RADIATION & ELECTRICAL CURRENTS

Transcription

1 HND 2 nd Year Interview Briefing RADIATION & ELECTRICAL CURRENTS The Electromagnetic Spectrum consists of a range of electromagnetic waves with differing wavelengths and frequencies that travel without a medium and at the same speed. The diagram below shows the spectrum with the varying radiations NB The shorter the wavelength the more dangerous it is Infra Red Radiation Infra-Red rays are electromagnetic waves with wave lengths between 700 nm and 400,000 nm. They are emitted naturally from the Sun as well as from hot objects electric fires, coal fires, hot packs, special heater lamps as well as you! Infrared is split into 2 different types: Luminous Infrared ( nm ) is nearest to the visible part of the spectrum (shortest wavelength, therefore more penetrating to the skin) Non Luminous Infrared (greater then 1400nm) is furthest from the visible part of the spectrum (longest wavelength, therefore less penetrating to the skin) HND 2 nd Year Interview Briefing Page 1

2 Ultra Violet Radiation Ultraviolet has a shorter wavelength than visible light and is invisible to the naked eye and although it only forms 3% of light from the sun it is one of the most damaging parts of the spectrum There are 3 types of UV radiation: UVA:- o Longest Wavelength o Is necessary for healthy growth Vit D o Causes premature ageing penetrates into the dermis causing fragmentation of the collagen and elastin fibres o Produces short term tan stimulates existing melanin UVB:- o Mid range Wavelength o Produces suntan and sunburn o Sunburn penetrates to the epidermis, will cause permanent damage to the skin body responds by realising histamine from the skin s cells, resulting in dilation of blood vessels allowing more blood to reach the epidermis = erythema o Produces long term tan - stimulates melanocytes to produce new melanin o Overexposure can lead to skin cancer UVC:- o Shortest Wavelength o Lethal to all organisms converts oxygen to ozone o UVC is filtered out by the Ozone layer around the earth o UVC causes skin cancer HND 2 nd Year Interview Briefing Page 2

3 Electrical Current: Electrical Current is the flow of electrons from a negative terminal to a positive terminal through a substance Direct Current: current that is flowing in one direction only such as from a battery electrons flow from negative electrode to the positive electrode Alternating Current: current that is alternating direction, i.e. its direction of flow changes regularly, in Britain this is 50 Hz or 50 cycles per second (frequency), normally from a generator : Faradic Current: a current that is produced from a direct current which is rapidly switched on and off (interrupted direct current). These signals have a relatively low frequency in the range of 10 to 120 hertz HND 2 nd Year Interview Briefing Page 3

4 Currents in Electrolytes Another material which is good at conducting electricity is a solution of ions (e.g. NaCl (salt) dissolved in water) known as an electrolyte an electrolyte is a solution which contains ions this includes human tissue cations (positive ions attracted to cathode, i.e. the negative electrode) anions (negative ions attracted to anode, i.e. the positive electrode) Uses of Electrical Current in Beauty Therapy Electrical current is used in many forms within the Beauty Industry due to their varying properties and effects GALVANIC: (Direct Current) o Direct Current = electrons/ions flow from ve to +ve in the same direction round the circuit at all times o Requires a constant current to prevent a tingling sensation during the treatment o Creates a movement of ions o Breaks down the skin s resistance due to a chemical reaction To carry out a galvanic treatment you need: Active Electrode - applies the current to the client s skin Indifferent Electrode - completes the circuit Application: Iontophoresis repulsion of ions with similar polarity active electrode is dependent on the polarity of the product used Desincrustation polar effects of alkali formation (Sodium Hydroxide) therefore active electrode is always the negative Electrolysis chemical destruction of tissues of the hair follicle using caustic soda - active electrode is always Cathode, shaped as a fine needle which is inserted into the hair follicle until it reaches the hair papilla where the moisture is converted to caustic soda HND 2 nd Year Interview Briefing Page 4

5 FARADIC: (Interrupted Direct Current ie a direct current which is rapidly switched on and off) Current must be interrupted to allow the muscle to adapt to the current. (This is sometimes called accommodation) the motor nerves of the muscle is stimulated resulting in a contraction therefore toning the muscle. A constant flow of current will not produce a contraction as the muscle will not have adapted Uses o Correction of figure faults o Tones undertone muscles o Girth reduction o Alteration of body contours HIGH FREQUENCY: (Alternating Current )- electrons flow one way around the circuit and then reverse direction and flow back the other way Produces a warming of the tissues by exciting or vibrating the water molecules within the tissues Only one electrode is needed no indifferent needed as circuit is complete through the client to earth Application: There are 3 ways of applying High Frequency in beauty treatments Direct : Indirect o uses a selection of glass electrodes for a germicidal effect o Gauze can be used to increase the germicidal effect due to the gap produced between the gauze and skin creating sparks o client holds a saturator electrode and the therapist gives a massage o Current flows from the electrode through the client towards therapist s hands then back to earth o Warmth is created under the therapist s hands directly on the client s skin HND 2 nd Year Interview Briefing Page 5

6 Shortwave Diathermy (thermolysis): o the current is applied through a fine needle inserted into the hair follicle for a short period of time o The heat that is produced brings about the destruction of the lower follicle o A much quicker process than Electrolysis but not as successful as it cannot treat curved or distorted follicles well HND 2 nd Year Interview Briefing Page 6