Cardiovascular System Overview

Questions and Answers

What shape is the heart primarily described as?

Cone (correct)

Rectangle

Cylinder

Square

Which chamber of the heart is responsible for pumping blood into the major arteries?

Right Ventricle

Left Ventricle (correct)

Left Atrium

Atria

What separates the right atrium from the left atrium?

Atrioventricular Valve

Bicuspid Valve

Interatrial Septum (correct)

Interventricular Septum

Which valve is located between the left atrium and the left ventricle?

Bicuspid (Mitral) Valve Signup and view all the answers

How much of the heart is positioned to the right of the sternal line?

2/3 Signup and view all the answers

What are the two upper chambers of the heart called?

Atria Signup and view all the answers

Which layer of the pericardium prevents the heart from overstretching?

Pericardium Signup and view all the answers

Where does the right atrium receive deoxygenated blood from?

Inferior vena cava Signup and view all the answers

Which valve is located between the left atrium and the left ventricle?

Mitral valve Signup and view all the answers

What is the function of the semilunar valves?

Prevent backflow of blood into the ventricles Signup and view all the answers

Which blood vessel carries oxygenated blood to the body?

Aorta Signup and view all the answers

Which chamber pumps deoxygenated blood into the pulmonary artery?

Right ventricle Signup and view all the answers

What is the role of the myocardium?

Thick muscular layer that pumps blood Signup and view all the answers

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

To provide the motive force to pump blood Signup and view all the answers

Which type of blood vessels carry oxygenated blood away from the heart?

Arteries Signup and view all the answers

What is the approximate size of the adult human heart?

25 cm long and 9 cm wide Signup and view all the answers

Which function is NOT performed by the cardiovascular system?

Control of blood pressure Signup and view all the answers

What is the significance of capillaries in the cardiovascular system?

They are the exchange vessels between blood and tissues Signup and view all the answers

Which of the following statements about veins is true?

Veins return deoxygenated blood to the heart Signup and view all the answers

At birth, what is the approximate weight of the heart?

20 g Signup and view all the answers

What substances does the cardiovascular system NOT transport?

Bacteria Signup and view all the answers

What is the primary function of systemic circulation?

To deliver oxygenated blood from the left ventricle to tissues and return deoxygenated blood Signup and view all the answers

Which artery is NOT part of the circle of Willis?

Circumflex artery Signup and view all the answers

How much blood does the brain typically receive per minute?

750ml-800ml Signup and view all the answers

What signifies the completion of systemic circulation?

Deoxygenated blood returning to the right atrium Signup and view all the answers

Which artery primarily supplies blood to the brain?

Basilar artery Signup and view all the answers

What is the primary function of the Sinoatrial (SA) node?

To generate electrical impulses causing atrial contraction Signup and view all the answers

Which structure is responsible for relaying impulses from the AV node to the ventricles?

Bundle of His Signup and view all the answers

What is the role of the AV node in the conduction system?

To synchronize atrial and ventricular contractions Signup and view all the answers

How fast is depolarization through the AV node?

0.05 m/sec Signup and view all the answers

What allows efficient blood flow through the heart?

Sequential contraction of atria before ventricles Signup and view all the answers

Which part of the conduction system quickly spreads the impulse throughout the ventricles?

Purkinje fibers Signup and view all the answers

What are Purkinje fibers specialized for?

Conducting impulses from cells to cells Signup and view all the answers

What is the final destination of the electrical impulse from the conduction system?

Ventricular free walls Signup and view all the answers

What percentage of left ventricular output is supplied to the heart muscles through the coronary artery?

4% - 5% Signup and view all the answers

During which phase of the cardiac cycle does blood flow in the coronary arteries increase significantly?

Diastole Signup and view all the answers

What is the primary source of oxygen supply to the liver?

Hepatic artery Signup and view all the answers

Which statement about the portal vein and its function is correct?

It supplies the majority of blood to the liver but only 25% of the oxygen. Signup and view all the answers

How much blood does the liver receive per minute?

1,500ml/min Signup and view all the answers

What is the main function of the SA node in the heart?

To initiate and propagate cardiac impulses. Signup and view all the answers

During which phase of the cardiac cycle do the ventricles contract?

Ventricular systole Signup and view all the answers

What is the primary role of the AV node?

To delay depolarization through the ventricles. Signup and view all the answers

How is cardiac output calculated?

By multiplying stroke volume by heart rate. Signup and view all the answers

Which valves close during the diastolic phase of the cardiac cycle?

Semilunar valves Signup and view all the answers

What does venous return refer to?

The blood returned to the heart by veins. Signup and view all the answers

Which of the following components is a part of the specialized conductive tissue in the heart?

Atrioventricular node Signup and view all the answers

What role do the Bundle of His fibers play in cardiac function?

They facilitate rapid impulse conduction in the ventricles. Signup and view all the answers

What is the definition of tachycardia?

A rhythm with a rate above 100 beats/min Signup and view all the answers

What does bradycardia refer to in terms of heart rate?

Heart rate below 60 beats/min Signup and view all the answers

What is considered a normal heart rate at rest?

60-100 beats/min Signup and view all the answers

What initiates a normal sinus rhythm in the heart?

Sinoatrial (SA) node Signup and view all the answers

Where does deoxygenated blood go in pulmonary circulation?

From the right ventricle to the lungs Signup and view all the answers

How long does it typically take for blood to pass through the pulmonary circulation?

4 seconds Signup and view all the answers

What does systemic circulation involve?

Pumping oxygenated blood to the body from the left ventricle Signup and view all the answers

Which arteries are involved in supplying blood to the brain?

Circle of Willis Signup and view all the answers

What is the primary cause of stroke?

Inadequate blood supply to localized areas of the brain Signup and view all the answers

Which statement about cutaneous circulation is true?

Vasodilation occurs during hyperthermia to increase blood flow. Signup and view all the answers

What role do arteriovenous anastomoses (AVAs) play in the skin?

Regulate temperature and blood flow. Signup and view all the answers

What happens during systole in the heart?

The left ventricle contracts, pushing blood into the aorta. Signup and view all the answers

How does the liver receive blood?

Via both the hepatic artery and portal vein. Signup and view all the answers

What is the function of the portal vein in hepatic circulation?

It transports oxygenated blood from the intestine to the liver. Signup and view all the answers

What is the main consequence of vasoconstriction during hypothermia?

Decreased blood flow to apical skin regions. Signup and view all the answers

What does the thermoregulation center in the hypothalamus do?

Regulates core body temperature. Signup and view all the answers

Hemorrhagic strokes are primarily caused by?

Rupture of a blood vessel in the brain. Signup and view all the answers

Which process occurs when the body is experiencing hyperthermia?

Increased blood flow to the skin. Signup and view all the answers

What is the normal range for systolic blood pressure?

110 mmHg - 140 mmHg Signup and view all the answers

How is pulse pressure calculated?

Systolic pressure - Diastolic pressure Signup and view all the answers

Which of the following factors does NOT affect blood pressure?

Body temperature Signup and view all the answers

What is the typical mean arterial pressure for a normal blood pressure reading of 140/80 mmHg?

100 mmHg Signup and view all the answers

During which condition is blood pressure typically lower?

During sleep Signup and view all the answers

Which category includes local factors affecting blood pressure?

Central factors Signup and view all the answers

What is the normal range for diastolic blood pressure?

60 mmHg - 90 mmHg Signup and view all the answers

Which of the following is NOT a potential influence on blood pressure?

Skeletal muscle mass Signup and view all the answers

Study Notes

Introduction

Cardiovascular system comprises the heart, arteries, capillaries, and veins, each with distinct structures and functions.
Heart pumps blood; arteries carry oxygenated blood to tissues, while veins return deoxygenated blood to the heart.
Exception: Pulmonary artery (deoxygenated blood to lungs) and pulmonary veins (oxygenated blood to heart).
Arteries have thicker walls, greater diameter, and are more elastic than veins; capillaries facilitate material exchange between blood and tissues.

Functions of the Cardiovascular System

Delivers oxygen and carbon dioxide to/from tissues.
Transports nutrients to cells and removes metabolic waste.
Distributes hormones (e.g., adrenaline, oxytocin).
Controls body temperature via heat distribution.

Heart Structure

Heart is a hollow muscular organ about the size of a fist, weighing 250-400g in adults.
Located in the mediastinum, with its base facing upwards and apex downwards.
Heart consists of four chambers: two atria (upper) and two ventricles (lower).
Atria: Receive blood; Ventricles: Pump blood to major arteries.
Includes valves to prevent backflow during contractions: Tricuspid (right atrium to right ventricle) and Bicuspid (left atrium to left ventricle) valves known as atrioventricular valves.

Dynamics of Heartbeat

Cardiac Cycle: Sequence of events during each heartbeat, including systole (contraction phase) and diastole (relaxation phase).
Normal resting heart rate is 72 beats per minute.
Cardiac Output (CO): Amount of blood ejected by the heart; calculated as CO = Stroke Volume (SV) x Heart Rate (HR).
Venous Return: The flow of blood back to the heart via veins.

Conduction System of the Heart

Synchronized contractions of the heart are regulated by specialized conductive tissues.
SA Node: Primary pacemaker located in right atrium; generates impulses for atrial contraction.
AV Node: Receives impulses from SA node and delays transmission to ventricles.
Bundle of His and Purkinje Fibers: Conduct impulses rapidly through myocardium for coordinated ventricular contraction.

Cardiac Arrhythmias

Alterations in heart rhythm due to various physiological or pathological conditions.
Normal sinus rhythm: 60-100 beats/min; tachycardia exceeds 100 beats/min; bradycardia falls below 60 beats/min.
Ectopic beats occur when other cells assume pacemaker roles.

Blood Circulation

Pulmonary Circulation

Transports deoxygenated blood from right ventricle to lungs for oxygenation and returns oxygenated blood to the left atrium.
Typically takes about four seconds for blood to complete the cycle.

Systemic Circulation

Carries oxygenated blood from the left ventricle to body tissues and returns deoxygenated blood to the right atrium via superior and inferior vena cava.

Cerebral Circulation

Provides blood flow to the brain, receiving 15-16% of cardiac output (approximately 750-800ml/min).
Blood supply from the basilar and internal carotid arteries; venous drainage via sinuses to the internal jugular vein.
The Circle of Willis ensures redundant blood supply to the brain.

Applied Physiology: Stroke

Stroke results from inadequate blood supply to the brain, leading to neuron death and potential paralysis.
Hemorrhagic stroke involves blood vessel rupture and bleeding into the brain.

Cutaneous Circulation

Supplies blood to the skin; relatively low metabolic requirements.
Blood flow through arteriovenous anastomoses aids in temperature regulation, with vasodilation and vasoconstriction altering heat loss.

Coronary Circulation

Heart muscles receive blood from the coronary arteries (left and right).
Cardiac output to the heart is about 4-5% during systole; increased flow observed during diastole.

Hepatic Circulation

Liver, a crucial blood reservoir, receives significant blood supply (1500ml/min) and detoxifies blood.
Blood from hepatic artery (25% oxygenated) and portal vein (75% from GI tract).

Blood Pressure

Defined as the pressure exerted by blood on arterial walls, measured in terms of systolic and diastolic pressure.
Normal systolic pressure: 110-140 mmHg; normal diastolic pressure: 60-90 mmHg.
Mean Arterial Pressure (MAP): Calculated as MAP = Diastolic Pressure + ½ Pulse Pressure.

Variations in Blood Pressure

Influenced by age, sex, body composition, exercise, emotions, meal timing, and sleep.
Normally increases throughout the day and peaks in the late afternoon.

Factors Affecting Blood Pressure

Local, central, and cardiac factors, including heart rate and vascular resistance.

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Description

This quiz explores the key components and functions of the cardiovascular system, including the structure of the heart and the roles of arteries, veins, and capillaries. Understand how these elements work together to transport blood, nutrients, and hormones throughout the body.