Anatomy and Physiology 2 - Coronary Arteries and Veins (lecture-based questions)

These are questions that were created around the online lecture of the coronary arteries and veins.

Why do cardiac muscle cells requires a lot of energy and oxygen?

Cardiac muscle cells require a lot of energy and oxygen because they work continuously to pump blood throughout the body, ensuring that all organs receive the nutrients and oxygen they need to function properly

Why can’t cardiac muscle cells absorb blood from the inside of the heart chambers?

Cardiac muscle cells cannot absorb blood from the inside of the heart chambers because the walls of the heart are too thick (myocardium). Instead, they get oxygen and nutrients from blood vessels called coronary arteries that supply the heart muscle directly.

What is the endocardium, and what is its function?

The endocardium is the innermost layer of tissue that lines the chambers of the heart. It is composed of endothelial cells and provides a smooth lining for the heart chambers, which helps in reducing the resistance to blood flow within the heart. The endocardium also plays a crucial role in maintaining the heart's structure and function, and it is involved in the regulation of contractions and the overall coordination of the heart's activity.

Where do the first coronary arteries emerge from?

The first coronary arteries emerge from the base of the aorta on both the left and right sides, just above the aortic valve

What are the two large arteries that the left coronary artery splits into?

The left coronary artery splits into the left anterior descending artery and the circumflex artery.

What is the pathway of the right coronary artery?

The right coronary artery (RCA) originates from the right aortic sinus and travels in the right coronary sulcus. It gives off several branches, including the right marginal artery and the posterior interventricular artery (or posterior descending artery). The RCA supplies blood to the right atrium, right ventricle, bottom portion of both ventricles, and the back of the interventricular septum

What happens during a heart attack, and why does it occur?

During a heart attack, part of the heart muscle doesn't get enough blood. This happens because one or more of the blood vessels that supply the heart (called coronary arteries) get blocked. The blockage is usually caused by a buildup of plaque, which is made of fat, cholesterol, and other substances. When the plaque breaks open, a blood clot forms around it and can block the blood flow to the heart. Without enough blood and oxygen, the heart muscle gets damaged.

What can lead to cardiac arrest during a heart attack?

A heart attack can lead to cardiac arrest if the heart's blood supply is severely reduced or blocked, causing the heart to stop pumping effectively

Why is the interventricular artery called the “Widow Maker”?

The interventricular artery, specifically the left anterior descending (LAD) artery, is often called the "widow maker" because a blockage in this artery can lead to a massive heart attack. The LAD artery supplies a significant portion of the heart muscle with blood. If it becomes blocked, it can result in a large amount of the heart muscle being deprived of oxygen, which can be fatal.

How do heart attacks affect troponin levels, and why is this significant?

Heart attacks cause damage to the heart muscle, leading to the release of troponin into the bloodstream. Elevated troponin levels are significant because they are a biomarker indicating heart muscle injury, making them crucial for diagnosing heart attacks.

What is the role of troponin in muscle function relating to cardiac muscle?

Troponin plays a critical role in muscle contraction, including in cardiac muscle. It is a complex of three regulatory proteins (troponin C, troponin I, and troponin T) that are integral to the regulation of skeletal and cardiac muscle contraction. In cardiac muscle, troponin regulates the interaction between actin and myosin, which are the proteins responsible for muscle contraction. When calcium ions bind to troponin C, it causes a conformational change that moves tropomyosin away from the binding sites on actin, allowing myosin to bind to actin and initiate contraction. This process is essential for the proper functioning of cardiac muscle and the rhythmic contractions of the heart.

Describe the pathway of blood through the coronary veins after it has been used by the heart

The pathway of blood through the coronary veins after it has been used by the heart starts with the deoxygenated blood being collected from the heart muscle (myocardium) by small cardiac veins. These veins then drain into larger veins, such as the great cardiac vein, middle cardiac vein, and small cardiac vein. The blood from these veins converges into the coronary sinus, a large vein located on the posterior aspect of the heart. Finally, the coronary sinus empties the deoxygenated blood directly into the right atrium of the heart, where it will then be sent to the lungs for reoxygenation.

What is the coronary sinus, and what is its role in cardiac circulation?

The coronary sinus is a large venous channel located on the posterior aspect of the heart, specifically within the coronary sulcus. Its primary role in cardiac circulation is to collect deoxygenated blood from the heart muscle (myocardium) and deliver it to the right atrium. This allows the blood to then flow into the right ventricle and be pumped to the lungs for oxygenation.

How does the heart manage the circulation of fresh and used blood?

The heart manages the circulation of fresh and used blood by using two main pumps: the right side and the left side. The right side of the heart receives used blood from the body and pumps it to the lungs to get fresh oxygen. The left side of the heart then receives the fresh, oxygen-rich blood from the lungs and pumps it out to the rest of the body.