Cardiology and the Cardiovascular System: Medical Terminology Study Guide

Cardiology and the Cardiovascular System

Introduction to Cardiology

Cardiology is the medical specialty focused on the anatomy, physiology, diseases, and treatments of the cardiovascular system. Understanding medical terminology in this field is essential for accurate communication and patient care.

• Cardi/o-: means heart

• -logy: means study of

• Cardiologists use diagnostic tests, medical and surgical procedures, and drugs to treat cardiovascular diseases.

Structures of the Cardiovascular System

The cardiovascular system consists of the heart and blood vessels, forming a continuous pathway that circulates blood throughout the body.

• Heart: Central organ located in the thoracic cavity, behind the sternum and between the lungs.

• Blood Vessels: Include arteries, veins, and capillaries.

Anatomy of the Heart

External and Internal Features

The heart is roughly the size of a fist and contracts at least once per second. Its external surface is irregularly shaped, with mounds and grooves reflecting internal chambers and containing fat, blood vessels, and nerves.

Membranes and Layers

• Pericardium: Two-layered membrane forming the pericardial sac.

• Parietal pericardium: Outer layer.

• Epicardium: Inner layer.

• Pericardial fluid: Fills space between layers.

• Myocardium: Muscular layer responsible for contraction.

• Endocardium: Innermost layer lining chambers and valves.

Heart Chambers

• Four chambers: Right atrium, Right ventricle, Left atrium, Left ventricle.

• Atrium: Small upper chamber.

• Ventricle: Large lower chamber.

• Septum: Central wall dividing right and left sides.

Heart Valves

• Four valves control blood flow:

• Tricuspid valve: Between right atrium and right ventricle.

• Pulmonary valve: Between right ventricle and pulmonary arteries.

• Mitral valve: Between left atrium and left ventricle.

• Aortic valve: Between left ventricle and aorta.

• Chordae tendineae: Ropelike strands supporting valve leaflets during contraction.

• Heart sounds: "Lubb" (tricuspid and mitral close), "Dupp" (pulmonary and aortic close).

Thoracic Cavity and Mediastinum

The thoracic cavity contains the lungs and the mediastinum, which houses the heart, great vessels, esophagus, trachea, and thymus.

• Mediastinum: Central area between lungs.

• Great vessels: Aorta, superior vena cava, inferior vena cava, pulmonary arteries, pulmonary veins.

Blood Vessels

Types and Functions

• Arteries: Carry blood away from the heart; most are oxygen-rich and lie deep beneath the skin.

• Capillaries: Smallest vessels; connect arteries and veins; deliver blood to cells.

• Veins: Carry blood toward the heart; most are oxygen-poor and have valves to ensure one-way flow.

Vasoconstriction and Vasodilation

• Vasoconstriction: Narrowing of blood vessels, increases blood pressure.

• Vasodilation: Widening of blood vessels, decreases blood pressure.

Major Arteries and Veins

• Aorta: Largest artery.

• Coronary arteries: Supply myocardium.

• Superior and inferior vena cava: Largest veins.

Vein Valves

• Valves prevent backflow and ensure blood returns to the heart.

• Blood moves through veins via muscle contractions.

Circulation Pathways

Systemic and Pulmonary Circulation

• Systemic circulation: Vessels throughout the body except lungs.

• Pulmonary circulation: Vessels to, within, and from the lungs.

• Blood passes through both pathways in one complete trip.

Blood Flow Sequence

1. Deoxygenated blood from upper body → superior vena cava → right atrium.

2. Deoxygenated blood from lower body → inferior vena cava → right atrium.

3. Right atrium → tricuspid valve → right ventricle.

4. Right ventricle → pulmonary valve → pulmonary arteries → lungs.

5. In lungs: blood releases CO2, picks up O2.

6. Oxygenated blood → pulmonary veins → left atrium.

7. Left atrium → mitral valve → left ventricle.

8. Left ventricle → aortic valve → aorta → body.

Physiology of the Heart

Conduction System

• Sinoatrial (SA) node: Pacemaker, initiates heartbeat.

• Atrioventricular (AV) node: Receives impulse from SA node.

• Bundle of His and bundle branches: Transmit impulse through septum.

• Purkinje fibers: Cause ventricles to contract.

Heart Rhythm and Rate

• Systole: Heart contracts.

• Diastole: Heart rests between contractions.

• Normal sinus rhythm (NSR): SA node controls heart rate.

• Ectopic sites: Other areas produce impulses, causing abnormal rhythms.

Autonomic Control

• Parasympathetic division: Releases acetylcholine, maintains resting heart rate.

• Sympathetic division: Releases norepinephrine and epinephrine, increases heart rate during activity and stress.

Common Cardiovascular Diseases

Heart Diseases

• Angina pectoris: Chest pain due to reduced blood flow to the heart.

• Congestive heart failure: Inability of the heart to pump effectively, leading to edema.

• Myocardial infarction: Heart attack caused by blocked coronary arteries.

Blood Vessel Diseases

• Aneurysm: Abnormal bulging of an artery wall.

• Atherosclerosis: Build-up of plaque in arteries, narrowing the lumen.

• Hypertension: High blood pressure.

• Varicose veins: Enlarged, twisted veins, often in the legs.

Conduction System Diseases

• Arrhythmias: Abnormal heart rhythms, including bradycardia, tachycardia, fibrillation, and asystole.

Laboratory and Diagnostic Procedures

Exercise Stress Tests

• Used to assess heart function under physical stress.

• Monitors blood pressure and electrical activity.

Electrocardiography (ECG)

• Records electrical impulses of the heart.

• Uses chest leads and produces a 12-lead ECG.

• Normal tracing includes P wave, QRS complex, and T wave.

Ultrasonography and Echocardiography

• Color flow duplex ultrasonography: Assesses blood flow and velocity in arteries.

• Echocardiography: Uses sound waves to visualize heart structures.

Medical Procedures

Blood Pressure Measurement

• Sphygmomanometer: Inflatable cuff, pressure gauge, and stethoscope used to measure systolic and diastolic pressures.

• Systolic pressure: Force of ventricular contraction.

• Diastolic pressure: Resting pressure in the artery.

Automatic External Defibrillator (AED)

• Used to restore normal heart rhythm in emergencies.

Pulse Points

• Locations where arterial pulse can be felt to assess heart rate and blood flow.

Drugs and Surgical Procedures

Cardiovascular Drugs

• Digitalis drugs: Derived from Digitalis purpurea (foxglove plant), used to treat heart conditions.

Open Heart Surgery

• Sternum is cut and retracted for access to the heart.

Pacemaker Implantation

• Pacemaker placed under skin, wires attached to heart to regulate rhythm.

Balloon Angioplasty and Stent Placement

• Balloon angioplasty: Balloon catheter compresses plaque to open artery.

• Stent placement: Expanded stent keeps artery open.

Valve Replacement

• Artificial valve implanted to restore normal blood flow.

Summary Table: Major Heart Structures and Functions

Structure	Function
Right Atrium	Receives deoxygenated blood from body
Right Ventricle	Pumps blood to lungs
Left Atrium	Receives oxygenated blood from lungs
Left Ventricle	Pumps oxygenated blood to body
Tricuspid Valve	Prevents backflow to right atrium
Pulmonary Valve	Prevents backflow to right ventricle
Mitral Valve	Prevents backflow to left atrium
Aortic Valve	Prevents backflow to left ventricle

Key Equations

• Blood Pressure: $\text{Blood Pressure} = \text{Cardiac Output} \times \text{Peripheral Resistance}$

• Cardiac Output: $\text{Cardiac Output} = \text{Heart Rate} \times \text{Stroke Volume}$

Additional info:

• Scientific names and drug origins are included for context.

• Descriptions of images and procedures are expanded for clarity.