+ All Categories
Home > Documents > 2. Skin Function

2. Skin Function

Date post: 28-Aug-2015
Category:
Upload: bobbygunarso
View: 26 times
Download: 0 times
Share this document with a friend
Description:
Skin Function Phrmaceutical Analysis Lab Work - Lecture - Pharmacy USD - ppt - Lecture - 2014
Popular Tags:
27
Skin Anatomy and Functions Sri Noegrohati Fac of Pharmacy Gadjah Mada University
Transcript
  • Skin Anatomy and FunctionsSri NoegrohatiFac of PharmacyGadjah Mada University

  • *Sri Noegrohati, Gadjah Mada UniversitySkinThe skin is the largest organ of the body, mainly intends to protect human beings against environmental aggressions.functions:receives and transports, accepts and expels substances according to the bodys needs. reacts to external stimuli, like sun exposure, toxins, and even psychological stimuli.protects the body from external factors such as bacteria, chemicals, and temperature (the blood vessels in the dermis constrict at a cold temperature region). The pigment melanin provides a chemical pigment defense against ultraviolet light that can damage skin cells.It is container, defender, regulator, breather, feeler, and adaptor.skin requires attention and maintenance to function properly.

  • Skin structureIt fills this barrier part through a complex structure: external part is made up by the stratum corneum, properly moisturized with a hydrolipidic protective film, since water is the keratin plasticizer.The underlying epidermis ensure the continuous and functional regeneration of the surface state (keratogenesis) and skin pigmentation (melanogenesis) enables to reinforce the skins defense capacity .The dermis plays as a nutritional structure whose function is maintain coherence, elasticity, and thermoregulation Finally, the hypodermis has a protective and reserve function*Sri Noegrohati, Gadjah Mada University

  • *Sri Noegrohati, Gadjah Mada UniversitySkin Layerstwo primary layers that differ in function, thickness, and strength. Epithelial component: epidermis Connective tissue component: dermis, subcutaneous tissue, or the hypodermis. The two layers are further differentiated by their respective amounts of hair follicle, pigmentation, cell formation, gland makeup, and blood supply.

  • *Sri Noegrohati, Gadjah Mada UniversityEpidermisFive layers:SC: stratum corneum, a keratinocyte; which is gradually migrates to the surfacesloughed off (desquamation). SL: the stratum lucidum (not seen in this photomicrograph) SGR: stratum granulosum accumlate dense basophilic keratohyalin granules (seen on the close-up view). These granules contain lipids, which along with the desmosomal connections, help to form a waterproof barrier that functions to prevent fluid loss from the body.SS: stratum spinosum SG: stratum germinativum

  • *Sri Noegrohati, Gadjah Mada UniversityStratum CorneumA corneocyte is a protein complex that is made of tiny threads of keratin in an organized matrix.The cell envelope is composed primarily of two proteins, loricirn and involucrin.Attached to the cell envelope is a layer of ceramide lipids that repel water. Corneodesmosomes are specialized protein structures that must be degraded for the skin to shed in a process called desquamation.Natural moisturizing factor (NMF) is a collection of water-soluble compounds that are only found in the stratum corneum.

  • *Sri Noegrohati, Gadjah Mada UniversityLipids in Stratum CorneumFree fatty acids and ceramides that are released from the lamellar bodies fuse together in the stratum corneum to form a continuous layer of lipids. Because there are two types of lipids, this layer is referred to as a lamellar lipid bilayer. This lipid bilayer plays a major role in maintaining the barrier properties of the skin

  • *Sri Noegrohati, Gadjah Mada UniversityWater retention in SCBecause the lamellar lipid bilayer also repels water, water molecules are held between the cell envelope lipids and the lipid bilayer. This helps maintain the water balance in the stratum corneum by trapping water molecules instead of letting them absorb into the lower layers of the epidermis.

  • *Sri Noegrohati, Gadjah Mada UniversityKeratinizationmaturation and migration of skin cellsstratum germinativum provides the germinal cells necessary for the regeneration of the layers of the epidermis After a mitotic division, a newly formed cell (keratinocytes) will undergo a progressive maturation called keratinization as its migrates to the surfacekeratinocytes, accumulate and move outward the stratum spinosum, stratum granulosm, skin cells pick up granules that contain lipids, the cell also becomes flattened, or horny, and the nucleus disappears remains is keratin In the next layer, the stratum lucidum, the cell is prepared to move into its final sublayer with the addition of melanin granules. sudden changes in enzyme function: rupture of lysosomal membranes release lysosomal enzymes cell death form the stratum corneum, which is consist of neatly packed dead horny cells.

  • *Sri Noegrohati, Gadjah Mada UniversityStratum spinosumaccumulate many desmosomes on their outer surface which provide the characteristic prickles (seen on the close-up view) of the stratum spinosum (SS), which is often called the prickle-cell layer.

  • *Sri Noegrohati, Gadjah Mada UniversityStratum GranulosumThe cells of the stratum granulosum (SGR) accumlate dense basophilic keratohyalin granules (seen on the close-up view). These granules contain lipids, which along with the desmosomal connections form a waterproof barrier prevent fluid loss from the body

  • *Sri Noegrohati, Gadjah Mada UniversityStratum LucidumThe stratum lucidum is normally only well seen in thick epidermis and represents a transition from the stratum granulosum to the stratum corneum. Epidermis varies in thickness: on frictional forces thickest on the palms of the hands and soles of the feet

  • *Sri Noegrohati, Gadjah Mada UniversityDermissubdivided into two zones, a papillary dermis with main function is thermoregulation and supports the vascular network to supply the avascular epidermis with nutrients. and a reticular layer. contains mostly fibroblasts which are responsible for secreting:collagen, elastin and ground substance that give the support and elasticity of the skin.immune cells that are involved in defense against foreign invaders passing through the epidermis.

  • *Sri Noegrohati, Gadjah Mada UniversityHair FolliclesHair follicles are tiny tubular chambers of the skin in which hair takes its root and from which it extends up through the epidermal layers. Each follicle aids in supplying its respective hair with blood via a vein, an artery, and a papilla at the bulblike base of the follicle. The follicle itself is based in the subcutaneous layer, beneath the dermis. By excreting oil, follicles act to move dead skin cells to the surface of the skin. For this reason, sebaceous (oil) glands, muscles, and nerves accompany every follicle.

  • *Sri Noegrohati, Gadjah Mada UniversitySebaceous GlandsOil-secreting glands are found in all types of skin, all over the body, and usually with a follicle. They occur alongside the hair follicle as tiny teardrop appendages. These glands, which resemble tree branches, are made up of a tube and one or two small sacs that are actually groups of smaller pockets called alveoli. Sebaceous glands excrete oil that is produced when cells in the alveoli die and break apart. Their function is:to lubricate hair and to facilitate sweating in the follicle.

  • *Sri Noegrohati, Gadjah Mada UniversityFatty materials

    SebumSkin surfaceFree fatty acidtrace34Esterified fatty acid61.529.6Unsaponifiable matter3333.8Total extraction94.597.5

    Analysis of the unsaponifiable:Squalene11.712.0Wax alcohol15.011.6Sterols2.73.4Unidentifiable1.53.6

  • oily skinresults from an overactivity of the sebaceous glands , overproduction of sebum overflowing on the skin oily and shiny appearance.One part of the triglycerides is immediately hydrolyzed by resident bacteria, the sebum excreted containing a significant quantity of free fatty acids acidity of the pH of the skin surface & the cholesterol is esterified, this sebum blends with epidermal lipids (from the destruction of the desquamated horny cells) surface lipidic film covering the stratum corneum. *Sri Noegrohati, Gadjah Mada University

  • Function of SebumSebum is a natural skin detergent gives the skin an amphiphilic wettabilitymaintenance of the functional qualities of hairs, a fungistatic activity, while having a nutritional function for useful bacterial species a protective function against excessive dehydration in a dry environment The change of its rate of production depends on genetic, endocrinic, and environmental factors (24).The opposite of oily skin would not be dry skin, since it is the results of a dysfunction involving moisture balance and protease regulation*Sri Noegrohati, Gadjah Mada University

  • *Sri Noegrohati, Gadjah Mada UniversitySweat GlandsA sweat gland is an elongated tubular structure that originates in the subcutaneous tissue beneath the dermis and extends up to the surface of the epidermis, where it ends at either a pore or a hair follicle. Two types of sweat gland:Eccrine sweat glands, ends at a pore, exist in a greater number than apocrine glands in the body, predominantly responsible for sweat secretion and cooling the body. found everywhere except the rim of the lips and most of the penis. Apocrine sweat glands ends at and feed hair follicles explicitly. larger than eccrine glands and are more developed in women.found in greatest number in the pubic region and in the armpit. secretes sweat, and some of its cells disintegrate depending on the amount and type of bacteria odor

  • *Sri Noegrohati, Gadjah Mada UniversitySweat composition

    EccrineApocrineWater99.02Sodium chloride0.7Acetic acid0.0096Propionic acid0.0062Caprylic and Caproic acid 0.0046Lactic acid0.1Citric acid0.04Ascorbic acid0.04Add:Fat and cellular fragments

  • *Sri Noegrohati, Gadjah Mada UniversitySkin PigmentationPigmentation of the skin, eyes, and hair is determined by the presence of melanin in cells of the epidermis called melanocytes. Varying amounts of melanin determine color in both skin type and body part. Function of Melanin protects the eyes from excessive harmful UV rays. Melanin absorbs high-energy light, like UV and blue light, more than it does other light in the spectrum protect the lens as well as the retina, by dispersing light throughout the eye according to its intensity. Overexposure to UV rays causes tanning and burning.

  • *Sri Noegrohati, GMUBIOSYNTHESIS OF MELANINMelanosit melanosoma(lapisan GERMINATIF)

    TIROSINASE tyrosin dopa (3,4-DIHIDROKSIFENILALANIN) DOPAOKSIDASEINDOL-5,6-KINON DOPAKINON

    POLIMERISASI OKSIDATIF

    TRANSFERMELANIN SEL MALPIGHI DENDRIT MELANOSITIK

  • *Sri Noegrohati, GMUSchematic diagram of the tyrosinase processing and degradation pathway.

  • *Sri Noegrohati, GMUMelanin synthetic pathway and the involvement of melanogenic enzymes.

  • CosmetologyBefore 1938, cosmetics were not regulated as drugs, cosmetology could often be considered as a way to sell dreams rather than objective efficacy; safety for consumers was also sometimes precarious.With industrialization, many new ingredients from several industries were used in preparation of cosmetics offering a list of new functions and forms products became diversified and started to claim a multitude of biologic actions competitive environment manufacturers has to promise more to the consumers and to develop cosmetic products of better quality and higher efficacy need a better control.

  • Raw materialToday, many cosmetic products aim at hydrating the skin, reducing or slowing the signs of aged skin, and protecting the skin barrier and the skin in its entity against the multitude of daily environmental aggressions raw materials became more efficacious, safe, bioavailable, and innovative, while remaining affordable Raw materials are not only produced from natural sources and are highly purified, but they can also be specifically synthesized or even produced from genetically manipulated microorganisms.However, the availability and use of these active ingredients are not always sufficient to be optimally delivered to their targets and to sustain their activity The cosmetic vehicle is also crucial (formulation)

  • Cosmetology at presentconstraints Cosmetology has thus become a science in its own, and the cosmetologist is not only a formulator chemist, but also a real-life science scientist who needs to fully understand the interaction of his or her products and ingredients with their targetsCosmetic composition and formulation are becoming increasingly complex, and cosmetic ingredients more sophisticated and functional cosmetology has become a science based on the combination of various expertise domains: chemistry, physics, biology, bioengineering, dermatology, microbiology, toxicology, statistics, and many others


Recommended