Coronary Circulation: Definition, Process, Diagram, Flow Chart

What Is Coronary Circulation?

Coronary circulation refers to the blood flow through coronary arteries and veins that supply oxygen and nourishment to the myocardium, that is, the heart muscle. The coronary arteries arise directly from the aorta and provide oxygenated blood to the myocardium, while the coronary veins collect deoxygenated blood, whereby it gets all the elements to function properly for the sustenance of life.

Anatomy Of The Coronary Circulation

Understanding the anatomy of coronary circulation is important in appreciating the way that the heart maintains its blood supply. This section shall consider the anatomy of the heart, including the coronary arteries and veins.

Anatomy Of The Heart

The heart is a muscular organ that pumps blood throughout the body. It contains four chambers: two atria and two ventricles.

Coronary Arteries

• Left Main Coronary Artery (LMCA): The blood supply is provided to the left side of the heart.

• Left Anterior Descending Artery (LAD): It comes as the side branch of the LMCA, passing towards the front portion of the heart.

• Left Circumflex Artery (LCA): It also goes as a side branch from the LMCA, giving supply to the side and the back portions of the heart.

• Right Coronary Artery (RCA): Blood supply to the right side of the heart.

Coronary Veins

• Great Cardiac Vein: Blood drainage from the front portion of the heart

• Middle Cardiac Vein: Blood drainage from the back portion of the heart.

• Small Cardiac Vein: Blood drainage from the inferior portion of the heart.

• Coronary Sinus: It is a large vessel that drains blood from the coronary veins and empties it into the right atrium.

Physiology Of Coronary Circulation

This section identifies how blood flows through the coronary circulation system to ensure appropriate oxygenation of heart muscle plus the necessary nutrition.

Blood Flow Dynamics

Blood flow to the coronary happens in the relaxation phase of the heart, and it provides oxygen-rich blood to the heart muscle.

Myocardial Perfusion And Oxygen Supply

Myocardial perfusion is the delivery of blood toward the tissue of the heart that ought to be enough to supply adequate oxygen to meet the metabolic needs of the heart.

Regulation Of Coronary Blood Flow

• The heart can change blood flow based on its needs.

• The change in the blood flow of the coronary through the hormonal and nervous systems.

Functions of Major Coronary Arteries

Describe each of the coronary arteries, including their function and what part of the heart muscle they provide blood flow to.

Left Main Coronary Artery (LMCA)

• It supplies blood to the left atrium and the left ventricle.

Left Anterior Descending Artery (LAD)

• Blood supply is directed towards the front and bottom of the left ventricle and to the front of the septum.

Left Circumflex Artery (LCA)

• Supplies blood to the outer side and back of the left ventricle.

Right Coronary Artery (RCA)

• It provides blood to the right atrium, the right ventricle, the lower part of both ventricles and the back of the septum.

Functions of Major Coronary Veins

This section talks about the details of all coronary veins and their functions in collecting oxygen-depleted blood from the cardiac muscle.

Great Cardiac Vein

• It drains blood from the front or anterior part of the heart.

Middle Cardiac Vein

• Drains blood from the back of the heart.

Small Cardiac Vein

• It drains blood from the lower portion of the heart.

Coronary Sinus

• Collects blood from the coronary veins emptying it into the right atrium.

Common Disorders Of Coronary Circulation

Some of the common disorders that affect coronary circulation, its causes, symptoms, and treatment options.

Coronary Artery Disease (CAD)

• Definition and Causes: CAD occurs when plaque builds up and the coronary arteries are narrowed or occluded.

• Symptoms and Risk Factors: The patient will feel chest pain with shortness of breath; other risk factors include smoking, high blood pressure, and a high count of cholesterol.

• Prevention and Treatment: Changes to the lifestyle, medication, and even surgical procedures such as angioplasty.

Myocardial Infarction (Heart Attack)

• Definition and Causes: A heart attack essentially refers to the clogging or blockage of the blood flow to parts of the heart.

• Symptoms and Emergency Response: One would be having discomfort in the chest, shortness of breath, and nausea. One should call for medical help immediately.

• Treatment and Recovery: Medications are involved along with lifestyle changes and surgical interventions.

Angina Pectoris

• Definition and Classification: Angina pectoris refers to chest pain, typically caused by a reduction in blood flow towards the heart. The most common forms of angina are stable and unstable angina.

• Symptoms and Treatment: These vary from chest pain to discomfort. Its treatment comprises drugs and changes in lifestyle.

Diagnosis of Coronary Circulation Disorders

The section sets out the various techniques used in diagnosing coronary circulation problems.

Electrocardiogram (ECG)

ECG measures the electrical activity of the heart and detects any irregularities therein.

Stress Tests

The way the heart works during physical stress is assessed.

Coronary Angiography

Dye is used, which is visible by X-ray, to show up the coronary arteries.

Cardiac MRI And CT Scans

Detailed pictures of the structure and function of the heart are obtained.

Treatment & Management Options

The treatment and management options include:

Lifestyle & Prevention

A healthy diet and regular exercise, with avoidance of smoking and alcohol.

Medications

• Anti-anginal drugs relieve chest pain.

• Blood Thinning agents prevent blood clots from forming.

• Cholesterol-reducing drugs prevent plaque deposition.

Surgical Interventions

• Angioplasty unblocks the blocked arteries surgically

• Stent placement opens up blocked arteries.

• Coronary Artery Bypass Grafting (CABG), by-passes obstructed arteries.

Recent Advances In Coronary Circulation Research

This section deals with the recent advances made in coronary circulation research in the form of new diagnostic techniques or newer modalities of treatment.

New Diagnostic Techniques

Better diagnostic tools using improved techniques of imaging.

New Treatment Modalities

Newer treatments for coronary artery disease.

New Therapies

Future therapies will help in the enhancement of coronary circulation.

Coronary Circulation NEET MCQs (With Answers & Explanations)

Types of questions asked from this topic are:

• Physiology of coronary circulation

• Disorders of coronary circulation

Practice Questions for NEET

Q1. The circulation of blood to and from cardiac musculature is

1. Coronary system

2. Pulmonary system

3. Systematic circulation

4. None of these

Correct answer: 1) Coronary system

Explanation:

The circulation of blood within the heart muscles is termed coronary circulation. It's a vital process involving a network of vessels that ensure the myocardium's oxygen and nutrient supply and waste removal. Key components include:

1. Coronary arteries: Emerging from the aorta's base, these arteries are crucial for delivering oxygenated blood. The major ones are:
- Left coronary artery (LCA) branching into left anterior descending artery (LAD) and left circumflex artery (LCx).
- Right coronary artery (RCA), serving the heart's right side and some left regions.

2. Coronary veins: These vessels collect deoxygenated blood from the myocardium, ultimately returning it to the right atrium via the coronary sinus.

Hence, the correct answer is option 1) Coronary system.

Q2. During systemic circulation, veins bring deoxygenated blood into the superior vena cava, inferior vena cava, or coronary sinus which opens into the

1. Right atrium

2. Left atrium

3. Right ventricle

4. Left ventricle

Correct answer: 1) Right atrium

Explanation:

As we have to know:

Circulation is important for transporting oxygen and nutrients to different tissues of the body and removing carbon dioxide and other wastes from the tissue

• This type of circulation includes the flow of oxygenated blood from the left ventricle to all parts of the body and deoxygenated blood from various body parts to the right atrium.

• The arteries of systemic circulation arise from the aorta. It also includes bronchial arteries which carry nutrients to the lungs

• Veins bring deoxygenated blood into the superior vena cava, inferior vena cava, or coronary sinus which opens into the right atrium

Hence, the correct answer is option 1. Right atrium.

Q3. A part of circulatory system that transports deoxygenated blood from heart to the lungs and brings oxygenated blood back to the heart is referred to as

1. Pulmonary circulation

2. Coronary circulation

3. Systemic circulation

4. Single circulatory system

Correct answer: 1) Pulmonary circulation

Explanation:

The heart ---------Lungs---------The heart
Deoxygenated blood travels from the right ventricle to the lungs as part of pulmonary circulation, whereas oxygenated blood returns to the left atrium from the lungs.
After emerging from the right ventricle, the pulmonary trunk splits into the left and right pulmonary arteries.
The left and right lungs get deoxygenated blood from the left and right pulmonary arteries, respectively. The lungs are where the gas exchange takes place.
Likewise, each lung's two pulmonary veins deliver oxygen-rich blood to the left atrium.

The chambers of the heart related to the lungs through pulmonary vessels together form pulmonary circulation.

Hence, the correct answer is 1) Pulmonary circulation.

Also Read:

• MCQs on Coronary Circulation

• Cardiac Cycle

• Difference between Single and Double Circulation

Recommended Video on Coronary Circulation