Cardiovascular System Quiz

Cardiovascular System

• The cardiovascular system consists of the heart, blood vessels, and blood.
• The heart acts as a pump ensuring blood circulates throughout the body, delivering oxygen and nutrients to cells, and removing waste products and CO2.

Blood Circulations

• The pulmonary circuit sends deoxygenated blood to the lungs to pick up oxygen and unload carbon dioxide.
  • Blood flow in the pulmonary circuit: Right ventricle – pulmonary arteries- lungs- pulmonary veins – left atrium
• The systemic circuit sends oxygenated blood and nutrients to all body cells, removing waste products and CO2.
  • Blood flow in the systemic circuit: Left ventricle – Aorta – body – vena cava – right atrium

The Course of Blood Through the Chambers of the Heart

• Deoxygenated blood enters the heart through the superior and inferior vena cava and empties into the right atrium.
• Blood passes through the right atrioventricular (tricuspid) valve into the right ventricle.
• From the right ventricle, blood is pumped through the pulmonary trunk to the right and left lungs.
• Oxygenated blood flows through the right and left pulmonary veins from the lungs into the left atrium.
• Blood passes through the left atrioventricular (bicuspid) valve into the left ventricle.
• From the left ventricle, blood is pumped out through the aorta to the body.

Blood Supply to the Heart - Coronary Circulation

• The coronary arteries supply the heart with oxygen and nutrients.
  • The two major coronary arteries, the left coronary artery, and the right coronary artery, branch off from the aorta.
• The coronary veins collect carbon dioxide and waste products from the heart muscle.
  • The main coronary veins, the great cardiac vein, middle cardiac vein, and small cardiac vein, drain deoxygenated blood into the coronary sinus.
  • The coronary sinus is a wide venous channel that empties into the right atrium.

How Does the Blood Flow?

• Blood flows from an area of high pressure to an area of low pressure within the cardiovascular system.
• The heart contracts and relaxes to create changes in pressure.
  • Contraction is called systole and creates high pressure.
  • Relaxation is called diastole and creates low pressure.
• Blood flows from high to low pressure created by contraction.

Important Terms

• Contraction of the heart chambers is called systole.
• Relaxation of the heart chambers is called diastole.
• Contraction of the atria is called atrial systole.
• Relaxation of the atria is called atrial diastole.
• Contraction of the ventricles is called ventricular systole.
• Relaxation of the ventricles is called ventricular diastole.

The Cardiac Cycle Phases

• Phase 1: Atrial Systole/Ventricular Diastole:*

• The atria contract, pumping the final volume of blood into the ventricles.

• The ventricles are relaxed.

• The atrioventricular valves (tricuspid and mitral) are open.

• The semilunar valves are closed.

• Phase 2: Ventricular Systole/Atrial Diastole:*

• The ventricles contract, closing the atrioventricular valves (lub sound).

• Semilunar valves open, allowing blood to pass to the arteries.

• As ventricles start to relax, the semilunar valves close (dub sound).

• The atria are relaxed and begin to fill with blood returning from veins.

• Phase 3: Diastole (Very Short Period):*

• All chambers are relaxed.

• The semilunar valves are closed.

• Pressure in the atria causes the atrioventricular valves to open.

• Blood drains to the ventricles.

Heart Sounds

• A heartbeat heard through a stethoscope sounds like "lub-dub".
• The "lub" sound is created by the closing of the atrioventricular valves.
• The "dub" sound is created by the closing of the semilunar valves.
• A murmur is a sound produced by faulty valve cusps that do not close properly.

The Conduction System of the Heart

• The heart contains two types of cells:
  • Cardiomyocytes (contractile fibers) make up 99% of the heart tissue.
  • Autorhythmic cells (myogenic cells) make up about 1% of the heart tissue and initiate action potentials.
• The intrinsic conduction system controls the heart rate by sending electrical impulses throughout the heart.
• The action potential is initiated by the sinoatrial node (SA node).
• The electrical impulses travel through the conduction system, which includes:
  • Sinoatrial node (SA node)
  • Atrioventricular node (AV node)
  • Bundle of His (AV bundle)
  • Right and left bundle branches
  • Purkinje fibers

The Conduction System of the Heart (SA Node):

• Located in the back wall of the right atrium near the entrance of the superior vena cava.
• Called the pacemaker of the heart.
• Initiates impulses 70-80 times per minute without any nerve stimulation from the brain.
• Establishes the basic rhythm of the heartbeat.
• Impulses move through the atria, causing the two atria to contract.
• Impulses simultaneously reach the AV node, initiating the next part of the conduction system.

Test your knowledge on the cardiovascular system, including the structure and functions of the heart, blood vessels, and blood. This quiz covers topics like blood circulation, pulmonary and systemic circuits, and the flow of blood through the heart chambers.