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[personal profile] liveonearth
Today at 8am I went into the lab and held in my hands a human heart. I have studied anatomy many times before. I have dissected a living pregant mouse, a frog, and a pelican whose gut contents did not reveal the reason he was dead on the beach. I have dissected a fetal pig, complete with colored plastic injected into his arteries and veins. I have held a cow's heart in my hands. I have studied the flows and construction of hearts. But holding a human heart is different.


In this lab there are several human cadavers that are being prosected for us by more advanced students. When we go into the laboratory we don plastic gloves, and are encouraged to touch the bodies, to pinch the arteries and feel the veins, to push aside tendons and muscles to reveal the deeper tissues. I am OK with the process, but deeply aware that these are people who have donated their bodies to science. Their heads and lower bodies remain covered, while we poke and prod around in their arms and backs. Hair peeks out from under the flannel sheet. Fingernails reveal gender when the form doesn't. There is a list on the wall that reveals their ages and gives them pseudonyms. When we leave the lab, the prosectors spray the cadavers with fabric softener (to keep them moist and keep them from decomposing) and cover them again.

The hearts that I handled were very fatty on the posterior apex. The TA in the class said that when you prosect an obese individual all the organs are not just surrounded, but filled, LADEN with fat. These hearts were large, sturdy, muscular things. Heavy. Meaty. Human.

Parts that we were asked to locate today:

Right atrium:
superior & inferior vena cava=large veins coming in from body
fossa ovalis=fetal hole between atria that seals around birth (except in murmur cases)
pectinate muscle
opening of coronary sinus

Left atrium:
auricle=no one could tell me its function
pulmonary veins (4)

Right and left ventricles:
bicuspid and tricuspid valve leavelets
chordae tendineae=cords holding valve leaflets so valve doesn't turn inside out
pappillary muscle=muscle where cords attach to heart wall
trabeculae carneae=rough muscle lining heart wall

Pulmonary artery with pulmonary valve

Aorta with aortic valve

Right coronary artery, marginal artery, posterior descending artery

Left coronary artery, anterior descending artery

Coronary sinus (in posterior groove between atria & ventricles)

Date: 2007-10-04 01:48 pm (UTC)
From: [identity profile] neptunia67.livejournal.com
Fascinating! But sobering at the same time. I have held many - *many* hearts - the pig being the closest in size to the human - and at times wondered if it would be the same weight, shape as mine.

Date: 2007-10-04 09:51 pm (UTC)
From: [identity profile] liveonearth.livejournal.com
These hearts were bigger than we expected. Much more than "fist sized" as they say in some text books.

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