Cardiovascular System Overview

General Structures and Functions of the Cardiovascular System

• Composed of the heart, blood vessels, and blood, forming a closed circulatory loop.
• Transports oxygen, nutrients, hormones, and waste products throughout the body.
• Regulates body temperature, pH levels, and fluid balance.

Location of the Heart in the Thoracic Cavity

• Positioned in the mediastinum, between the lungs and posterior to the sternum.
• Base of the heart is located at the level of the second rib, while the apex points towards the left, at the fifth intercostal space.

Layers of the Heart Wall

• Composed of three main layers: epicardium, myocardium, and endocardium.
• Epicardium: Outermost layer, also known as the visceral pericardium; reduces friction during heartbeats.
• Myocardium: Thick, muscular middle layer; responsible for the heart's contraction and pumping action.
• Endocardium: Innermost layer; provides a smooth lining for the heart chambers and valves.

Major Structural Features of the Heart

• Chambers: Four chambers - right atrium, right ventricle, left atrium, left ventricle.
  • Right atrium receives deoxygenated blood from the body.
  • Right ventricle pumps blood to the lungs for oxygenation.
  • Left atrium receives oxygenated blood from the lungs.
  • Left ventricle pumps oxygenated blood to the body; has the thickest wall.
• Valves: Four key valves prevent backflow of blood.
  • Atrioventricular valves (tricuspid and mitral) control flow between atria and ventricles.
  • Semilunar valves (pulmonary and aortic) regulate blood flow out of the ventricles.
• Great Vessels: Major blood vessels include:
  • Superior and inferior vena cava (return deoxygenated blood to the right atrium).
  • Pulmonary arteries (carry deoxygenated blood from the right ventricle to the lungs).
  • Pulmonary veins (bring oxygenated blood from the lungs to the left atrium).
  • Aorta (distributes oxygenated blood from the left ventricle to the body).

Pathway of Blood Through the Adult Heart

• Blood enters the right atrium from the body via vena cavae.
• Passes through the tricuspid valve into the right ventricle.
• Ejected into the pulmonary arteries through the pulmonary valve to the lungs.
• Oxygenated blood returns via pulmonary veins to the left atrium.
• Flows through the mitral valve into the left ventricle.
• Pumped into the aorta through the aortic valve to supply the body.

Coronary Vessels and Their Functional Significance

• Coronary arteries supply oxygenated blood to the heart muscle itself.
• Major arteries include the right coronary artery and left coronary artery (which branches into the anterior interventricular and circumflex arteries).
• Coronary veins collect deoxygenated blood from the heart muscle and drain into the coronary sinus, which empties into the right atrium.
• Importance of coronary circulation: ensures adequate oxygen supply to the myocardium, preventing ischemia and heart attacks.

This quiz covers the general structures and functions of the cardiovascular system, including the heart's location in the thoracic cavity. It also explores the layers of the heart wall, with a focus on the myocardium, and details major structural features of the heart such as chambers, valves, and blood pathways. Additionally, it compares coronary vessels and their functional significance.