Cardiovascular and Respiratory Systems Flashcards
what is the definition of heart rate
the number of beats per minute (HR)
what is the average heart rate
72bpm
how do you calculate a persons maximum heart rate
220-age
what is bradycardia
a resting heart lower than 60bpm
what is the definition of stroke volume
the volume of blood ejected from the left ventricle per heart beat
what is the average stroke volume at rest
70ml
what is the definition of cardiac output
the volume of blood pumped from the left ventricle in 1 minute
how do you calculate cardiac output
cardiac output (Q)= stroke volume (SV) X heart rate (HR)
what is systole
the contraction of cardiac muscle that pumps blood out of the heart
what is diastole
the relaxation of cardiac muscle that allows blood to fill the heart
describe the cardiac cycle
atrial systole, ventricular systole, atrial diastole, ventricular diastole
describe the cardiac conductions system
- the sinoatrial node sends an electrical impulse across the atria
- this causes atrial systole
- impulse then travels the the AV node which sends the impulse to the bundle of His.
- impulses are then sent down the purkinje fibres
- a new impulse causes ventricular systole
describe the shape of a graph showing the relationship between heart rate and rest, exercise and recovery at submaximal exercise
- there is an anticipatory rise due to the release of adrenalin
- and a sharp rise as exercise starts due to anaerobic work
- there is a plateau as the oxygen supply meets the demand
- and then a sharp, rapid decline when exercise stops
- the recovery slows as the body returns to pre-exercise state
describe the shape of a graph showing the relationship between heart rate and rest, exercise and recovery during maximal exercise
- there is an anticipatory rise due to the release of adrenalin
- and then a sharp ride due to anaerobic work at the start of exercise
- heart rate continues to rise due to the maximal workloads stressing the anaerobic system
- then there is a rapid decline as energy stops
- and a much slower recovery to return to the pre-exercise state
how does stroke volume respond to exercise
stroke volume will increase linearly as intensity increases but only up to 40-60% of max speed and intensity.
how does exercise effect cardiac output
Q increases linearly with exercise and plateaus during maximal exercise
what is the job of the sympathetic nervous system
to stimulate the heart to beat faster
what is the job of the parasympathetic nervous system
to decrease heart rate
describe how the sympathetic nervous system control heart rate during exercise
- chemoreceptors detect an increase in CO2 levels, proprioceptors detect an increase in movement and baroreceptors detect an increase in blood pressure
- this information gets sent to the cardiac control centre
- this increases the impulse to the sympathetic nervous system
- which increases the firing of the SA node via the sympathetic accelerator nerve to increase heart rate
describe how the parasympathetic nervous system controls heart rate during recovery
- chemoreceptors detect a decrease in CO2, proprioceptors detect a decrease in movement and baroreceptors detect a decrease in blood pressure
- this information is sent to the cardiac control centre
- where the impulses sent to the parasympathetic nervous system are increased
- this decreases the firing of the SA node via the parasympathetic vagus nerve to decrease heart rate
how does hormonal control during exercise effect heart rate
HR increases due to the release of adrenalin via the sympathetic accelerator nerve known as anticipatory rise
how does hormonal control during recovery effect heart rate
when the parasympathetic vagus nerve is stimulated it causes the inhibition of adrenalin to decrease heart rate
what are arterioles
blood vessels carrying oxygenated blood from the arteries to the capillary beds which can vasodilate and vasoconstrict to regulate blood flow
what are pre-capillary sphincters
rings of smooth muscle at the junction between arterioles and capillaries which can dilate and constrict to control blood flow through the capillary bed
what is the vascular shunt mechanism
the redistribution of cardiac output
at rest what is the distribution of blood
80-85% of cardiac output is sent to internal organs
15-20% of cardiac output is sent to the muscles
during exercise how is cardiac output distributed
85% of Q to muscles
15% of Q to internal organs
describe the vascular shunt mechanisms during exercise
- chemoreceptors detect an increase in CO2 and baroreceptors detect an increased stretch of vessel walls
- this information is sent to the vasomotor control centre
- this results in the sympathetic stimulating decreasing meaning there is vasodilation of arterioles and pre-capillary sphincters dilate
- this increases blood flow to the muscle cells
- the sympathetic stimulation is increased to vasoconstrict arterioles and the pre-capillary sphincters
- this decreases blood flow to the non-essential organs.
describe the vascular shunt mechanisms during recovery
- chemoreceptors detect an decrease in CO2 and baroreceptors detect an decreased stretch of vessel walls
- this information is sent to the vasomotor control centre
- this results in the sympathetic stimulating decreasing meaning there is vasodilation of arterioles and pre-capillary sphincters dilate
- this increases blood flow to the non-essential organs
- the sympathetic stimulation is increased to vasoconstrict arterioles and the pre-capillary sphincters
- this decreases blood flow to the muscle cells
what is the definition of venous return
the volume of blood returning to the heart via the veins
what is starlings law
increase venous return leads to increased stroke volume due to an increased stretch of the ventricle walls and therefore force of contraction
how does starlings law happen
increased venous return leads to greater diastolic filling of the heart and a increased stretch of the cardiac muscle and increases the force of contractions which increases the ejection fraction
what is blood pooling
accumulation of blood in veins due to gravitational pull and lack of venous return
what is active recovery
low intensity activity post- exercise to maintain an elevated heart and breathing rates
what are the 5 venous return mechanisms
pocket valves, muscle pump, respiratory pump, smooth muscle of the veins, gravity
what are pocket valves
one way valves in veins that prevent the backflow of blood
what is skeletal muscle pump
veins between skeletal muscle, which when contracting push blood back towards the heart
what is respiratory pump
during exercise, breathing is deeper, increasing the pressure in the thoracic cavity, squeezing the large veins in that area, forcing blood back to the heart
what is smooth muscle of the vains
venoconstriction and venodilation of the smooth muscle in the middle layer of the vein pushes blood back towards the heart
what does gravity do
blood from the upper body is aided by gravity, so flows back to the heart quicker
what is tidal volume
the volume of air breathed in or out per breath
what is minute ventilation
the volume of air breathed in or out per minute
how do you calculate minute ventilation
minute ventilation= breathing frequency X tidal volume
what is the resting value of breathing frequency
12-15 bpm
what is the resting value for tidal volume
500ml `
what is the resting value for minute ventillation
6-7.5 l/min
what is inspiration
when the pressure in the lungs is lower than the atmosphere
what is oxygen
an essential gas required for aerobic energy production in muscles
what is carbon dioxide
the waste product if aerobic energy production
what is expiration
pressure in the lungs is higher than in the atmosphere
describe the mechanisms for breathing for inspiration at rest
- the external intercostals contract and the diaphragm flattens
- to cause the ribs and sternum to move up and out
- which increase the the volume of the thoracic cavity
- this causes the lung air pressure to decrease
- this causes inspiration
describe the effect of different intensities of exercise of breathing frequency
the higher the intensity the more breaths you take until the max of 50-60 bpm
submaximal exercise is steady state where the supply of oxygen meets the demand
describe the effect of different intensities of exercise on tidal volume
TV linearly increases as intensity increases at submax up to 3 litres where it reaches a plateau
describe the graph showing the relationship between minute ventilation and rest, exercise and recovery during submax
- the starting Ve is approx 10 L/min
- anticipatory rise due to the release of adrenaline
- rapid rise to 60-120 L/min
- plateau at 60-120 L/min
- rapid decrease at the end of exercise
slower decrease during recovery to return to resting Ve
describe the graph showing the relationship between minute ventilation and rest, exercise and recovery during maximal exercise
- starting Ve approx 10l/min
- anticipatory rise due to release of adrenaline
- rapid rise to 80-140l/min
- there is a continued rise towards maximal values due to continued stimulation of chemoreceptors from the lactic acid 120-180l/min
- rapid decrease at the end of exercise
- much slower decrease towards resting Ve value. Elevated level of respiration to recover and remove waste products
describe the mechanics of breathing for inspiration during exercise
- the external intercostals contract and the diaphragm flattens as well as the sternocleiodomastoid and pectoralis major contract
- causing the ribs and sternum to move up and out further
- which further increases the thoracic cavity volume
- which means the lung pressure decreases further
describe the mechanics of breathing for expiration during exercise
- the external intercostals relax and the diaphragm recoils and the abdoinals and internal intercostals contract
- meaning the ribs and sternum moves down and in further
- decreasing the volume of the thoracic cavity further
- increasing the pressure of the lungs further
what is the job of the respiratory control centre
to receive information from the sensory nerve and send impulses to the IC or EC
what is the IC
the inspiratory centre stimulated the inspiratory muscles to contract and rest during exercise
what is the EC
the expiratory centre is inactive at rest but will stimulate additional respiratory muscles to contract during exercise
describe neural control of breathing during exercise of different intensities
- thermorecpetors detect an increase in temperature,
- proprioceptors detect an increase in movement,
- baroreceptors prevent over inflation of the lungs during exercise by sending impulses to the expiratory centre
describe chemical control of breathing during exercise of different intensities
- chemoreceptors located in the aorta and ceratoid arteries detect an increase in blood CO2 and acidity
what is the definition of diffusion
the movement of gas molecules from an area of high concentration or PP to an area of lower concentration pf PP
what is the definition of a diffusion gradient
when the is a difference in partial pressure
what is the definition of partial pressure
the pressure a gas exerts in a mixture of other gases.
what is millimetres of mercury(mmHg)
a unit for measuring atmospheric pressure
what gasses exchange during external respiration and where
exchange of 02 and CO2 between blood and lungs
describe the exchange of gasses and where during internal respiration
exchange of O2 and CO2 between the blood and muslces
during external respiration which direction does does oxygen diffuse at rest
highPP02 in alveolar air —> lowPP02 in capillary blood
during external inspiration which way does oxygen diffuse during exercise
high PPO2 in the alveolar air ——> lower PPO2 in capillary blood
