Cardiovascular System - Detailed Summary 1. Functions of the Cardiovascular System • The cardiovascular system is a closed system consisting of the heart and blood vessels. • Main functions: • Transport oxygen, nutrients, hormones, and waste. • Maintain blood pressure and circulation. • Aid in immune function (through WBCs in blood). 2. Anatomy of the Heart • Location: Thoracic cavity, between the lungs, within the mediastinum. • Size: About the size of a fist. • Orientation: • Apex: Points toward the left hip (bottom). • Base: Directed toward the right shoulder (top, where large blood vessels attach). Heart Layers (Inside to Outside) 1. Endocardium – Inner lining of the heart, smooth to prevent clotting. 2. Myocardium – Thick muscular layer responsible for contraction. 3. Epicardium (Visceral Pericardium) – Outer covering of the heart. • Pericardium: A double-walled sac surrounding the heart. • Parietal Pericardium: Outer layer. • Visceral Pericardium: Inner layer (epicardium). • Pericardial Fluid: Lubricates and reduces friction during heartbeats. 3. Chambers of the Heart The heart has four chambers: • Atria (Right & Left): Upper receiving chambers. • Ventricles (Right & Left): Lower pumping chambers. • Right Side of the Heart: Pumps deoxygenated blood to the lungs (Pulmonary Circulation). • Left Side of the Heart: Pumps oxygenated blood to the body (Systemic Circulation). 4. Heart Valves Valves prevent backflow of blood: 1. Atrioventricular (AV) Valves – Between atria and ventricles: • Right AV Valve: Tricuspid Valve • Left AV Valve: Bicuspid (Mitral) Valve 2. Semilunar Valves – Between ventricles and arteries: • Pulmonary Semilunar Valve: Right ventricle → Pulmonary artery • Aortic Semilunar Valve: Left ventricle → Aorta • Chordae Tendineae (“Heart Strings”) anchor AV valves to prevent them from inverting. 5. Blood Flow Through the Heart 1. Deoxygenated Blood Pathway (Blue): • Superior/Inferior Vena Cava → Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Semilunar Valve → Pulmonary Artery → Lungs 2. Oxygenated Blood Pathway (Red): • Lungs → Pulmonary Veins → Left Atrium → Bicuspid Valve → Left Ventricle → Aortic Semilunar Valve → Aorta → Body 6. Electrical Conduction System (Intrinsic Conduction System) The heart has automaticity (can contract on its own). • Sinoatrial (SA) Node (“Pacemaker”) – Sets the heart’s rhythm (~75 bpm). • Atrioventricular (AV) Node – Delays impulse so atria can contract first. • AV Bundle (Bundle of His) – Carries signal to ventricles. • Purkinje Fibers – Cause ventricles to contract. Disruptions in this system can cause arrhythmias (irregular heartbeats). 7. Cardiac Cycle (Heartbeat) Each cycle consists of: 1. Atrial Systole – Atria contract, pushing blood into ventricles. 2. Ventricular Systole – Ventricles contract, pumping blood to the lungs/body. 3. Diastole – Heart relaxes and fills with blood. • Heart Sounds: • “Lub” – Closing of AV valves during ventricular contraction. • “Dub” – Closing of semilunar valves during ventricular relaxation. 8. Cardiac Output (CO) • Definition: The amount of blood pumped by each ventricle per minute. • Formula: • CO = Heart Rate (HR) × Stroke Volume (SV) • Average CO = 5.25 L/min Factors affecting CO: • Sympathetic nervous system → Increases HR (exercise, stress) • Parasympathetic nervous system → Decreases HR (rest, sleep) • Hormones (epinephrine, thyroxine) → Increase HR 9. Blood Vessels & Circulation • Arteries: Carry oxygenated blood away from the heart (except pulmonary artery). • Veins: Carry deoxygenated blood to the heart (except pulmonary vein). • Capillaries: Tiny vessels for gas/nutrient exchange. Blood Vessel Structure 1. Tunica Intima – Inner layer, smooth to reduce friction. 2. Tunica Media – Middle layer, made of smooth muscle (controls blood pressure). 3. Tunica Externa – Outer layer for support. 10. Major Circulatory Routes • Pulmonary Circulation: Right ventricle → Lungs → Left atrium. • Systemic Circulation: Left ventricle → Body → Right atrium. Special Circulations: • Hepatic Portal Circulation: Blood from digestive organs goes through the liver before reaching the heart. • Fetal Circulation: Blood bypasses the lungs using special shunts (foramen ovale, ductus arteriosus). 11. Blood Pressure & Disorders • Blood Pressure (BP): The force of blood against vessel walls. • Normal BP: ~ 120/80 mmHg • Hypertension (High BP): >140/90 mmHg – Can damage arteries. • Hypotension (Low BP): <90/60 mmHg – Can cause dizziness or shock. Factors affecting BP: • Cardiac Output (CO) • Blood Volume • Vessel Resistance (narrower arteries = higher BP) 12. Common Cardiovascular Disorders • Hypertension (High Blood Pressure): Can lead to stroke, heart attack. • Atherosclerosis: Hardening of arteries due to plaque buildup. • Myocardial Infarction (Heart Attack): Blockage in coronary artery cuts off oxygen. • Arrhythmia: Irregular heartbeats due to conduction system issues no

What was the ruling of Brown v. Board of Education in 1954?

It ruled that 'separate educational facilities are inherently unequal.'

What does the term 'separate but equal' relate to in the context of American education?

It refers to the doctrine that racial segregation in public schools was constitutional as long as the separate facilities were equal.

What impact did Brown v. Board of Education have on American schools?

It led to the desegregation of public schools across the United States.

Which amendment was primarily clarified by the Brown v. Board of Education decision?

The Fourteenth Amendment, which guarantees equal protection under the law.

Who was the Chief Justice during the Brown v. Board of Education ruling?

Chief Justice Earl Warren.