40. Circulatory System

Heart Physiology

Electrical Conduction in the Heart

 No. Consider what happens in the ventricle as it contracts. 

 No. During diastole the heart is relaxed, and blood enters the atria. 

 AV valves are open and semilunar valves are closed 

 No. Think about the location of the heart valves and when they would be open or closed during ventricular contraction. 

 the atria contract during early systole 

 No. The pressure of atrial contraction is not sufficient to open semilunar valves. 

Think about pressure-volume relationships.

Pressure is greatest in the ventricles when __________.

 the left atrium, causing ventricular contraction 

 No. The AV node transfers the impulse from the atria to the ventricles. 

 the left ventricle wall, from which the impulse is carried to the bundle branches and on to the Purkinje fibers 

 No. Consider what the "A" in "SA" stands for. 

 the left ventricle, causing atrial contraction 

 No. One of the other choices is correct. 

 the right atrium, causing atrial contraction 

Consider what "SA" stands for.

The SA node generates an electrical impulse from its location in __________.

Development of atherosclerosis

Paul’s blood pressure is 150/90. The 150 indicates _________ , and the 90 indicates _________ . 
a. pressure in the left ventricle; pressure in the right ventricle 
b. pressure during ventricular contraction; pressure during heart relaxation 
c. systemic circuit pressure; pulmonary circuit pressure 
d. pressure in the arteries; pressure in the veins

Cardiac Action Potential, Animation.

Cardiovascular | Cardiac Cycle

Cardiac cycle 2- Atrial ventricular diastole

Electrical activity in the Heart

 No. The walls of arteries are thicker to resist the higher blood pressures. 

 No. The walls of arteries are thicker to resist the higher blood pressures as blood moves away from the heart. 

 No. Veins carry blood with lower blood pressure toward the heart. 

 No. Arteries are thicker to resist the higher blood pressure as blood moves away from the heart. 

Arteries are carrying blood away from the heart.

When we compare the structures and functions of arteries and veins, we find that the walls of arteries are __________, the blood pressure inside arteries is __________, and the blood in arteries is moving __________ the heart.

When the doctor listened to Janet’s heart, he heard “lub-hiss, lub-hiss” instead of the normal “lub-dup” sounds. The hiss is most likely due to _________ . (Explain your answer.)
a. a defective atrioventricular (AV) valve
b. a damaged pacemaker (SA node)
c. a defective semilunar valve
d. high blood pressure

Cardiac cycle, stages, physiology, Diastole and systole in the cardiac cycle.

ATHEROSCLEROSIS and CARDIOVASCULAR DISEASE

Electrical Signals of the Heart

Some babies are born with a small hole in the wall between the left and right ventricles. How might this affect the oxygen content of the blood pumped out of the heart into the systemic circuit?

How the heart actually pumps blood - Edmond Hui

The Cardiac Cycle, Animation

How blood pressure works - Wilfred Manzano

Cardiovascular Disease

Cardiology - Heart Physiology I (Cardiac Myocyte and Membrane Potential)

Which of the following initiates the process of blood clotting? 
a. damage to the lining of a blood vessel 
b. conversion of fibrinogen to fibrin 
c. attraction of white blood cells to a site of infection 
d. conversion of fibrin to fibrinogen

Cardiac Cycle and Conduction System of Heart [Physiology Animation]

Cardiac cycle 4- Early ventricular systole

SCIENTIFIC THINKING The studies described in Module 23.6 were funded by both government agencies and major pharmaceutical and medical supply companies. NIH grants for research on heart disease total more than $1.2 billion per year. Gather more information and form an opinion on how heart disease research should be funded, whether by private enterprises such as pharmaceutical companies, donor-supported nonprofit organizations, or government agencies. Write an essay arguing your point of view.

The Cardiac Cycle | A-Level Biology

Cardiac Cycle | Cardiovascular Physiology

During exercise, the cardiovascular system must supply muscles with large amounts of oxygen and fuel and get rid of a lot of wastes. How do the cardiovascular systems of athletes respond to prolonged exercise?

Researchers used echocardiography, a sonogram of the heart, to estimate the mass of the left ventricle in current athletes, non-athletes, and ex-athletes. The data are graphed below (*** means P<0.001, and the P value comparing non-athletes and ex-athletes is >0.05). What conclusion can be drawn from the graph? <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/9675998c2c520f29-1677307487044.jpg" style="width: 300px;">

The Cardiac Cycle

Cardiovascular | Fundamentals of Blood Pressure

Blood pressure is highest in _________ , and blood moves most slowly in _________ .
a. veins; capillaries
b. arteries; capillaries
c. veins; arteries
d. arteries; veins

Atherosclerosis, Causes, Signs and Symptoms, Diagnosis and Treatment.

 No. The right atrium receives deoxygenated blood from the veins. 

 No. The left atrium receives oxygenated blood from the lungs, but where does this oxygenated blood go next before being propelled out of the aorta? 

 No. The right atrium receives deoxygenated blood from the veins and passes it into the right ventricle for delivery to the lungs, where it is oxygenated. 

 No. The left ventricle does receive oxygenated blood, but from which chamber does it receive the oxygenated blood? 

Which side of the heart receives blood returning from the lungs?

Which chamber(s) of a human heart receive(s) and pump(s) oxygenated blood?

Role of oxidative stress in atherosclerosis

During exercise, the cardiovascular system must supply muscles with large amounts of oxygen and fuel and get rid of a lot of wastes. How do the cardiovascular systems of athletes respond to prolonged exercise?

Researchers have also observed that athletes and non-athletes have the same mean resting cardiac output, even though athletes have a far lower resting heart rate. How is this possible?

"Basic Cardiac Anatomy and Physiology" by Nancy Braudis for OPENPediatrics

 No. Decreasing the diameter of blood vessels increases blood pressure. 

 No. This chemical is the most potent known inducer of vasoconstriction, which increases blood pressure. 

 Contraction of the ventricles of the heart 

 No. When the ventricles contract, blood pressure increases. 

 All of the listed responses are correct. 

 No. Only one of the choices above decreases blood pressure. 

Heart contractions and the contraction of blood vessel walls can increase blood pressure.

Which of the following decreases blood pressure?

 No. Nitric oxide, when bound to receptors in the smooth muscle wall, results in vasodilation; however, the absence of functioning NO receptors would not necessarily result in vasoconstriction. 

 No. Nitric oxide results in vasodilation when it binds to its receptor. An inability of the receptor to bind NO would decrease vasodilation, not vasoconstriction. 

 No. The binding of NO to its receptor results in vasodilation, which subsequently lowers blood pressure. An inability of the receptor to bind NO would decrease vasodilation, making it less likely that blood pressure will drop. 

 No. Nitric oxide stimulates vasodilation when it binds to its receptor; an inability of the receptor to bind NO would decrease, not increase, the likelihood of vasodilation. 

What is the function of NO (nitric oxide)?

A mutation that results in a nonfunctioning nitric oxide receptor would cause __________.

Juan has a disease in which damaged kidneys allow some of his normal plasma proteins to be removed from the blood. How might this condition affect the osmotic pressure of blood in capillaries, compared with that of the surrounding interstitial fluid? One of the symptoms of this kidney malfunction is an accumulation of excess interstitial fluid, which causes Juan’s arms and legs to swell. Can you explain why this occurs?

Blood flows more slowly in the arterioles than in the artery that supplies them because the arterioles 
a. have thoroughfare channels to venules that are often closed off, slowing the flow of blood. 
b. have sphincters that restrict flow to capillary beds. 
c. are narrower than the artery. 
d. collectively have a larger cross-sectional area than does the artery.

Pathogenesis of Atherosclerosis

Atherosclerosis

During exercise, the cardiovascular system must supply muscles with large amounts of oxygen and fuel and get rid of a lot of wastes. How do the cardiovascular systems of athletes respond to prolonged exercise?

Explain the advantage of the observed difference between current athletes and non-athletes in the graph shown here.

How the cardiac cycle is produced by electrical impulses in the heart

Cardiac cycle 3- Atrial systole

Explain why a person who survives a myocardial infarction might need to have an artificial pacemaker implanted.

BTEC nervous control of the cardiac cycle

Hypertension | Blood Pressure Regulation | Hypotension | Dr Najeeb Lectures

 pressure in the left ventricle; pressure in the right ventricle 

 No. Both ventricles contract at the same time. 

 pressure in the left ventricle; pressure in the left atrium 

 No. The top number is the systolic pressure, which is the pressure in the arteries when the ventricles are contracting. The other number is the diastolic pressure, which is the pressure during the relaxation phase. 

 pressure in the systemic system; pressure in the pulmonary system 

 No. Consider how and where blood pressure is taken. 

 arterial pressure during heart contraction; arterial pressure during heart relaxation 

What causes these differences in blood pressure?

Your blood pressure is 120/70. The "120" indicates __________, and the "70" indicates __________.

Cardiac Cycle

 No. Coronary arteries are more likely to be blocked than to burst. 

 No. Angina is a painful condition, caused by blocked arteries, which may eventually lead to heart attack. 

 A blood clot moving through the chambers of the heart 

 No. If the blood clot lodges in a blood vessel supplying the heart, it will cause a heart attack; however, the movement of a clot through the heart itself will not cause a heart attack. 

 No. Scar tissue may form after a heart attack. This tissue will weaken the heart's ability to pump blood because it is not able to contract. 

 A blood clot lodging in a blood vessel supplying the heart 

The heart muscle is supplied with oxygen by blood vessels that run along the surface of the heart.

What is the physiological cause of a heart attack?

 mix blood thoroughly as it passes through the heart 

 No. Valves only open and close. This would not cause any significant mixing of the blood as it passes through the heart. 

 control the amount of blood pumped by the heart 

 No. Cardiac output is controlled by the strength and rate of contraction. 

 slow blood down as it passes through the heart 

 No. Because nothing is added or removed from the blood while it is in the heart, there would be no advantage to slowing it down. 

 propel blood as it passes through the heart 

 No. Valves are compliant, passive structures. They are not constructed from muscle, and they do not contract. 

 keep blood moving forward through the heart 

Consider the pattern of blood flow through the heart.

Heart valves function to __________.

 No. The semilunar valves present in the aorta and pulmonary trunk prevent backflow into the ventricles. 

 No. A blocked coronary artery can lead to irregularities in ventricular contraction because the larger ventricular muscle mass requires more oxygen than the atria. The problem, however, would be continuous rather than intermittent. 

 No. The SA node, or pacemaker, sets the heart rate. Problems here would also affect the atria. 

 No. The AV valves prevent backflow into the atria during ventricular systole. 

Consider how the impulse to contract is relayed from the atria to the ventricles.

A recording of the electrical activity of a patient's heart shows that the atria are contracting regularly and normally, but every few beats the ventricles fail to contract. Which of the following is probably functioning improperly?

During exercise, the cardiovascular system must supply muscles with large amounts of oxygen and fuel and get rid of a lot of wastes. How do the cardiovascular systems of athletes respond to prolonged exercise?

Athletes are not the only people with enlarged hearts. Many patients with cardiovascular disease also have enlarged hearts. Suggest a cause of this enlargement.

 No. The left atrium receives blood from the pulmonary vein; the venae cavae return blood from the systemic circuit to the right atrium. 

 No. Blood moves directly from the right ventricle of the heart through the pulmonary artery into the lungs. 

 No. Blood does not pass from veins into arteries without first cycling through the heart. 

 No. Both venae cavae return blood from the systemic circuit into the right atrium. 

Review the pattern of blood flow through the mammalian heart.

Blood leaves the inferior vena cava and flows directly into the __________.

Pulse is a direct measure of
a. blood pressure.
b. stroke volume.
c. cardiac output.
d. heart rate.

Blood Pressure Regulation (Lecture)

What is Coronary Artery Disease - Mechanism of Disease

Blood Pressure

Cardiac cycle 1- Introduction

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