Introduction
This write up is about our last science lesson where we did a sheep’s heart dissection. We did this dissection to see the functions of the heart and how it operates for the body to work.
Equipment
For this dissection, we only needed a few equipment to help with that dissection. About 5 sheets of newspaper to prevent blood from leaking onto the table, and a pair of scissors to help get through the heart, and a scalpel – though only our teacher used it to prevent injuries between students.
What steps did you take during the dissection?
In the middle of class where our teacher worked, all students gathered around to watch our teacher’s demonstration, showing us what to do, giving us examples and naming each of the parts which we could already see without having to make any cuts. After that demonstration, we started off by analyzing the heart, having a feel and taking a guess on which side was left and right, even poking our fingers down the Aorta, the pulmonary artery and the Verna Cava, and tried finding each of the four bedroom houses which are called the left and right Ventricle and Atrium.
Already having explored the outside, each groups laid their hearts down on their sheets of newspapers and using a pair of scissors, we made an incision from the bottom to the top of both the left and right sides of the heart. After making a cut, we then explored the inside, trying to locate each of the four bedroom houses and even finding the veins, arteries, the right and left atrium, the right and left ventricle, and some tendons holding some of the heart’s pieces together.
What parts of the heart did you see during each step?
From what I saw in the beginning after making the incision was a ton of blood clots scattered around the walls of the heart, and the second thing I noticed was the left wall was definitely thicker than the right side. After cutting through the middle from the inside, I saw how each chamber was separated and beneath some of those was the papillary muscles which I caught a glimpse of.
why is the left side thicker than the right?
Because the right only has to pump blood only through the lungs whilst the left side has to pump through the whole rest of the body, which requires immense strength to do – that’s the cause of the left side being more thicker.
How and why does the heart pump blood around the body?
How? – De-oxygenated blood returns to the right side of the heart and enters the two big veins – “Superior Verna Cava” and the “Inferior Verna Cava”, then gets emptied into the right atrium which gets squeezed through a valve and to the right Ventricle. The right Ventricle contracts, moving the blood through the pulmonary valve then into the pulmonary arteries. These arteries carry the blood to the lungs where it drops off carbon dioxide (or de-oxygenated blood) while picking up a fresh supply of oxygen (oxygenated blood).
The newly oxygenated blood enters through the left side of the heart through the pulmonary veins. Emptying in the left atrium which gets pushed through another valve and into the left ventricle. The left ventricle is the heart’s strongest chamber – having the job of generating pressure to pump oxygenated blood through a valve and into the Aorta –the largest artery of the body – which then goes through smaller artery branches out to deliver oxygen and nutrients to every single organ, tissue and cell through the whole body.