Anatomy of the Skin (Integumentary System)

Hey guys...this is what i have found. I used Saladin, Wheater's and a website for this...i wont label the images nor post them up coz they cannot be uploaded here..so i will post the link for you guys to refer to the images aites?...the images cl..early show both thick and thin skin enjoy your night ppl

1. Draw and label a diagram showing histological features of thick skin
2. Draw and label a diagram showing histological features of thin skin for
comparison.
Answer: refer to website-
connectiondev.lww.com/Products/eroschenko/documents/.../Ch10.pdf



3. List the 4 major cell types in epidermis and state their function. What are the key changes seen in disorders involving melanocytes such as vitiligo & malignant melanoma.
Answer:
Keratinocytes-synthesize keratin by a process known as keratinisation or cornification.Keratinocytes of the stratum basale undergo mitosis and produce new epidermal cells to replace the dead ones that exfoliate (flake off) from the surface.

Melanocytes-synthesize the pigment melanin. They have long branching processes that spread among the basal keratinocytes and continually shed melanin-containing fragments from their tips. The keratinocytes phagocytize these fragments and accumulate melanin granules on the “sunny side” of the nucleus. Like a little parasol, the pigment shields the DNA from ultraviolet radiation. People of all skin colors have about equal numbers of melanocytes. Differences in color result from differences in the rate of melanin synthesis and how clumped or spread out the melanin is in the keratinocytes. In light skin, the melanin is less abundant and is relatively clumped near the nucleus, imparting less colour to the cells.

Merkel cells-relatively few in number, are receptors for the sense of touch. The tactile cell and its dermal nerve fiber are collectively called a tactile (Merkel) disc.

Langerhan’s cell-antigen presenting cells(APC),express a large number of lymphocyte and macrophage surface markers.

Vitiligo-common disease in which symmetrical areas of depigmentation of the skin occur,often on the hands,fingers and face. The disease destroys all the melanocytes in the affected skin and skin becomes glaringly white, the keratinocytes are not affected. It is an autoimmune disease and destroys the melanocytes.

Malignant melanoma-malignant tumour of melanocytes, particularly affecting pale-skinned people who are exposed to excessive UV light.


4. With the help of a diagram, highlight the microscopic features of the major skin appendages.
Answer:
Refer to Saladin 4th Ed integumentary System


5. What is psoriasis? Briefly describe the main histopathological features associated with this disease.
Answer:
The transition of keratinocytes from replicating basal cell,through the keratinocytes of the prickle cell layer(stratum spinosum), to the flattening and degenerating granular layer cells(stratum granulosum) packed with tonofibrils and keratinohyaline granules can be regarded as an efficient sequence culminating in the production of a tough resistant keratin layer on the surface of skin. The normal transit time is 50-60 days but psoriasis causes the transition to only take about 7 days. It isa common skin condition with unknown aetiology but with an element of multifactorial inheritance. The maturation process is so rushed that there is insufficient time for full development of tonofibrils and keratohyaline in the stratum spinosum and the granular layer does not form. Instead of normal keratin, there is a surface opaque white scale composed of a mixture of keratin and nuclear and cytoplasmic debris of keratinocytes. The rapidly proliferating epidermis is thickened to produce raised red patches under the white scale.


Hope it helps...XD....