Integumentary system -The organs of the integumentary system include the skin and its accessory structures including hair, nails, and glands, as well as blood vessels, muscles and nerves. -Dermatology is the medical specialty for the diagnosis and treatment of disorders of the integumentary system. Structure Of The Skin The skin (cutaneous membrane) covers the body and is the largest organ of the body by surface area and weight. Its area is about 2 square meters (22 square feet) and weighs 4.5-5kg (10-11 lb), about 7% of body weight. It is 0.5 – 4 mm thick, thinnest on the eyelids, thickest on the heels, the average thickness is 1 – 2 mm. It consists of two major layers: Outer, thinner layer called the epidermis, consists of epithelial tissue. Inner, thicker layer called the dermis. Beneath the dermis is a subcutaneous layer (also called hypodermis) which attaches the skin to the underlying tissues and organs. 1. EPIDERMIS -Covers, protects and waterproofs. Contains five main layers: - Stratum Basale - Stratum Spinosum - Stratum Granulosum - Stratum lucidum - Stratum corneum The epidermis has a number of important characteristics: The epidermis is composed of keratinized stratified squamous epithelium. -It contains four major types of cells: Keratinocytes (90% of the cells): It produce keratin which is a tough fibrous protein that provides protection. -Melanocytes: which produce the pigment melanin that protects against damage by ultraviolet radiation. -Langerhans cells: involved in immune responses, arise from red bone marrow. -Merkel cells: which function in the sensation of touch along with the adjacent tactile discs. 2. DERMIS -It is a deeper layer of skin, composed of connective tissue containing collagen and elastic fibers. -It contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands. -The epidermis is avascular and cells of this layer get their oxygen and nutrients from capillaries in the dermis. -The dermis can be divided into papillary layer and reticular layer. Hypodermis : - The hypodermis (also called the subcutaneous layer) is a layer directly below the dermis and serves to connect the skin to the underlying fascia (fibrous tissue) of the bones and muscles. --Two types of glands are present in the skin over most of the body These are sweat glands and sebaceous glands. --Function Of Skin Protection: Sensation: Heat regulation: Storage and synthesis: Synthesis of vitamin D: Excretion and homeostasis: Secretion: Absorption: Water resistance: Colour : Healing of wounds: Aids in the diagnosis:

1. integumentary system
Miss. Sheetal Patil M. Pharm
Rani Chennamma College Of Pharmacy,
Belagavi

2.  INTRODUCTION
• The organs of the integumentary system include the skin and its accessory
structures including hair, nails, and glands, as well as blood vessels, muscles
and nerves.
• Dermatology is the medical specialty for the diagnosis and treatment of
disorders of the integumentary system.

3. Human Skin Diagram

4.  Structure Of The Skin
• The skin (cutaneous membrane) covers the body and is the largest organ of
the body by surface area and weight.
• Its area is about 2 square meters (22 square feet) and weighs 4.5-5kg (10-11
lb), about 7% of body weight.
• It is 0.5 – 4 mm thick, thinnest on the eyelids, thickest on the heels, the
average thickness is 1 – 2 mm.

5.  Structure Of The Skin
• It consists of two major layers:
• Outer, thinner layer called the epidermis, consists of epithelial tissue. Inner,
thicker layer called the dermis.
• Beneath the dermis is a subcutaneous layer (also called hypodermis) which
attaches the skin to the underlying tissues and organs.

6. Layers of the skin

7. 1. EPIDERMIS
• Covers, protects and waterproofs.
• Contains five main layers:
a) Stratum Basale
b) Stratum Spinosum
c) Stratum Granulosum
d) Stratum lucidum
e) Stratum corneum

8.  The epidermis has a number of important characteristics:
• The epidermis is composed of keratinized stratified squamous epithelium.
 It contains four major types of cells:
i. Keratinocytes (90% of the cells): It produce keratin which is a tough fibrous
protein that provides protection.
ii. Melanocytes: which produce the pigment melanin that protects against
damage by ultraviolet radiation.
iii. Langerhans cells: involved in immune responses, arise from red bone marrow.
iv. Merkel cells: which function in the sensation of touch along with the adjacent
tactile discs.

9. a) Stratum Basale
• It is also called stratum germinativum, is the deepest epidermal layer and
attaches the epidermis.
• It contains cuboidal-shaped stem cell which are a precursor of the
keratinocytes of the epidermis.
• Stem cells undergo cell division to produce new keratinocytes and is known
as stratum germinativum.
• Two other cell types are found:
– Merkel cell: Which functions as a receptor and is responsible for stimulating sensory
nerves that the brain perceives as touch. These cells are abundant on surfaces of the
hands and feet.
– Melanocyte: Cell that produces the pigment melanin. Melanin gives hair and skin its
color, and also helps protect the DNA in the nuclei of living cells of the epidermis from
ultraviolet (UV) radiation damage.

10. b) Stratum spinosum (Prickle cell layer)
• This layer gives the skin strength as well as flexibility.
• It contains Langerhans cell, which functions as a macrophage by engulfing
bacteria and melanocytes.
c) Stratum granulosum (granular layer)
• Is a thin layer of cells in the epidermis. Keratinocytes migrating from the
underlying stratum spinosum become known as granular cells in this layer.
• These cells contain keratohyalin granules which helps to bind keratin
filaments together and lamellar granules which forms hydrophobic lipid
envelipe responsible for skins barrier properties.

11. d) Stratum lucidum (Clear layer)
• It is a thin, clear layer of dead skin cells in the epidermis , contains keratin.
• Found only on palms of hands and soles of feet.
• Protects against UV sunrays to prevent sunburn.
e) Stratum corneum (horny layer)
• It is the outermost epidermal layer, consists of dead cells which contain
keratin.
• Prevents loss or entry of water.
• Protects deeper layer against pathogens and chemicals.

13. Anatomy of Epidermis

14. 2. DERMIS
• It is a deeper layer of skin, composed of connective tissue containing
collagen and elastic fibers.
• It contains blood and lymph vessels, nerves, and other structures, such as
hair follicles and sweat glands.
• The epidermis is avascular and cells of this layer get their oxygen and
nutrients from capillaries in the dermis.
• The dermis can be divided into papillary layer and reticular layer.

15. a. Papillary layer
• The papillary layer is made of loose, areolar connective tissue which means the
collagen and elastin fibers.
• Its surface area is greatly increased by small, fingerlike structures called dermal
papillae.
• Papillary layer contains fibroblasts, fat cells and small blood vessels.
• The papillary layer contains phagocytes, defensive cells that help fight bacteria
or other infections.
• This layer also contains lymphatic capillaries, nerve fibers, and touch receptors
called the Meissner corpuscles.
• In a growing fetus, fingerprints form where the cells of the stratum basale of the
epidermis meets the papillae of the underlying dermal layer (papillary layer),
resulting in the formation of the ridges on your fingers that you recognize as
fingerprints.

16. b. Reticular Layer
• Underlying the papillary layer is the much thicker reticular layer, composed
of dense irregular connective tissue.
• The reticular layer appears reticulated (net-like) due to a tight meshwork of
fibers.
• Few adipose cells, hair follicles, nerves, sebaceous glands and sudoriferous
(sweat) glands occupy the spaces between fibres.
• Elastin fibers provide some elasticity to the skin, collagen fibers provide
structure and tensile strength.

17. Dermal Layer

18.  Hypodermis
• The hypodermis (also called the subcutaneous layer) is a layer directly
below the dermis and serves to connect the skin to the underlying fascia
(fibrous tissue) of the bones and muscles.

19.  Two types of glands are present in the skin over most of the body
• These are sweat glands and sebaceous glands.
1. Sebaceous Glands: Produce sebum, which lubricates and protects skin and
hair.
2. Sweat glands : Sweat glands, also known as sudoriferous or
sudoriparous glands, these are small tubular structures of the skin that
produce sweat.

20.  Function Of Skin
• Protection: Skin protects underlying soft tissues and organs from injury due to
presence of keratin.
• Sensation: contains a variety of nerve endings that react to heat and cold, touch,
pressure, vibration and tissue injury.
• Heat regulation: Dilated blood vessels increase perfusion and heat loss while
constricted vessels greatly reduce blood flow in the skin and conserve heat. Storage
and synthesis: acts as a storage center for lipids, fats and water.
• Synthesis of vitamin D: Synthesis of vitamin D by action of UV on certain parts of
the skin.
• Excretion and homeostasis: Sweat secreated by sweat glands, contains metabolic
wastes like urea, uric acid and ammonia.
• Barrier to germs and chemicals: Presence of keratin and tightly locked keratinocytes
prevent the entry of microbes and absorption of poisonous chemicals.

21. • Secretion: Cutaneous glands secrete sebum, sweat,oil, ear wax.
• Absorption: Oxygen, nitrogen and carbon dioxide can diffuse into the epidermis in
small amounts, some animals use their skin for their sole respiration organ. In
addition, medicine can be administered through the skin, by ointments or by means
of adhesive patch. The skin is an important site of transport in many other
organisms.
• Water resistance: The skin acts as a water resistant barrier so essential nutrients are
not washed out of the body.
• Colour : Melanin in the epidermal cells provides colour to the skin.
• Healing of wounds: A great power of regeneration of the epidermis of skin helps in
rapid healing of wounds.
• Aids in the diagnosis: Certain rashes reveal infectious diseases like ckicken pox,
small pox, allergy etc.