Circulatory System Overview

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Questions and Answers

What is the primary function of the heart in the circulatory system?

To dissolve nutrients in the bloodstream

To drive blood through the cardiovascular system (correct)

To filter waste from the blood

To regulate body temperature

Which component is NOT part of the cardiovascular system?

Blood vessels

Heart

Blood

Lymph nodes (correct)

How does the circulatory system maintain the flow of blood?

By keeping blood constantly contained within vessels (correct)

By ensuring blood only flows back to the heart

By alternating blood flow direction

By allowing blood to pool in the heart

Where is the heart located in the human body?

Between the lungs and to the left of the midline Signup and view all the answers

What characterizes the human circulatory system?

It has unidirectional flow and is closed Signup and view all the answers

What does the stroke volume represent in cardiac physiology?

The volume of blood pumped out of the ventricles per beat Signup and view all the answers

How is cardiac output (CO) calculated?

CO = Heart Rate x Stroke Volume Signup and view all the answers

What is the approximate cardiac output for a healthy resting adult?

5-6 litres per minute Signup and view all the answers

Which of the following statements about the ejection fraction is true?

It indicates the percentage of blood leaving the heart with each contraction Signup and view all the answers

What do end diastolic volume (EDV) and end systolic volume (ESV) help to determine?

The stroke volume of the heart Signup and view all the answers

What is the primary function of the pulmonary circuit?

To provide blood flow between the heart and lungs Signup and view all the answers

What is defined as the amount of blood pumped out of the ventricles per beat?

Stroke Volume Signup and view all the answers

Which of these cardiac structures is responsible for initiating electrical impulses in the heart?

SA node Signup and view all the answers

How is Cardiac Output (CO) calculated?

Heart Rate x Stroke Volume Signup and view all the answers

During which phase do the ventricles experience relaxation?

Diastole Signup and view all the answers

What is the typical range of electrical impulse generation in the SA node per minute?

60 - 100 Signup and view all the answers

Which statement correctly describes End Systolic Volume?

It is the amount of blood in the ventricles at the end of contraction. Signup and view all the answers

Which part of the heart receives deoxygenated blood from the body?

Right atrium Signup and view all the answers

Study Notes

Circulatory System

The circulatory system is made up of the cardiovascular and lymphatic systems.
These systems are responsible for the flow of blood, lymph, nutrients, hormones, oxygen, and other gases to and from the cells of the body.

The Heart

It is a hollow muscular organ located between the lungs in the center and to the left of the midline.
It is cone-shaped and about the size of a clenched fist.
The heart's primary function is to pump blood through the cardiovascular system, delivering oxygenated blood to tissues and organs, and deoxygenated blood to the lungs for gas exchange.

Cardiovascular System

The average adult has 4-6 liters of blood constantly circulating throughout the body in a closed system.
This means blood is always contained within the heart and blood vessels and flows in a forward direction.

Structures of the Heart

The heart is divided into four chambers: two atria and two ventricles.
The atria receive blood and are surrounded by myocardial cells capable of relaxation and contraction.
The cardiovascular system includes the pulmonary circuit, which provides blood flow between the heart and lungs, the systemic circuit, which allows blood flow to and from the rest of the body, and the coronary circuit, which provides blood to the heart.
The heart valves are essential for ensuring unidirectional blood flow within the system.

Conduction System of the Heart

Heart muscle cells (myocytes) include contractile myocardial cells that respond to electrical impulses and contract, and specialized cells that generate electrical impulses and transmit them through the myocardium.
These specialized cells compose the conduction system and determine the rate of impulse generation:
- SA node (60 - 100 bpm)
- AV node (40 - 60 bpm)
- Ventricles (< 40 bpm)

Cardiac Cycle

Chamber contraction = Systole
Chamber relaxation = Diastole

Key Terms

End Diastolic Volume (EDV): Amount of blood in the ventricles at the end of filling (diastole).
End Systolic Volume (ESV): Amount of blood in the ventricles at the end of contraction (systole).
Stroke Volume (SV): Amount of blood pumped out of the ventricles per beat (approximately 70 ml in a healthy adult male).
- EDV - ESV = SV
Cardiac Output (CO): Amount of blood ejected by the heart per minute (approximately 5-6 liters in a healthy resting adult).
- CO = Heart Rate x Stroke Volume
Ejection Fraction: Percentage of blood leaving the heart with each contraction. Measured with imaging techniques such as ECHO, cardiac catheterization, and MRI.

Key Points

The left and right sides of the heart must maintain balanced output.
The amount of blood in the ventricles at the end of filling (EDV) and the end of contraction (ESV) are significant factors in cardiac function.
The ventricles never completely empty.
The difference between EDV and ESV equals the stroke volume (SV).

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Description

Explore the components and functions of the circulatory system in this quiz. Discover the roles of the heart, blood circulation, and the significance of the cardiovascular and lymphatic systems. Test your knowledge on heart structures and their functions.