3.6.1.3 Control of heart rate

Front

What is the primary function of the sinoatrial node (SAN) in the heart?

Back

To act as the heart's natural pacemaker

Answer explanation

The sinoatrial node (SAN) is the heart's natural pacemaker, generating electrical impulses that initiate the heartbeat. This makes it crucial for maintaining the heart's rhythm, unlike the other options which describe different functions.

Front

Where is the atrioventricular node (AVN) located in the heart?

Back

Between the atria and ventricles

Answer explanation

The atrioventricular node (AVN) is located between the atria and ventricles. It plays a crucial role in the heart's electrical conduction system, coordinating the timing of atrial and ventricular contractions.

Front

What is the role of Purkyne tissue in the heart?

Back

To conduct electrical impulses rapidly to the ventricles

Answer explanation

Purkyne tissue conducts electrical impulses rapidly to the ventricles, ensuring coordinated contraction and efficient pumping of blood. This is crucial for maintaining a proper heartbeat rhythm.

Front

What is myogenic stimulation?

Back

Heartbeat initiated by the heart muscle itself

Answer explanation

Myogenic stimulation refers to the heart's ability to initiate its own heartbeat through the heart muscle itself, rather than relying on external nerves, hormones, or blood pressure regulation.

Front

What is the primary role of chemoreceptors in the cardiovascular system?

Back

To detect changes in blood pH and carbon dioxide levels

Answer explanation

Chemoreceptors primarily detect changes in blood pH and carbon dioxide levels, which are crucial for regulating respiratory and cardiovascular functions, rather than directly regulating heart rate or blood pressure.

Front

Where are pressure receptors, also known as baroreceptors, primarily located?

Back

In the carotid arteries and aorta

Answer explanation

Baroreceptors, or pressure receptors, are primarily located in the carotid arteries and aorta. They detect changes in blood pressure and help regulate cardiovascular function.

Front

How does the autonomic nervous system influence heart rate?

Back

By adjusting the rate of electrical impulses from the SAN

Answer explanation

The autonomic nervous system influences heart rate by adjusting the rate of electrical impulses from the sinoatrial node (SAN), which acts as the heart's natural pacemaker, regulating how fast the heart beats.

Front

Which part of the autonomic nervous system is responsible for increasing heart rate?

Back

Sympathetic nervous system

Answer explanation

The sympathetic nervous system is responsible for the 'fight or flight' response, which includes increasing heart rate to prepare the body for action. In contrast, the parasympathetic nervous system decreases heart rate.

Front

What effect does the parasympathetic nervous system have on heart rate?

Back

It decreases heart rate

Answer explanation

The parasympathetic nervous system primarily functions to decrease heart rate by promoting relaxation and reducing the body's stress response, making 'It decreases heart rate' the correct choice.

Front

Effector in the control of heart rate: Sinoatrial node, Atrioventricular node, Heart muscle, Purkyne tissue

Back

Heart muscle

Answer explanation

The heart muscle is the effector that responds to signals from the sinoatrial and atrioventricular nodes, contracting to pump blood and thus directly controlling heart rate.