Sheep's heart dissection

Aim: I want to investigate the structure of a sheep's heart.

Equipment: The sheep's heart, dissecting tray, scalpel, dissecting scissors, latex gloves.

Safety: Wear safety glasses and gloves.
Try not to cut yourself with the scalpel/scissors.


Method:

Looking at the external structure of the heart:

1. Rinse off the remaining preservative with tap water then place the heart on the dissecting tray.

2. locate the thin membrane called the pericardium that covers the heart, then remove the tissue and put it to the side.

3. Underneath the pericardium is the myocardium. The myocardium is the type of muscle that the heart is made out of.












4. Locate the bottom of the heart/apex and observe how the left ventricle is the only chamber that extends all the way to the apex.

5. Rotate the heart so the ventral side of the heart is facing the roof. The ventral side is recognized by a groove that extends from the right side of the broad end of the heart diagonally to a point above and
to your left of the apex.

6. Now the heart is in a position where the heart is in a body facing you.

7. Locate the left and right ventricle. And locate the left and right atrium.

8. leaving the heart in the same position, locate the Aorta, Coronary artery, Pulmonary artery, Pulmonary veins, Aortic arch, and the Inferior and Superior Vena Cava.

Looking at the internal structure of the heart:



1. Use scissors to cut through the side of the pulmonary artery and continue cutting down into the wall of the right ventricle. Be careful to just cut deep enough to go through the wall of the heart chamber.

2. Use your fingers to open up the cut and examine the internal structure of the heart. If there is any dried blood in the heart, rinse it out with tap water.

3. Locate where the superior and inferior Vena Cava enter the right Atrium.

4. Locate the different valves between the Atriums and the Ventricles.

5. Feel the difference in the thickness of each chamber.

6. Once you're done with the examining, cut out whatever sections of the heart you want.

7. Examine that stuff as well. Once you're done with the experiment, put everything on the tray.

9. Take photo.

Result: 













Discussion

Blood traveling through the heart:
Deoxygenated blood from around the body enters the heart via Superior and Inferior Vena Cava. these blood vessels connect to the Right Atrium. From the Right Atrium, blood flows into the Right Ventricle then gets pumped through the Pulmonary arteries and into the lungs. Once the blood is in the lungs, the blood gets oxygenated and travels back to the heart through the Pulmonary veins. When the oxygenated blood arrives back at the heart, it enters the Left Atrium and then the blood empties out into the Left Ventricle and then gets pumped around the body through the Aorta.

Breathing:
Breathing consists of two steps. inhalation and exhalation. When we inhale, the muscle between the ribs called the intercostal muscles, lift the ribcage up and out, expanding the chest. at the same time, a sheet of muscle under the lungs called the diaphragm flattens. This makes the space inside the ribcage bigger and reduces air pressure in the lungs. Air moves into the lungs because the air pressure outside is higher. The inhaled air first enters the lungs through the windpipe called the trachea. Then the trachea divides into two bronchi, with one bronchus going to each lung. Each bronchus divides further in the lungs into smaller tubes called bronchioles. At the end of each bronchiole, there is a group of tiny air sacs. These air sacs have bulges called alveoli to increase their surface area and speed up the absorption of oxygen. When we exhale, the intercostal muscles and diaphragm relax. this lowers the chest and raises the diaphragm back up. This reduces the space in the ribcage gets smaller so the air pressure increases. this forces air out of the lungs. Also when we exhale, carbon dioxide leaves the body.

Aerobic Cellular Respiration:
Cellular Respiration comes in three stages. The glycolysis, the Krebs cycle, and Electron transport. During the glycolysis stage, Glucose (C6 H12 O6) enters the mitochondria a catabolic reaction takes place. This breaks down the glucose molecules into 6 Carbon, 12 Hydrogen, and 6 Oxygen. Also, a small amount of ATP is released. Then in the Krebs cycle, oxygen (O2) is added. As a result, the 6 carbon molecules chemically react with the added oxygen producing carbon dioxide (CO2). Also During this stage, more energy is released. Then during the final stage. The 12 hydrogen molecules react with oxygen to produce water (H2O) and even more, energy is released.