Lecture 29 - Overview Flashcards
What effect does exercise have on homeostasis
It initially disrupts it and often requires prolonged coordination of most body systems
During exercise what happens to the heart rate, stroke volume, cardiac output, systolic pressure and diastolic pressure
The heart rate, stroke volume, cardiac output and systolic pressure all increase and the diastolic pressure decreases
Values of heart rate, stroke volume, cardiac output, systolic pressure and diastolic pressure at rest
Heart rate - 70bmp Stroke volume - ~70ml Cardiac output -5l/min Systolic pressure - 120mmHg Diastolic pressure - 80mmHg
Values for heart rate, stroke volume, cardiac output, systolic pressure and diastolic pressure during exercise
Heart rate - 200bmp Stroke volume - ~130ml Cardiac output - 25l/min Systolic pressure - 180mmHg Diastolic pressure - 70mmHg
During exercise what does CO increase in proportion to
Workload
What is the control of the heart rate coordinated by
The cardiovascular control centre
Where is the cardiovascular control centre found
In the brain stem
What is the immediate response to exercise
The HR increases to deliver more oxygenated blood to the exercising muscles
What is the long term adaption to exercise
Increased strength and efficiency of the heart
What is SV controlled by
Intrinsic and extrinsic control mechanisms
What are the intrinsic control methods involved in SV
Muscular contractions compressing the veins and venoconstriction
What are the extrinsic controls involved in SV
Sympathetic stimulation and adrenaline
What effects do working muscles have on the local environments
Local Po2 falls, local Pco2 increases, local H+ concentration rises (pH falls) and muscle temperature rises
When local Po2 falls, local Pco2 increases, local H+ concentration rises (pH falls) and muscle temperature rises what happens
Metabolic hyperaemia
What is blood pressure proportional to
TPR
To meet the metabolic demands of skeletal muscle there is
A large drop in TPR brought about by vasodilation of arterioles supplying the working muscle
What effect does decreased TPR have on diastolic pressure
It causes diastolic pressure to drop
What is produced in severe exercise
Lactic acid
What are the values for ventilation, VO2 and VCO2 at rest
Ventilation - ~6l/min
VO2 - ~0.25l/min
VCO2 - ~0.20l/min
What are the values for ventilation, VO2 and VCO2 during exercise
Ventilation - ~120l/min
VO2 - ~3.5l/min (5 in trained athletes)
VCO2 - 4+
What does H+ stimulate and what does this cause
H+ stimulates peripheral chemoreceptors and ventilation is excessively stimulated
What is the O2 deficit
The difference between the oxygen uptake of the body during early stages of exercise and during a similar duration of steady state of exercise
What is the O2 debt
The amount of extra oxygen required by muscle tissue to oxidise lactic acid and replenish depleted ATP and phosphocreatine following vigorous exercise
What factors may increase ventilation during exercise
Reflexes originating from body movements, increased body temeperature, adrenaline being released and impulses from the cerebral cortex
What is a predictor of a persons work capacity
The determination of maximal O2 consumption
How can VO2 max be determined
Through exercise on a bike/treadmill where the workload is progressively increased until exhaustion and the expired air is collected during the last minutes and the %O2, %CO2 and volume of air are measured
What effect does regular exercise have on VO2 max
It will improve it
What classifications of a persons V02 max are there
Low, fair, average, good or excellent
During exercise what does the increase in surface area for gas exchange allow
An enhance rate of gas transfer
What do increased CO and an increased pulmonary BP do
They force open previously closed capillaries
