS
 Is a vascular stratified squamous epithelium
 Nutrients and oxygen diffuse from capillaries in the dermis
 Cells of the Epidermis: Keratinocytes
 Contain large amounts of keratin and are the most abundant cells in the epidermis
 Thin Skin: Covers most of the body and has four layers of keratinocytes
 Thick Skin: Covers the palms of the hands and soles of the feet and has five
layers of keratinocytes

13. STRUCTURES OF THE EPIDERMIS
 The five strata of keratinocytes in thick skin
 From basal lamina to free surface
1. Stratum corneum
2. Stratum lucidum
3. Stratum granulosum
4. Stratum spinosum
5. Stratum basale

14. A. STRATUM BASALE
 It is attached to the basement membrane by hemidesmosomes
 Forms a strong bond between epidermis and dermis.
 Forms epidermal ridges. Eg fingerprints
 It is the lowermost layer of epidermis
 It is the single cell layer, thick in nature
 Consists of cells that only get adequate nutrition and oxygen by diffusion from
tissues below
 These are the actively dividing cells
 bordered below by basement membrane

15. B. STRATUM SPINOSUM
 The “spiny layer”
 Produced by division of stratum basale
 Eight to ten layers of keratinocytes bound by desmosomes
 Cells shrink until cytoskeletons stick out (spiny)
 Continue to divide, increasing the thickness of the epithelium
 Contain dendritic (Langerhans) cells, active in immune response.

16. C. STRATUM GRANULOSUM
 the "grainy layer"
 Three to five layers of keratinocytes
 Three to five rows of flattened keratinocytes, in which organelles are beginning to
degenerate;
 cells contain the protein keratohyalin, which converts tonofilaments into keratin,
and lamellar granules, which release a lipid-rich, water-repellent secretion.

17. D. STRATUM LUCIDUM
 Present only in the skin of fingertips, palms, and soles;
 consists of three to five rows of clear, flat, dead keratinocytes with large amounts
of keratin.

18. E. STRATUM CORNEUM
 the "horn layer"
 Exposed surface of skin
 15 to 30 layers of keratinized cells
 Water resistant
 Shed and replaced every 2 weeks

20. DERMIS
 Located between epidermis and subcutaneous layer
 Anchors epidermal accessory structures (hair follicles, sweat glands)
 Two components
1. Outer papillary layer
2. Deep reticular layer

21. o The Papillary Layer
 Consists of areolar tissue with thin collagen and fine elastic fibers
 Contains smaller capillaries, lymphatics, and sensory neurons
 Has dermal papillae projecting between epidermal ridges
o The Reticular Layer
 Consists of dense irregular connective tissue
 Contains larger blood vessels, lymphatic vessels, and nerve fibers
 Contains collagen and elastic fibers
 Spaces between fibers contain some adipose cells, hair follicles, nerves,
sebaceous glands, and sudoriferous glands.

23. THE STRUCTURAL BASIS OF SKIN COLOR
 Melanin, hemoglobin, and carotene are three pigments that impart a wide variety of
colors to skin.
 The amount of melanin causes the skin’s color to vary from pale yellow to reddish
and brown to black.

24. HYPODERMIS
 The Hypodermis (Subcutaneous Layer)
 Lies below the integument
 Stabilizes the skin
 Allows separate movement
 Made of elastic areolar and adipose tissues
 Connected to the reticular layer of integument by connective tissue fibers
 Deposits of Subcutaneous Fat
 Distribution patterns determined by hormones
 Reduced by cosmetic liposuction (lipoplasty)

26. HAIR: STRUCTURE OF HAIR
A. The Hair Follicle:
o Hair follicles are the organs that form the hairs.
o Located deep in the dermis.
o Produces nonliving hairs.
o Wrapped in a dense connective tissue sheath.
o The base is surrounded by sensory nerves (root hair plexus).

27. STRUCTURE OF HAIR
B. Accessory Structures of Hair:
 Arrector pili
o Involuntary smooth muscle
o Causes hairs to stand up
o Produces “goosebumps"
o Sebaceous glands Lubricate the hair

28. STRUCTURE OF HAIR
Regions of the Hair:
A. Hair root
o Lower part of the hair
o Attached to the integument
B. Hair shaft
o Upper part of the hair
o Not attached to the integument

29.  Hair Shaft Structure
 Medulla: Core, dead cells contain soft keratin and
air to provide flexible
 Cortex: Middle layer, dead cells contain hard
keratin to provide stiffness
 Cuticle: Outermost, overlapping dead keratinized
cells form the shiny surface

30. FUNCTIONS OF HAIRS
 Head:
o UV protection
o Cushion from trauma
o Insulation
 Nostrils, Ear canals, Eyelashes: Prevent entry of foreign material
 Body Hair: sensory detection
 Root hair plexus: Sensory nerves at the base of the hair follicle that detect slight
movement of hair
 Arrector pili muscle: Attached to every hair follicle Contract to stand hair perpendicular
to the skin surface

31. NAILS
 Protect fingers and toes
 Made of dead cells packed with keratin
 Metabolic disorders can change nail structure

32. STRUCTURE OF NAILS
 Nail body
o The visible portion of the nail
o Covers the nail bed
 Lunula
o The pale crescent at the base of the nail
 Sides of nails
o Lie in lateral nail grooves
o Surrounded by lateral nail folds