The cardiac cycle Flashcards
what kind of pump is the heart?
double
What are the 2 top chambers of the heart called?
Atrium
What are the 2 bottom chambers of the heart called?
Ventricles
what is the muscular wall that separates the sides?
septum
Atria and Ventricles divided by which valve?
Atrioventricular
What is the valve on the right called?
Tricuspid valve
what is the valve on the left called?
Bicuspid
which side of the heart is bigger and why?
Left, to transport oxygenated blood around the body
How long does the systole phrase last?
0.3 seconds
How long does the diastole phrase last?
0.5 seconds
What order does the conduction system go?
myogenic sinoatrial node (SA) arioventrioular (AV) Bundle of HIS Purtinye Fibers
what does the myogenic do?
creates its own impulses
what does the sinoatrial node do?
Pace maker
Initiates heart beat
contracts Artrium
What does the Arioventricular node do?
Delays the impulse
Sends impulse to appex of the heart via bundle of HIS
what do the bindle of HIS do?
sends impulses to appex of the heart
What do the purtinye fibres do?
Sends impulses cross ventricles
what are the three controls of heart rate?
Neural
Hormonal
Intinsic
What are the four recpeptors which tell the brain that exercise is taking place?
Proprio receptors
Bara receptors
thermo receptors
Chemo recpeptors
what are the hormonal factors which control heart rate?
Adrenaline
Noradrenaline
Acetlychloline
What are the Intrinsic factors which control heart rate?
Stretch recpeptors
comes from inside
what are the two types of nerves which control heart rate?
parasympathetic nerve (slows heart rate) sympathetic( increases heart rate)
How does the neural control of the heart work?
The 4 recpeptors tell the brain something has changed, temprature for example
Which then tells the cardiac control centre, which decides which nerve to activate
Then via the sympathetic nerve tells the heart rate to increase or via parasympathetic tells the heart rate to decrease.
then send this to the SA node.
What does venous return mean?
Ways to get back to the heart via VEINS
What are the 5 mechanisms which aid venous return?
muscular pump the respiratory pump pocket valves smooth muscles Gravity
How does the muscular pump aid venous return?
the contraction and relaxation of the muscles during exercise creates a massaging effect, which sqeezes flood towards the heart.
How does the respiratory pump aid venous return?
Increases breathing rate, changes pressure in abdomen and thorax, this increases pressure in abdomen, compressing veins further and forces blood into veins towards the heart.
How does the pocket valve aid venous return?
present in veins and snap shot ensure no back flow and blood flows in one direction.
How does the smooth muscle aid venous return?
Located in walls of veins (thin) works with muscles to squeeze blood back towards the heart.
How does gravity aid venous return?
assists the flow of blood from upper extremities (head) into superior vena carva and into the right atruim.
what is the systole phase ?
contraction phrase (atrial and ventricular)
what is the diastole phase?
relaxation phase
What happens in the diastole phase?
Atria fill with blood pressure rises atrioventricular valves open blood passes by gravity into ventricles semi lunar valves closed
What happens in the systole phase?
ATRIAL SYSTOLE atria contract forces remaining blood into ventricles ventricles remain relaxed VENTRICULAR SYSTOLE ventricles contract at same time blood pressure increases AV valves forced shut (prevent back flow) semi-lunar valves forced open blood pushed into aorta and pulmonary artery
What is stroke volume?
The volume of blood pumped out of the heart per beat
What two factors make cardiac functioning more efficient?
Stroke volume
heart rate
What is stroke volume determined by?
venous return
elasticity of cardiac fibers
The contractability of cardiac tissues
How does venous return effect stroke volume?
The more blood that goes in, the more comes out as there is more blood available to be pumped out.
How does elasticity of cardiac fibres effect stroke volume?
the greater the stretch the stronger the contraction, which increases stroke volume i.e. sterlings law
How does the contractability of cardiac tissue effect stroke volume?
increased contractability leads to greater force of contraction , which increases stroke volume. Ejection fraction also contributes to this.
What does ejection fraction mean?
The actual % of blood pumped out the left ventricles per contraction
How to work out ejection fraction?
stroke volume / end diastolic volume
What is the matter between cardiac cells?
intercalating discs
How much can ejection fraction increase to during exercise?
85%
What is heart rate?
The number of times the left ventricle ejects blood into the aorta per minute
What is bradycardia?
The reduction of resting heart rate below 60bmp.
Who is expected to have bradycardia?
athletes
What 2 factors effect heart rate?
bradycardia
cardiac output
what is cardiac output defined as?
the volume of blood ejected form the heart per minute
What is the equation to work this out?
stroke volume x heart rate
What does a steady state mean?
O2 demands meets O2 supply = comfy
what makes the heart rate increase prior to exercise?
anticipatory rise
Which hormone causes an anticipatory rise?
Adrenaline
what does then the release of adrenaline trigger?
The SA node to increase heart rate
Why does the heart take a while to return to resting heart rate ?
THE BODY’S RECOVERY PERIOD
what happens during the body’s recovery period?
the heart rate must remain slightly elevated in order to remove waste products
What increase in direct proportion to exercise intensity?
heart rate
stroke volume
which factor stops at a certain point and plateaus ?
stroke volume only is directly proportional until 40-60% max effort then plateaus
What factors effect stroke volumes response to exercise?
increase venous return
muscle pump
starlings law
cardiac outputs efficiency
Why does the heart take a while to return to resting heart rate ?
THE BODY’S RECOVERY PERIOD
what happens during the body’s recovery period?
the heart rate must remain slightly elevated in order to remove waste products
What increase in direct proportion to exercise intensity?
heart rate
stroke volume
which factor stops at a certain point and plateaus ?
stroke volume only is directly proportional until 40-60% max effort then plateaus
What factors effect stroke volumes response to exercise?
increase venous return
muscle pump
starlings law
cardiac outputs efficiency
what is the definition of blood pressure?
the force exerted by the blood on the inside of the blood vessels
How does sterling’s law increase stroke volumes?
The increased venous return causes more blood to enter ventricles causing them stretch more and contract more forcefully.Ejecting more blood per beat
what does cardiac output determine?
endurance capacity
What is cardiovascular drift?
when during training heart rate shifts upwards over time, as due to sweating removing water from the blood makes it more difficult to pump around the body, so the heart has to work harder therefore increasing heart rate.
What are the two main factors of blood pressure?
blood flow and peripheral resistance
What is a healthy value of blood pressure?
120mmHG/ 80mmHG
what happens to blood pressure during aerobic activity?
causes systolic pressure to increase to the equivalent of the intensity of the exercise
What happens to blood pressure during anaerobic activity?
both pressures rise, due to performer holding their breath and increasing pressure in thorax and abdomen, which squeezes on blood vessels, increasing overall pressure.
What are the two main factors of blood pressure?
blood flow and peripheral resistance
What is peripheral resistance?
resistance offered to the flow of blood due to friction
