Cardiovascular Physiology Basics

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Questions and Answers

How many chambers does the human heart have?

4 (correct)

What is the average weight of the human heart as a young adult?

250-300g (correct)

350-400g

300-350g

200-250g

What is the typical cardiac output of a human at rest?

7-8 L/min

4-5 L/min

5-6 L/min (correct)

2-3 L/min

What does HRV stand for in cardiovascular physiology?

Heart Rate Variability Signup and view all the answers

During peak exercise, how much blood can the heart pump in elite athletes?

40 litres a minute Signup and view all the answers

What are the upper chambers of the heart called?

Atria Signup and view all the answers

How much blood does the heart typically pump in a day?

7,500 litres Signup and view all the answers

Where is the heart located in the human body?

Between the sternum and vertebrae Signup and view all the answers

What is the primary function of coronary vasculature?

To supply oxygen and nutrients and remove metabolic by-products Signup and view all the answers

During which phase of the cardiac cycle does ventricular ejection occur?

Ventricular contraction (systole) Signup and view all the answers

What role do valves play in the heart?

They ensure 1-way flow of blood through the heart Signup and view all the answers

Which structure prevents eversion of the atrio-ventricular valves?

Chordae tendinae Signup and view all the answers

What type of blood does the pulmonary arteries carry?

Deoxygenated blood to the lungs Signup and view all the answers

Which of the following best describes the direction of blood flow through the left ventricle?

To the body via the aorta Signup and view all the answers

What happens to blood during diastole?

Blood fills the heart chambers Signup and view all the answers

What is a potential consequence of ischemia in coronary circulation?

Heart attacks Signup and view all the answers

Which type of valve is found in the left ventricle?

Bicuspid (mitral) valve Signup and view all the answers

What is the significance of the aortic valve in the heart?

Prevents blood from flowing back into the left ventricle Signup and view all the answers

What occurs during the ventricular filling period?

Blood flows into the ventricles with the AV valves open Signup and view all the answers

What characterizes the isovolumetric contraction period of the cardiac cycle?

All valves are closed, and ventricles are full Signup and view all the answers

Which phase of the cardiac cycle involves blood being ejected from the heart?

Ventricular ejection period Signup and view all the answers

What happens during the isovolumetric relaxation period?

Ventricles are relaxed, and all valves are closed Signup and view all the answers

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

Sympathetic nervous system Signup and view all the answers

What is the main consequence of chronic stress on the nervous system?

Disruption of the natural interplay between the SNS and PNS Signup and view all the answers

What is the primary function of the atria in the heart?

Deliver blood to the ventricles Signup and view all the answers

What does the term 'contractility' refer to in the context of the heart?

The force of contraction generated by the heart muscle Signup and view all the answers

What happens to the foramen ovale after birth in most individuals?

It may stay patent and is referred to as a patent foramen ovale Signup and view all the answers

Which chamber of the heart is known as the most powerful?

Left ventricle Signup and view all the answers

What is a unique characteristic of cardiac muscle?

It is an involuntary muscle specialized for endurance Signup and view all the answers

What does the sinoatrial (SA) node primarily regulate?

The electrical activity and heart rate Signup and view all the answers

Which layer of the heart provides the most strength and support?

Myocardium Signup and view all the answers

Study Notes

Cardiovascular Physiology (Normal)

Cardiovascular system is a complex network including the heart and vasculature.
There are approximately 100,000 km of blood vessels in the human body, enough to encircle the Earth twice.
The heart beats over 100,000 times daily, pumping about 7,500 liters of blood.

The Heart

The heart is a hollow muscular organ, about the size of a fist (280-300 g in young adults).
Located between the sternum and vertebrae.
Functions as a dual-pump, delivering blood, acting as a suction device, and a performance engine.
The human heart beats more than 2.5 billion times during an average lifetime.
It's a highly adaptive and incredibly enduring organ.

Heart Structure and Anatomy

Divided into right and left halves, consisting of four chambers (two for deoxygenated, and two for oxygenated blood).
Two atria: upper chambers that receive blood returning to the heart and transfer it to the lower chambers.
Two ventricles: lower chambers that pump blood from the heart - either to the lungs or to the rest of the body.

Heart Circulation

The heart pumps 4-5 liters of blood per minute at rest.
The heart performs two types of circulation: pulmonary and systemic.
Pulmonary Circulation: Blood is pumped from the right ventricle to the lungs for oxygenation.
Systemic Circulation: Oxygenated blood is pumped from the left ventricle to the rest of the body.

Cardiac Output

Cardiac output is the amount of blood pumped by the heart per minute.
In a resting adult, cardiac output is generally 5-6 liters per minute.
During peak exercise, cardiac output can increase to over 40 liters per minute.

Heart Rate Variability (HRV)

Heart rate changes constantly, and HRV measures the variability of heart rate changes over time.
HRV depends on activity levels and stress.
Low HRV is associated with chronic stress.

The Role of Atria

Two atria (right and left) with thinner walls compared to ventricles.
Deliver blood to the ventricles.
Contains a septum (dividing wall).
The sinoatrial (SA) node is located in the upper wall of the right atrium (RA) and controls the heart rate and heart rate variability (HRV).

The Role of Ventricles

The primary pumps of the heart, responsible for oxygenating and delivering blood to the rest of the body and the lungs.
Right ventricle: sends blood to the lungs for oxygenation.
Left ventricle: the most powerful chamber, delivers oxygenated blood to the body.
Thicker walls for greater force of contraction (contractility).
Can handle larger blood volumes during exercise.

Layers of the Heart

The heart has three layers:
Endocardium: the inner lining.
Myocardium: the middle layer made of muscle tissue.
Epicardium: the outer layer.
Cardiac muscle is involuntary and specialized for endurance.

Coronary Circulation

The coronary vasculature supplies oxygen and nutrients to the heart muscle, removes metabolic waste products, and is crucial for heart function.
Ischemia, plaque formation, and heart attacks are potential problems in the coronary circulation.

Blood Flow Through The Heart

Deoxygenated blood enters the right atrium via the superior and inferior vena cava.
Blood flows from the right atrium to the right ventricle through the tricuspid valve.
The right ventricle pumps blood to the lungs via the pulmonary arteries.
Oxygenated blood returns to the heart from the lungs via the pulmonary veins and enters the left atrium.
Blood flows from the left atrium to the left ventricle through the mitral valve.
The left ventricle pumps oxygenated blood to the body via the aorta.

The Cardiac Cycle

The cardiac cycle is a continuous cycle of contraction and relaxation of the heart muscle.
Systole: Ventricular contraction (ejection of blood).
Diastole: Ventricular relaxation (filling with blood).
Valves play a critical role ensuring one-way blood flow.

4 Main Phases of the Cardiac Cycle

Ventricular filling period (diastole): AV valves open, passive filling, and atrial contraction.
Isovolumetric contraction period: all valves closed, ventricular pressure rises.
Ventricular ejection period (systole): semilunar valves open, blood ejected.
Isovolumetric relaxation period: all valves closed, ventricular pressure falls.

Control of Heart Rate

Factors influencing heart rate include:
Autonomic nervous system (sympathetic and parasympathetic).
Exercise.
Environmental factors (e.g., temperature, toxins).

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Description

Test your knowledge of human heart anatomy and physiology with this quiz. Explore important concepts such as the number of heart chambers, average weight, and cardiac output. Perfect for students and enthusiasts interested in cardiovascular health.