CVS correction fc Flashcards
in atrial fibrolation, blood pools in the left atria. what feature of the left atria results in pooling of blood?
left auricle
how would you best describe the folding thatbrings the primitive heart tube into the thoracic region of the embryo?
Cephalo-caudal folding
which membrane channels of cardiac monocytes are inactivated in hyperkalaemia?
voltage-gated Na+ channels
which receptors allow for the release of calcium from inside the sarcoplasmic reticulum?
Ryanodine Receptors
where on the chest wall would you palpate for the apex beat?
Left fifth intercostal space, midclavicular line
why does a sudden build up of blood or fluid in the pericardial sac prevent the heart properly filling in diastole?
the outer layer of fibrous pericardium cannot expand causing the fluid to compress the heart
what structures does the transverse pericardial sinus separate?
The aorta and pulmonary trunk from the venous inflow to the heart
Where does the coronary artery which gives rise to the anterior interventricular and circumflex arteries arise from?
left aortic sinus
what causes the valves between the atria and ventricles to close?
small backflow of blood as the ventricles contract
Ventricles contract, increasing pressure of blood. This pushes the AV-valves closed. Papillary muscles contract at start of ventricular systole, tensioning the tendinous cords and preventing valve cusps from prolapsing into atria.
which congenital heart defect has a continuous murmur?
patent ductus arteriosus
In which week of development does the embryo fold?
4th
what is meant by the term pre-load?
The amount the ventricles are stretched in diastole
what channel type is responsible for the upstroke of the action potential in pacemaker cells?
L-type calcium channels
what is the typical resting membrane potential in ventricular myocytes?
-85mV
how is electrical activity in the heart initiated?
spontaneous depolarisation
The heart spontaneously activates; cells in the conductance system depolarise and fire action potentials, with the cells of the SA node depolarising quickest and setting the heart rate.
what causes discolouration of skin in varicose veins?
Macrophages oxidise iron from red blood cells that have leaked from the blood vessels. This oxidation causes the iron to rust under the skin which stains it
what is the cardiothoracic ratio?
ratio between the maximum cardiac diameter (horizontal width of the heart at the widest point) and the maximum thoracic diameter (horizontal width of the chest at the widest point) on a chest X-ray
(≤50% in healthy patient)
what type of drug is Amiodarone?
potassium channel blocker
what type of drugs are Verapamil and Diltiazem?
calcium channel blockers
what drug is an example of an ACE inhibitor?
Ramipril
all ACE inhibitors end in -pril
what drug reduces blood pressure by reducing circulating volume + reducing peripheral vasoconstriction?
angiotensin II receptor blocker - blocks the effects of AngII at peripheral vessels and will reduce aldosterone production thus reducing Na+ and water retention at kidney
how to calculate rate from an ECG?
300/time between R-R intervals
Why does pericarditis present with shoulder pain?
- Somatic afferent nerves
- Pericardium innervated by phrenic nerve which enters spine at level C3-C5
- Feel pain in dermatome associated with these areas
what drug can be given to relieve pain of stable angina?
GTN spray - vasodilator - relieves pain
what are some precipitants of angina?
- cold weather
- eating
- exercise
- stress
- emotions
what part of the history can differentiate between pericarditis and STEMI?
pericarditis - sharp pain
STEMI - dull pain