Ch.9 Flashcards
3 Cardiac responses
Heart rate
Stroke volume
Cardiac output
2 vascular responses
Blood pressure
Blood flow
Untrained HR rest
60 to 80bpm
Traine HR rest
Low as 30 to 40bpm
What can affect testing HR? (NTA)
Neural tone, temperature, altitude
HR increases above RRHR just before start of exercise
Anticipatory response
Decrease in vagal tone
Parasympathetic withdrawal
Increase in Catecholamine
Sympathetic stimulation
TF: HR during exercise is parallel to exercise intensity
False
Proportional
Highest HR achieved in all-out effort to volitional fatigue
Maximum Heart Rate
Point of plateu
Steady state Heart Rate
TF: If intensity increases, so does steady state HR
True
Stroke volume plateaus after increasing ___ VO2max
40-60%
What 3 things control stroke volume? (PCA)
Preload
Contractility
Afterload
End-diastolic volume (EDV)
Preload
The more the ventricles are “stretched” (i.e. greater EDV), the more forceful the contraction
Frank-Starling mechanism
Preload: SV increases as ventricular EDV __
Increases
Sympathetic nerve activity that circulates Catecholamine
Cardiac contractility
Amount of free calcium in the cytosine
Cardiac contractility
Cardiovascular responses that increase stroke volume (IID)
-Increase in Venous Return & Preload
-Increase in Contractility
-Decrease in Afterload
Cardiac Output (Q) equation
HR x SV
Where does Cardiac Output plateau?
Near VO2max
Q normal values (RUT)
– Resting Q
• ~5 L/min
– Untrained Q
•
max ~20 L/min
– Trained Q
•
max >40 L/min
What does O2 consumption depend on? (2)
Blood flow to tissue
Amount of O2 extracted by tissue
Fick Equation for VO2
VO2 = Q x (a-v)O2 difference
What is (a-v)O2 difference?
Arterial O2 - mix d venous O2
Resting O2 per 100ml blood
~6mL
Max exercise O2 per 100mL blood
~18mL
During endurance exercise, Systolic BP __ proportional to exercise intensity
Increase
During endurance exercise, Diastolic BP does not change or slightly __
Decreae
Resistance training triggers large __ in MAP
How high can MAP go during resistance exercise?
480/350mmHg
Method that is potentially dangerous but accompanies certain types of exercise
Valsalva maneuver
Parts of the Valsalva maneuver
– Close glottis (opening between the vocal
cord)
– ⬆️Intra-abdominal P (contracting
diaphragm)
– ⬆️Intrathoracic P (contracting respiratory
muscles)
Consequences of Valsalva maneuver
Dizziness, disorientation, syncope
High pressure from Vm collapse great veins to trigger decrease ___, ___, ___
Venous return
Cardiac output (Q)
Arterial blood pressure
Increase Cardiac Output triggers increase in available blood flow
Blood flow redistribution
Shunts blood away from less active regions
Sympathetic vasoconstriction
Less active regions that Sympathetic vasoconstriction pulls blood away
Kidneys
Splanchnic circulation (liver, pancreas , GI)
Permits additional blood flow in exercising muscle
Local vasodilation
Local Vasodilation is triggered by __,__ products
Metabolic, endothelial
Sympathetic vasoconstriction in muscle offset by local vasodilation
Functional sympatholysis
TF: Local vasodilation < neural vasoconstriction
False
>
Exercise + (other demands for blood) =
Competition for Cardiac Output (Q)
Exercise + heat(skin) =
Competition for Q
As temperature rises, __ VD also occurs
Skin
In skin VD, how can heat be released?
When blood moves close to the skin
Cardiovascular drift is associated with increase in __ & __
Core temperature
Dehydration
Decrease in stroke volume drifts causes (SSV)
Skin blood flow increase
Small decrease in plasma volume
Venous return decrease
During Cardiovascular Drift, HR drifts __ to compensate
Up/increases
