Cardio 17

Where is the heart located in the body?

• In the abdomen, tilted to the right

• In the mediastinum, tilted forward and to the left

• In the pelvis, tilted backward

• In the thoracic cavity, tilted to the right

Answer explanation

The heart is located in the mediastinum, which is the central compartment of the thoracic cavity. It is tilted forward and to the left, making this the correct answer compared to the other options.

What is the function of the myocardium?

• It lines the surface of the heart chambers

• It acts as the outermost protective layer

• It contracts to pump blood

• It stores blood

Answer explanation

The myocardium is the muscular layer of the heart responsible for contraction. It pumps blood throughout the body, making 'It contracts to pump blood' the correct choice. The other options describe different heart structures.

Which layer of the heart wall is responsible for lining the surface of the heart chambers?

• Epicardium

• Myocardium

• Endocardium

• Pericardium

Answer explanation

The endocardium is the innermost layer of the heart wall, responsible for lining the heart chambers. It provides a smooth surface for blood flow, distinguishing it from the myocardium (muscle layer) and epicardium (outer layer).

What is the function of the double-layered pericardium surrounding the heart?

• It acts as a barrier to infection and prevents displacement of the heart.

• It increases the heart rate and blood pressure.

• It stores oxygen for the heart.

• It regulates the temperature of the heart.

Answer explanation

The double-layered pericardium serves to protect the heart by acting as a barrier to infection and preventing its displacement within the thoracic cavity, ensuring proper heart function.

What are the two layers of the pericardium?

• Fibrous and parietal

• Muscular and epithelial

• Endocardial and myocardial

• Visceral and epicardial

Answer explanation

The pericardium consists of two layers: the fibrous pericardium, which is the outer layer providing protection, and the parietal pericardium, which is the inner layer that forms a sac around the heart.

How much fluid is typically present in the pericardial cavity?

• 30-50 mL

• 10-20 mL

• 60-80 mL

• 5-15 mL

Answer explanation

The pericardial cavity typically contains 30-50 mL of fluid, which serves to lubricate the heart and reduce friction during its movements. This amount is considered normal for healthy individuals.

What is the function of the right-side pump of the heart?

• It is a high pressure system that pumps oxygenated blood through the systemic circulation.

• It is a low pressure system that receives deoxygenated blood and pumps it through the lungs.

• It separates the right and left sides of the heart.

• It directs the flow of blood through the heart chambers.

Answer explanation

The right-side pump of the heart is a low pressure system that receives deoxygenated blood from the body and pumps it to the lungs for oxygenation, distinguishing it from the left side, which handles oxygenated blood.

How does the left-side pump of the heart function?

• It receives deoxygenated blood and pumps it through the lungs.

• It is a low pressure system that directs blood flow.

• It receives oxygenated blood from the lungs and pumps it through the systemic circulation.

• It separates the right and left sides of the heart.

Answer explanation

The left-side pump of the heart receives oxygenated blood from the lungs and pumps it through the systemic circulation, delivering oxygen to the body's tissues.

What role does the septum play in the heart?

• It pumps deoxygenated blood through the lungs.

• It separates the right and left sides of the heart.

• It directs the flow of blood through the heart chambers.

• It receives oxygenated blood from the lungs.

Answer explanation

The septum is a muscular wall that separates the right and left sides of the heart, preventing the mixing of oxygenated and deoxygenated blood, which is crucial for efficient circulation.

What is the purpose of the cardiac valves in the heart?

• They pump deoxygenated blood through the lungs.

• They separate the right and left sides of the heart.

• They direct the flow of blood through the heart chambers.

• They receive oxygenated blood from the lungs.

Answer explanation

The cardiac valves ensure unidirectional blood flow through the heart chambers, preventing backflow and maintaining efficient circulation. This is crucial for proper heart function.