Cardiovascular system Flashcards
What are the 5 components of the O2 transport system?
- Pulmonary ventilation
- Hb concentration
- Blood volume and Q
- Peripheral blood flow
- Aerobic metabolism
A tubes resistance is _______ proportional to the __th power of its radius.
inversely; 4th
______ muscle fibers in arterioles control blood flow to capillary beds
smooth
_______ pressure witting capillaries draws fluid back.
osmotic
______ pressure forces fluid from capillary
blood
What are the 3 key components for delivering blood to working muscles?
- Heart function
- Blood flow distribution (including blood pressure)
- Oxygen extraction at muscles
Exercise = _______ overload.
functional
What are 4 anatomical changes with exercise?
- Increase mass and volume
- Increase size left ventricle cavity
- Modest increase left ventricle wall thickness
- Increase left ventricle EDV at rest and with exercise
_____ ______ = amount of blood ejected with each stroke
stroke volume
_____ _____ = amount of blood pumped by each heart beat
cardiac output
Blood flow from heart increases in ______ proportion to exercise intensity.
direct
If a steady state type exercise, Q then ______ as blood flow matches exercise metabolic requirements.
plateaus
When does SV approximately plateau?
at 50% VO2 max
What is another formula for stroke volume?
EDV - ESV
HR increases less rapidly in untrained (T/F).
FALSE (more)
What is the main training response to exercise?
increase in SV
What are two causes of increases pre-load?
- Increase with plasma volume
2. Greater blood volume
What two hormones cause an increase in plasma volume?
- anti-diuretic hormone
2. aldosterone
What are 4 results of increased pre-load?
- Enhances circulatory dynamics
- Enhances thermoregulatory dynamics
- Facilitates oxygen delivery to muscle during exercise
- Contributes to training-induced enlargement of left ventricle
What 3 factors lead to enhanced cardiac filling in diastole?
- Increased venous return (pre-load)
- Slower heart rate
- Increased compliance of left ventricle
Increased end-diastolic volume stretches myocardial fibers = more powerful ________ stroke when heart contracts.
ejection
_____ ______ law = relationship between muscle force and resting fibre length.
frank-starling
What are the 3 mechanisms that increase SV with training?
- Pre-load
- Enhanced cardiac filling in diastole filling
- Greater systolic emptying
_______ = stretch and recoil of arterial cells in superficial artery
pulse
______ = results from factors that oppose blood flow.
TPR
What is the formula for resistance?
(lengthxviscosity)/radius^4
Normally, length and blood ________ do not change substantially.
viscosity
What can change a lot that contributes to TPR?
Radius
BP = ?
Q x TPR
______ _____ ______ estimates the work of the heart.
systolic blood pressure
______ ______ ______ = force that blood exerts against the arterial walls during ventricular contraction or systole.
systolic blood pressure
________ ______ ____ = the relaxation phase of the cardiac cycle.
diastolic blood pressure
________ _______ _______ = indicates peripheral resistance and ease that blood flows from the arterioles into the capillaries.
diastolic blood pressure
______ = the resistance the heart has to pump against
resistance
_______ = primarily based on blood pressure in the major arteries
after load
The heart and blood vessels provide a _________ response to optimize tissue perfusion and maintain blood pressure.
coordinated
_______ = rate of heart rate.
chronotopic
_______ = the force of energy of muscular contraction
iontropic
Extrinsic regulation of the heart = _______ by sympathetic influence, _______ by parasympathetic influence.
increased; decreased
Brains higher ________ central command centre continually modulate medullary activity,
somatomotor
_____ _____ = provides greatest control over HR.
central command
The HR rapidly turns on during exercise by _______ parasympathetic inhibitory input and _______ stimulating input from the central command.
decreased; increased
CV centre receives reflex sensory input from peripheral receptors in what 3 areas?
- blood vessels
- joints
- muscles
What two things are located in muscles and its vasculature that monitor chemical and physical states, especially with exercise?
- chemoreceptors
2. mechanoreceptors
Peripheral input modifies either _____ or _______ outflow to bring about appropriate CV and respiratory response to various intensities of PA.
parasympathetic; sympathetic
Amount of Q received by an area depends on the ______ and ______ of arterioles supplying that area.
- number
2. caliber
What are 4 intrinsic regulation of arterioles?
- Directly impact arteriole smooth muscle
- Local metabolic changes
- Local physical changes
- Signalling via endothelial cells lining vessels
What are 2 extrinsic regulation of arterioles?
- Sympathetic and parasympathetic influences
2. Governed by central command
What is blood flow at rest (mL)? What is blood flow at exercise? (mL)
5000mL; 25,000mL
Regulation of capillary blood flow at exercise increases what two things?
- Increase blood flow to muscle
2. Increase interface for gas exchange between blood and muscle fibres
Venous return is very important to maintain ____ _____.
cardiac output
Why is there an increase in VR with exercise?
- Muscle pump
2. Change in diameter of veins due to constriction from vascular smooth muscle
During submaximal exercise, blood flow is _______ or _____.
unchanged; lower
There is a _____ increase in muscle blood flow during maximal exercise.
large
What is the large increase in muscle blood flow during maximal exercise due to?
- Increase in Q
- Redistribution of blood from non-active areas
- Increased capillarization within trained muscles
What are normal resting BP levels?
<120, <80
What are prehypertensive values?
120-139/80-89
What are stage 1 HTN values?
140-159/90-99
What are stage 2 HTN values?
> or equal to 160/> or equal to 100
As exercise starts, there should be a _____ increase in SBP and a _____ increase during a graded exercise test.
rapid; linear
Regular ______ training may reduce systolic and diastolic BP during rest and submaximal exercise.
aerobic
The largest reduction in blood pressure occurs in _____ pressure, particularly in ________ subjects.
diastolic; hypertensive
What are 4 reasons that BP ages higher with resistance type activity?
- Straining type activity increases BP dramatically
- Sustained muscular force compresses peripheral arterioles
- Increased resistance to blood flow
- Elevated work of the heart to pump against increased TPR
Valsalva maneuver generates compressive forces to increase _________ pressure.
Intrathoracic
The _______ ______ causes thin wall, low pressure thoracic veins to collapse.
thin wall
The valsalva maneuver causes (increased/reduced) venous return.
reduced
The valsalva maneuver ______ SV.
lowers
The decrease in SV due to the valsalva maneuver results in an ____ drop in BP.
acute
What is the main reason that blood pressure increases more for upper body exercises compared to lower body ?
Smaller vasculature offers greater resistance to blood flow
What are the 2 key mechanisms to increase supply of oxygen to working muscles?
- increase in blood flow
2. greater oxygen extraction
___-___ difference = oxygen extraction from the arterial blood as it circulates throughout the body.
a-vO2
What is the a-vO2 difference at rest?
5mL/dL
What is the a-vO2 difference at exercise?
~18mL/dL
What are 4 factors affecting a-vO2 difference?
- hemoconcetration with exercise
- diversion of Q to active tissue
- increase in skeletal muscle microcirculation
- increased number and size of mito
Increased levels of anaerobic substrates = increased what two things?
- higher ATP
2. higher PCr
What are 3 adaptations to short-term and immediate energy systems due to training?
- Increased levels of anaerobic substrates
- Increased quantity and activity of key enzymes
- Increased capacity to generate high levels of lactate
What 3 things leads to increased capacity to generate high levels of lactate?
- Increased enzymes (to buffer lactate)
- “pain” tolerance
- Clearance capacity
There is a potential for change in immediate and short-term energy systems with _______ exercise.
strenuous
What are 3 metabolic adaptations to long-term aerobic exercise?
- increased mitochondrial size and number
- Increased aerobic system enzymes
- Increased fat and CHO catabolism
What are two adaptations that happen to blood lactate concentration with long term aerobic exercise?
- decreased rate of lactate formation for given exercise intensity
- increased lactate clearance
What are 4 adaptations to the long-term energy system (aerobic) with exercise?
- Metabolic
- Blood lactate [ ]
- CV adaptations
- Pulmonary adaptations
Q is the product of what variables?
SV and HR
Endurance athletes are able to achieve higher Q through large increases in what variables?
SV
_______ _______ is the difference in O2 content of blood between arterial blood and mixed venous blood.
a-vO2 difference
What is the main reason that BP is higher in upper body exercise compared to lower?
upper body vasculature is smaller in diameter than the lower