mos 3344 ch.5

the body core temperature range is

35 degrees to 38.5 degrees, and normal is 37 degrees

the body thermal balance is illustrated as follows:

S = (M-W) +/- R +/- C +/- V — E when there is heat, th body will gain heat if R,C, and V, are positive

segmental vibration

affects only parts of the body, include sore neck and shoulder muscles, sore joints, and white fingers (restricted blood circulation in the fingers), necrosis (death or decay of tissue), decalcification (loss of lime salts and calcium in the bones)

whole body vibration

affects the whole body as a unit

key factors that influence the human body's response to the cold:

air temperature, wind speed, humidity, physical activity, work schedule, and protective clothing

ambient

all encompassing condition associated with a given environment, being usually a composite of inputs from sources all around us

gradual hearing loss is also called

alled temporary threshold shift can sometimes be reversed by removal from the noise source

each of these agents may be

ambient or acute (resulting from a single exposure)

ionizing radiation

any form of electromagnetic energy capable of producing ions through interaction with matter types of ionizing radiation include xrays, gamma rays, alpha particles, beta particles, and neutrons X-rays common in medical facilities, the others more common in nuclear operations or research companies radiant exposure or dosage is usually measured in a unit called a rem, natural radiation is 125 mrem

sociological hearing loss causes extra

auditory effects such as startled response to a loud, unexpected noise; cardiovascular, neurologic, endocrine, and biochemical changes; and nausea, malaise, and headaches

as body heat increases

blood flow increases, capillaries move closer to the surface of the skin and sweating increases, thereby allowing increased heat exchange to the atmosphere

noise can affect humans in 3 ways

by using physiological damage that affects hearing, by causing more general physiological effects in some cases referred to as sociological, and by causing psychological effects

noonfreezing injuries can occur in temperatures above the freezing mark and include chilblains, immersion foot, and trench foot

chilblains —a mild injury caused by reduced circulation in the extremities after prolonged exposure to temperatures above freezing, result i redness, swelling, and tingling in the hands and feet immersion foot —an injury that occurs after an individual's foot or feet have been wet but not frozen for prolonged periods of time (days,weeks), skin may turn blue or purple trench foot is caused by prolonged exposure to colder (up to 10 degrees) wet conditions, can result in muscle tissue or nerve damage

3 methods of heat transfer:

conduction —heat transfer occurring when two surfaces are in contact convection —heat transfer occurring when one surface adds heat to the surroundings radiation —heat transfer occurring when energy is transmitted by electromagnetic waves

2 basic types of hearing loss

conductive —restricts the transmission of sound to the cochlea or inner ear, caused by wax buildup, infection, or trauma sensorineural —referred to as nerve deafness and affects the cochlea and is usually irreversible

noise

defined as any unwanted sound and is often referred to as the most comma workplace hazard sound and noise differ by definition in that noise is unwanted sound

non-ionizing radiation

electromagnetic radiation that does not have energies great enough to ionize matter include ultraviolet radiation, visible (white light), infrared, microwave, and radio the eye is the primary organ at risk from non-ionizing radiation refer to p.134 for effects of non ionizing radiation

human hearing response is conditional on three characteristics

frequency, duration, and loudness

freezing injuries occur in colder temperatures and are caused by local freezing of muscles and tissues, include frosting and frostbite

frostnip —mildest form of a cold injury and can affect the earlobes, nose, cheeks, finers, and toes after exposure to temperatures below the freezing mark, symptoms include the top layer of skin freezing, numbness tingling, and the skin turning white and hard frostbite —similar to frostnipp but the underlying tissues freeze in addition to the outer layer of he skin, results in restricted blood flow to the tissue and can cause permanent tissue damage, blisters, infection, and gangrene

heat cramps

heat cramps occur in the muscles of the body and may or may not occur in conjunction with other heat related illnesses such as heat rash, heat cramps are a result of an imbalance of salt in the body and are often felt in the arms and legs first

heat related illness: heat edema

heat edema occurs most often in individuals who are not acclimatized to working in hot environments and typically results in parts of the body swelling

heat exhaustion

heat exhaustion occurs when an individual is sweating excessively and loses too much body water, exhibit dizziness, blurred vision, nausea, headache, vomiting, etc

heat rash

heat rash is one of the first signs of the body's intolerance to heat and results in the sweat glands becoming swollen and plugged

heat stroke and heat hyperpyrexia

heat stroke and heat hyperpyrexia occur when the body is unable to control its thermal balance resting in a dangerous rise in core temperature (above 41 degrees)

heat syncope

heat syncope or fainting is the result of an inadequate amount of blood in the brain due to lowered blood pressure and often occurs while an individual is standing or working

hypothermia

hypothermia occurs when cold causes the body's ability to regulate its thermal temperature fails and is not able to compensate of rate loss of heat, occurs after the body's core temperature falls below 33 degrees, can lead to heart and respiratory failure refer to table 5.1 p. 131 for signs and symptoms of hypothermia

permanent threshold shift (PTS)

identifies a hearing disability that is permanent and may not be correctable

thermal stress

involve hot and cold temperature extremes the human body can be seen as a machine that takes in chemical energy (food) and converts it to mechanical energy (muscles) and heat temperature, like water, flows from the high point to he low point when an imbalance occurs, the body is stressed thermally

second strategy (path)

involves moving the worker away fro the source or erecting sound barriers between the noise and the worker, or both

the third strategy (human)

involves the use of personal protective equipment (PPE); this approach is the least costly and the one that is most commonly used two basic classes of hearing protection are earplugs and earmuffs

nonfreezing injuries

nonfreezing injuries happen when body parts such as hands and feet cool but do not freeze

free field effect

noting like a wall is around to reflect he sound back on the worker, objects such as the other machines will cause reflections that can reduce the amount of attenuation from this fixed amount objects such as the walls of the building and other machines will cause reflections that can reduce the amount of attenuation from this fixed amount this process is usually less costly than the source approach

radiation divided into 2 groups

radiation divided into 2 groups: ionizing and non-ionizing identified primarily by wavelength range (short for ionizing and long for non-ionizing) and by their action on tissue

attenuated or attenuation

reduction of noise at one location compared to another farther form the source

physical agents

s —sources of energy that may cause injury or disease examples of physical agents: noise, vibration, radiation, and extremes in temperature and pressure

hyperreflexia

the condition of unusually quick reaction by the nerves to some external stimulus the first strategy or reducing noise is to make the source quieter

cold related illnesses

the human body does not become acclimatized to the cold in the same way it does in hot environments however, certain body parts are able to develop a tolerance to the cold (Eg. hands)

vibration

the oscillating motion of a particle or body moving about a reference position vibration is measured by examining the frequency, amplitude, and acceleration of an object vibrations are classified into 2 categories: low frequency (discussed above) and high frequency

vasoconstriction

the process of causing a constriction of th blood vessels

early warning change

—a deterioration of hearing in the upper frequency —the earliest detectable sign of noise induced hearing loss just because we cannot hear the sound does not mean that it is not present an possibly causing hearing damage

threshold of hearing

—the envelope or range of sound that the human ear can receive or hear