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?

Blood flows in one direction Signup and view all the answers

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

Pressure gradient Signup and view all the answers

What is the best definition of an artery?

A vessel that carries blood away from the heart Signup and view all the answers

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

Increase radius by 1 unit Signup and view all the answers

What is a function of the pericardial fluid?

Reduce friction between the heart and the pericardium Signup and view all the answers

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

Diameter of a vessel Signup and view all the answers

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

Tube 1, because the pressure gradient is the highest Signup and view all the answers

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

Digestive tract Signup and view all the answers

Where are valves located in the heart?

Between the atria and ventricles and between ventricles and arteries Signup and view all the answers

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

Velocity of flow Signup and view all the answers

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

Decreased vessel diameter Signup and view all the answers

What type of blood vessels return blood to the heart?

Veins Signup and view all the answers

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

Two cardiac muscle cells are connected by gap junctions Signup and view all the answers

What structures make up the cardiovascular system?

the heart, blood vessels, blood Signup and view all the answers

Which arteries are the first to branch from the aorta?

coronary arteries Signup and view all the answers

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

pulmonary circuit Signup and view all the answers

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

septum Signup and view all the answers

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

pulmonary trunk Signup and view all the answers

What term describes reduced blood flow to the cardiac muscle?

coronary ischemia Signup and view all the answers

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

Papillary muscles Signup and view all the answers

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

chordae tendineae Signup and view all the answers

What causes the action potentials of myocardial autorhythmic cells?

increasing Na2+ influx and decreasing K+ efflux Signup and view all the answers

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

closing of Ca2+ channels and opening of K+ channels Signup and view all the answers

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

at least 200 milliseconds Signup and view all the answers

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

preventing tetanus Signup and view all the answers

Why can myocardial cells generate action potentials spontaneously?

they possess unstable ion channels Signup and view all the answers

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

tricuspid valve Signup and view all the answers

Which blood vessels carry blood away from the heart?

Arteries Signup and view all the answers

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

Atria Signup and view all the answers

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

Decreases 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?

Decreases Signup and view all the answers

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

Total cross-sectional area increases 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?

Increases Signup and view all the answers

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

Increases heart rate by increasing calcium ion flow Signup and view all the answers

What is the resting membrane potential for contractile myocardium?

-90 mV Signup and view all the answers

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

Sodium entry Signup and view all the answers

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

Shorter than contractile myocardium 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?

The heart rate will decrease. Signup and view all the answers

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

The drug would slow down this individual's heart rate. Signup and view all the answers

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

The heart would beat less forcefully. Signup and view all the answers

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

The long refractory period prevents tetany. Signup and view all the answers

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

It stores Ca2+ ions. Signup and view all the answers

Which statement is true regarding calcium channel blockers?

They can decrease the force of cardiac contraction. 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?

Blood pressure will decrease. 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?

Flow between those points is unchanged. Signup and view all the answers

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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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.