Assessment of skin and Ear
The skin on any living organism is the largest organ that covers the inner organs of an organism thus serving as a protective organ as well having some aesthetic characteristic of any organism. The skin can be assessed to determine some of the parameters that affect its functionality. This paper will be looking at the ways in which how these aspects can be assessed using some known methods and the tools used in the assessment (Igarashi, Nishino & Nayar,2007).
A water adherence factor on the human skin is one of the most important aspects that can be assessed. This is usually done by estimating the dermal exposures on the skin, which in turn is used in human health risk assessment. Determination of human skin adherence factor have led to development of models and techniques that are used to determine the amount of chemicals that have been absorbed in the body through skin in form of water soluble chemicals and contaminated water. To obtain this factor, the amount of water that is retained on the surface of the skin need to be determined. The units for determining this is always in mass of allergen per unit area (mg/L). The guideline for the determination of water adherence factor has been developed by the environmental protection agency and the formulas used to determine the dermal absorbed doses (Gujral.et al., 2011).
In the methodology of determining the water adherence factor, a sharper maker is used to outline approximately 10cm2 tissues from a dorsum of the participants’ hand. Then using a micropipette, about 10µL of water is to be applied at the area that was outlined earlier. Using the tip of the micropipette, water is spread evenly on the outlined area. In case the initial applied water is not sufficient, more water is added in proportions of 5-10µL (Gujral.et al., 2011).
The hand of the participant is then tilted gently until it is vertically upright. Apply the water on the surface until it runs gently off the outlined area. The container placed next to the outline area then collects the runoff. Using the micropipette, the runoff water is then measured. To find the water retained on the surface of the skin is then determined as the difference between the water that was applied on the surface and the runoff water that was collected and measured using the micropipette. The retained water will then used as a determinant on how much contaminants dissolved in water can enter the body through the skin.
The other aspect of the skin assessment is the complex assessment for age specific morphofunctional features of the skin at different anatomic locations. At this aspect, different areas on the human body are established set for study sampling different people at different age groups. The measurement is usually done using the Optical Coherence Tomography (OCT). The OCT has to be equipped with the removable flexible micro scanner having a longitudinal and a transverse resolution of about 20µm. This is used in determining the structural structures of the skin (Shlivko, et al., 2013).
The participants in this assessment are to be classified into about five age groups after getting consent from their parents with an approval from the local ethic committee. The participants with skin complications are excluded from the exercise. To avoid the impact of genetic pigmentation on the images of the OCT, the study is carried out without any immersion. The OCT scanner will take the images of the skin, which rare then used to assess several aspects of the skin.
From the pictures, arrangement of skin layers can be assessed as shown the fig .1 below:
Figure 1: Skin Layers (Source: Shlivko, et al., 2013)
From the image above, it can be noted that
- Corneal layer. 2. Cellular layers of epidermis. 3. Dermoepidermal junction zone. 4. Upper part of the reticular dermis.
The thickness of the skin can also be assessed by establishing the trough (minimum) and the peak (maximum) levels of the skin. The trough and the peak are best illustrated as on the graph on fig.2 below.
Figure 2: Skin thickness (Source: Shlivko, et al., 2013)
In some cases, the OCT images can be used to assess the contrast between layers. This is usually done on a homogeneous section along the transverse of the isolated tissue. The signal intensity is then assessed then obtained as in fig.3 below. The contrast in decibels is obtained as the difference in the intensities.
Figure 3. Skin contrast between the layers (Source: Shlivko, et al., 2013)
Lastly, the useful signal depth can be assessed at the region of the OCT image without the bio tissue. The noise level at the beginning and at the end of the scan are obtained then marked on the graph. The useful vertical depth can therefore be obtained by finding the distance between the two vertical lines as shown on figure 4b below.
Figure 4 .Skins Useful Signal Depth (Source: Shlivko, et al., 2013)
Gujral, J. S., Proctor, D. M., Su, S. H., & Fedoruk, J. M. (2011). Water Adherence Factors for Human Skin. Risk Analysis: An International Journal, 31(8), 1271-1280. doi:10.1111/j.1539-6924.2011.01601.x
Igarashi, T., Nishino, K., & Nayar, S. K. (2007). The appearance of human skin: A survey. Hanover, MA: Now Publishers.
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Shlivko, I. L., Petrova, G. A., Zor’kina, M. V., Tchekalkina, O. E., Firsova, M. S., Ellinsky, D. O., & … Donchenko, E. V. (2013). Complex assessment of age-specific morphofunctional features of skin of different anatomic localizations. Skin Research & Technology, 19(1), e85-e92. doi:10.1111/j.1600-0846.2012.00613.x