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 Identify anatomy and physiology of skin  Differentiate between merocrine and apocrine sweat glands  Identify structure of nail Understand the functions of skin 


 

  

Largest organ in the body In adults it covers an area of 2 sq. meters or 22 sq. ft. Weighs around 4.5 kg to 5 kg It contains glands, hair and nails Skin is made up of 2 major layers – › Epidermis › Dermis


    



Most superficial layer Composed of stratified epithelium Thickest on the palms of the hand and sole of the feet It has no blood vessels or nerve endings hujungan saraf New cells formed push older cells to the surface where they slough gugur or flake off Outermost cells protect the cells underneath and the deeper cells replace the cells lost from the surface

 Cells in the deepest layer of the epidermis produce melanin, a dark pigment that colours the skin and protects it from harmful mudarat rays of sunlight.  Cells that produce this pigment is called melanocytes.  Irregular patches tompok-tompok tak sekata of melanin are called freckles




   





Epidermis is made up of several layers or strata Stratum corneum Stratum lucidum Stratum granulosum Stratum germitivum / germinative layer › › › ›

Made up of dense or thick layer of connective tissue, under the epidermis Contains fibroblasts, fat cells and microphages Also contains blood capillaries which supply bekal food and oxygen Collagen and elastic fibres in the dermis are responsible for most of the structural strength of the skin Rupture pecah of the elastic fibres occur when the skin is over-stretched menjadi terlalu tegang resulting in permanent kekal striae jaluran or stretch marks tanda regangan Developed terjadi on the abdomen during pregnancy or obesity


 Dermal papillae are portions of the upper part of the dermis that extend upwards into the epidermis  Dermal papillae contain many blood vessels that supply the epidermis with nutrients, remove memindahkan /mengeluarkan

waste materials and aid membantu in regulating body temperature.

 It can be seen on surface of thick skin, such as tips of fingers and toes.  Here they form membentuk satu corak batas yang jelas distinct pattern of ridges batas that help to prevent slipping when grasping an object.  The patterns are unchanged and unique berlainan to each person such as fingerprints.


 







Is a layer below the dermis It is attached terlekat to the underlying bone and muscle pada tulang dan otot dibawah and supply membekal it with blood vessels and nerves Hypodermis is not part of the skin is also known as subcutaneous tissue It is a loose connective tissue that contains about half of the body’s stored fat lemak yang tersimpan dalam badan

Fat in the hypodermis functions as padding pelapik and insulation penebat

 Formed terbentuk around the nerve fibre endings hujungan gentian saraf

 They are numerous on the fingertips and palms  They are touch receptors reseptor sentuhan i.e they send impulses isyarat to the brain when the skin makes contact menyentuh with an object


 

 Formed around single nerve fibre endings, terbentuk di sekeliling satu hujung gentian saraf lying terletak in the lower skin layers and the walls of the inner organs  They are pressure receptors merupakan reseptor tekanan i.e they send impulses to the brain when the tissue is receiving deep pressure tekanan yang dalam

Shaft of the hair protrudes menonjol above the surface

Root and hair bulb

located under the surface of the skin

 Follicles are long narrow tubes each containing hair. If the surface epidermis is damaged the epithelial cells within the hair follicles can divide membahagi , thus producing menghasil new cells  The bulb is located at the base of the follicles made up of a cluster gumpulan of cells


 Papilla is found in the bulb. Contains many blood vessels, which supply membekal the bulb with nourishment needed to produce hair

The bulb contains matrix cells, responsible bertanggungjawab for growth of existing hair rambut yang sedia ada and also produces new hairs

 Hair is formed by the multiplication lipat gandaan of cells of the bulb and they are pushed upwards away from the source sumber of nutrition, the cells die and become keratinized keras 

 







Arrector pilli means hair raiser. These are little bundles bungkusan of smooth muscles attached to the hair follicles When the muscles contract in cold the hairs stand erect and raises the skin around the hair causing “goose flesh� this traps memerangkap air which acts insulating layer The muscles are stimulated by sympathetic nerve fibres in response to fear and cold This is an efficient warming mechanism especially terutama when accompanied diiringi by shivering mengigil.










 

Are exocrine glands connected disambung by ducts, open into the hair follicles Produce oil called sebum – waterproof hair and epidermis Keep hair soft, act bertindak as bactericidal and fungicidal agent Most numerous banyak in skin of scalp, face, axillae and groins Present hadir all over the body except –palms and sole Also prevent drying and cracking keretakan of skin

 Are coiled lingkaran tubular exocrine glands which secrete sweat Also called eccrine 

sweat gland

 There are 2 types of sweat glands

1. Merocrine sweat glands 2. Apocrine sweat glands


 A coiled berlingkar tubular glands, located in almost every part of the skin and are most numerous in the palms and sole  They produce secretion that is mostly water with some salts  They have ducts and open onto the surface of the skin thro’ the sweat pores

 A coiled lingkaran tubular glands that produce a thick secretion rich in organic substances  Open into hair follicles only in the axillae and genitalia  Become active at puberty bila sesorang itu mencapai kematangan because of the influence di pengaruhi of sex hormones The organic secretion which is colourless 


B = Sweat Glands

Label the cutaneous glands shown below.

A = Sebaceous Glands


 Nail is a thin plate  Consists of layers of dead stratum corneum cells that contain a very hard type of

keratin protein byk tdpt-kuku,rambut dan epidermis  Protect melindungi tips hujung of fingers and toes  Visible kelihatan part of the nail is called the nail body  Nail body  appears kelihatan pink because of underlying lapisan bawah capillaries

 Free edge - part that extend past the distal end of digit  Free edge is white because - no underlying capillaries  Part of the nail covered by the skin is the nail root  Nail root and body – attached to nail bed


  



Nail root- covered by eponychium / cuticle Whitish crescent-shaped area – lunula Production of cells within the nail matrix tissue at the base of a nail results in the growth of the nail Nails grow all the time, their rate of growth slows down with age and poor circulation. menurun mengikut umur kitaran darah yg. lemah

 Fingernails grow faster than toenails at a rate of 3mm per month. It takes 6 months for a nail to grow from the root to the free edge. Toenails grow about 1 mm per month and take 12-18 months to be completely sepenuhnya replaced.


 Prevents menghalang entry of microorganism and other foreign substances into the body  Protects underlying lapisan bawah structures against abrasion kecederaan  Hair on the head act bertindak as heat insulator penebat haba  Eyebrows keep sweat out of the eyes  Eyelashes protect eyes from foreign objects  Hair in the nose and ear prevent menghalang entry of dust and other materials

 Regulation of body temperature by sweat gland excrete watery sweat to cool body surface.  Excretion by removal mengeluarkan of waste product from the body  Synthesis penghasilan of vitamin D When the skin is exposed terdedah to UV light Vitamin D is formed  Sensation because skin has receptors sekumpulan sel yang dapat mengesan perubahan persekitaran in the epidermis and dermis that can detect mengesan pain, heat, cold and pressure


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Label the diagram of a nail With the aid of the diagram describe the nail Describe the dermis Describe the epidermis Describe the hypodermis State the functions of the skin Describe Meissner’s corpuscles Describe Pacinian corpuscles Describe the glands Describe the hair Describe the Arrector pili


Label the following portions of the skin


Skin integumentary system