What are the four chambers of the heart?	Right atrium, right ventricle, left atrium, and left ventricle. Atria receive blood; ventricles pump it out.
Trace the pathway of blood through the heart and lungs.	Vena cavae -> right atrium -> right ventricle -> pulmonary arteries -> lungs -> pulmonary veins -> left atrium -> left ventricle -> aorta -> body.
What is the difference between pulmonary and systemic circulation?	Pulmonary circulation carries deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood to the left atrium. Systemic circulation delivers oxygenated blood from the left ventricle to the body.
What are the four heart valves and their locations?	Tricuspid (right AV), mitral/bicuspid (left AV), pulmonary semilunar (right ventricle outflow), and aortic semilunar (left ventricle outflow).
What is the function of heart valves?	They prevent backflow of blood, ensuring unidirectional flow through the heart chambers and into the great vessels.
What is the cardiac conduction system pathway?	SA node -> AV node -> Bundle of His -> right and left bundle branches -> Purkinje fibers. The SA node is the primary pacemaker.
What are the two phases of the cardiac cycle?	Systole (ventricular contraction, ejecting blood) and diastole (ventricular relaxation, filling with blood). One full cycle is one heartbeat.
What is cardiac output and how is it calculated?	The volume of blood pumped by one ventricle per minute. CO = heart rate x stroke volume. Normal resting CO is approximately 5 L/min.
What are the three types of blood vessels?	Arteries (carry blood away from the heart), veins (return blood to the heart), and capillaries (exchange gases, nutrients, and wastes with tissues).
How do arteries differ structurally from veins?	Arteries have thicker, more elastic, muscular walls to withstand high pressure. Veins have thinner walls and contain valves to prevent backflow.
What is blood pressure and what do systolic/diastolic values represent?	The force blood exerts on vessel walls. Systolic is peak pressure during ventricular contraction; diastolic is lowest pressure during relaxation. Normal: ~120/80 mmHg.
What are the three layers of a blood vessel wall?	Tunica intima (inner endothelium), tunica media (smooth muscle and elastic tissue), and tunica adventitia/externa (outer connective tissue).
What are the major components of blood?	Plasma (~55%), red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). Plasma is mostly water with dissolved proteins.
What is the primary function of red blood cells?	To transport oxygen from the lungs to tissues and carry carbon dioxide back to the lungs, using the protein hemoglobin.
What is the role of platelets in the blood?	Platelets are cell fragments that initiate clot formation at injury sites by aggregating and releasing clotting factors, preventing excessive blood loss.
What is the Frank-Starling law of the heart?	The heart contracts more forcefully when its ventricles are stretched by greater blood volume, increasing stroke volume to match venous return.
What do the coronary arteries supply?	Oxygenated blood to the myocardium (heart muscle) itself. Blockage of a coronary artery causes a myocardial infarction (heart attack).