Temperature

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TEMPERATURE

• Tooba Qaiser
• PGDCP-07-18
• toobaqaiser722_at_gmail.com

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Temperature

• The degree of sensible heat or cold, expressed in
  terms of a specific scale. Body
  temperature is measured by a clinical thermometer 
  and represents a balance between the heat
  produced by the body and the heat it loses.
  Though heat production and heat loss vary with
  circumstances, the body regulates them, keeping a
  remarkably constant temperature.
• An abnormal rise in body temperature is called
  Fever.

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Normal Body Temperature

• Body temperature is usually measured by a
  thermometer placed in the mouth, the rectum, or
  the auditory canal. The normal oral temperature
  in 37 Celsius (98.6Fahrenheit).
• Normal temperature varies from person to person
  and at different times in each person.
• It is usually slightly higher in the evening
  than the morning and is somewhat higher during
  and immediately after eating, exercise, or
  emotional excitement.
• Temperature in infants varies than in adults.

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Abnormal Body Temperature

• Abnormal body temperature occurs when the bodys
  regulating system is upset by diseases or other
  physical disturbance.

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Thermoregulatory System

• Thermoregulation is the bodily system that
  performs function that is maintenance of a
  consistent internal body temperature, even when
  there are significant fluctuations in the
  external environmental temperature. The
  thermoregulatory system operates within two
  general boundaries
• Hypothermia the condition where the body becomes
  so cold that its systems will not properly
  function.
• Hyperthermia the corresponding opposite
  physical state where the body is overheated.

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Mechanism

• Thermoregulation has three mechanisms afferent
  sensing, central control, and efferent responses.
  There are receptors for both heat and cold
  throughout the human body.
• Afferent sensing works through these receptors to
  determine if the body is experiencing either too
  hot or too cold of a stimulus.
• The hypothalamus is the central controller of
  thermoregulation.
• Efferent responses are carried out primarily by
  the bodys behavioral reactions to fluctuations
  in body temperature.

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How does thermoregulation work?

• If your body needs to cool down, these mechanisms
  include
• Sweating Your sweat glands release sweat, which
  cools your skin as it evaporates. This helps
  lower your internal temperature.
• Vasodilatation The blood vessels under your skin
  get wider. This increases blood flow to your skin
  where it is cooler away from your warm inner
  body. This lets your body release heat through
  heat radiation.

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• If your body needs to warm up, these mechanisms
  include
• Vasoconstriction The blood vessels under your
  skin become narrower. This decreases blood flow
  to your skin, retaining heat near the warm inner
  body.
• Thermo genesis Your bodys muscles, organs, and
  brain produce heat in a variety of ways. For
  example, muscles can produce heat by shivering.
• Hormonal thermo genesis Your thyroid gland
  releases hormones to increase your metabolism.
  This increases the energy your body creates and
  the amount of heat it produces.

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The Physiological Consequences of Hyperthermia
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• Heat Rash
• It is a mild inflammation of clogged sweat ducts.
• When the sweat ducts are blocked the sweat
  cannot come to the skin surface to evaporate and
  becomes trapped under the skin.
• The rash is characterized by small, raised bumps
  spread evenly across small patches of skin.
• The rash usually goes away on its own and
  resolves in hours to a few days.

• Causes
• Blocked sweat glands are the main cause of heat
  rash. Sweat glands can get blocked for many
  reasons but the most common reasons include
• Skin around the neck, armpit, or groin that
  touches or rubs adjacent skin prevents sweat
  evaporation.
• Tight clothing around the waist, abdomen, chest,
  or groin that prevents evaporation of sweat.
• Bundling up in heavy clothing where sweat can
  accumulate on the skin.
• Heavy creams, oily lotions, or adhesive bandages
  can clog sweat ducts.

Symptoms The common symptoms of heat rash
include a fine, bumpy, itchy rash, skin burning,
and a "prickly" feeling (like something is
crawling on skin).
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Heat Cramps Heat cramps are painful. Muscles
may spasm or jerk involuntarily. Heat cramps can
occur during exercise or work in a hot
environment or begin a few hours later. Heat
cramps usually involve muscles that are fatigued
by heavy work, such as calves, thighs, and
shoulders.

• Causes of Heat Cramps
• The exact cause of heat cramps is unknown.
• They are probably related to electrolyte
  problems.
•  Electrolytes include various essential minerals,
  such as sodium, potassium, calcium,
  and magnesium.
• They are involved in chemical reactions in your
  muscles.
• An imbalance can cause problems.

• Symptoms of Heat Cramps
• Muscle spasms that are
• Painful
• Involuntary
• Brief
• Intermittent
• Usually self-limited (go away on their own)

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Heat Exhaustion It is a heat-related illness
that can occur after you've been exposed to high
temperatures, and it often is accompanied
by dehydration.

• Symptoms of Heat Exhaustion
• The most common signs and symptoms of heat
  exhaustion include
• Confusion
• Dark-colored urine (a sign of dehydration)
• Dizziness
• Fainting
• Fatigue
• Headache
• Muscle or abdominal cramps
• Nausea, vomiting, or diarrhea
• Pale skin
• Profuse sweating
• Rapid heartbeat

Types There are two types of heat
exhaustion Water depletion Signs include
excessive thirst, weakness, headache, and loss of
consciousness. Salt depletion Signs
include nausea and vomiting, muscle cramps,
and dizziness
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Heat Stroke Heat stroke is an emergency
condition where the body's core temperature is
markedly elevated (depending on who provides the
definition, about 104 F 40 C or above in adults
and 105 F or 40.5 C in children) after being
exposed to high environmental temperatures
combined with neurologic symptoms and loss of
body thermal auto regulation (ability of the
brain to control the body temperature).

• Causes
• The major cause of heat stroke is prolonged
  exposure to high temperatures and/or doing
  strenuous activity in hot weather. The body's
  ability to control the core temperature
  (sweating, evaporative cooling, for example) is
  overwhelmed by heat.
• Infants, children, pregnant females and the
  elderly are at higher risk for heat stroke
  because they are less able to control their core
  temperature.
• Other causes that can contribute to the condition
  of heat stroke are
• Dehydration
• Drinking alcohol
• Dide effects of certain medications (for
  example, dehydration, increased urination,
  sweating)
• Wearing excess and/or tight clothing can
  contribute to causing heat stroke by inhibiting
  cooling by evaporation.
• Sunburn

• Symptoms
• Heat stroke usually follows two other
  heat-related problems heat cramps and heat
  exhaustion. These two conditions are marked
  by muscle cramps followed by exhaustion and
  profuse sweating.
• As these conditions progress of heat cramps and
  heat exhaustion progress, a rapid pulse, rapid
  breathing, dizziness, and headache may occur.
• These symptoms may linger and progress to heat
  stroke when the body temperature reaches 104 F or
  40 C or 105 F and 40.5 C in children, and the
  body stops sweating.
• In addition to stopping sweating, the skin of a
  person suffering from a heat stroke is hot and
  dry, and sometimes becomes a reddish color.
• Stroke-like symptoms occur in heat stroke.
  Confusion, hallucinations, seizures, loss of
  consciousness, organ damage, coma, and death can
  occur if not treated quickly and effectively
  mental status changes help differentiate heat
  exhaustion from heat stroke.

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The Physiological Consequences of Hypothermia
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• Endocrine and metabolic consequences
• Decreased metabolism and oxygen consumption
• Decreased carbohydrate metabolism and
  hyperglycaemia
• Decreased drug metabolism and clearance
• Essentially unchanged electrolytes
• Hematological consequences
• Increased hematocrit and blood viscosity
• Neutropenia and thrombocytopenia
• Coagulopathy and platelet dysfunction
• Respiratory consequences
• Decreased respiratory rate and medullary
  sensitivity to CO2

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• Acid-base changes alkalosis and hypocapnea
• Rise of pH with falling body temperature
• Fall of PCO2 with falling body temperature
• Increased oxygen solubility and O2-haemoglobin
  affinity
• Cardiovascular consequences
• Decreased cardiac output and bradycardia
• QT prolongation and the J wave
• Arrhythmias - classically AF and VF
• Resistance to defibrillation
• Vasoconstriction
• Renal consequences
• Cold diuresis" due to decreased vasopressin
  synthesis
• Central nervous system effects
• Confusion and decreased level of consciousness
• Shivering
• Increased seizure threshold
• Immunological consequences
• Decreased granulocyte and monocyte activity

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Seasonal Depression OR Seasonal Affective Disorder
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• Seasonal depression is a mood disorder that
  happens every year . A rare form of seasonal
  depression, known as "summer depression," begins
  in late spring or early summer and ends in fall.
  In general, though, seasonal affective disorder
  starts in fall or winter and ends in spring or
  early summer

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Causes

• Some scientists think that certain hormones made
  deep in the brain trigger attitude-related
  changes at certain times of year. Experts believe
  that SAD may be related to these hormonal
  changes.
• One theory is that less sunlight during fall and
  winter leads to the brain making less serotonin,
  a chemical linked to brain pathways that regulate
  mood. When nerve cell pathways in the brain that
  regulate mood don't function normally, the result
  can be feelings of depression. Along with the
  symptoms fatigue and weight gain.
• SAD usually starts in young adulthood and is more
  common in women than men. Some people with SAD
  have mild symptoms and feel out of sorts or
  irritable. Others have worse symptoms that
  interfere with relationships and work.
• Because the lack of enough daylight during
  wintertime is related to SAD, it's less often
  found in countries where there's plenty of
  sunshine year-round.

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• Winter Symptoms
• Less energy
• Trouble concentrating
• Fatigue
• Greater appetite
• Increased desire to be alone
• Greater need for sleep
• Weight gain
• Summer Symptoms
• Less appetite
• Trouble sleeping
• Weight loss

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