Cardiovascular Flashcards
what is meant by the term myogenic?
signals itself
what is meant by the term audtorhythmicity?
generates its own rhythm
where are pacemaker cells located and why are they different from other cells?
in the right atrium
they spontaneously generate action potentials
how does the heart beat? (initiation and conduction)
- pacemaker cells depolarise.
- bundles take this depolarisation message from the SA node to the AV node.
- AV node created delay between atrial and ventricle contraction.
- AV node transmits signal to bundle of HIS
signal travels down left and right bundle (left bundle splits into left posterior fascicle and left anterior fascicle) - right and left bundles split into purkinji fibres at the ape of the heart - they signal the muscles.
what is the purpose of bachmann’s bundle?
way for depolarisation to move from the right atrium to the left quickly.
why can someone not move during an ECG?
skeletal muscles cause electrical activity.
what does the P wave represent in an ECG?
atrial depolarisation
what does the QRS complex represent in an ECG?
ventricle depolarisation
what does the T wave represent in an ECG?
ventricle repolarisation
what does the PQ interval represent in an ECG?
AV node conduction
what does the QT interval represent in an ECG?
systolic
what does the TQ interval represent in an ECG?
diastole
what does the R-R interval represent?
heartbeat
why isn’t atrial depolarisation shown on an ECG?
because it happens at the same time as the QRS complex.
what does the 1st noise on the heart beat from?
- tricuspid and mitral valves closing. start of systole
what does the 2nd noise on the heart beat from?
- pulmonary and aortic semilunar valves closing.
what are the 2 figures representing in blood pressure?
systolic blood pressure / diastolic blood pressure.
what causes arrhythmia?
abnormal SA firing causing fast or slow HR
what is meant by third degree block arrhythmia?
atrium and ventricles are contracting normally but at random.
what is meant by the term ventricular fibrillation?
heart beats are no longer synchronised and so the blood cannot be pumped efficiently can be deadly.
what is meant by the term atrial fibrillation?
weakness to heat beats but not deadly as ventricles still contract sufficiently,
what part of the ECG represents the 1st sounds in the heart beat?
QRS complex
what part of the ECG represents the 2nd sounds in the heart beat?
end of the T wave.
what is meant by the term venous return?
blood returning to the heart - passes through the AV valves under its own pressure.
what is meant by the term isovolumetric contraction?
ventricles relax, not enough pressure to allow AV valves to open and not enough pressure to maintain semilunar open.
Therefor all valves are shut snd no change in blood volume in ventricles.
what is meant by the term ventricular filling?
blood enters ventricles from atria
how do you work out pulse pressure?
systolic pressure - disatolic pressure.
what could a high pulse pressure indicate?
hardening of the arteries
how do you work out mean arterial pressure?
diastolic pressure + (pulse pressure /3)
what is end diastolic volume?
volume of blood in the ventricles at the end of diastole.
what is end systole volume?
volume of blood in the ventricles at the end of systole
what is meant by the term stroke volume?
volume of blood pumped out of the heart.
how do you work out stroke volume?
end diastole volume - end systole volume
what is meant by the term ejection fraction?
ratio of volume ejected in one beat to volume immediately prior to ejection.
how do you work out ejection fraction?
stroke volume / end diastole volume.
what causes coronary artery disease?
build up of plaques in coronary arteries.
reducing blood flow to the heart and causing strain to the heart.
what things could cause coronary artery disease?
endothelial dysfunction
fatty streaks
complicated lesions
what are the treatments available for coronary artery disease?
Percutaneous Transluminal Coronary Angleoplasty (PTCA)
Coronary Artery Bypass Graft (GABG)
what is a Percutaneous Transluminal Coronary Angleoplasty (PTCA)?
ballon used to stretch blood vessel with plaque in it squashing the plaque and making the vessel open again.
Stent can also be placed after to ensure the vessel doesn’t close again.
what is a Coronary Artery Bypass Graft (GABG)?
unblocked vein is taken from another area in the body and placed where the blocked vein is through open chest surgery.
but it does involve stopping the heart.
what happens if you have cyanotic congenital heart disease?
blood to systemic circulation have reduced level of O2 - darker blood colour (blueish)
what happens if you have septal defect congenital heart disease?
blood is able to flow from right to left in the heart.
what happens if you have ventricular septal defect?
incomplete development of the the septum - oxygenated and deoxygenated blood can mix.
what happens if you have coarctation of the aorta?
narrowing of the aorta, so reduced flow meaning that the left ventricle has to pump harder and you have a highter blood pressure.
what happens if you have patent ductus arteriosus?
the ductus arteriosus allows O2 exchange in utero - if blood vessel between pulmonary trunk and aorta remain open, blood destined for aorta flows to lower pressure pulmonary trunk, increasing trunk blood pressure and overworking the ventricles.
what happens if you have Tetralogy of Fallot?
- ventral septal defect
- stenose pulmonary valve
- enlarger right ventricle.
meaning little blood reaches pulmonary circulation so cyanosis occurs - Blue Baby.