What is the function of the cardiovascular system?
The cardiovascular system delivers blood per unit time per gram of tissue, a process called perfusion, which is essential for supplying oxygen and nutrients to tissues.
What generalization can be made about all arteries?
All arteries carry blood away from the heart, usually oxygenated except for pulmonary arteries.
What generalization can be made about all veins?
All veins carry blood toward the heart, usually deoxygenated except for pulmonary veins.
Describe the path of blood flow through the heart starting at the right atrium.
Blood flows: right atrium → tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary trunk → lungs → pulmonary veins → left atrium → bicuspid valve → left ventricle → aortic semilunar valve → aorta → systemic circulation.
What is the difference between pulmonary and systemic circulation?
Pulmonary circulation moves blood between the heart and lungs for oxygenation; systemic circulation moves oxygenated blood from the heart to the body tissues.
What are the three layers of the heart wall?
The heart wall consists of the epicardium (outer layer), myocardium (muscle layer), and endocardium (inner lining).
What is the function of the pericardium?
The pericardium encloses the heart, providing protection and reducing friction via serous fluid in the pericardial cavity.
What structures make up the pericardium?
The pericardium includes the fibrous pericardium, parietal layer of serous pericardium, and visceral layer of serous pericardium (epicardium).
What is the role of chordae tendineae and papillary muscles?
Chordae tendineae anchor atrioventricular valves to papillary muscles, preventing valve prolapse during ventricular contraction.
Compare atrioventricular and semilunar valves.
Atrioventricular valves (tricuspid and bicuspid) prevent backflow into atria; semilunar valves (pulmonary and aortic) prevent backflow into ventricles.
What is the fibrous skeleton of the heart?
A dense connective tissue structure that supports valves and electrically isolates atria from ventricles.
Describe the structure of cardiac muscle.
Cardiac muscle cells are striated, branched, connected by intercalated discs containing desmosomes and gap junctions for mechanical and electrical coupling.
How does cardiac muscle meet its energy needs?
Cardiac muscle has abundant mitochondria and myoglobin to support aerobic respiration for continuous energy supply.
Name the major coronary arteries and their function.
The left and right coronary arteries supply oxygenated blood to the heart muscle; their branches cover different heart regions.
What is the coronary sinus?
A large vein that collects deoxygenated blood from coronary veins and drains into the right atrium.
What is the heart's conduction system path?
SA node → AV node → AV bundle (bundle of His) → bundle branches → Purkinje fibers, coordinating heartbeats.
What is autorhythmicity in cardiac nodal cells?
The ability of pacemaker cells to spontaneously depolarize due to unique ion channels, initiating heartbeats without external stimuli.
What are the phases of the cardiac action potential in muscle cells?
Depolarization, plateau, and repolarization phases regulate contraction and relaxation of cardiac muscle.
What is the significance of the cardiac muscle refractory period?
The extended refractory period prevents tetanus, allowing the heart to relax between beats.
What are the main components of an ECG?
P wave (atrial depolarization), QRS complex (ventricular depolarization), and T wave (ventricular repolarization).