cardio vascular system Flashcards
what are the 4 parts of the heart?
right atrium
left atrium
right ventricle
left ventricle
what are the 4 types of vessels?
superior vena cava – deoxygenated blood to RA
pulmonary artery – deoxygenated blood from RV to lungs
pulmonary vein – oxygenated blood from lungs to LA
aorta – oxygenated blood from LA to rest of body
what does myogenic mean?
the heart is myogenic as it creates its own impulse.
what are the 2 phases of the cardiac cycle?
systole – contraction; lasts 0.3 seconds
diastole –relaxation; lasts 0.5 seconds
what is Diastole?
atria fill with blood, AV closes - atrial blood pressure increases above the ventricular. blood pressure forces the AV valves open + blood passively enters into both ventricles
what is systole?
atria contract forcing remaining blood to ventricles - semi lunar valve closes - both ventricles contract increase ventricular pressure. Aortic + pulmonary valves are forced open, AV valves closes. blood forced out of aorta to body tissues.
what is oxygenated blood?
blood that is saturated with oxygen and nutrients (eg/glucose)
what is deoxygenated blood?
blood depleted of oxygen but saturated with carbon dioxide and waste products.
what are the stages of the conduction system?
1) sino-atrial node generates electrical impulse and fires it through atrial walls, making them contract.
2) atrioventricular node, collects impulse + delays it for 0.1 seconds to allow atria to finish contracting, then releases impulse to the bundle of his.
3) bundle of his; carry impulse to base of each ventricle
4) purkyne fibres; distribute impulse through ventricle walls, causing them to contract.
what does heart rate mean?
the number of times the heart beats per minute
what does stroke volume mean?
the volume of blood ejected from the left ventricle per beat.
what does cardiac output mean?
the volume of blood ejected from the left ventricle per minute
HR x SV = Q
what is bradycardia?
a resting heart rate below 60 bpm.
what is venous return?
the return of the blood to the right atria through the veins.
what are the 2 types of intensity?
submaximal – aerobic
maximal – anaerobic
what is the cardiac response to exercise?
oxygen demand will increase when exercise starts
what is the heart rate response to exercise?
heart rate will increase in proportion to exercise until we reach our max.
what happens to stroke volume as intensity of exercise increase?
it increase linearly with intensity.
what is the hearts ability to ‘fill’ dependant on?
venous return and the ventricles ability to stretch
what is the hearts ability to ‘empty’ dependant on?
greater end diastolic volume and greater stretch will increase the force of ventricular systole.
why does heart rate continue to rise during maximal exercise?
there will be a growing demand for oxygen and removal of carbon dioxide.
what is the Frank Starlin mechanism?
increased venous return will lead to an increase in stroke volume due to an increase in stretching of ventricle walls and therefore force of contraction will also increase.
what is the cardiac control centre?
controlled by the nervous system (involuntary) - consists of sensory and motor nerves from either sympathetic + parasympathetic nervous system.
what does the cardiac control centre control?
it initiates sympathetic or parasympathetic to stimulate the SA node.
what does the sympathetic nervous system do?
nerves increase the heart rate
what does the parasympathetic nervous system do?
nerves decrease the heart rate back to normal.
what affects the cardiac control centre?
neural control, hormonal control intrinsic control
what stimulates the neural control?
proprioceptors - inform ccc activity has increased
chemoreceptors - inform ccc lactic acid+co2 has increased
baroreceptors - inform ccc blood pressure has increased
what does the hormonal control do?
releases adrenaline from adrenal glands that stimulates the SA node.
what affects intrinsic control during exercise?
increase temperature, which increases speed of nerve impulses and increases heart rate.
venous return increases which increase EDV + SV
what affects intrinsic control after exercise?
temperature decreases and heart rate drops.
venous return decreases which decreases SV
what does the circulatory network consist of?
pulmonary circulation and systemic circulation.
where does the pulmonary circulation take blood?
de-oxygenated blood from the right ventricle to the the lungs and oxygenated blood back to left atrium.
where does the systemic circulation take blood?
oxygenated blood from the left ventricle to muscles + deoxygenated blood to the right atrium.
