Heart Structures and Blood Flow Quiz
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Questions and Answers

If blood pressure doubles while peripheral resistance also doubles, what happens to blood flow through a vessel?

  • Unchanged
  • Halves
  • 1/16 as much (correct)
  • Doubled

What physiological change causes a decrease in resistance in a vessel?

  • Vasoconstriction
  • Vasodilation (correct)
  • Increased blood viscosity
  • Increased vessel length

Which blood vessels are known to have the lowest blood pressure?

  • Arteries
  • Veins (correct)
  • Capillaries
  • Venules

The primary role of valves in the cardiovascular system is to ensure what?

<p>Blood flows in one direction (D)</p> Signup and view all the answers

Which type of gradient serves as the driving force for blood flow?

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

What is the best definition of an artery?

<p>A vessel that carries blood away from the heart (D)</p> Signup and view all the answers

Which of the following changes would increase blood flow in a vessel the most?

<p>Increase radius by 1 unit (A)</p> Signup and view all the answers

What is a function of the pericardial fluid?

<p>Reduce friction between the heart and the pericardium (C)</p> Signup and view all the answers

Which factor, when doubled, would have the greatest effect on peripheral resistance?

<p>Diameter of a vessel (B)</p> Signup and view all the answers

In which tube would the flow be the highest based on the given pressures?

<p>Tube 1, because the pressure gradient is the highest (C)</p> Signup and view all the answers

The hepatic portal vein carries blood away from which of the following?

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

Where are valves located in the heart?

<p>Between the atria and ventricles and between ventricles and arteries (B)</p> Signup and view all the answers

What does a flow rate of '4 cm/min' describe?

<p>Velocity of flow (B)</p> Signup and view all the answers

Which change will NOT result in increased blood flow to a tissue?

<p>Decreased vessel diameter (D)</p> Signup and view all the answers

What type of blood vessels return blood to the heart?

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

At an intercalated disc in cardiac muscle, what is true?

<p>Two cardiac muscle cells are connected by gap junctions (C)</p> Signup and view all the answers

What structures make up the cardiovascular system?

<p>the heart, blood vessels, blood (A)</p> Signup and view all the answers

Which arteries are the first to branch from the aorta?

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

Which circuit is responsible for carrying blood to and from the alveoli of the lungs?

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

What is the name of the wall that separates the two sides of the heart?

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

Which structure directs blood from the right ventricle to the lungs?

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

What term describes reduced blood flow to the cardiac muscle?

<p>coronary ischemia (B)</p> Signup and view all the answers

Which component helps provide stability for the chordae tendineae in the heart?

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

Which component is NOT part of intercalated disks in cardiac muscle?

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

What causes the action potentials of myocardial autorhythmic cells?

<p>increasing Na2+ influx and decreasing K+ efflux (B)</p> Signup and view all the answers

What is the reason for the end of the plateau phase in myocardial cells?

<p>closing of Ca2+ channels and opening of K+ channels (C)</p> Signup and view all the answers

How long does a typical action potential of a myocardial contractile cell last?

<p>at least 200 milliseconds (D)</p> Signup and view all the answers

What is the primary purpose of the plateau phase in myocardial cells?

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

Why can myocardial cells generate action potentials spontaneously?

<p>they possess unstable ion channels (A)</p> Signup and view all the answers

Which type of valve is described as having three flaps and being an AV valve?

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

Which blood vessels carry blood away from the heart?

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

Which chamber of the heart primarily receives blood from the veins?

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

When a blood vessel dilates, what happens to resistance through that vessel?

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

What effect does an increase in total cross-sectional area of blood vessels in an organ have on the velocity of blood through that organ?

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

In the context of blood flow, what occurs when all capillary beds in the digestive tract are open?

<p>Total cross-sectional area increases (B)</p> Signup and view all the answers

What happens to blood velocity if blood flow to an organ increases but the total cross-sectional area remains constant?

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

How do sympathetic stimulations affect heart rate in the pacemaker cells?

<p>Increases heart rate by increasing calcium ion flow (B)</p> Signup and view all the answers

What is the resting membrane potential for contractile myocardium?

<p>-90 mV (B)</p> Signup and view all the answers

What initiates the rising phase of the action potential in skeletal muscle?

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

What is the duration of the action potential in skeletal muscle compared to contractile myocardium?

<p>Shorter than contractile myocardium (B)</p> Signup and view all the answers

What happens to the heart rate if the membranes of cardiac muscle cells in the SA node become more permeable to potassium ions?

<p>The heart rate will decrease. (D)</p> Signup and view all the answers

What effect does ivabrandine have on an individual's heart rate?

<p>The drug would slow down this individual's heart rate. (C)</p> Signup and view all the answers

How would the presence of manganese ions impact the contraction of heart muscle?

<p>The heart would beat less forcefully. (A)</p> Signup and view all the answers

Which of the following accurately describes the reason cardiac muscle cannot exhibit tetany?

<p>The long refractory period prevents tetany. (B)</p> Signup and view all the answers

What is the role of sarcoplasmic reticulum in cardiac muscle cells?

<p>It stores Ca2+ ions. (D)</p> Signup and view all the answers

Which statement is true regarding calcium channel blockers?

<p>They can decrease the force of cardiac contraction. (C)</p> Signup and view all the answers

If a patient develops a medical condition that decreases blood viscosity, what is the likely effect on blood pressure?

<p>Blood pressure will decrease. (B)</p> Signup and view all the answers

What conclusion can be drawn if the blood pressure at point A drops from 20 units to 15 units while at point B it falls from 10 units to 5 units?

<p>Flow between those points is unchanged. (C)</p> Signup and view all the answers

Flashcards

Effect of Resistance on Blood Flow

As resistance increases, blood flow decreases, and vice versa.

Blood Flow with Doubled Pressure/Resistance

If pressure and resistance both double, the flow remains the same.

Vasodilation Effect on Resistance

Vasodilation decreases resistance, leading to increased blood flow.

Lowest Blood Pressure Vessels

Venules have the lowest blood pressure in the circulatory system.

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Valves in Cardiovascular System

Valves ensure that blood flows in one direction.

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Driving Force of Blood Flow

Pressure gradient is the driving force for blood flow.

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Blood Flow with Constant Pressure

If blood pressure remains the same between two points, flow is unchanged.

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First Branches from Aorta

The first branches from the aorta are the coronary arteries, supplying the heart.

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Myocardial Autorhythmic Cells Action Potential

Combination of increasing Na+ influx and decreasing K+ efflux

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Plateau Phase End (Myocardial Cells)

Closing of Ca2+ channels and opening of K+ channels

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Myocardial Contractile Cell AP Duration

50-100 milliseconds

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Plateau Phase Importance (Myocardial Cells)

Prevents tetanus and fibrillation by regulating Ca2+ availability to the cells

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Myocardial Cell Spontaneous AP Generation

Due to unstable ion channels and prolonged Ca2+ influx

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Tricuspid Valve

An atrioventricular valve with three flaps.

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Pulmonary Valve

Semilunar valve with the right ventricle on one side.

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Bicuspid (Mitral) Valve

An atrioventricular valve with two flaps, also known as mitral valve.

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Peripheral Resistance Doubling

The change (among vessel length, diameter, blood viscosity, turbulence, or white blood cells) in blood flow that most affects peripheral resistance is doubling the viscosity of the blood.

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Highest Blood Flow Tube

Tube 1, with the largest pressure difference (25 mmHg to 1 mmHg), possesses the highest blood flow due to its greatest pressure gradient.

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Hepatic Portal Vein Source

Blood in the hepatic portal vein originates from the digestive tract.

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Heart Valve Location

Heart valves are located between the atria and ventricles, and between the ventricles and arteries.

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Blood Flow Path (Left Atrium to Right Atrium)

Blood traveling from the left atrium follows this path: left ventricle, abdominal aorta, hepatic artery, superior vena cava, right atrium.

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Flow Rate Units

"4 cm/min" describes the flow rate of a fluid, indicating the volume moving per unit time.

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Decreased Blood Flow Cause

A decreased vessel diameter leads to increased peripheral resistance and subsequently decreased blood flow.

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Blood Return Vessels

Veins are the blood vessels responsible for returning blood to the heart.

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Cardiovascular system components

The cardiovascular system comprises the heart, blood vessels, and blood.

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Aorta's first branches

The coronary arteries branch off the aorta to supply blood to the heart.

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Pulmonary circuit

The circuit carrying blood to and from the lungs.

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Systemic circuit

Carries blood to and from all body parts (except lungs).

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Driving pressure

The pressure generated in ventricles, the force for blood flow.

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Coronary ischemia

Reduced blood flow to the heart muscle.

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Heart's enclosure

The heart is enclosed in the pericardial membrane.

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Heart's muscle layer

The myocardium is the heart's muscular layer.

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Cardiac Muscle Calcium Storage

Cardiac muscle cells store calcium ions in the sarcoplasmic reticulum.

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Calcium-induced Calcium Release

Extracellular calcium triggers the release of stored calcium from the sarcoplasmic reticulum.

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Intercalated Disks Composition

Intercalated disks have desmosomes for attachment and gap junctions for communication.

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Cardiac Muscle Oxygen Demand

Cardiac muscle cells need a lot of oxygen due to their many mitochondria.

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SA Node Potassium Permeability Increase

Increased potassium permeability in SA node cells slows the heart rate.

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Cardiac Muscle Refractory Period

Long refractory period prevents tetany (sustained contraction) in cardiac muscle.

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Ivabradine Effect

Ivabradine slows the heart rate by blocking If channels.

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Manganese Effect on Calcium Channels

Manganese blocking calcium channels reduces heart muscle contraction force.

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Blood Vessel Dilation Effect on Resistance

Blood vessel dilation decreases resistance to blood flow.

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Blood Vessel Length and Resistance

Longer vessels generally increase resistance in comparison to shorter ones, all else being equal.

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Increased Cross-Sectional Area Effect on Velocity

Increased cross-sectional area of blood vessels decreases blood velocity.

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Blood Flow and Cross-Sectional Area in Digestive Tract (Eating)

When eating, more capillary beds open in the digestive tract, leading to an increased total cross-sectional area.

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Autorhythmic Cell Channel Opening

If channels open at -60 mV in pacemaker cells, allowing Na+ and K+ flow.

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Pacemaker Cells Resting Potential

Autorhythmic cells have an unstable pacemaker potential, usually starting at -60 mV, while contractile myocardium is -90mV, and skeletal muscle's is -70mV.

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Action Potential Rising Phase (Autorhythmic)

The rising phase of an autorhythmic cell action potential is due to calcium influx.

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Action Potential Duration Comparison

Skeletal muscle action potentials are brief (1-2 msec), while contractile myocardial potentials are longer (200+ msec) than those of autorhythmic cells (generally 150+ msec).

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Study Notes

Valves and Heart Structures

  • Bicuspid (mitral) and tricuspid valves have chordae tendineae
  • Capillaries are thin walled vessels that exchange materials with interstitial fluid
  • Blood pressure decreases as blood moves away from the heart due to friction
  • Hydrostatic pressure is the pressure exerted by a fluid when it's not moving
  • A patient given a beta 1 agonist would experience an increase in heart rate and cardiac output

Blood Flow Through The Heart

  • Blood returning to the heart flows through the right atrium, right ventricle, pulmonary arteries, pulmonary veins, left atrium and finally the left ventricle.
  • The sac surrounding the heart is called the pericardium.
  • Blood pressure decreases as blood moves farther from the heart due to friction, and the vessels get smaller.

Resistance and Flow

  • Resistance increases as blood vessel lengths increase, and flow decreases
  • Flow decreases but resistance increases as blood viscosity increases
  • Resistance decreases and flow increases as blood vessel radius increases
  • Doubles the blood flow with the same peripheral resistance if blood pressure and resistance are doubled.

Blood Pressure and Vessels

  • When blood pressure doubles, and peripheral resistance doubles, there is no change in blood flow through the vessel
  • Flow is unchanged when blood pressure and resistance are both doubled in a vessel
  • Vasodilation decreases resistance in a vessel

Blood Vessels and Pressure

  • Capillaries have the lowest blood pressure
  • Valves ensure blood flow in only one direction in the cardiovascular system
  • The purpose of valves is to ensure that blood flows in the correct direction, prevents blood from flowing too quickly.

Definitions and Functions

  • An artery carries blood away from the heart, veins carry blood toward the heart
  • Hydrostatic pressure refers to the pressure when a fluid isn't moving
  • The heart has four chambers: two atria and two ventricles
  • The cardiovascular system transports materials to and from all parts of the body
  • The primary function of the cardiovascular system is to transport material to and from all parts of the body
  • The pulmonary circuit carries blood to and from the alveoli of the lungs
  • The systemic circuit carries blood to all parts of the body except the alveoli of the lungs
  • Arteries carry oxygenated blood, veins carry deoxygenated blood

Heart Function and Structures

  • The pressure created in the ventricles is called driving pressure
  • Coronary ischemia is reduced blood flow to the cardiac muscle
  • The hepatic portal vein carries blood away from the pancreas and digestive tract.
  • Blood flows from the digestive tract, to the liver, then to the heart

Additional Notes

  • The plateau phase of the myocardial action potential is important for efficient oxygen use by cells and prevents tetanus (repeated muscle contractions).
  • The heart has an unstable ion channel that allows it to generate spontaneous action potentials, which are essential for heartbeat regulation.
  • Myocardial cells can generate action potentials spontaneously due to their unstable ion channels
  • Gap junctions allow communication between cardiac muscle cells
  • Intercalated disks are cell junctions in contractile cells, which consist of desmosomes and gap junctions.
  • Sympathetic stimulation increases the heart rate and efficiency of calcium use by the cells

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Cardiovascular Quiz (PDF)

Description

Test your knowledge on the anatomy and functioning of the heart with this quiz. Explore key concepts such as the roles of valves, capillaries, and the effects of blood pressure and resistance on cardiovascular performance. Ideal for students learning about human physiology.

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