HEART DISSECTION LAB

Matthew Correia | Olivia Ibbott | Melissa Machado | Michael Pileggi

Ms. Pimental

SBI3U1

23 Feb. 2015

Purpose:
The purpose the study being conducted is to investigate and apply principles in class with regards to the structure and make up of the heart.
Observations:
See attached sheets for drawings.
1.a) The pig hearts general shape is a fist it is skinny at the top (aorta)and gradually gets bigger as it progress down. b) The difference between the walls of the right atrium and the right ventricle is that the walls of the right atrium are a lot thinner. Also they feature a wrinkled flap shaped like a floppy dog ear, called the auricle. The auricle increases the internal volume of the right atrium.

2.a) The top of the heart feels hollow when it is squeezed, this is because the top of the heart contains the hollow aorta the bottom of the heat contains the four chambers.

3.a) The major differences between the diagram on page 168 from the actual heart is the live heart does not have all three aorta's , inferior vena cava and the pulmonary artery. This difference occurred because these part were copped off.

4.a) There are many vessels that were found at the top of the dissected pig heart. These vessels are the following arteries, capillaries, venules and veins. Although they all lie in an arrangement within the heart they vary in structure. Arteries are very different in structure because they contain thick walls composed of smooth muscle fiber that are able to contract and relax when instructed to do so by the nervous system. Arteries contain such thick walls because they, unlike veins carry blood for a long period of time and need to be able to withstand great amounts of pressure in order to do so. Although veins contain three layers of tissue called the tunica Adventita, tunica Media and the tunica Intima, they are substantially thinner and less elastic than arteries. They do not need to withstand great amounts of pressure because they carry diffused blood passed on from the capillaries for a short period of time. Capillaries vary based on their structure because they are only 5-20 micrometres in diameter which makes them extremely narrow. They are so narrow that cells can only pass through them one at a time; this prevents the exchange of materials between the contents of the capillary and surrounding tissues. Finally, Venules are the tiniest vessel that can potentially form veins. They drain blood from capillaries to the veins.
5.a) While dissecting the pig heart, there were two flaps of round, wrinkled tissue on the upper part of the heart. These flaps form the left atrium and the right atrium. Since the atria are found at the top of the heart, they collect blood as it enters the heart.
6.a) The blood vessels that surround the interventricular groove have a distinct function since they do not carry blood into any of the four chambers. These vessels mark the separation between the ventricles on the front and back surfaces of the heart. These vessels can build up plaque which blocks the amount of oxygen to the heart; this is why this is the site of heart attacks.
7.a) While conducting the dissection of the pig heart, the interventricular groove was examined. Observed was that the coronary arteries based in the interventricular groove feed the heart. After further dissection and observation, the task was to determine where the blood comes from that feeds the heart. The blood that feeds the heart is received from the coronary arteries based in the heart. There are two major coronary arteries that branch off from the aorta near the point where the aorta and the left ventricle meet. These arteries supply the heart with blood.
Discussion Questions:
1. If the blood vessel in the interventricular groove became blocked with fatty deposits it may be fatal leading to a heart attack. The interventricular groove is one of the coronary vessels of the heart if this