CVS Formative Flashcards
What does the right atrium posses?
An Opening for the coronary sinus
During embryological development what gives rise to the common carotid arteries?
3 aortic arch
Whats is the fate of the fourth arch?
Right-Right subclavian
Left- Arch of aorta
The arterioles function as resistance vessels because?
They have a relatively narrow lumen and strong muscular wall
In the heart the fast depolarising phase of the cardiac action potential is caused by?
INflux of Na+ ions
What is the resting membrane potential due to in cardiac cells?
Leaky K+ Channels
In the ECG depolarisation of the atria corresponds to the?
P-wave
What is the U wave?
Occurs after T wave and is caused by the last part of ventricular repolarising (septum or pap muscles)
A heart rate in excess of 150 bpm is likely to:
Decrease preload and therefore decrease stroke volume
Activation of Beta 1 receptors on cardiac myocytes will:
Increase contractility and therefore increase stroke volume
What is afterload dependent on?
TPR primarily controlled of noradrenaline on alpha 1 -adrenorecpetors
What is the most significant feature of the pulmonary circulation?
Pulmonary arteries constrict in hypoxic conditions
During exercise venous pressure (and hence venous return to the heart) may be increased by?
- Increases in systemic filling pressure
- Contraction of smooth muscle surrounding the veins
- Increased rate and depth of respiration
- Rhytmic contraction of skeletal muscle
What can the valsalva manoeurve help?
Supraventricular tachycardia
Why does the valsalva manoeuvre cure supraventricular tachycardia?
Increases vagal tone and the effect at AV.
