The Cardiovascular System

Flashcards covering key terms and concepts related to the cardiovascular system, including the heart's structure, function, and electrical activity.

Sinoatrial (SA) node

The pacemaker of the heart located in the right atrium that initiates each heartbeat.

Atrioventricular (AV) node

The node at the junction of the atria and ventricles that delays the impulse to allow the atria to finish contracting.

Cardiac cycle

The events occurring during one complete heartbeat, including contraction and relaxation of the heart chambers.

Systole

The phase of the cardiac cycle when the heart contracts and pumps blood.

Diastole

The phase of the cardiac cycle when the heart relaxes and fills with blood.

Stroke volume

The amount of blood pumped out of a ventricle with each heartbeat.

Tachycardia

A condition characterized by a rapid heart rate of over 100 beats per minute.

Bradycardia

A condition characterized by a slow heart rate of fewer than 60 beats per minute.

Fibrillation

A rapid, uncoordinated quivering of the ventricles that prevents effective pumping of blood.

Electrocardiogram (ECG)

A graphical representation of the electrical activity of the heart, used to identify abnormalities.

Cardiac output (CO)

The volume of blood pumped by each ventricle in one minute, calculated as heart rate multiplied by stroke volume.

Intrinsic conduction system

The system of nodes and fibers in the heart that generates and conducts electrical impulses to regulate heartbeats.

Afterload

The pressure the ventricles must overcome to eject blood during systole.

Preload

The degree of stretch of the cardiac muscle cells prior to contraction, influencing stroke volume.

Elements of the heart's intrinsic conduction system

The intrinsic conduction system consists of the Sinoatrial (SA) node, Atrioventricular (AV) node, Bundle of His, right and left bundle branches, and Purkinje fibers.

Pathway of impulses through the intrinsic conduction system

Impulses begin at the SA node, travel to the AV node, move through the Bundle of His, down the right and left bundle branches, and finally spread through the Purkinje fibers.

What information does an electrocardiogram provide?

An electrocardiogram (ECG) provides a graphical representation of the electrical activity of the heart, allowing for the identification of abnormalities in heart rhythms and other cardiac issues.

Systole

The phase of the cardiac cycle when the heart contracts and pumps blood.

Diastole

The phase of the cardiac cycle when the heart relaxes and fills with blood.

Stroke volume

The amount of blood pumped out of a ventricle with each heartbeat.

Cardiac cycle

The events occurring during one complete heartbeat, including both contraction and relaxation of the heart chambers.

Heart sounds

The sounds made by the closure of heart valves during the cardiac cycle, typically described as 'lub' (first heart sound) and 'dub' (second heart sound).

Heart murmur

An abnormal heart sound caused by turbulent blood flow, often due to valvular defects.

Effects of vagus nerve stimulation on heart rate

Stimulation of the vagus nerve decreases heart rate by promoting parasympathetic activity.

Effects of exercise on heart rate

Exercise increases heart rate by stimulating the sympathetic nervous system, releasing hormones like epinephrine.

Effects of epinephrine on heart rate

Epinephrine increases heart rate by enhancing sympathetic stimulation.

Effects of various ions on heart rate

Alterations in levels of ions such as potassium and calcium can affect heart rhythm and contraction strength, influencing overall heart function.