aHeart chamber is a general term used to refer to any chambers of the mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

ian heart

Heart

The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

. The heart consists of four chambers: the right and left atrium and the right and left ventricle. The top chambers are connected to the bottom chambers by valves and are separated by the coronary sulcus

Coronary sulcus

The atria of the heart are separated from the ventricles by the coronary sulcus ; this contains the trunks of the nutrient vessels of the heart, and is deficient in front, where it is crossed by the root of the pulmonary artery.-External links:*...

. The left and right side of the heart are separated by the posterior interventricular sulcus.

Function and Location

• Right atrium
  Atrium (anatomy)
  In anatomy, the atrium , sometimes called auricle , refers to a chamber or space. For example, the term is used for a portion of the lateral ventricle in the brain and the blood collection chamber of the heart...
  
  : Situated in the upper right section of the heart, this chamber receives oxygen
  Oxygen
  Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
  
  -depleted blood
  Blood
  Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
  
   from the body via two major veins, the superior vena cava
  Superior vena cava
  The superior vena cava is truly superior, a large diameter, yet short, vein that carries deoxygenated blood from the upper half of the body to the heart's right atrium...
  
   and the inferior vena cava
  Inferior vena cava
  The inferior vena cava , also known as the posterior vena cava, is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart....
  
  . This chamber then pumps blood through the tricuspid valve
  Tricuspid valve
  The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, between the right atrium and the right ventricle. The normal tricuspid valve usually has three leaflets and three papillary muscles. They are connected to the papillary muscles by the chordae...
  
   into the right ventricle situated below.
• Right ventricle
  Ventricle (heart)
  In the heart, a ventricle is one of two large chambers that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. The Atria primes the Pump...
  
  : Located below the right atrium, this chamber receives oxygen-depleted blood from the right atrium and pumps it through the pulmonary valve
  Pulmonary valve
  The pulmonary valve is the semilunar valve of the heart that lies between the right ventricle and the pulmonary artery and has three cusps. Similar to the aortic valve, the pulmonary valve opens in ventricular systole, when the pressure in the right ventricle rises above the pressure in the...
  
   and into the lung
  Lung
  The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
  
  s via the right and left pulmonary artery
  Pulmonary artery
  The pulmonary arteries carry deoxygenated blood from the heart to the lungs. They are the only arteries that carry deoxygenated blood....
  
  .
• Left atrium: This chamber sits opposite the right atrium and is the upper part of the heart that receives oxygen-rich blood from the lungs via the right and left pulmonary vein
  Pulmonary vein
  The pulmonary veins are large blood vessels that carry blood from the lungs to the left atrium of the heart. In humans there are four pulmonary veins, two from each lung...
  
  s and pumps it through the bicuspid valve or mitral valve
  Mitral valve
  The mitral valve is a dual-flap valve in the heart that lies between the left atrium and the left ventricle...
  
   into the left ventricle.
• Left ventricle: This chamber is the lower part of the heart that receives oxygen-rich blood from the left atrium above it, and pumps it through the aortic valve
  Aortic valve
  The aortic valve is one of the valves of the heart. It is normally tricuspid , although in 1% of the population it is found to be congenitally bicuspid . It lies between the left ventricle and the aorta....
  
   to be distributed throughout the entire body via the aorta
  Aorta
  The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
  
  , including to the heart muscle itself through the coronary arteries.

The right atrium makes up the majority of the right boarder of the heart and the right ventricle makes up the majority of the inferior boarder. The left boarder of the heart consists of the left ventricle. In addition, the heart chamber located in the most superior position is the left atrium. The bottom left region, which includes the apex of the heart

Apex of the heart

The apex of the heart is the lowest superficial part of the heart.It is directed downward, forward, and to the left, and is overlapped by the left lung and pleura.-External anatomy:...

, sticks out more anteriorly compared to the rest of the heart.

Valves

Each heart chamber includes valves vital to the efficiency of the circulatory system. These valves open to allow the blood to flow in the right direction into, within, or out of the heart, and close to prevent the backflow of blood. There are four main valves that allow the chambers of the heart to carry out their function efficiently and they relax and contract during a heartbeat

Heartbeat

Heartbeat may refer to:* Cardiac cycle of the heart* Heart sounds* Pulse* The interval for keeping alive a push e-mail connection* Heartbeat , a British police drama* HeartBeat Heartbeat may refer to:* Cardiac cycle of the heart* Heart sounds* Pulse* The interval for keeping alive a push e-mail...

.

The Tricuspid Valve

The tricuspid valve is located between the right atrium and the right ventricle. Blood passively fills the right atrium during diastole

Diastole

Diastole is the period of time when the heart fills with blood after systole . Ventricular diastole is the period during which the ventricles are relaxing, while atrial diastole is the period during which the atria are relaxing...

 phase of the right atrium. When the right atrium is in systole

Systole

Systole may refer to:*Systole , a term describing the contraction of the heart*Systolic array, a term used in computer architecture*Systolic geometry, a term used in mathematics...

 phase, the contraction forces this valve open, thereby forcing any additional de-oxygenated blood into the ventricle.

The Semi-Lunar Pulmonary Valve

The semi-lunar pulmonary valve is located between the right ventricle and the pulmonary trunk. During ventricle systole, the pressure within the chamber will increase until the valve is forced open. De-oxygenated blood can thereby be carried through the pulmonary arteries to each lung. This valve is named because the shape resembles half-moon pockets. When the ventricle relaxes, the pressure within the chamber decreases and blood fills these pockets causing them to close.

The Mitral Valve

The mitral valve is located between the left atrium and the left ventricle. Similar to the tricuspid valve, during the atrium's systole phase, the valve is forced open to allow the oxygenated blood from the lungs to enter into the left ventricle.

The Semi-Lunar Aortic Valve

The semi-lunar aortic valve is located at the exit of the aorta and the left ventricle. The function of this valve mirrors that of the semi-lunar pulmonary valve, with one exception. Once the pressure in the left ventricle falls back during relaxation phase, oxygenated blood will fill up in the cusps of the semi-lunar aortic valve eventually causing them to close. This blood is what supplies the right and left coronary arteries which distribute blood to the muscle tissues of the heart.

Ventricle Structure

The two ventricles are separated by a septum into the left ventricle and the right ventricle. The ventricles of the heart are muscular chambers because they are responsible for propelling blood out of the heart. The left ventricle is the thickest of the four chambers because it is the final chamber that oxygenated blood must be pumped through before it is distributed throughout the body via the circulatory system

Circulatory system

The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...

. The ventricles are also larger in size compared to the atria.

Atria Structure

The right atrium contains the sinoatrial node

Sinoatrial node

The sinoatrial node is the impulse-generating tissue located in the right atrium of the heart, and thus the generator of normal sinus rhythm. It is a group of cells positioned on the wall of the right atrium, near the entrance of the superior vena cava...

 which sends an impulse throughout the heart causing the cardiac muscle of the atrium to contract in a coordinated, wave-like manner. Since the atria are thin-walled and much less muscular than the ventricles, they are able to easily expand with the addition of blood.
The forces of contraction are much weaker within the atria as a result. The contraction is strong enough, however to force 1/4 of the total blood volume entering into the ventricles. The rest of the blood enters the atria passively.

See also

• Cardiac cycle
  Cardiac cycle
  The cardiac cycle is a term referring to all or any of the events related to the flow or blood pressure that occurs from the beginning of one heartbeat to the beginning of the next. The frequency of the cardiac cycle is described by the heart rate. Each beat of the heart involves five major stages...
  
  
• Electrical conduction system of the heart
  Electrical conduction system of the heart
  The normal intrinsic electrical conduction of the heart allows electrical propagation to be transmitted from the Sinoatrial Node through both atria and forward to the Atrioventricular Node. Normal/baseline physiology allows further propagation from the AV node to the ventricle or Purkinje Fibers...
  
  
• Haematopoiesis
  Haematopoiesis
  Haematopoiesis is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells...
  
  
• Heart disease
  Heart disease
  Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...
  
  
• Heart failure

External links

• Heart Disease
• Heart Animation See the heart chambers at work.
• American Heart Association
• Heart Anatomy Interactive animation.
• Ventricular Septal Defect