Differences Between Left and Right Ventricles Explained
The ventricle meaning can be defined as the lower chamber of the heart that is used to pump the blood to the rest of the body. Ventricles pump the blood out of the body into the circulatory system. In the human body, there are two heart ventricles which are termed as right and left ventricles, the important muscular differentiation of the ventricles from the atrium is the presence of the thick muscular wall compared to the atrium. This article focuses on the understanding of what are ventricles, the location and features of the right ventricle, location, and features of the left heart ventricle, interventricular septum, ventricle function, and pathology of the ventricle. This article also deals with a brief review of cardiac anatomy.
Cardiac Anatomy
The cardiac system of the human body consists of two atriums and two ventricles. The heart location can be described as the mediastinal located structure in the pericardial cavity. The heart is obliquely positioned, according to the anatomical position, the heart is posterior to the sternum, superior to the diaphragm. The heart is surrounded by a heart wall, the heart wall has three layers they are as follows,
Pericardium- The outermost layer of the heart has a fibrous sac-like structure from the outside and the inner surface is parietal.
Epicardium- This is the layer just below the pericardium. It is also known as the visceral layer of the pericardium, it is the layer that is surrounded by the blood vessels that allow the coronary circulation in the heart.
Myocardium- It is the middle thickest layer of the heart. It is important to note that the heart ventricles have thicker layers of the myocardium than the heart atrium. One of the specializations of the myocardium is the presence of the intercalated disk; an intercalated disk can be defined as the border or plasma membrane of the two muscle fiber cells. These intercalated disks ensure the connection between the left and right ventricle and similarly left and right atrium. The coordinated contraction of the atrium and ventricle is gained through the action of this intercalated disk. It is important to note that the valves of the heart lack this intercalated disk
Endocardium- The endocardium is the innermost layer of the heart wall. The coronary arteries and veins are present till this layer to ensure coronary circulation.
The important part of heart anatomy is the presence of valves. It is also important to understand the anatomical positioning and function of the valve to understand the ventricle function. There are four major valves present in the heart; they are two atrioventricular valves and two semilunar valves. Atrioventricular valves are present in between each heart atrium and heart ventricles. The valve between the left atrium and left ventricle is known as the bicuspid valve or mitral valve, whereas the valve present between the right atrium and right ventricle is known as the tricuspid valve. The semilunar valves are present between the heart ventricles and blood vessels carrying blood out of the heart, there are two semilunar valves namely, the pulmonary valve and aortic valve.
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Right Ventricle
It is important to understand what ventricles are to understand the function of the ventricle. The right ventricle is the lower chamber of the heart which is closer to the apex of the heart. The right heart ventricle collects blood from the right atrium through the tricuspid valve. The deoxygenated blood from the right ventricle is carried to the lungs by the pulmonary artery. According to the ventricle meaning the ventricle pumps blood out of the heart. It is interesting to note that the overall size of the right ventricle is smaller than the left ventricle. The right ventricle is one-third of the thickness of its atrium counterpart. It is convex in shape and lies between the 3rd and 6th costal cartilages. The interventricular septum acts as the left wall of the posterior of the right ventricle. The right ventricle has the pulmonary semilunar valve. These valves guard the flow of blood out of the heart.
The tendon of the infundibulum also known as the conus ligament is one of the important structures of the right ventricle. It can be defined as the band of collagenous tissue. These tissues extend from the conus arteriosus to the aortic root.
Another important internal feature of the right ventricle is the presence of the papillary muscles, the primary function of these muscles is to prevent leakage of the blood through AV valves during the systole (ventricular contraction).there are three types of papillary muscle they are as follows,
Anterior Papillary Muscle- It originates from the right ventricle’s anterior walls. They are connected to the tricuspid leaflet at the anterior and posterior sides. That is the largest muscle among all the papillary muscles.
Posterior Papillary Muscle- They are comparatively smaller than the anterior muscle. The origination can be defined anatomically from the inferior wall of the right ventricle. They are attached to the tricuspid valve via the septal and posterior sides of the valve.
Septal Papillary Valve- They are attached to the interventricular septum, they are also attached to the tricuspid valve.
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Left Ventricle
According to ventricle meaning the left ventricle maintains the coronary circulation during the relatively high-pressure systemic circulation. The left ventricle is comparatively larger. The pulmonary veins carry oxygenated blood to the left atrium, the blood moves into the ventricle through the bicuspid valve ( also known as a mitral valve) to the left ventricle. The ventricle pushes the blood out from the heart by ventricular contraction (systole) through the aortic valve and into the aorta, which then divides into various capillaries.
The cardiac grooves are also an important feature of the left ventricle, these grooves provide the physical distinction between the right atrium and the left atrium. It is also important to note that the valves both semilunar and atrioventricular are closely associated with each other in comparison to the right heart ventricles. There is the presence of a fibrous subaortic curtain, this originated from the right and left arches of the posterior side of the aortic valve. The work of this fibrous subaortic curtain is to separate the aortic valve from the mitral valve. The left ventricle also contains the papillary muscle but they are comparatively larger in size. The papillary muscle prevents blood leakage during the ventricular systole.
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Ventricle Function
The primary role of the ventricle is to pump blood out of the heart either in pulmonary circulation or in systemic circulation. In medical terms, the contraction is termed as systole, when the ventricles contract they are termed as ventricular systole. The relaxation of the heart chamber is known as the diastole similarly when the ventricle is in a relaxed state they are termed as the ventricular diastole.
The atrial chamber when undergoing the systole the ventricles are in diastole that is the passive flow of the blood into the ventricles. At the end of the atrial systole, there is enough atrium pressure to push the residual blood into the ventricle and depolarize.
As the blood volume reaches a critical level in the ventricle, it generates enough pressure for the opening of semilunar valves and the closure of AV valves, as the systole of the ventricle ends blood moves out through blood vessels, and the ventricles depolarize.
Isovolumetric contraction is that phase during which the ventricles are in systole but the intraventricular contraction is not sufficient to open the semilunar valves thus there is no net blood loss from the ventricle. To exit the isovolumetric contraction phase the pressure required is approximately 8 mmHg on the right side, and 85 mmHg on the left ventricle.
Ventricular Pathology
The disorders associated with ventricles can be broadly classified as congenital and acquired disorders that affect the ventricles. The table listed below gives an overview of the disorder:
FAQs on Ventricle in Biology: Anatomy & Roles
1. What is a ventricle in the context of the human heart?
In the human heart, a ventricle is one of the two lower chambers. These chambers are responsible for the powerful pumping action that pushes blood away from the heart. The heart has a right ventricle and a left ventricle, each playing a crucial role in circulation.
2. What is the main difference between the right and left ventricles?
The primary difference lies in their function and the destination of the blood they pump. The right ventricle pumps deoxygenated blood to the lungs for oxygenation (pulmonary circulation). The left ventricle pumps oxygenated blood to the rest of the body (systemic circulation), which requires significantly more force.
3. What is the importance of the muscular walls of the ventricles?
The thick, muscular walls of the ventricles, known as the myocardium, are essential for generating the high pressure needed to pump blood throughout the body. Their powerful contractions, called systole, propel blood into the major arteries, ensuring it reaches every tissue and organ.
4. Why is the wall of the left ventricle significantly thicker than the right ventricle?
The left ventricle's wall is thicker because it has a much more demanding job. It must generate enough force to pump oxygenated blood through the aorta to the entire body, from the head to the toes. In contrast, the right ventricle only needs to pump deoxygenated blood a short distance to the lungs, which requires far less pressure. The structural difference is a direct result of this functional difference.
5. How do ventricles and atria differ in their roles during the cardiac cycle?
Atria and ventricles have distinct and complementary roles:
- Atria: These are the upper, thinner-walled chambers that act as receiving rooms. They collect blood returning to the heart (deoxygenated in the right atrium, oxygenated in the left atrium) and pump it into the ventricles.
- Ventricles: These are the lower, thicker-walled chambers that act as powerful pumps. They receive blood from the atria and contract forcefully to eject it from the heart into the arteries.
6. What happens during ventricular systole and diastole?
- Ventricular Systole: This is the contraction phase. The ventricles contract, increasing the pressure inside them. This forces the atrioventricular (AV) valves shut to prevent backflow and pushes the semilunar (aortic and pulmonary) valves open, ejecting blood into the aorta and pulmonary artery.
- Ventricular Diastole: This is the relaxation phase. The ventricles relax and expand, causing the pressure inside to drop. The semilunar valves snap shut to prevent blood from flowing back into the ventricles, and the AV valves open to allow blood from the atria to refill the ventricles.
7. Are the ventricles found in the heart the same as the ventricles in the brain?
No, they are completely different structures with unrelated functions. Heart ventricles are muscular chambers that pump blood. Brain ventricles are an interconnected series of cavities within the brain that produce and circulate cerebrospinal fluid (CSF). The CSF acts as a cushion, protecting the brain and spinal cord from trauma and providing nutrients.
8. What is the role of the valves connected to the ventricles?
The valves ensure that blood flows in only one direction. There are two main types:
- Atrioventricular (AV) Valves: The tricuspid (right) and mitral (left) valves are located between the atria and ventricles. They prevent blood from flowing back into the atria when the ventricles contract.
- Semilunar (SL) Valves: The pulmonary and aortic valves are located at the exit of each ventricle. They prevent blood from the arteries from flowing back into the ventricles after they have contracted.
