Exam 1 Flashcards
Who was Claude Bernard?
First author to observe that humans’ (internal environment) can remain constant despite external environment.
Normal Body Temp
37 degrees Celsius
What did Walter Cannon say?
Coined the term homeostasis from studying response to various body systems to different stressors.
Who was Hans Selye?
Discovered stressors which are stimuli that disturb homeostasis.
Came up with General Adaptation Syndrome.
Homeostasis
The maintenance of a constant or unchanging internal environment.
Stress
A stimulus, force, or influence that elicits a biological response.
Example of Stressors
Heat, Cold, Odor, Food, Water, Hypoxia, Noise, Light, Darkness, Trauma, Shock, Threat, Bacteria
Short-term Adaptive Response (Accommodation)
Attempts to reestablish homeostasis. EX: Stretching
Long-Term Adaptive Response (Acclimation/Acclimatization)
Acclimation is changing your thermostat vs acclimatization which is the natural environment
Three components of a biological control system
A receptor, An integrating center, an effector or target organ.
Example of biological control system
Thermoreceptors respond to heat and cold then sends stimulus to integrating center (brain) which then sends a signal to the effector which attempts to restore the internal environment.
Stress Proteins
High stress causes damage to cellular proteins and can result in a disturbance of homeostasis. Cell produce stress proteins which repair damaged proteins to restore homeostasis.
Sympathetic-adrenal-medullary (SAM)
Secretes catecholemines into blood stream during fight-or-flight response.
Hypothalamic-pituitary-adrenocortical (HPA)
Adrenal cortex secretes corticosteroids (cortisol) into the bloodstream.
Factors that determine heat exchange
Temperature, reflective heat, wind, humidity and barometric pressure.
How is Behavioral Temperature Regulation measured?
Measured by physiological means like RPE. Gagge Scale.
How do we try to adjust to the new temperature?
Thermostat, clothes.
Five factors that influence Physiological Thermoregulation
Time of day, phase of menstrual cycle, fever, heat acclimation and diurnal rhythm.
Thermoregulatory Set Point
Reference temperature that is necessary for the control of thermoregulatory responses.
Thermoreceptors
Provide hypothalamus with information regarding our temperature.
Types of thermoreceptors
Skin - Respond to heat and cold
Core - Unknown Stimuli
Hypothalamus
Anterior - stimulated by heat
Posteriors - stimulated by cold
Four methods of heat exchange
Convection - Heat exchange between a surface and a fluid, normally air or water.
Conduction - Heat exchange between two solid surfaces in direct contact.
Radiation - Heat transfer from the surface of one object the surface of another with no physical contact.
Convection is dependent on three factors
Fluid density, thermal gradient, area of exposure
Three types of solar radiation
Direct, diffuse (barrier between sun and you), reflected (ice, water)
Hyperthermia
Increased temperature, high humidity and exercise intensity
Effects of Hyperthermia
Muscular endurance decreases but no effect on muscular strength, shift from aerobic to anaerobic, peripheral vasodilation can cause blood pooling
Effects of Dehydration
Dry mouth, sleepiness, thirst, decreased urine output, dry skin, headache, dizziness, rapid heart rate, low blood pressure.
Effects of Hyperthermia AND Dehydration
Reduced endurance performance, reduced plasma volume and a decrease in cardiac output.
Heat Acclimatization
(10-14 days) Improves heat transfer by increasing plasma volume and improved cardiovascular function.
Water and Exercise
500mL should be consumed at least 2 hours prior to exercise, during exercise consume water equal to your sweating rate, fluid should be 15-22 degrees celsius.
How much water is lost per day?
2.5 L
Commercial Beverages
Should be consumed instead of water if there is a CHO deficiency (4-8%), during strenuous exercise (>70%), if there is a sodium deficiency or a rapid replacement of plasma water is needed.
Functions of Sodium
Regulation of water movement, nerve conduction, cellular metabolism, blood osmolality, volum and pressure maintenence.
Maintenance of sodium in the body and factors that affect sodium loss
Maintained by aldosterone
Factors that affect sodium include sweat rate and concentration, dietary intake, exposure to heat (duration/day; total duration)
S/S of hyponatremia
increased body mass, fatigue, nausea, disorientation, seizure, edema, respiratory arrest
Training Considerations
Wear light-weight clothing, follow weather reportsm know S/S, adjust intensity and duration accordingly, performance may vary
What causes heat exaustion?
A depletion in circulatory fluids (plasma), increased heart rate/switching to anaerobic.
S/S of heat exhaustion?
Inability to continue work, muscle cramps, vomiting, progressive weaknesses.
Treatment for heat exhaustion
Replenish fluids and electrolytes. In more extreme cases, IV may be needed.
What causes exertional heat stroke?
Body Temp at 39-40 degrees celsius
S/S of heatstroke?
Blood enzymes rise, body cooling is absent, CNS impaired thus impairing heat loss via sweat evaporation, mental acuity causes disorientation, coma or bizarre behavior.
Treatment of heatstroke
Cold water immersion of the core rather then limbs in order to prevent shivering, shock and tissue damage
What causes heat cramps?
Linked to large losses of sodium content or replacement of sweat losses with a large volume of water.
S/S of heat cramps
Hyponatremia, hypokalemia, altered muscle contraction
Treatment of heat cramps
Replacing sodium lost, water loss either orally or by IV
What causes heat syncope?
Exposure to hot environments over long periods especially while standing up-right for extended periods of time. Insufficient blood flow to the brain.
S/S of heat syncope
Paleness, nausea, blurred visions
Treatment of syncope
Cool fluids and elevated legs.
