1.2 - Cardiovascular and Respiratory Systems Flashcards
pulmonary circuit definition + role
circulation of blood through the pulmonary artery to the lungs and pulmonary vein back to the heart
- carries deoxy blood to lungs and oxy blood back to the heart
systemic circuit definition
circulation of blood through the aorta to the body and vena cava back to the heart
- carries oxy blood to the body and deoxy blood back to the heart
why does the left side of cardiac muscle have thicker muscular walls?
so it can contract with more force as it is sending oxygenated blood to the rest of the body
left side of the heart
- blood oxygenated at lungs and brought back to left atria through pulmonary vein
- oxygenated blood moves from left atria through the left AV valve into the left ventricle to be forced out into the aorta
- aorta carries oxygenated blood to muscles and organs
right side of the heart
- deoxygenated blood from the muscles and organs arrives back at the right atria through the vena cava
- it moves from the right atria, through the right AV valve into the right ventricle to be forced out into pulmonary artery
- pulmonary artery carries deoxy blood to lungs
myogenic definition
capacity of the heart to generate its own electrical impulse, which causes the cardiac muscle to contract
the conduction system definition
set of 5 structures which pass the electrical impulse through the cardiac muscle in a coordinated system
part 1 of conduction system
- SA node - located in right atrial wall, SA node generates the electrical impulse and fires it through the atria walls = they contract
part 2 of conduction system
AV node - collects the impulse and delays it for approximately 0.1 seconds to allow the atria to finish contracting
- then releases the impulse to the bundle of HIS
part 3 of conduction system
bundle of HIS - located in the septum, bundle of HIS splits the impulse in two, ready to be distributed through each separate ventricle
part 4 of conduction system
bundle branches - they carry the impulse to the base of each ventricle
part 5 of conduction system
purkinje fibres - these distribute the impulse through the ventricle walls, causing them to contract
Diastole process
- as atria and ventricles relax, they expand, drawing blood into the atria
- pressure in atria increases, opening the AV valves
- blood passively enters the ventricles
- SL valves are closed to prevent blood from leaving the heart
atrial Systole process
- atria contract, forcing remaining blood into ventricles
ventricular systole process
- ventricles contract, increasing the pressure closing the AV valves to prevent backflow into the atria
- SL valves are forced open as blood ejected from ventricles into aorta and pulmonary artery
heart rate
number of times heart BPM
220 - age
stroke volume
volume of blood ejected from heart per beat
average is 70ml
venous return
volume of blood returning to the heart
- higher venues return = more blood available in ventricles for ejecting
higher ventricular elasticity and contractility =
higher the force of contraction = higher stroke volume
cardiac output
volume of blood pumped out of the heart per minute
HR x SV
what is sub maximal exercise?
low to moderate intensity within a performers aerobic capacity or blow the anaerobic threshold
- heart rate likely plateaus after supply of oxygen delivery meets demand
what is maximal exercise?
high intensity above a performers aerobic capacity, which will take a performer to exhaustion
how does stroke volume change when we exercise?
increases in proportion until plateau
increases because of:
- increased venous return
- frank starling mechanism - increased vol of blood back to heart = increased end diastolic volume in ventricles = greater stretch = more force ventricular contraction = ejecting a larger volume of blood
why does stroke volume reach a plateau during sub - maximal intensity?
- increased heart rate towards max intensities doesn’t allow enough time for the ventricle to completely fill with blood in the diastolic phase = limited frank - starling mechanism
neural control
- chemoreceptors located in the muscles, aorta and carotid arteries inform the CCC of chemical changes in the blood stream, such as increased levels of CO2/ lactic acid
- proprioreceptors located in the muscles, tendons and joints inform the CCC of motor activity
- baroreceptors located in the blood vessel walls inform the CC of increased BP
intrinsic control
- temperature changes will affect the viscosity of the blood and speed of nerve impulse transmission
- venous return changes will affect the stretch in the ventricle walls, force of ventricular contraction and so SV changes
hormonal control
adrenaline and noradrenaline are released from the adrenal glands increasing the force of ventricular contraction and the spread of electrical activity through the heart increases
CCC actions either an
increase or decrease in stimulation of the SA node, which will raise or lower heart rate