Special Topics Flashcards
Regulation of body temperature is mediated by:
Hypothalamus
Most potent mechanism for heat generation
Shivering
What is the role of fat and skin in terms of regulation of body temperature
Fat: Insulator
Skin: Radiator system ( cold: blood vessels constrict; hot: blood vessels dilate)
Most of the body heat is lost through which way?
Radiation > Evaporation > Conduction to air > Conduction to objects
What is the pathophysiology of fever?
Pyrogens increase IL-1 (alpha and beta) and IL-6 –> increase prostaglandins –> increase set point temperature in hypothalamus
What is the difference between heat exhaustion and heat stroke?
Heat exhaustion: excessive sweating causing fainting
Heat stroke: high temperature causing tissue damage and impaired responses
High temperature secondary to the use of succinylcholine and halothane
Malignant hyperthermia
What is the pathophysiology of Malignant hyperthermia?
Defective ryanodine receptors causes Ca2+ to move out of SR very fast –> overexcitation of skeletal muscles –> consume ATP and produce heat
Treatment of malignant hyperthermia
Dantrolene - Ca2+ channel blocker
Strength per square centimeter of crosssectional area of a muscle in both men and women
3-4 kg/cm2
Energy system that uses cell ATP and cell phosphocreatinine; utilized during the first 8 - 10 seconds
Phosphagen energy system
Energy system that uses anaerobic glycolysis; utilized for the 1.3 to 1.6 minutes after phosphagen system is used up
Glycogen-Lactic acid system
Energy system that uses aerobic glycolysis; utilized for unlimited time as long as with energy supply
Aerobic system
What is the basis for muscle endurance?
Glycogen levels in the body
100g stored in liver, 400g stored in muscles
For every gram of glycogen, 3mL H20 is needed
What is the best diet for muscle glycogen recovery
High carbohydrate diet
How long does it take to recover muscle glycogen
2 days
An increase in muscle strength is always due to what?
Increase in muscle size
Maximal breathing capacity
150 - 170 L/min
Pulmonary ventilation during maximal exercise
100 - 110 L/min
Formula to get the maximal heart rate
220 - age
Muscle blood flow increases by how much during the most strenous exercise?
20 times
In athletes, resting cardiac output is 5L/min. In exercise this increases to ___ and accounts for ___ percent increase.
30L/min, 600% increase
In non-athletes, resting cardiac output is 5L/min. In exercise this increases to ___ and accounts for ___ percent increase.
20L/min, 400% increase
Change from resting cardiac output to exercise cardiac output is called:
Cardiac reserve
At maximal exercise, CO is at __% maximum which pulmonary ventilation is at __% maximum
CO: 90%
Pulmonary ventilation: 65%