Dissect, display and identify an ox's or a sheep's heart. Flashcards
How did you distinguish between the ventral and dorsal surfaces of the heart?
The ventral (front) surface is more rounded and has a deeper groove (coronary sulcus) where the coronary arteries run. The dorsal (back) surface is flatter and has less prominent blood vessels.
How would you distinguish the left side from the right side of the heart?
The left side feels firmer and thicker due to the thick muscular wall of the left ventricle. The right side is softer and thinner because the right ventricle has a thinner wall. The left side pumps oxygenated blood to the body, requiring more force, while the right side pumps blood to the lungs.
Name the arteries through which the heart obtains its own blood supply. Are these arteries visible in the dissected heart?
The coronary arteries supply blood to the heart. Yes, they are visible as thin, red blood vessels on the ventral surface of the heart.
What is the meaning of cardiac muscle?
Cardiac muscle is a specialized, involuntary muscle that contracts continuously without fatigue, enabling the heart to pump blood throughout life.
What conclusions did you draw from the results obtained?
The left ventricle is more muscular than the right. The heart has four chambers (two atria, two ventricles). Valves ensure one-way blood flow, preventing backflow. The coronary arteries supply oxygenated blood to the heart muscle.
What is the purpose of the semi-lunar valve in the heart?
The semi-lunar valves (aortic and pulmonary valves) prevent backflow of blood into the ventricles after contraction.
What separates the right side of the heart from the left?
The septum, a muscular wall, separates oxygenated and deoxygenated blood.
Which chamber of the heart has the greatest amount of muscle in its wall?
The left ventricle because it pumps blood at high pressure to the entire body.
Why is the wall of the left ventricle considerably thicker than that of the right?
The left ventricle must generate high pressure to pump blood around the body. The right ventricle only pumps blood to the lungs, requiring less force.
What small openings can be found at the base of the aorta just above the semi-lunar valve?
The openings of the coronary arteries, which supply oxygen-rich blood to the heart muscle.
Give reasons for the sterilisation of the dissecting equipment after dissection.
Prevents contamination with bacteria or pathogens. Ensures hygiene and safety for future use.
State the procedure that you followed to expose the semi-lunar valve.
Located the aorta and pulmonary artery. Made a vertical incision through the base of the aorta. Opened the vessel to reveal the semi-lunar valve flaps inside.
Where in your dissection did you find the origin of the coronary artery?
At the base of the aorta, just above the semi-lunar valve.
State one way in which heart muscle differs from other muscles in the body.
Cardiac muscle is involuntary and does not fatigue, unlike skeletal muscle, which requires rest after exertion.
