Body Fluids and Circulation
Blood vessels 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.
Pulmonary circulation – consists of closed loop of vessels carrying blood between the heart and lungs.
Systemic circulation – is a circuit of vessels carrying blood between the heart and other parts of body systems.
Cardio pulmonary resuscitation (CPR) – Serves as a life saving measure until appropriate therapy can restore the heart to normal function.
Aorta – A single large artery carrying blood away from the left ventricle.
Bicuspid valve – also called mitral valve. Left Auricular ventricular valve with two flaps that is present between the left auricle and left ventricle.
Tricuspid valve – right auricular valve with three flaps that is present between the right auricle and right ventricle.
Chordate tendineae – 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.
Papillary muscles – 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
Atrioventricular node (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
Purkinje fibres – 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 = EDV-ESV
Isovolumetric 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.
Lub sound – is associated with the closure of the AV valves.
Dub sound – is associated with the closure of the semilunar valves.
Chordae tendinae – tendon like cords which are connected to the tip of the cuspid valves
Diastole – Relaxation of heart chambers
Endocardium – Inner cardiac muscle
Epicardium – outer cardiac muscle
Inter ventricular septum – Partition between right and left ventricle
Interatrial septum – Partition between right and left atria
Left atrioventricular valve – Bicuspid valve or Mitral valve