Today, we did examples finding the equivalent resistance, total current, current in each resistor, and potential difference across each resistor when connected in a series or parallel.

We discussed and used video images to outline the results on the body of toxic chemicals which can be found in cosmetics. Aluminum products found in antiperspirants were singled out and the effect on skin and eventually on the system when absorbed was presented.
We discussed absorption of essential oils which are found in many products, and how the location of application will effect the absorption.

Define and discuss the difference between permeability (penetration) and absorption. Permeability represents the amount of a topically applied substance that exists between the top and the bottom layer of the epidermis. There is no absorption into the blood and cannot affect the body systems. Skin absorption occurs when the applied chemical reaches the dermal layer and absorbs into the blood stream. Briefly discussed how skin care ingredient penetration works. Small particle size products are permeable and can be uptaken by skin cells. After a period of time they will be secreted out of the skin cells and enter the blood. Large particles will move between the skin cells and enter the circulation. Non absorbed particles may be temporarily absorbed by some glands and absorbed over time.

Discussion of the importance of considering the "ecological diversity" of the skin when considering a product for topical use. Substances should be used carefully on the skin as many compounds may cause an allergic response or act as feeding grounds for some of the 1000 species of bacteria which inhabit the skin. The allergic response was outlined, including terms like antigen, allergen, antibodies, and histamine. The overgrowth of bacteria or yeast when topical cosmetics are used needs to be addressed when manufacturing these products. A list of 26 allergenic substances will be presented and briefly discussed.

We went over his Impulse-Momentum Test (81/100), and then started to review topics that we covered last week on Circuits.
He went to listen to a lecture today.

Using a educator video,the anatomy and physiology of the skin was reviewed, and new areas addressed. We reviewed the epidermal, dermal and subdermal layers. Each layer was discussed in regards to major structures, how they effect the health of the person and the effects of applying various materials to the skin will bring about.
Melanin, keratin, blood vessels, sweat glands, sebaceous glands and hair follicles were discussed, along with how these parts are affected by topical applications like makeups and foundations.

We discussed what changes occur to the skin on aging, the thinning of the skin, particularly in certain areas, and that the skin is more easily damaged with decreasing ability to heal itself. There is a decrease in elasticity and skin volume with a decrease in blood flow and lower glandular activity. Laxity, Rhytids, and erythema are all part of the aging process of skin. The use of products developed to counter some of these effects was discussed, along with the possible side effects which may develop, such as allergic responses.

We continued with our anatomical and physiological examination of human skin by concentrating on the dermal layer. The inclusion of nerve endings, blood vessels, sweat glands, hair follicles, and fat molecules allowed us to discuss the role of each in the physiology of the skin. The occurrence of melanin, a pigment, in this layer was discussed as to how it effects skin color and developed as protective chemical against UV rays. The need to adjust lotions, creams, ointments and makeup because of the presence of this pigment was also discussed

Using the skin image, the dermal layer of the skin, its anatomy and physiology were discussed, including cushioning, stress and strain, nerve endings responsive to temperature and touch, the function of hair follicles and sweat glands, and blood vessels. The effect on these anatomical parts due to the application of cosmetics, moisturizers, and cleansers was briefly described.
The differences in skin color, the role of melanin and the natural selection which brought about these differences was discussed. The need for topical products which are required will be discussed.

I allowed Vlad to choose the next chapter that we look at, and he decided to do circuits. We started to talk about schematic diagrams with circuits, and calculations regarding circuits that included resistors in series.