3.1 ;part 2Anatomy of the Cardiovascular System

The Cardiovascular System: Heart Anatomy

• The heart is a hollow, muscular organ located in the mediastinum, inside the parietal pericardium.
• It has four chambers: right atrium, left atrium, right ventricle, and left ventricle.
• The heart has four valves: tricuspid, mitral, pulmonary, and aortic.
• The heart has two separate, but integrated pumps: right ventricle pumps into pulmonary circulation, and left ventricle pumps into systemic circulation.

Valves, Septa, and Chambers

• The tricuspid valve is located between the right atrium and ventricle.
• The mitral valve is located between the left atrium and ventricle.
• The pulmonary valve is located between the right ventricle and pulmonary artery.
• The aortic valve is located between the left ventricle and aorta.

Flow of Blood Through the Heart

• The flow of blood through the heart is: superior and inferior vena cavae → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta.

Conduction System of the Heart

• The sino-atrial (SA) node is located in the superior wall of the right atrium and generates electrical impulses at a rate of 1-2 times per second.
• The electrical impulses travel through the atria, causing contraction, and then to the atrio-ventricular (AV) node.
• The AV node sends the electrical impulses to the AV bundle, which splits into the right and left bundle branches, and finally to the Purkinje fibers, causing ventricular contraction.

Intrinsic Regulation - Pacemaker

• The cardiac cycle consists of heart beats, atrial contraction, ventricular contraction, and relaxation.
• The SA node is the pacemaker of the heart, generating electrical impulses that regulate the heart rate.

Coronary Arteries and Heart Attack

• The coronary arteries supply oxygen to the heart muscles, which have a high oxygen demand.
• The coronary arteries are divided into two main branches: right and left.
• Atherosclerosis is a condition where fats, cells, and calcium accumulate on the inner walls of arteries, leading to ischemia, angina, and potentially myocardial infarction (heart attack).

Myocardial Infarction

• Myocardial infarction occurs when the coronary arteries become significantly blocked, leading to a lack of blood flow and death of heart muscle.
• The condition can lead to complications such as arrhythmias, left ventricular failure, cardiogenic shock, rupture, and thromboembolism.
• Cardiac enzymes such as troponin, creatine kinase (CK-MB), and lactate dehydrogenase (LDH) can be used to diagnose myocardial infarction.

This quiz covers the basic structure and functions of the heart, including its chambers, valves, and circulation pathways.