Name: how the heart gets its blood
Uploaded: 2024-07-18T13:37:01.000Z
Duration: 1 min 21 s
Channel: JoVE

K12 Standards

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

9-12

Human Anatomy and Physiology

Transport

Cardiovascular System

Coronary Circulation

The myocardium has its own network of blood vessels, separate from the systemic and pulmonary circuits, called the coronary circulation.
The left and right coronary arteries originate from the ascending aorta, supplying oxygenated blood to the myocardium.
The left coronary artery divides into the left anterior descending artery or LAD, supplying blood to the ventricular walls, and the circumflex artery, supplying blood to the left atrial and ventricular walls.
The right coronary artery supplies blood to the right atrium. It further branches into the posterior descending artery or PDA, serving the ventricular walls, and the marginal branch, serving the right ventricle.
Anastomoses link different coronary arteries, providing alternate routes for blood supply when arteries are blocked.
The coronary sinus, a large vein fed by many small ones, transports deoxygenated blood to the right atrium.
The great and middle cardiac veins drain the area supplied by the LAD and PDA, respectively.
The small cardiac vein collects blood from the right atrium and ventricle.
Collecting blood from the right ventricle, the anterior cardiac vein empties directly into the right atrium.

coronary circulation

The heart, an organ critical to survival, gets nourishment not from the blood it pumps but from a separate circulation system known as coronary circulation. This is the shortest circulation in the body and is responsible for supplying the heart with the nutrients it needs to function effectively.
Coronary circulation begins at the base of the aorta, where two main arteries arise&#8212;the left and right coronary arteries. These arteries encircle the heart in the coronary sulcus and supply the arterial blood the heart requires.
The left coronary artery moves toward the left side of the heart and divides into two major branches. The left anterior descending artery, or LAD, follows the anterior interventricular sulcus and delivers blood to the anterior two-thirds of the interventricular septum and the anterior walls of both ventricles. The circumflex artery, on the other hand, supplies the left atrium and the posterior walls of the left ventricle.
The right coronary artery also divides into two branches on the right side. The right marginal artery serves the myocardium of the lateral right side of the heart. In contrast, the posterior descending artery, or PDA, runs in the posterior interventricular sulcus to the heart apex and supplies the posterior ventricular walls. Near the apex of the heart, this artery merges with the anterior interventricular artery. The branches of the right coronary artery supply the right atrium and almost all of the right ventricle.
It&#39;s important to recognize the significant variability in the origin of the&#160; PDA. For example, in 70-80% of individuals who are right-heart dominant, the PDA stems from the right coronary artery. In contrast, around 5-10% of the population is left-heart dominant, where the PDA originates from the left circumflex artery. Additionally, about 10-20% of people have a codominant circulation, with the PDA receiving blood from both the circumflex and right coronary arteries.
The coronary arteries provide intermittent, pulsating blood flow to the myocardium. They are located in the epicardium and send branches inward to nourish the myocardium. These arteries deliver blood when the heart is relaxed but are less effective when the ventricles are contracting as they get compressed by the contracting myocardium. Despite the heart accounting for just 1/200 of the body&#39;s weight, it requires about 1/20 of its blood supply, with the left ventricle receiving the most plentiful blood supply.
After passing through the capillary beds of the myocardium, the venous blood is collected by the cardiac veins, which roughly follow the paths of the coronary arteries. These veins join to form an enlarged vessel called the coronary sinus, which empties the blood into the right atrium. The coronary sinus has three large tributaries: the great cardiac vein in the anterior interventricular sulcus, the middle cardiac vein in the posterior interventricular sulcus, and the small cardiac vein running along the heart&#39;s right inferior margin. Several anterior cardiac veins also empty directly into the right atrium.

The myocardium has its own network of blood vessels, separate from the systemic and pulmonary circuits, called the coronary circulation.
The left and ...

Education

JoVE Core

Anatomy and Physiology

Unit 1

The Heart

KEY TERMS AND CONCEPTS

how the heart gets its blood

Coronary circulation is the blood supply that keeps the heart muscle alive. The heart does not use the same blood it pumps to feed itself. Instead, it depends on a separate vessel network that delivers oxygen and nutrients to the myocardium, or heart muscle. This is the shortest circulation in the body.

Coronary circulation begins at the base of the aorta, where the left and right coronary arteries arise. These arteries wrap around the heart in the coronary sulcus and send blood inward to the myocardium. The left coronary artery travels to the left side of the heart and splits into two major branches. The left anterior descending artery, or LAD, runs in the anterior interventricular sulcus and supplies the anterior two-thirds of the interventricular septum and the front walls of both ventricles. The circumflex artery supplies the left atrium and the posterior walls of the left ventricle.

The right coronary artery also divides into two main branches on the right side. The right marginal artery supplies the myocardium along the lateral right side of the heart. The posterior descending artery, or PDA, runs in the posterior interventricular sulcus to the apex of the heart and supplies the posterior ventricular walls. Near the apex, it joins the anterior interventricular artery. The branches of the right coronary artery supply the right atrium and almost all of the right ventricle.

The origin of the PDA can vary among people. In about 70 to 80 percent of individuals with right-heart dominance, the PDA comes from the right coronary artery. In about 5 to 10 percent of people with left-heart dominance, it comes from the left circumflex artery. Another 10 to 20 percent have codominant circulation, where the PDA receives blood from both the circumflex and right coronary arteries.

Coronary arteries sit in the epicardium and send branches inward through the myocardium. They provide intermittent, pulsating blood flow. They supply blood most effectively when the heart is relaxed. When the ventricles contract, the vessels are compressed by the muscle and flow is reduced. Even though the heart is only about 1/200 of body weight, it uses about 1/20 of the body's blood supply. The left ventricle receives the greatest supply.

Venous blood leaves the myocardium through cardiac veins that roughly follow the coronary arteries. These veins join to form the coronary sinus, a large vessel that empties into the right atrium. Its three major tributaries are the great cardiac vein in the anterior interventricular sulcus, the middle cardiac vein in the posterior interventricular sulcus, and the small cardiac vein along the heart's right inferior margin. Several anterior cardiac veins also drain directly into the right atrium.

How the Heart Gets Its Blood

overview of the heart

How the Heart Pumps Blood

The heart is a muscular organ in the chest that pumps blood through the body. It works as the main pump of the vascular system. The heart has four chambers. The two atria are on top, and the two ventricles are below. Blood enters the right atrium from the body as deoxygenated blood, which means it has less oxygen. It then moves to the right ventricle. The right ventricle pumps this blood to the lungs for oxygenation. Oxygenated blood returns from the lungs to the left atrium. It then passes to...

location and orientation of the heart

Heart Position, Apex, and Pericardium

The human heart sits in the mediastinum, the middle space of the thorax. It is about the size of a fist and weighs about 250 to 350 grams. The heart lies on the superior surface of the diaphragm and extends obliquely for about 12 to 14 cm. The heart is positioned anterior to the vertebral column and posterior to the sternum. About two-thirds of its mass lies to the left of the midsternal line. The lungs lie on either side of the heart. The broad base of the heart points toward the right...

layers of the heart wall

Heart Wall Layers and Their Roles

The heart wall has three layers: the epicardium, myocardium, and endocardium. Each layer has a different structure and job. Together, they help the heart pump blood through the body. The outermost layer is the epicardium. It is the visceral layer of the serous pericardium. This layer has a thin, transparent mesothelial surface and an inner layer of areolar connective tissue. Fat deposits are also found here, and they increase with age. The myocardium is the thickest layer of the heart wall.

chambers of the heart

Heart Chambers and Blood Flow Pathway

The heart chambers work together to move blood through the body and the lungs. The human heart has four chambers: the right atrium, right ventricle, left atrium, and left ventricle. The atria are the upper chambers, and the ventricles are the lower chambers. They are separated by the interatrial septum and the interventricular septum. The outside of the heart also shows clear dividing lines. The coronary sulcus separates the atria from the ventricles. The anterior and posterior...

heart valves

How Heart Valves Prevent Backflow

The heart valves keep blood moving in one direction through the heart. The main valve groups are the atrioventricular, or AV, valves and the semilunar valves. Together, they help stop blood from flowing backward as the heart chambers contract and relax. The AV valves stop blood from moving back into the atria when the ventricles contract. They work with the chordae tendineae, which are tough cord-like strands, and the papillary muscles. When the ventricles relax, the chordae tendineae are...

overview of systemic and pulmonary circulation

overview-of-systemic-and-pulmonary-circulation

Pathway of Blood Through Heart and Lungs

The circulatory system moves blood in two linked routes: pulmonary circulation and systemic circulation. Together, these circuits carry blood between the heart, the lungs, and the rest of the body. Pulmonary circulation comes first in this cycle. In pulmonary circulation, deoxygenated blood is pumped from the right ventricle to the lungs through the pulmonary trunk and pulmonary arteries. In the lungs, the blood picks up oxygen. It then returns to the heart through the pulmonary veins and...

Coronary circulation is the blood supply that keeps the heart muscle alive. The heart does not use the same blood it pumps to feed itself. Instead, it depends on a separate vessel network that delivers oxygen and nutrients to the myocardium, or heart muscle. This is the shortest circulation in the body. Coronary circulation begins at the base of the aorta, where the left and right coronary arteries arise. These arteries wrap around the heart in the coronary sulcus and send blood inward to the...

conduction system of the heart

How the Heart Sets Its Own Beat

The heart sets its own beat through autorhythmicity, which is its built-in ability to generate electrical signals and start muscle contractions. This process depends on a self-regulating conduction system. It includes pacemaker cells and specialized conducting cells. Pacemaker cells are found in two main nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node can depolarize on its own. That electrical change starts an action potential that causes the atria to contract. <br...

electrocardiogram

Reading Heart Waves on an ECG

An electrocardiogram, or ECG/EKG, records the heart’s electrical signals during each heartbeat. Electrodes are placed on the arms, legs, and chest. The electrocardiograph then amplifies the signals and creates 12 tracings that show the heart’s electrical activity from different views. A normal ECG has three main waveforms. The P wave shows atrial depolarization, which is the spread of action potentials through the atria. The QRS complex shows rapid ventricular depolarization, and the T wave...

cardiac cycle

Heartbeat Stages and Valve Action

The heartbeat follows a set of stages that move blood through the heart. This process is driven by changes in pressure and by the opening and closing of the heart valves. It includes systole, or contraction, and diastole, or relaxation. The sequence starts in mid-to-late diastole, when the heart is fully relaxed. During this time, blood flows passively from the atria into the ventricles. Atrial systole then begins as the atria contract and push the remaining blood into the ventricles. Next...

correlation between ecg and cardiac cycle

correlation-between-ecg-and-cardiac-cycle

ECG Waves Across the Cardiac Cycle

ECG waves show how the heart’s electrical signals line up with the cardiac cycle. The electrical activity appears before the heart muscle’s mechanical contraction and relaxation. On an electrocardiogram, the main waves help link each electrical event to a specific stage of the heartbeat. A cardiac action potential starts in the SA node, or sinoatrial node, and spreads through the atria and the AV node in about 0.03 seconds. This creates the P wave on the ECG and triggers atrial contraction.

disturbances in heart rhythm

Heart Rhythm Disorders and Emergency Care

Heart rhythm disorders, also called arrhythmias or dysrhythmias, happen when the heart’s conduction system has a defect. They can make the heart beat irregularly, too fast, or too slow. People may notice chest pain, shortness of breath, or fainting. Many things can trigger an arrhythmia. Stress, caffeine, alcohol, nicotine, cocaine, certain drugs, congenital defects, diseases, and electrolyte imbalances are all possible causes. These triggers can disrupt the electrical signals that control the...

heart sounds

Auscultation and Normal Heart Sounds

Auscultation is the process of listening to internal body sounds with a stethoscope. Heart sounds are created by turbulence in blood flow when the heart valves close. These sounds are usually heard best a little away from the valves, where the blood flow spreads the sound. The heart makes four types of sounds, but a stethoscope usually picks up only S1 and S2. S1 is the “lub” sound. It happens when the atrioventricular, or A-V, valves close at the start of ventricular systole. S1 is usually...

cardiac output and stroke volume

How Heart Rate Shapes Cardiac Output

Cardiac output shows how much blood the heart pumps each minute. It is the volume ejected by the left or right ventricle into the aorta or pulmonary trunk. Heart rate and stroke volume work together to set this value. Heart rate is the number of heartbeats per minute, and stroke volume is the amount of blood pumped out with each beat. Cardiac output is found by multiplying heart rate by stroke volume. In an average resting adult male, it is about 5.25 L/min. That estimate uses a heart rate of...

regulation of stroke volume

Stroke Volume: Preload to Afterload

Stroke volume depends on preload, contractility, and afterload. These three factors work together to control how much blood a ventricle ejects with each heartbeat. Understanding them helps explain how the heart keeps blood moving through the circulatory system. Preload is the stretch on the heart before it contracts. It is linked to the Frank-Starling law of the heart, which says that when the heart fills with more blood during diastole, it contracts more forcefully during systole. Preload is...

regulation of heart rates

How the Heart Adjusts Its Beat

Heart rate changes through signals from the autonomic nervous system, hormones, and the heart's own built-in control systems. The autonomic nervous system has two main parts. The sympathetic nervous system raises heart rate, and the parasympathetic nervous system lowers it. The sympathetic nervous system releases norepinephrine and epinephrine. These chemicals act on beta-1 adrenergic receptors in the heart. They increase the rate of depolarization in the sinoatrial (SA) node, which is the...

exercise and cardiac output

How Exercise Strengthens the Heart

Exercise strengthens the heart and improves cardiovascular health. Aerobic exercise is especially effective. The American Heart Association recommends 150 minutes of moderate to intense aerobic exercise each week for a healthy heart. Brisk walking, running, bicycling, cross-country skiing, and swimming are all examples. These activities are best done three to five times per week. During sustained exercise, muscles need more oxygen. The body meets this demand through enough cardiac output and...

imbalances in cardiac output

Congestive Heart Failure Causes and Effects

Congestive heart failure (CHF) happens when the heart becomes an inefficient pump. The heart normally keeps blood leaving the heart and blood returning to it in balance. When that balance is disrupted, blood circulation drops and the body does not get enough flow. CHF can affect the left side of the heart, the right side, or both. Left-side failure can cause pulmonary congestion, which means blood backs up in the lungs. The right side may still send blood to the lungs, but the left side cannot...

development of the heart

Heart Tube Formation and Folding

Heart tube formation and folding shape the early human heart. The process begins in the mesoderm, a middle layer of embryonic tissue, on day 18 or 19 after fertilization. It starts in the cardiogenic area, a group of mesodermal cells at the head end of the embryo. These cells extend into cardiogenic cords and then change into hollow endocardial tubes. As the embryo folds from side to side, the paired tubes move closer together. They join into one primitive heart tube by day 21. By day 22, this...

key terms and concepts

Learn how coronary arteries and veins supply the heart muscle, including the LAD, PDA, coronary sinus, and blood flow patterns in the heart.

How the Heart Gets Its Blood | JoVE K12

anatomy and physiology

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

Overview of the Cardiovascular System

The cardiovascular or circulatory system comprises the blood, the heart, and the blood vessels.
Blood is a specialized fluid comprising cells in a liquid ...

Characteristics and Functions of Blood

Approximately 8% of the body mass comprises whole blood, a specialized connective tissue vital for transportation, regulation, and protection.
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Composition of Blood

Whole blood consists of the blood plasma, a fluid extracellular matrix, and formed elements, including cells and cell fragments.
Blood plasma, which makes ...

Composition of Blood Plasma

Blood plasma is a fluid that contains approximately 92% water and 8% solutes. The solutes include various types of proteins, which constitute about 7% of ...

Overview of Hematopoiesis

Hematopoiesis, or hemopoiesis, is the production of the formed elements in blood from common progenitors, called hematopoietic stem cells, or HSCs.
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Production of Formed Elements

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Role of Hematopoietic Growth Factors

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...

Erythropoiesis

Factors Affecting Erythropoiesis

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Structure and Function of Erythrocytes

There are 4.2 to 6 million erythrocytes, or red blood cells, per microliter of blood. These small cells are flattened biconcave discs with depressed ...

Hemoglobin

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Structure and Function of Leukocytes

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Classification of Leukocytes

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Structure and Function of Platelets

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Introduction to Hemostasis

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Vascular Spasm

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Formation of the Platelet Plug

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Coagulation

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extrinsic-and-intrinsic-pathways-of-hemostasis

Extrinsic and Intrinsic Pathways of Hemostasis

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Clot Retraction and Fibrinolysis

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Disorders of Hemostasis

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The ABO Blood Group

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Rh Blood Group

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Blood Typing

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Blood Transfusion

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Bone Marrow Sampling and Transplants

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Blood

Content elaboration: Blood is composed of plasma and the formed elements: red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). The primary functions of blood are transportation, protection and regulation. Plasma, the most abundant component of blood, is the liquid portion that transports dissolved nutrients, waste, hormones, antibodies and proteins throughout the body. Red blood cells carry oxygen used during cellular processes throughout the body. White blood cells identify and protect the body against infectious disease and foreign cells. Platelets bind together when a blood vessel is damaged resulting in blood clot formation. The major ABO blood types, A, B, AB and O, are determined by the presence or absence of antigens on the surface of red blood cells. An additional antigen is present or absent on the surface of red blood cells determining Rh factor. Blood type antibodies are found in plasma. Processes related to blood include the production of blood cells and platelets, and hemostasis. Homeostatic imbalances are explored. These include, but are not limited to, sickle cell anemia, hemophilia, deep vein thrombosis, leukemia and lymphoma. Investigations are used to understand and explain blood in a variety of inquiry and design scenarios that can incorporate evolutionary concepts, scientific reasoning, comparative analysis, communication skills and real-world applications.

Blood

Overview of the Heart

The heart is a hollow muscular organ that pumps blood through the body.
It is cone-shaped and weighs about 250 to 300 grams on average.
The heart is ...

Location and Orientation of the Heart

The heart is located in the mediastinum and spans from the first rib to the diaphragm. It lies anterior to the vertebral column, posterior to the sternum, ...

Layers of the Heart Wall

The heart wall has three layers&#8212;the epicardium, the myocardium, and the endocardium.
The outermost layer, the epicardium, is the visceral layer of ...

Chambers of the Heart

The heart has four chambers&#8212;the right atrium, right ventricle, left atrium, and left ventricle.
Externally, the coronary sulcus separates the atria ...

Heart Valves

The heart valves open and close in response to the pressure gradients created by the contracting heart chambers.
These valves regulate the blood flow by ...

Overview of Systemic and Pulmonary Circulation

The pulmonary and systemic circuits work sequentially to move blood between the heart, lungs, and peripheral tissues.
Pulmonary circulation transports ...

Conduction System of the Heart

Autorhythmicity refers to the innate ability of the heart to initiate electrical signals and trigger muscle contractions.
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Electrocardiogram

An electrocardiogram, abbreviated as ECG, or EKG, is a test that captures a record of the heart&#39;s electrical activity.
It is performed by placing ...

Cardiac Cycle

The cardiac cycle comprises the contraction, or systole, and relaxation, or diastole, during one heartbeat.
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Correlation between ECG and Cardiac Cycle

The electrical signals recorded on an electrocardiogram (ECG) occur before the mechanical processes of contraction and relaxation during the cardiac ...

Disturbances in Heart Rhythm

Disturbances in the heart rhythm, or arrhythmia, can cause irregular heartbeats.
If the heart rate falls below fifty beats per minute, it is called ...

Heart Sounds

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These are best heard at chest locations slightly away from the valves ...

Cardiac Output and Stroke Volume

Cardiac output is the blood volume ejected from the ventricles into the blood vessels each minute. It is calculated by multiplying the stroke volume by ...

Regulation of Stroke Volume

The stroke volume, which is the volume of blood ejected by a ventricle with each heartbeat, is regulated by three factors: preload, contractility, and ...

Regulation of Heart Rates

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Exercise and Cardiac Output

Physical activity is beneficial for cardiovascular health.
For example, the American Heart Association recommends moderate-intensity aerobic exercises, ...

Imbalances in Cardiac Output

Congestive heart failure, or CHF, can reduce the heart's pumping efficiency.
In CHF, an increase in preload excessively stretches the myocardium, ...

Development of the Heart

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Overview of Blood Vessels

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Structure of Blood Vessels

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Arteries and Arterioles

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Venous Return

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Capillaries and Their Types

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Pulse

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Capillary Beds

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Capillary Exchange

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Venules

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Neural Regulation of Blood Pressure

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Cardiovascular System

Content elaboration: The cardiovascular system consists of the heart and blood vessels. The heart is mostly comprised of cardiac muscle which is supplied with oxygenated blood by coronary arteries. The structure of the heart includes four chambers, four valves and major vessels leading to and from the heart. The flow of blood through the heart, pulmonary and systemic circuits should be explored. Blood flows from arteries, to arterioles, to capillaries, to venules, then to veins. In the capillaries, oxygen, nutrients, and chemical messengers diffuse out (leave) and carbon dioxide and other waste products diffuse in (enter). Veins have valves that keep the blood flowing toward the heart. The primary function of the cardiovascular system is the transport of oxygen, carbon dioxide, hormones, nutrients, waste products and chemical messengers. Processes involved in the cardiovascular system include the cardiac cycle and cardiac and conductive pathway which is measured by electrocardiograms and blood pressure. Homeostatic imbalances are explored. These include, but are not limited to, a variety of cardiovascular diseases and structural imperfections of the heart, valves and vessels. Examples include, but are not limited to, myocardial infarction, aneurysm, atherosclerosis, hypertrophic cardiomyopathy, hypo/hypertension and arrhythmias. Investigations are used to understand and explain the cardiovascular system in a variety of inquiry and design scenarios that can incorporate evolutionary concepts, scientific reasoning, comparative analysis, communication skills and real-world applications.

How the Heart Gets Its Blood

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