Your Heart....part 1know Your Heart Inside Out.....in Structure And Function An Important Preamble.
The general audience may limit themselves to the allusions rendered below while the medical audience would prefer to read the the entire text. The latter group may even find it humorous! The human heart and its "apputenances" are not the easiest things to explain to the laity.
The heart is a pump...well, two blood pumps lying side by side. One is like the initiator...and the other the relay pump....left and right sides respectively!
Ordinarily, the phenomena of how our hearts function would be more easily understood had we been created with two hearts....not necessarily lying contiguous or even in proximity to each other....but beating in synchrony...(such that we have just one pulse!)
But nature....sorry, the Creator....has chosen to construct both the right and left sides of the heart like two duplexes....totally bisected down the middle....from top to bottom....such that there may be no communication whatsoever between both sides...under normal circumstances!
Liken them to a single block of Twin Duplexes each with just one room per floor....for that's exactly what they are!
The upper rooms are the atria....singular, atrium....one to each side. The lower rooms are the ventricles....one to each side.
The upper room and lower room on each side are separated by swing doors....called valves....which swing in only one direction....outward!
Only that in the duplex on the right, strangely enough, there are three...not two swing doors to the exit from the upper to the lower room. This is called the Tricuspid Valve. No big deal! Three cusps...or cups....form this particular door.
Liken them to the cups of the female bra....turned edge-to-edge...tightly as to be water tight....strings and all! The hollow side of the bras facing outwards!
There are two swing doors to the exit between both rooms on the left...called the Bicuspid or Mitral Valves.
With regard to the major veins and arteries of the heart connected directly to it, imagine these major blood vessels to be viaducts. Imagine each room to be connected to the outside via its viaduct. Imagine that each duplex can only be entered via the viaduct to its upper room. Each duplex can only be exited through the viaduct from its ground-floor room. (A minor exception to this rule is that two viaducts connect to the upper room on the right side and not one!)
Both the inferior and superior vena cavae connect to, and discharge deoxygenated blood into the right atrium. The pulmonary artery connects to the right ventricle and "collects" such oxygen-depleted blood from it for onward transport to the lungs for replenishment.
The pulmonary vein connects to, and discharges freshly-oxygenated blood into the left atrium. The aorta connects to the left ventricle and "collects" such oxygen-rich blood for onward distribution to the (rest of the) body...except of course, the lungs!
There is a valve at the entry point to each atrium. In a similar manner, there is a valve at the exit point from each ventricle.
Liken each of these directional valves to a group of swing doors to each exit.
So, you have a door to the entry of each upper room; a door between each upper and lower room; and a door between each lower room and its exit viaduct!
Understand that the left side of the heart carries only oxygenated blood while the right side conveys deoxygenated blood.
A fine pnemonic for recalling this fact is to imagine that the duplex on the left is inhabited by an affluent well-nourished family while the one on the right is populated by a poor malnourished family!
As to the fact that blood in these chambers is in motion and not static, you may liken such blood to nomadic families which are constantly on the move!
NOTE that ordinarily, arteries carry oxygenated blood and veins carry deoxygenated blood.
NOTE also however, that the pulmonary arteries carry deoxygenated blood into the lungs to be replenished with oxygen.
This exception to the rule occurs only once and only in this instance under normal circumstances in human anatomy!
"Similarly", blood freshly replenished with oxygen is carried into the left atrium via the pulmonary veins. NOTE again....vein, but oxygenated blood! This is also an exception to the general rule that veins carry deoxygenated blood.
The left side of the heart pumps blood to the whole body except the lungs while the right side of the heart pumps blood to the lungs only.
As blood returns to the heart (right side)....aptly called venous return, it is depleted in both oxygen and pressure. It makes to pick up such fresh oxygen supply from the lungs but before it can do that successfully, it needs to pick up "fresh pressure " from the further pumping by the right side of the heart.
Another fact: The prefix Pulmo refers to Lungs.
A word of caution. The human heart is tilted to one side....and does not stand erect. You may liken this tilt in balance to tilted buildings now in vogue in Europe!
BLOOD SUPPLY TO HEART MUSCLE.
Though this article may seem utterly tasking and boring to laymen already, they must endeavour to read it severally to grasp this rare chance at understanding it.
Yet, we must broach the subject of blood supply to the heart muscle....for a disarray of this causes heart attacks!
Arteries and veins designed for this purpose....named Coronary arteries and veins connect directly to the major vessels as described above.
They need to stay pliant and free.....not hardened and unclogged. We may only achieve such state of health by eating right and living right. Avoid alcohol and tobacco abuse, avoid undue amounts of fat, rein in your temper, exercise moderately regularly and have a liberal outlook on life!
I do not know the origin of the word "coronary"....but it sounds like "coronal"....or crown.
Dr Tosin Akindele is a medical practitioner and public affairs analyst.