INTEGUMENTARY SYSTEM

Prepared by,

Abhay S. Joshi

Assistant Professor

Yash Institute of Pharmacy, Aurangabad

abhay.joshirss@gmail.com

THE SKIN

• It is outer covering of body.

• In humans, it is the largest organ ofintegumentary system.

• It helps to maintain a constant bodytemperature, protects the body and providesensory information.

• Dermatology: It is the branch of medicalscience that deals with the diagnosis andtreatment of skin disorders.

STRUCTURE OF SKIN

• The skin is the cutaneous membrane covers the external surface of the body/

• It is the largest organ of the body in both surface area and weight.

• The thickness of skin ranges from 0.5mm on the eyelids to 4.00 mm on the feet.

• The skin is composed of 2 layers

1. Epidermis

2. Dermis

EPIDERMIS

• It is the outermost layer of skin.

• It is composed of keratinized stratified

squamous epithelium.

• It consists of principal types of cells

a) Keratinocytes

b) Melanocytes

c) Langerhans cells

d) Markel cell

CELLS OF EPIDERMIS

Keratinocytes:

• About 90% of epidermal cells are keratinocytes

• Keratin is a tough, fibrous protein that helps toprotect the skin and underlying tissues from heat,microbes and chemicals.

Melanocytes:

• About 8% of the epidermal cells are melanocytes andproduce pigment melanin.

• Melanin is the yellow red or brown black pigmentthat contribute the skin color and absorb damagingUV light.

CELLS OF EPIDERMIS

Langerhan’s cells:

• They arise from red bone marrow and migrate to the

epidermis & contribute a small fraction of the

epidermal cells.

• They participate in immune responses mounted

against microbes.

Markel cells:

• These are the least numerous epidermal cells.

• They are located in the deepest layer of epidermis.

CELLS OF EPIDERMIS

LAYERS OF EPIDERMIS

• Epidermis is composed of 5 layers:

1. Stratum corneum

2. Stratum lucidum

3. Stratum granulosum

4. Stratum basale (innermost layer)

LAYERS OF EPIDERMIS

LAYERS OF EPIDERMIS

1. Stratum corneum:

• It is the outermost layer of epidermis.

• Made up of 25-30 layers of flat, dead cells,

completely filled with keratin.

• Between the cells are lipids from smaller granules,

making it water repellant barrier.

• It is effective barrier against light, heat, bacteria,

water and many chemicals.

LAYERS OF EPIDERMIS

2. Stratum Lucidum:

• It lies below the stratum corneum.

• It consist of 3-5 layers of clear, flat, dead cells lacking

granules and nuclei.

• The cells of stratum lucidum are also filled with

keratin.

• It is present only in skin of fingerprints, palms, and

soles.

LAYERS OF EPIDERMIS

3. Stratum granulosum:

• In the middle of the epidermis is the stratum

granulosum.

• It consist of 3-5 layers of flattened keratinocytes.

• Cell contain the protein keratohyaline , which

converts tonofilaments into keratin and smaller

granules, which release a lipid rich, warer repellant

secretions.

LAYERS OF EPIDERMIS

4. Stratum Spinosum:

• Superfacial to stratum basale.

• It consist of 8-10 layers of keratinocytes fits closely

together.

• It include projrctions of melanocytes and langerhans

cells.

LAYERS OF EPIDERMIS

5. Stratum Basale:

• It is the deepest layer of the epidermis.

• It is composed of single layer of cuboidal or

columnor keratinocytes.

• Stem cells undergo cell division to produce new

keratinocytes.

THE DERMIS

• Second deeper layer of the skin is dermis.

• It is composed of mainly connective tissue.

• Blood vessels, nerves, glands and hair follicle are

embedded in the dermis tissue.

• The dermis can be divided into:

1. Papillary region

2. Reticular region

THE DERMIS

• The papillary region makes up to the 1/5th thickness

of total layer.

• It consist of areolar connective tissue containing fine

elastic fibers.

• Its surface area is greatly increased by small,

fingerlike structure called as dermal papillae.

THE DERMIS

• The reticular region which is attached to thesubcutaneous layer, consists of dense irregular tissuecontaining fibroblast, bundles of collagen and someelastic fibers.

• A few adipose cells, hair follicles, nerves, sebaceous(oil) glands and sweat glands are present in thereticular region.

• The combination of collagen and elastic fibers in thereticular region provides the skin with strength,extensibility and elasticity.

ACCESSORY STRUCTURE OF

THE SKIN

• The accessory structure of the skin

includes

1. Hairs: Protects the body.

2. Skin glands: Regulate body temperature

3. Nails: Protects the body

HAIRS (PILI)

Hair anatomy:

- composed of dead columns of keratinized cells.

- shaft: is the superficial portion of hair.

- root: below the surface in the dermis.

• Shaft and root are composed of three layers: inner medulla, middle cortex and outer cuticle.

• Inner medulla has 2-3 rows of polyhedral cells where pigment is located.

• Cortex is major portion of shaft.

• Cuticle is scaly and heavily keratinized (shingles).

HAIR

HAIR

• Cuticle of the hair:• Surrounding the root hair is the hair follicle which is made up of

external root sheath and internal root sheath .

• Together these are referred as epithelial root sheath.

• The dense dermis surrounding the hair follicle is called as dermal root sheath.

• The base of each hair follicle is called as dermal root sheath.

• The base of each hair follicle is an anion shaped structure called bulb.

• The bulb contains nipple structure called as papilla of the hair contains many blood vessels that nourish the growing hair follicle.

HAIR

• Cuticle of the hair:

SKIN GLANDSGlands:Two types of glands exist in the integument.

- Sebaceous glands (oil glands)- Sudoriferous glands (sweat glands)

Sebaceous glands: (oil or holocrine glands)- connected to hair follicle- not found on palms and soles of feet- secretes sebum (fats, cholesterol andproteins

- keep hair from drying out, keeps skin moist- whiteheads, blackheads and acne

SKIN GLANDS

SKIN GLANDS

• Whitehead: When the trapped sebum and bacteria stay below the skin surface, a whitehead is formed.

SKIN GLANDS• Blackhead: A blackhead occurs when the trapped

sebum and bacteria partially open to the surface and

turn black due to melanin, the skin's pigment.

Blackheads can last for a long time because the

contents very slowly drain to the surface.

SKIN GLANDS

Sudoriferous glands: ( Sweat gland)

exocrine glands

- millions located throughout the skin

- It has two types:

1. Eccrine sweat gland

2. Apocrine sweat gland

SKIN GLANDS

Eccarine :more common (merocrine)

- originate in subQ layer

- duct empties on skin surface

- palms and soles of feet

- sweat is watery (99% H20)

- sweating regulated by

-sympathetic nervous system

SKIN GLANDS- Apocrine: axillary and pubic region

- duct empties onto hair follicle

- viscous fluid

- causes body odor (“b-o “) when

bacteria break it down

SKIN GLANDS

Ceruminous glands: located in ear only

- modified apocrine glands

- originate in Sub Q layer

- ducts open onto EAM.

- produces cerumen (ear wax) : brown

sticky substance that prevents foreign

material from entering.

THANK YOU