Homeostasis
� the maintenance of a constant or unchanging internal environment
� during rest or unstressed conditions
Steady State
� constant internal environment or metabolism
� during exercise or elevated metabolism
� balance has been achieved between demands of the body and the body's response
Temperature
� core temperature is a very important metabolic parameter
� needs to be maintained within a very narrow range
� much heat is generated during exercise, but is dissipated to maintain constancy
� homeostatic condition will not differ from steady state grea
Blood Pressure
� blood pressure is another important metabolic parameter
� will vary to a greater extent from rest to exercise � will be constant during homeostasis or steady state though
� Effector-
corrects disturbance and removes stimulus
integrating center
relay station (dispatcher)
Receptor-
receives the stimulus �
Stimulus-
excites a receptor �
� Power =
work / time - units - W, hp, kpm/min
� Work =
force x distance - units - kpm, kgm, kcal, J, ft-lbs
Force =
mass x acceleration
Ergometry/ergometer
Ergo = work �
Ergometry is the measurement of work �
Ergometer is a device used to measure work
Indirect Calorimetry
� Measurement of Oxygen consumption as estimate of metabolic rate
Direct Calorimetry
� Measurement of heat production as estimate of metabolic expenditure
When we eat a meal, our blood glucose will increase, the response of the body will be to??
Release insulin to decrease blood glucose
Compute the amount of work performed during cycle ergometer exercise in the following example: pedaling rate= 100rpm (6 meters per revolution) 3kg resistance against the fly wheel: total time 10 minutes. The amount of work is?
18000kpm (100 x 6) x 3kg x10
Power is defined as??
Work per unit time
Most control system of the body operates via??
Negative feedback
Negative feedback , the response of the system is ......
opposite that of the stimulus
a. Calculate the amount of work performed during 5 minutes of treadmill exercise by a 100kg subject running at 300 meters/min up a 10%grade?
b. how much power is produced? 300 kpm/min
15,000kpm/5 min
15,000kpm
100kg x (300x .10) x 5
300 kpm/min
15,000kpm/5 min
What is the most common technique to measure oxygen consumption in exercise physiology laboratories is????
Open circuit spirometry/indirect calorimetry
I f a 50 kg subject were performing a Harvard bench step test and stepping up a .5meter bench at a rate of 50 steps per min, how much work would hey produced in 10 minutes?
12,500 kpm
50 kg x (50 x.5) x 10
Physiologist use the term steady state to denote...?
A steady and unchanging internal environment