What are the three main jobs of the cardiovascular system?

• Circulate oxygen, circulate nutrients, and remove waste

• Produce hormones, regulate temperature, and store energy

• Digest food, absorb nutrients, and excrete waste

• Protect against infection, regulate blood sugar, and maintain balance

Answer explanation

The cardiovascular system's main jobs are to circulate oxygen and nutrients to cells and remove waste products. This ensures that the body functions properly and maintains homeostasis.

Which factors affect the volume of blood to the working tissues during exercise?

• Cardiac output and redistribution of blood flow

• Blood sugar levels and body temperature

• Hormone production and energy storage

• Oxygen absorption and nutrient digestion

Answer explanation

During exercise, cardiac output increases to pump more blood, while blood flow is redistributed to active muscles, enhancing oxygen and nutrient delivery. This makes 'cardiac output and redistribution of blood flow' the correct choice.

Stroke volume is regulated by which of the following?

• End diastolic volume, average aortic blood pressure, and contractility

• Blood sugar levels, body temperature, and hormone production

• Oxygen absorption, nutrient digestion, and energy storage

• Infection protection, blood sugar regulation, and balance maintenance

Answer explanation

Stroke volume is influenced by end diastolic volume (preload), average aortic blood pressure (afterload), and contractility (force of contraction). These factors directly affect the heart's ability to pump blood effectively.

What causes the heart to beat?

• Chemical stimulation of the heart tissue

• Spontaneous electrical stimulation of the heart tissue

• Mechanical stimulation of the heart tissue

• Thermal stimulation of the heart tissue

Answer explanation

The heart beats due to spontaneous electrical stimulation from specialized cells called pacemaker cells. These cells generate electrical impulses that trigger heart contractions, making this the primary cause of the heartbeat.

Where does the electrical impulse that causes the heart to beat start?

• Left ventricle

• Right ventricle

• Right atrium

• Left atrium

Answer explanation

The electrical impulse that causes the heart to beat starts in the right atrium, specifically at the sinoatrial (SA) node, which acts as the heart's natural pacemaker.

What is the sinoatrial node (SA node) commonly referred to as?

• The "conductor" of the heart

• The "pacemaker" of the heart

• The "regulator" of the heart

• The "controller" of the heart

Answer explanation

The sinoatrial node (SA node) is commonly referred to as the "pacemaker" of the heart because it generates electrical impulses that initiate the heartbeat, regulating the heart's rhythm.

What is the role of the sinoatrial node (SA node) in the heart's conduction system?

• It delays the depolarization to allow for ventricular filling.

• It acts as the pacemaker, initiating depolarization.

• It conducts impulses throughout the ventricles.

• It passes depolarization to the ventricles.

Answer explanation

The sinoatrial node (SA node) is the heart's natural pacemaker, responsible for initiating depolarization and setting the rhythm of the heartbeat, making it crucial for maintaining proper heart function.

Which part of the heart's conduction system is responsible for passing depolarization to the ventricles?

• Sinoatrial node (SA node)

• Purkinje fibers

• Atrioventricular node (AV node)

• Bundle Branches

Answer explanation

The Atrioventricular node (AV node) is crucial for passing depolarization from the atria to the ventricles, ensuring coordinated contraction. The SA node initiates the impulse, but the AV node is responsible for transmitting it to the ventricles.

What is the function of the Purkinje fibers in the heart's conduction system?

• They initiate depolarization.

• They delay depolarization for ventricular filling.

• They conduct impulses throughout the ventricles.

• They pass depolarization to the ventricles.

Answer explanation

The Purkinje fibers are specialized fibers that conduct electrical impulses rapidly throughout the ventricles, ensuring coordinated contraction. This is crucial for effective pumping of blood.

Where do the bundle branches conduct electrical impulses in the heart?

• To the sinoatrial node

• To the atrioventricular node

• To the left and right ventricles

• Throughout the atria

Answer explanation

The bundle branches are responsible for conducting electrical impulses specifically to the left and right ventricles, facilitating their contraction and ensuring effective blood pumping.