Skin presentation

definition classification disease associated

1. SKIN Anatomy, Physiology and Disease related to skin BARKHA SARMA B.PHARM 3 rd year 16HPH012 PHARMA CEUTICS VI

2. Skin is the soft outer covering and is one of the largest organ of the body. It is made up of different tissues that are joined to perform a specific function. It covers the surface area of 20-22 sq. ft. Thickness varies from 3-3.5mm.   CLASSIFICATION- Skin is broadly divided into three types- 1) Epidermis which is made up of epithelial cells. 2) Dermis which is made up of connective tissues. 3) Hypodermis which is a subcutaneous tissue.  

3. Skin contains subcutaneous tissue which is essentially fat which helps in the storage of fat and participates in thermal regulation. There are blood vessels inside the layers of skin. Hair follicles are also present which is connected to the sebaceous gland. Sebaceous gland is present all over the body except for palms of hands and soles of feet and it secretes sebum which lubricates our hair. It also acts as defence mechanism against pathogens. Within the sebaceous gland or residing around the hair follicle there is commensal pathogen of hair follicle and sebaceous gland.

4. These are rod shaped bacteria called Propionii bacterium, which is a gram positive. It is stimulated by some hormones like Androgens and Testosterone which helps in the secretion of sebum and hypertrophy of sebaceous gland. Connected to the hair follicle there is a erector pilli muscle, this muscle pulls the hair follicle. The phenomenon called goose bumps is due to the erector pilli contracting our hair follicle to stick upwards .  

5. Another important gland is the sweat gland which secretes sweat. Sweat gland is of two types- 1) Eccrine gland- it is found in the palms of hands and soles of feet. 2) Apocrine gland- it is found in the auxiliary and endogenital area which functions only after puberty.

6. The skin is the largest organ in our body. The skin provides- Protection from environment (Abrasion, fluid loss) Containment from bodies structures and vital organs. Heat Regulation – sweat, dilation and constriction of blood vessels. Sensation Synthesis and storage of vitamin D Blood reservoir Excretion of unwanted substances through sweat.

7. EPIDERMIS In epidermis layer there is a basement membrane which in the upward direction is connected to epithelial cells and in the downward direction is connected to the connective tissues of the dermis. The very first layer of the epidermis closest to the dermis is the stratum basili where we have epithelial cells that are dividing and some of these new cells will move upwards and these cells are able to divide because they are receiving blood vessels from the dermis and so as they divide some of the cells will migrate up to the top of the epidermis. To the top of stratum basili is the stratum spinosum where the epithelial cells are becoming keratinized because they are not receiving any blood vessels or blood supply. There are also other cells found in this area

8. called the melanocytes , which produces a substance called melanin which is responsible for skin colour . Other cells found in this area is the dendritic cells which helps in the capturing of the foreign particles. Next layer is the stratum granulosum where the cells began to die or they start becoming flattened and the organelles within the cells are being destroyed. The fourth layer is the stratum lucidum where all the dead cells are present and are more flattened. The fifth layer is stratum corneum where the old cells are being shed off and they are super thin. Eg - if you are rubbing your arm you are actually shedding off your stratum corneum .

9. DERMIS The reticular dermis is the deeper and thicker layer of the dermis, which lies above the subcutaneous layer of the skin. It contains dense connective tissue, which includes blood vessels. It is the thickest layer of the skin, and is made up of fibrous and elastic tissue. Thus it provides strength and flexibility to the skin. The dermis is comprised of two layers – 1)Papillary dermis 2)Reticular dermis The primary role of the dermis is to support the epidermis and enable the skin to thrive. It also plays a number of other roles due to the presence of nerve endings, sweat glands, sebaceous glands, hair follicles and blood vessels

10. HYPODERMIS The innermost layer of the skin, which helps to insulate the body and cushion internal organs. The hypodermis consists of well- vascularized , loose, areolar connective tissue and adipose tissue, which functions as a mode of fat storage. The hypodermis is home to most of the fat that concerns people when they are trying to keep their weight under control. Adipose tissue present in the hypodermis consists of fat storing cells called adipocytes .

11. DISEASE RELATED TO SKIN 1)Acne- Acne is a skin disorder that causes pimples when the passageway that connects the skins pores to the oil glands become clogged. Acne, which appears most often on the face, neck, shoulders, chest and back, can come in many forms. Whiteheads and blackheads are the most commonly known, nodular and cystic acne are more severe because they from deep in the skin and cause scars.  

12. 2 ) Eczema- Eczema is a “grab-bag term” , which comes from the Greek word for “boils over”. There are three common forms of eczema: Atopic dermatitis is the most common and is seen most often in children. It is a genetic disease, which causes itchy rashes in the crux of the elbows and behind the knees. Allergic contact dermatitis begins to show in adulthood and is caused by environmental factors such as cosmetic agents, fragrances and the metals in jewellery . Nummular dermatitis looks like red and flaky coin shaped patches of skin and is due to dry skin. This can be very itchy.

13. 3) Seborrheic Dermatitis- Seborrheic dermatitis, which causes oily, waxy patches to develop on the scalp, is distinct from other forms of dermatitis. It can affect babies, typically in the first six months of their lives in the form of “cradle cap” – a flakey, dandruff like condition on the scalp. After the symptoms clear up, it rarely appears again until puberty. 4)Skin Cancer- Skin cancer is the most common type of cancer in the United States. Basal cell carcinoma and squamous cell carcinoma are the most common types of skin cancer. But 75% of skin cancer deaths are from melanoma, the third most common form.