Unit II, Chapter-1-Integumentary System

Unit II, Chapter-1-Integumentary System.
As per PCI Syllabus.
HAP-I,
Integumentary system
Structure and functions of skin

1. BP101T. Human Anatomy And Physiology-I (Theory) Unit-II 1. INTEGUMENTARY SYSTEM Represented By, Mr. Audumbar Mali. (Assistant Professor) Sahyadri College of Pharmacy Methwade

2. THE SKIN It is outer covering of body. In humans, it is the largest organ of integumentary system. It helps to maintain a constant body temperature, protects the body and provide sensory information . Dermatology: It is the branch of medical science that deals with the diagnosis and treatment of skin disorders.

3. STRUCTURE OF SKIN The skin is the cutaneous (related to skin) 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 Epidermis Dermis

4. Fig.: Structure of Skin

5. EPIDERMIS It is the outermost layer of skin. It is composed of keratinized stratified squamous epithelium. It consists of principal types of cells Keratinocytes Melanocytes Langerhans cells Markel cell

6. CELLS OF EPIDERMIS Keratinocytes: About 90% of epidermal cells are keratinocytes Keratin is a tough, fibrous protein that helps to protect the skin and underlying tissues from heat, microbes and chemicals. Melanocytes: About 8% of the epidermal cells are melanocytes and produce pigment melanin. Melanin is the yellow red or brown black pigment that contribute the skin color and absorb damaging UV light.

7. 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 . These cells are very close to the nerve endings that receive the sensation of touch and may be involved in touch. The cells also contain substances that may act as hormones.

8. CELLS OF EPIDERMIS

9. LAYERS OF EPIDERMIS Epidermis is composed of 5 layers: Stratum corneum Stratum lucidum Stratum granulosum Stratum Spinosum Stratum basale (innermost layer)

10. LAYERS OF EPIDERMIS

11. LAYERS OF EPIDERMIS 1. Stratum corneum: It is the outermost layer of epidermis. Made u p o f 25 - 3 layers o f flat, dead c e lls, completely filled with keratin. B e twe e n t he cells are li p ids f r om s m aller g r anu l es, making it water repellant barrier. It is e f fe c ti v e bar r i e r against light, hea t , bacteria, water and many chemicals.

12. 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 c e lls o f s t ratum l u cidum are al s o fi l led with keratin. It is p r esent o n l y in s k in o f fi n ger p rint s , p al m s, a n d soles.

13. LAYERS OF EPIDERMIS 3. Stratum granulosum: In t h e m i d dle o f t h e ep i d e r m is is t he st r a t um 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 , wa t er repellant secretions.

14. LAYERS OF EPIDERMIS 4. Stratum Spinosum : Superfacial to stratum basale. It consist of 8-10 layers of keratinocytes fits closely together. It include proj e ctions of melanocytes and langerhans cells.

15. 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 .

16. 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: Papillary region Reticular region

17. THE DERMIS The papillary region makes up to the 1/5 th 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.

18. THE DERMIS The reticular region which is attached to the subcutaneous layer, consists of dense irregular tissue containing fibroblast, bundles of collagen and some elastic fibers. A few adipose cells, hair follicles, nerves, sebaceous (oil) glands and sweat glands are present in the reticular region. The combination of collagen and elastic fibers in the reticular region provides the skin with strength, extensibility and elasticity.

19. ACCESSORY STRUCTURE OF THE SKIN The accessory structure of the skin includes Hairs: Protects the body. Skin glands: Regulate body temperature Nails: Protects the body

20. HAIRS (PILI) Hair :- A natomy : 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).

21. HAIR

22. 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.

23. HAIR Cuticle of the hair:

24. SKIN GLANDS Glands: 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 and proteins keep hair from drying out, keeps skin moist whiteheads, blackheads and acne

25. SKIN GLANDS

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

27. 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.

28. SKIN GLANDS Sudoriferous glands: ( Sweat gland) exocrine glands millions located throughout the skin It has two types: Eccrine sweat gland Apocrine sweat gland

29. SKIN GLANDS Eccarine : more common (merocrine) originate in subQ layer duct empties on skin surface palms and soles of feet sweat is watery (99% H 2 0) sweating regulated by -sympathetic nervous system

30. SKIN GLANDS Apocrine: axillary and pubic region duct empties onto hair follicle viscous fluid causes body odor (“b-o “) when bacteria break it down

31. 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.

32. References: Presentation on Introduction To Human Anatomy & Physiology, By Mr. Abhay Shripad Joshi. 2. Human Anatomy and Physiology-I, By Dr. Mahesh Prasad, Dr. Antesh Kumar Jha , Mr. Ritesh Kumar Srivastav , Nirali Prakashan , As per PCI Syllabus. Page No. 2.1 to 1.4. 3. www.google.com.

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