Fluids and Circulation
serve as a passage way through which the blood is directed and distributed from
the heart to all parts of the body and subsequently returned to the heart.
– consists of closed loop of vessels carrying blood between the heart and
– is a circuit of vessels carrying blood between the heart and other parts of
resuscitation (CPR) – Serves as a life saving measure until
appropriate therapy can restore the heart to normal function.
– A single large artery carrying blood away from the left ventricle.
– also called mitral valve. Left Auricular ventricular valve with two flaps
that is present between the left auricle and left ventricle.
– right auricular valve with three flaps that is present between the right
auricle and right ventricle.
– these are chords that extend from the edge of each flap and attach to the
papillary muscles that prevent the AV valves from being forced to open due to
high ventricular pressure.
– small nipple shaped muscles protrude from the inner surface of the
ventricular walls. Papilla means ‘nipple’.
Sinoatrial node (SA
node), – a small, specialised region in the right atrial
wall near the opening of the superior vena cava
(AV node), – a small bundle of specialized cardiac muscle
cells locted at the base of the right atrium near the septum, just above the
junction of the atria and ventricles.
Bundle of His
– (atrioventicular bundle), a tract of specialized cells that originates at the
AV node and enters the interventricular septum
– small terminal fibres that extend from the bundle of His and spread
throughout the ventricular myocardium
Stroke volume (SV)
– The amount of blood pumped out of each ventricle with each contraction, SV =
ventricular contraction – Isovolumetric means constant
volume and length. During ventricular contraction, when all valves are closed,
no blood can enter or leave the ventricle during this time. Because no blood
leaves or enters the ventricles the ventricular chamber has a constant volume
and the muscle fibres stay at a constant length.
End systolic volume
(ESV) – The ventricles do not empty completely during
ejection, only half of the blood within the ventricle at the end of diastole is
pumped out during subsequent systole. The amount of blood left in the ventricle
at the end of systole when ejection is complete is called ESV.
End diastolic volume
(EDV) – The volume of blood in the ventricle at the end
of diastole is known as the end diastolic volume.
– is associated with the closure of the AV valves.
– is associated with the closure of the semilunar valves.
– tendon like cords which are connected to the tip of the cuspid valves
– Relaxation of heart chambers
– Inner cardiac muscle
– outer cardiac muscle
septum – Partition between right and left ventricle
– Partition between right and left atria
valve – Bicuspid valve or Mitral valve