The cardiovascular system

Pulmonary vein

A blood vessel that transports blood from the lungs to the left atrium. The only vein in the body to carry oxygenated blood.

Bundle of His (Atrioventricular bundle)

A bundle of fibers that originate in the AV node and enter the interventricular septum conducting electrical impulses to the left and right bundle branches.

Pericardium

A double layer sac that encloses the heart. The inner layer, or visceral pericardium, is also called the epicardium, the outer layer is the parietal pericardium.

Intraventricular septum

A partition or wall (septum) that divides the right and left ventricles.

Segment

A portion or part of the electrical tracing produced by the heart.

Pulmonary semilunar valve

A valve found in the pulmonary artery that prevents backflow of blood into the right ventricle during pulmonary circulation.

Semilunar valve

A valve with half moon shaped cusps that open and close, allowing blood to travel only one way; located in the pulmonary artery and the aorta.

What separates the right and left sides of the heart?

A wall called the Septum.

Sinoatrial (SA) node

An area of specialized cells in the upper right atrium that initiates the heartbeat.

Oxygenated blood

Blood having oxygen (oxygen rich blood)

Deoxygenated blood

Blood that has little or minimal oxygen (oxygen -poor blood).

The right atrium receives what kind of blood from the systemic circulation?

Deoxygenated blood by way of the inferior and superior vena cava

Endocardium

Inner layer of the heart that lines the chambers and valves. The purkinje fibers are located here.

The outer most layer (pericardium) consists of what?

It consists of connective tissue that forms a sac around the heart.

What is the middle layer, or myocardium composed of?

It is composed of involuntary striated muscle tissue. It is responsible for physically propelling blood forward.

Ischemia

Lack of blood supply to an area of tissue due to a blockage in the circulation of the area.

Pulmonary artery

Large artery that transport deoxygenated blood from the right ventricle to the lungs. This is the only artery in the body that carries deoxygenated blood.

Bundle branches

Left and right branches of the bundle of His that conduct impulses down either side of the interventricular septum to the left and right ventricles.

Myocardium

Middle, thickest muscular responsible for heart contraction.

Atrium (Atria)

One of the upper two small chambers of the heart. The right atrium receives blood from the body through the Vena Cava, and the left atrium receives blood from the lungs, through the pulmonary vein.

Atrioventricular (AV) node

Specialized cells that delay the electrical conduction through the heart and allow the atria time to contract.

Automaticity

The ability of a cardiac cell to initiate an electrical impulse, without being stimulated by another source, causing a cardiac contraction.

Conductivity

The ability of the heart cells to receive and transmit an electrical impulse.

Excitability

The ability of the heart muscle cells to respond to an impulse or stimulus

Contractility

The ability of the heart muscle cells to shorten in response to an electrical stimuli.

where is the blood oxygenated and returned to?

The blood is oxygenated in the capillary beds of the lungs and returned to the left atrium via the pulmonary veins.

Systemic circulation

The circulation between the heart and the entire body, excluding the lungs.

Coronary Circulation

The circulation of blood to and from the heart muscle.

Systole

The contraction phase of the cardiac cycle, during which the heart is pumping blood out to the body.

Depolarization

The electrical activation of the cells of the heart that initiates contraction of the heart muscle.

What are the three distinct layers that compose the heart wall?

The endocardium, myocardium and pericardium.

Purkinje fibers

The fibers within the heart that distribute electrical impulses from cell to cell throughout the ventricles.

what is the layer that lines the chambers of the heart and forms the valves?

The innermost layer, or endocardium.

Aorta

The largest artery of the body, which transports blood from the left ventricle of the heart to the entire body.

left Ventricle

The left lower chamber of the heart which pumps oxygenated blood through the body. It is the biggest and strongest chamber, Known as the work horse of the heart.

left Atrium

The left upper chamber of the heart, which receives blood from the lungs.

Cardiac cycle

The period from the beginning of one heartbeat to the beginning of the next: the cardiac cycle is made up of the systole and diastole.

Interval

The period of time between two activities within the heart.

Isoelectric

The period when the electrical tracing of the EKG is at 0 or a straight line, no positive or negative deflections.

Diastole

The phase of the cardiac cycle when the heart is expanding and refilling; also known as the relaxation phase.

The four chambers consist of :

The right and left Atria and the right and left ventricles.

Right Ventricle

The right lower chamber of the heart, which pumps blood to the lungs.

Right atrium

The right upper chamber of the heart, which receives blood from the heart.

Apex

The rounded lower end of the heart, below the ventricles.

Polarization

The state of cellular rest in which the inside is negatively charged and the outside is positively charged.

Pulmonary Circulation

The transport of blood to and from the lungs; blood is oxygenated in the lungs during pulmonary circulation.

What are the four valves that are found in the heart?

The tricuspid valve which separates the right atrium from the right ventricle. The bicuspid or mitral valve separates the left atrium from the left ventricle. The pulmonary semilunar valve lies between the right ventricle and pulmonary arteries. The aortic valve lies between the left ventricle and the aorta.

Superior Vena Cava

Transports blood from the head, arms, and upper body.

Tricuspid valve

Valve located between the right atrium and right ventricle; it prevents backflow of blood into the right atrium.

Aortic Semilunar valve

Valve located in the aorta that prevents the backflow into the left ventricle.

Mitral (bicuspid) valve

Valve with two cusps or leaflets located between the left atrium and left ventricle; it prevents backflow of blood into the left atrium.

Repolarization

When the heart cells return to their resting electrical state and the heart.

Inferior Vena cava

transports blood from the lower body and legs.