Cardiovascular System

Heart Anatomy

The diagram above is a simple illustration of the heart anatomy. The image is essential in learning the basic of the heart as opposed to others that have intricate details of the parts such as the marginal arteries and small cardiac veins. The image illustrates the four parts of the chambers of the heart which are left atrium, left ventricle, right ventricle and right atrium. The diagram also displays the major arteries and veins of the heart which are pulmonary artery, superior vena cava, pulmonary vein and aorta. The diagram clearly indicates that the left chambers have thicker walls than the ones on the right. The colors of the veins and arteries indicate the type of oxygen transported by each.

The electrical conduction system 

The diagram above indicates the critical elements in the heart’s electrical conduction system. The heart’s electrical activity is responsible for the expansion and contraction of the heart muscles. The electrical activity starts at the SA node (sinoatrial node) which is responsible for initiating the electrical pulses. The SA node is the peacemaker and beats at 60-100 bpm. The electrical pulses go down through the intermodal pathways to the AV node (atrioventricular node). It is the gatekeeper as it beats at a slower rate of 40 – 60 bpm to cause a delay that would allow atrium empty into the ventricles. The electrical activity then moves to the Purkinje fibers that causes impulse to all parts of the ventricles which causes contraction. The diagram is resourceful as it indicates the three main parts of the heart electrical conduction system and the path they follow. 

Blood Flow Through the Heart

The diagram above is a simple illustration of how blood flows through the heart. The diagram illustrates how blood flows between the four chambers of the heart. The red arrows indicate oxygenated blood while the blue arrows indicate the deoxygenated blood. The blood is oxygenated in the lungs, after which it passes through the left atrium, then to the left ventricle and finally to the body where it is deoxygenated. After deoxygenation in the body, the blood moves to the right atrium, then to the right ventricle before moving to the lungs for oxygenation. 

Blood flow through the body

The diagram above illustrates how blood flows through the human body. It indicates the critical parts of the human body such as the head, upper abdomen, lower abdomen and the limbs. There are two routes used by blood in travelling throughout the body: through the lungs where there is oxygenation and through the rest of the body. Using the diagram, it is easy to understand the areas where oxygenated blood (in red) and deoxygenated blood (in blue) passes. More so, there are areas where there is a mix of oxygenated and deoxygenated blood such as the intestines, liver, spleen and stomach. Lastly, it indicates which type of vessel transports which type of blood throughout the body. 


Cardiac Cycle

The cardiac cycle indicates the mechanical (contraction and relaxation) and electrical activity that transpire in the heart. The diagram above indicates where the heart activity starts as there is both relaxation and filling of the chambers (diastole). The diastole is followed by atrial systole where there is contraction and additional blood is let into the ventricles. The third stage is the ventricular contraction that forces the opening of the semilunar valves. The fourth step is the ventricular ejection where there is excessive pressure that forces the semilunar valves to open. The last stage is the ventricular relaxation where pressure is relaxed and the blood flows back in the semilunar valves which eventually close. The process is repeated again.

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