and mitral valves open and close simultaneously - the
pulmonic and aortic valves close and open
Systole (contraction) = When the Tricuspid Valve and the
Mitral Valve are closed, and the Pulmonic Valve and Aortic
Valve are open (systolic pressure).
Diastole (relaxation) = When the Tricuspid Valve and the
Mitral Valve are open, and the Pulmonic Valve and Aortic
Valve are closed (diastolic pressure).
fraction represents the ability of the left ventricle to
pump blood. An ejection fraction of >55% is considered
normal. If the right ventricle fails, blood pools in
systemic circulation, leading to fluid buildup in parts of
body most affected by gravity, usually feet and lower legs.
A weak left ventricle can result in systolic failure. For
more information on BP, visit my Blood
page. I was not able to find a simplified heart and blood
circulation drawing on the web, so I made this
activity of the heart is regulated by the Sinus node, the AV
Node, the bundle of His, the right and left bundle branches,
and finally the Purkinje Fibers, in that order. Then the
heart muscle contracts, producing the systolic BP. When the
heart is relaxed, the diastolic pressure is
- Vagus Nerve
Parasympathetic stimulation - decreases heart rate, which
reduces blood pressure
The right Vagus nerve is said to operate on the SN, and the
left Vagus nerve upon the AV Node.
Motor = efferent (slows down the heart)
Sympathetic Stimulation - increases heart rate -
vasoconstriction, which increases blood pressure
Sensory = afferent (speeds up the heart)
for heart muscle relaxation (diastole)
Mg (magnesium) and Ca (calcium) for heart muscle