Introduction to Cardiovascular Physiology
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Questions and Answers

What effect does exercise have on arterial blood pressure?

  • It has no effect on arterial blood pressure.
  • It typically causes a temporary increase in blood pressure. (correct)
  • It decreases arterial blood pressure for all individuals.
  • It consistently increases it regardless of individual factors.

Which of the following is a characteristic of primary hypertension?

  • It often presents without a specific identifiable cause. (correct)
  • It is typically a result of renal failure.
  • It is caused by excessive salt intake.
  • It accounts for 10% of hypertension cases.

What is the primary role of veins in the circulatory system?

  • To drain capillary blood and return it to the heart. (correct)
  • To store blood and regulate pressure.
  • To increase arterial blood pressure during exercise.
  • To filter blood and remove waste products.

What happens when blood loss exceeds 20% of total blood volume?

<p>Death can occur unless blood transfusion is provided. (B)</p> Signup and view all the answers

Which of the following does NOT affect arterial blood pressure?

<p>Body temperature (C)</p> Signup and view all the answers

What is the correct sequence of impulse conduction in the heart?

<p>Sino-atrial node -&gt; Atrioventricular node -&gt; His-Purkinje system (D)</p> Signup and view all the answers

Which of the following factors will decrease the heart rate?

<p>Parasympathetic stimulation (C)</p> Signup and view all the answers

The cardiac output can be calculated using which formula?

<p>Heart rate X stroke volume (D)</p> Signup and view all the answers

Which type of blood vessel primarily represents resistance vessels?

<p>Arterioles (D)</p> Signup and view all the answers

During which phase of the cardiac cycle does blood flow from the atria to the ventricles?

<p>Atrial systole (B)</p> Signup and view all the answers

What is the average heart rate for adults?

<p>72 beats/min (A)</p> Signup and view all the answers

Which physiological change increases heart rate by 10 beats/min for every degree Celsius rise in temperature?

<p>Fever (C)</p> Signup and view all the answers

Which statement regarding the stroke volume is correct?

<p>The average stroke volume is about 80 ml/beat. (A)</p> Signup and view all the answers

What is the role of the papillary muscles in the heart?

<p>To prevent the eversion of atrioventricular valves during ventricular contraction (D)</p> Signup and view all the answers

Which component of the heart is responsible for separating the left atrium from the left ventricle?

<p>Bicuspid valve (B)</p> Signup and view all the answers

What is the primary function of the systemic circulation?

<p>To transport oxygenated blood from the left ventricle to the body (B)</p> Signup and view all the answers

Which of the following factors primarily affects the stroke volume?

<p>Ventricular contractility (A)</p> Signup and view all the answers

Which statement best describes the atrioventricular valves?

<p>They prevent backflow of blood into the atria during ventricular contraction (B)</p> Signup and view all the answers

What is the primary purpose of the pericardium surrounding the heart?

<p>To protect the heart and reduce friction during contraction (A)</p> Signup and view all the answers

How does increasing heart rate typically influence cardiac output?

<p>It increases cardiac output by raising the volume of blood pumped (B)</p> Signup and view all the answers

Which of the following most directly affects arterial blood pressure?

<p>All of the above (D)</p> Signup and view all the answers

Which of the following is a characteristic of secondary hypertension?

<p>It is directly linked to renal failure or endocrine disorders. (B)</p> Signup and view all the answers

Which factor does NOT directly influence venous return to the heart?

<p>Capillary filtration (B)</p> Signup and view all the answers

Which statement accurately describes compensatory mechanisms during hemorrhage exceeding 20% of total blood volume?

<p>They primarily aim to increase arterial blood pressure and cardiac output. (D)</p> Signup and view all the answers

What is the primary cause of primary hypertension according to its characteristics?

<p>Narrow arterioles due to vascular constrictor stimuli. (B)</p> Signup and view all the answers

Which of the following best describes shock in medical terms?

<p>Decreased tissue perfusion leading to insufficient oxygen and nutrient delivery. (D)</p> Signup and view all the answers

What is the primary role of the papillary muscles in the heart?

<p>They anchor the valves to prevent backflow. (C)</p> Signup and view all the answers

Which structure prevents the backflow of blood into the ventricles after it has entered the aorta and pulmonary artery?

<p>Aortic valve (A), Pulmonary valve (D)</p> Signup and view all the answers

In which part of the circulation does deoxygenated blood enter the heart?

<p>Through the superior and inferior venae cavae (C)</p> Signup and view all the answers

Which statement best describes the systemic circulation route?

<p>It carries oxygenated blood to the body from the left ventricle. (C)</p> Signup and view all the answers

What is the function of the pericardium surrounding the heart?

<p>To facilitate lubrication and reduce friction during heartbeats. (A)</p> Signup and view all the answers

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

<p>Tricuspid valve (D)</p> Signup and view all the answers

What role do chordae tendineae play in the heart's function?

<p>They connect papillary muscles to the atrioventricular valves. (D)</p> Signup and view all the answers

During ventricular contraction, what is prevented by the atrioventricular valves?

<p>Backflow into the atria. (D)</p> Signup and view all the answers

Which structure initiates the electrical impulse that causes the heart to beat?

<p>Sino-atrial node (A)</p> Signup and view all the answers

What is the effect of sympathetic stimulation on heart rate during stressful situations?

<p>It increases heart rate. (C)</p> Signup and view all the answers

What is the average duration of one cardiac cycle?

<p>0.8 seconds (D)</p> Signup and view all the answers

How does a fever affect heart rate, based on temperature changes?

<p>It increases heart rate by 10 beats/min for each degree Celsius. (A)</p> Signup and view all the answers

What is the stroke volume of the heart approximately in adults?

<p>80 ml/beat (A)</p> Signup and view all the answers

Which type of blood vessel is primarily known as exchange vessels?

<p>Capillaries (A)</p> Signup and view all the answers

What happens during ventricular systole?

<p>Blood is pumped from the ventricles to the body and lungs. (A)</p> Signup and view all the answers

Which hormone is known to increase heart rate?

<p>Thyroxin (D)</p> Signup and view all the answers

Flashcards

Arterial blood pressure function

The force pushing blood through circulation, ensuring adequate tissue perfusion and capillary filtration.

Hypertension

High blood pressure, typically defined as a blood pressure reading above 140/90. Different classifications exist based on age groups.

Primary Hypertension

90% of cases, occurs without an identifiable cause, characterized by narrowed arterioles.

Venous return

The volume of blood entering the right ventricle per minute. It's equal to cardiac output.

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Hemorrhage

Significant blood loss from the cardiovascular system, classified as external or internal.

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Heart Chambers

The heart has four chambers: two atria (receiving chambers) and two ventricles (pumping chambers).

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Heart Valves

Heart valves are flaps of tissue that ensure one-way blood flow through the heart. They include the tricuspid, mitral, pulmonary, and aortic valves.

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Atrioventricular Valves

Tricuspid and mitral valves, located between the atria and ventricles, prevent backflow during ventricular contraction.

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Papillary Muscles

Muscles in the ventricles that connect to the chordae tendineae, helping prevent valve inversion.

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Systemic Circulation

The circulation of blood from the left ventricle to the body and back to the right atrium.

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Pulmonary Circulation

The circulation of blood from the right ventricle to the lungs and back to the left atrium.

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Blood Flow Direction

Heart valves ensure that blood flows in one direction through the heart and circulatory system.

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Heart Function

The heart's function is to pump blood throughout the body, delivering oxygen and nutrients.

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Heart Rate

The number of heartbeats per minute.

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Sino-atrial node (SA node)

The pacemaker of the heart; initiates the heartbeat.

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Cardiac Cycle

One complete sequence of contraction and relaxation of the heart.

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Cardiac Output

The amount of blood pumped by the ventricles per minute.

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Stroke Volume

The amount of blood pumped per heartbeat.

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Sympathetic Stimulation

Increases heart rate and cardiac output.

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Parasympathetic Stimulation

Decreases heart rate and cardiac output.

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Blood Vessel Types

Elastic arteries, muscular arteries, arterioles, and exchange vessels.

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Pericardium

A tough, protective sac that surrounds the heart, reducing friction during contractions.

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Atrioventricular (A-V) Valves

Valves located between the atria and ventricles, preventing blood from flowing back into the atria during ventricular contraction.

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Aortic Valve Function

Regulates blood flow from the left ventricle into the aorta, preventing backflow into the ventricle.

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Pulmonary Valve Function

Regulates blood flow from the right ventricle into the pulmonary artery, preventing backflow into the ventricle.

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Atrium Function

The atria are the entry points for blood into the ventricles, receiving deoxygenated blood from the body (right atrium) and oxygenated blood from the lungs (left atrium).

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What causes the heart to beat?

The electrical impulse originates at the sino-atrial node (SA node), located in the right atrium, leading to atrial contraction. The impulse then travels to the atrioventricular node (AV node) and finally to the ventricles via the His-Purkinje system, causing ventricular contraction.

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How does exercise affect heart rate?

Exercise increases heart rate. This happens because the body needs to deliver more oxygen and nutrients to muscles during activity.

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What increases cardiac output?

Sympathetic nervous system stimulation, catecholamines (like adrenaline), and thyroxin increase cardiac output.

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What are windkessel vessels?

Windkessel vessels are elastic arteries, like the aorta, that help to maintain blood pressure between heartbeats.

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Resistance vessels

These are small blood vessels called arterioles that regulate blood flow and pressure.

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What type of blood vessel is the aorta?

The aorta is an elastic artery, also known as a windkessel vessel.

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Arterial Blood Pressure

The force that pushes blood through the circulatory system, ensuring adequate blood flow to all tissues. It's also responsible for filtering fluids from capillaries.

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What causes primary hypertension?

Primary hypertension is characterized by narrow arterioles caused by the blood vessels being overly sensitive to constricting stimuli.

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What are the functions of veins?

Veins carry blood back to the heart, allowing for proper circulation. Their main function is to drain blood from capillaries towards the heart.

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What is the difference between external and internal hemorrhage?

External hemorrhage is blood loss that's visible, like a cut. Internal hemorrhage is a serious loss of blood inside the body, making it difficult to diagnose.

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Study Notes

Introduction to Cardiovascular Physiology

  • Presented by Dr. Sherif Diaaeldin
  • Assistant Professor of Physiology

Functional Anatomy of the Heart

  • The heart is a hollow muscular organ
  • Surrounded by a connective tissue sac called the pericardium
  • The pericardium protects the heart and minimizes friction during contraction
  • The heart wall is made of cardiac muscle
  • Divided into right and left halves
  • Each half consists of one atrium and one ventricle

Heart Valves

  • The right atrium is separated from the right ventricle by the tricuspid valve
  • The left atrium is separated from the left ventricle by the bicuspid (or mitral) valve
  • Both valves are called atrioventricular (A-V) valves
  • In the ventricles, there are papillary muscles with tendons (chordae tendineae)
  • These are attached to the A-V valves to prevent everting into the atria during ventricular contraction

Function of Heart Valves

  • Allow blood flow in one direction only

Divisions of the Circulation

  • Systemic Circulation:
    • Begins at the left ventricle
    • Aorta
    • Arteries
    • Arterioles
    • Capillaries
    • Venules
    • Veins
    • Superior and inferior vena cava
    • Right atrium
  • Pulmonary Circulation:
    • Begins at the right ventricle
    • Pulmonary artery
    • Lungs
    • Pulmonary capillaries
    • Pulmonary veins (4 in number)
    • Left atrium

Functions of the Atria and Ventricles

  • Atria are entryways for ventricles
  • Ventricles pump blood to the whole body
  • The aorta pumps oxygenated blood throughout the body
  • Pulmonary veins carry oxygenated blood to the heart from the lungs
  • Pulmonary artery carries deoxygenated blood to the lungs

Mechanism of Heart Beating

  • Heart rate: 60-90 beats/min (average 72 beats/min in adults)
  • Impulse originates at the sino-atrial (SA) node (in the right atrium)
  • SA node contraction of atria
  • Impulse travels to the atrioventricular (AV) node
  • Impulse travels to the ventricles through the His-Purkinje system
  • This causes ventricular contraction

Factors Affecting Heart Rate

  • Increasing Heart Rate:
    • Sympathetic stimulation (e.g., fear, stress)
    • Exercise
    • Increased body temperature (e.g., fever)
    • Thyroxin and adrenaline hormones
  • Decreasing Heart Rate:
    • Parasympathetic stimulation
    • Sleep
    • Decreased body temperature
    • Drugs (e.g., beta blockers)

Normal Heart Sounds

  • S1 ("Lubb"): Sound of mitral and tricuspid valve closure, start of systole, heard loudest at the apex of the heart
  • S2 ("Dubb"): Sound of pulmonic and aortic valve closure, end of systole, heard loudest at the base of the heart

The Cardiac Cycle

  • Consists of one systole-diastole sequence
  • Duration is about 0.8 seconds
  • Atrial systole: Blood flows from the atria to the ventricles
  • Ventricular systole: Blood flows from the ventricles (to the lungs on the right side and to the rest of the body on the left side)
  • Atrial diastole: Atria receive blood from the superior and inferior vena cava
  • Ventricular diastole: Ventricles fill with blood from the atria

The Cardiac Output

  • Amount of blood pumped by each ventricle per minute
  • Approximately 5.5 liters per minute
  • Stroke volume: Amount of blood pumped by each ventricle per beat (approximately 80 ml/beat)
  • Cardiac output = heart rate x stroke volume

Factors Affecting Cardiac Output

  • Sympathetic stimulation increases cardiac output
  • Parasympathetic stimulation decreases cardiac output
  • Catecholamines and thyroxin increase cardiac output

Blood Vessels

  • Types of blood vessels :
    • Elastic arteries (e.g., aorta)
    • Muscular arteries (e.g., large arteries)
    • Resistance vessels (e.g., arterioles)
    • Exchange vessels (e.g., capillaries)

Arterial Blood Pressure

  • The force that pushes blood through the circulatory system
  • Ensures adequate tissue perfusion
  • Responsible for capillary filtration

Determinants of Arterial Blood Pressure

  • Age
  • Sex
  • Diurnal variations
  • Sleep
  • Emotions
  • Exercise
  • Gravity

Hypertension in Man

  • High blood pressure
  • Types: Primary (essential) or Secondary
    • Primary (90%): Often no identifiable cause, characterized by narrowed arterioles
    • Secondary (10%): Caused by other health conditions (e.g., kidney failure, endocrine disorders)
  • Predisposing factors: Smoking, obesity, excess salt intake

Functions of Veins

  • Passageways for blood flow to the heart, crucial for circulation
  • Drain capillary blood to the heart
  • Blood returned to the heart determines venous return (equal to cardiac output) 

Shock & Haemorrhage

  • Hemorrhage: Blood loss from the cardiovascular system (external or internal)
  • Shock: Decreased tissue perfusion due to inadequate oxygen and nutrient delivery to cells (blood loss > 20% of total volume)
  • Compensatory mechanisms: Increase arterial blood pressure and cardiac output (temporary measures) to restore blood volume (delayed measures)

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Explore the functional anatomy of the heart, including its valves and their roles in ensuring unidirectional blood flow. This quiz will cover essential concepts about the heart's structure and the significance of its components in cardiovascular physiology.

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