mastering quiz unit 20: the heart

What causes the heart sounds hear with a stethoscope?

The turbulence of blood against the closed valves

What happens to Caleb's systemic cardiac output as a result of his ventricular septal defect (VSD)? Explain your answer.

This shunt decreases stroke volume and cardiac output from the left ventricle into the aorta

What term describes the "heart strings?"

chordae tendineae

What fibrous structure functions to anchor the atrioventricular valves in a closed position?

chordae tendineae Chordae tendineae are the fibrous cords that attach the atrioventricular valves to papillary muscles. They help anchor the atrioventricular valves in a closed position during ventricular contraction.

To examine the internal anatomy of the heart, you will make which type of cut?

coronal

Which of the following correctly describes what happens to Caleb's heart as a result of his VSD?

decreased stroke volume in the LV - Stroke volume is the amount of blood pumped out of the heart per left ventricular systole

What causes striations in the cardiac muscle cells?

The overlapping of the actin and myosin proteins of the myofilaments

what is the parietal pericardium?

The parietal pericardium is the outer layer of the serous pericardium. It is fused to the inner surface of the fibrous pericardium.

ECG is a graphic recording of __________.

electrical activity of the heart

The tracing of recorded electrical activity of the heart obtained by using electrodes on the skin is called an ____________.

electrocardiogram

Name the inner lining of the heart.

endocardium The endocardium is the smooth, slick lining of the chambers of the heart. Endocardium is a continuation of endothelium that lines blood vessels. Both endocardium and endothelium are composed of simple squamous epithelial tissue, which minimizes friction between the wall of the chamber/vessel and the blood

The visceral pericardium is most closely associated with which of the following?

epicardium

T orF: As a result of Caleb's defect, the blood volume entering the pulmonary trunk and arteries decreases

false

T or F: The base of the heart is located at the bottom of the heart

false the base is located at the top of the heart. It is unusual to see the largest portion of an organ at the top. Typically, the base is at the bottom of an organ, as in the lungs.

Which structure is a remnant of the foramen ovale?

fossa ovalis

what is this structure on cardiac muscle tissue?

intercalated disc

Which structure separates the right and left ventricles?

interventicular septum

What part of Caleb's heart has a defect?

interventricular septum - The interventricular septum is a muscular wall that separates the two ventricles

What would happen to the myocardium of Caleb's right ventricle as a result of his VSD?

it would be enlarged and hypertrophied

If a drop of blood is located in aorta and needs to go to the infero-anterior apex of the heart, what vessel will it pass through next?

left coronary artery

what is this structure?

the mitral (bicuspid valve)

what is the first heart sound?

- mitral valve closure - tricuspid valve closure - beginning of ventricular systole

what is the second heart sound?

- pulmonary vein closure - aortic valve closure - beginning of ventricular diastole

What is the ligamentum arteriosum?

A remnant of the ductus arteriosus The ligamentum arteriosum is a remnant of the ductus arteriosus. The ductus arteriosus is a fetal shunt that connects the pulmonary trunk to the aorta

Which is a good description of cardiac muscle fibers?

Branched, uninucleate cells with intercalated discs

Which is the function of an intercalated disc?

Contains both desmosomes for tensile strength and gap junctions for communication

In which direction is the blood in Caleb's heart moving as a result of his defect?

LV - RV - The blood pressure in the left ventricle is higher than that in the right ventricle.

T or F: Oxygenated blood flows through the right side of the heart.

False Oxygenated blood returning from the lungs is received by the left atrium, then to the left ventricle before being pumped out to the body. This pathway of blood flow is known as the systemic circulation.

T or F: The moderator band is found on both the right and left side of the heart.

False The moderator band is a cord like structure found in the right ventricle. It contains portions of the cardiac conduction system that help convey the electrical message for the ventricles to contract. It works as a shortcut within the cardiac conduction system.

If Caleb's defect involved the bundle branches, which part of the ECG would NOT be affected?

P wave

Based on your knowledge of the heart and the great vessels, describe other anatomical abnormalities that cause the mixing of oxygenated and deoxygenated blood.

PATENT DUCTUS ARTERIOSUS (PDA)= a blood vessel in the developing fetus connecting the trunk of the pulmonary artery to the aorta. Bcs of this, there is an increase in the volume of blood that goes to the lungs. OR(ASD)= a hole in the wall btw the two upper chambers. Bcs of this, there is an increase in the volume of the blood that goes to the lungs.

Name the ridged bundles of muscle found projecting inside the right atrium

Pectinate muscles The pectinate muscles are ridge like elevations of muscle. They are parallel to each other and resemble teeth of a comb. They are easily observed inside the right atrium

Which of the following is NOT part of auscultating normal first and second heart sounds?

Position the earpieces so they are angled backward in the ears

Identfiy the valve located at the exit of the right ventricle

Pulmonary semilunar valve The pulmonary valve is the semilunar valve found between the right ventricle and the pulmonary trunk. Deoxygenated blood travels through the pulmonary valve as it exits the right side of the heart on its way to the lungs.

___: Ventricular depolarization ______: Period of uniform depolarization of the ventricles ______: Ventricular repolarization _____: Atrial depolarization

QRS complex S-T segment T wave P wave

Which component of the cardiac conduction system is known as the pacemaker?

SA node

Based on the location of Caleb's defect, what part of the conduction system might be at risk for abnormalities?

The bundle of his (atrioventricular bundle) and the bundle branches are along the inter-ventricular septum. So, if the defect included a large portion of the septum, all of these areas could be at risk for abnormalities.

Predict what would happen to cardiac muscle cells if desmosomes were not present in intercalated discs.

The cells would pull apart with each contraction.

Distinguish between the base of the heart and the apex of the heart

The great vessels are located on the base, and the apex ends at a point

Question part a: Due to this defect would you expect the blood to move from left-to-right ventricle or right-to-left ventricle during systole? Question part b: Based on your understanding of blood pressure and resistance in the heart and great vessels, explain your answer to question 3a

a. Caleb's defect causes blood to move from the left ventricle to the right ventricle during systole (L-R) b. The blood pressure in the right ventricle is lower than the pressure in the left ventricle. This occurs bcs the afterload in the right ventricle is lower than the afterload of the left ventricle. The difference in btw these afterloads is due to the pulmonary blood vessels creating less resistance when compared to the systemic blood vessels.

Question part a: Name the normal sounds of the heart and indicate what causes these sounds. Question part b: In relation to the normal heart sounds, when would you expect to hear the abnormal sound Dr. Baker heard? Explain your answer.

a. S1 is the first heart sound or "lub" and occurs due to closure of the atrioventricular (tricuspid and bicuspid) valves. S2 is the second heart sound or "dup" and occurs due to closure of the pulmonary and aortic (semilunar) valves. b. VSDs generate a pan-systolic (spanning the length of systole) murmur between S1 and S2.

Question part a: In a healthy baby, what color would the blood be within the right and left ventricles, respectively? Question part b: In Caleb's heart, what color would the blood be within the right and left ventricles, respectively?

a. The right ventricle has deoxygenated blood (blue) The left ventricle has oxygenated blood (red) b. -The RIGHT ventricle has BOTH deoxygenated blood and oxygenated blood (both blue and red).-The LEFT ventricle has oxygenated blood (red)

Question part a: Describe what would happen to the blood volume and pressure entering the pulmonary circuit as a result of his VSD. Question part b: Describe what would happen to the myocardium of Caleb's right ventricle as a result of his VSD.

a. There is an increase in the total amount of blood pumped to the pulmonary trunk during each systole, as a consequence, the total pressure in these vessels also increases. -It causes failure to the heart (difficulty feeding & poor growth). b. Due to the right-to-left shunt, the blood volume within the right ventricle increases. Due to volume overload, the right ventricle cannot effectively pump out blood, causing an increase in end-systolic volume and stretching of the myocardium

Question part a: Where on the thoracic surface do you auscultate to the tricuspid, mitral (bicuspid), pulmonary, and aortic valves? Question part b: Where do you think would be the best place to auscultate Caleb's abnormal heart sound? Explain your answer.

a. Tricuspid is the 4th intercostal space on the lower left sternal border; mitral (bicuspid) is the 5th intercostal space; pulmonary is the 2nd intercostal space on the upper left border; and aortic is the 2nd intercostal space on the upper right sternal border. b. It would be from the lower left sternal border to the right lower sternal border because this is the area that overlies the defect.

Of the systemic vessels listed, which one receives blood last?

abdominal aorta

If a drop of blood is located in the left ventricle, through what structure will it next pass?

aortic semilunar valve

Identify the ear like flaps that are attached to the top chambers of the heart.

auricle The auricles are flap like extensions of the atria that are observed on the external surface of the heart

The normal heart sounds are S1 and S2. When do you predict you would hear Caleb's abnormal heart sound?

between S1 and S2 - This timing occurs because the atrioventricular valves close first (S1), then the ventricles contract and blood shunts rapidly from left ventricle to right ventricle (pansystolic murmur). Finally, the semilunar valves close (S2).

Blood passes through the ________ valve before entering the left ventricle

bicuspid or mitral

Identify the valve found between the left atrium and left ventricle.

biscupid/mitral vlave The atrioventricular valve on the left is the bicuspid valve. The mitral valve is also called the mitral valve.

Identify the most muscular chamber.

left ventricle The left ventricle is responsible for pumping blood out to the body. This requires a lot of force. The left ventricle is the most muscular in order to pump the blood with adequate force.

What heart chamber pushes blood through the aortic semilunar valve?

left ventricle The aortic valve is located between the left ventricle and the aorta. The left ventricle pumps oxygenated blood out of the heart through the aortic valve to the body.

Which term describes the abnormal sounds produced by Caleb's heart?

murmur - Murmurs are heart sounds that are produced by turbulent blood flow and valve closure.

Which layer of the heart wall is composed of cardiac muscle tissue?

myocardium

How many electrodes are attached to the forearm to record the ECG?

one

What is the function of the coronary circulation?

provide a blood supply to the heart The coronary circulation provides oxygenated blood to the heart through coronary arteries. Coronary veins return the deoxygenated from the heart to the coronary sinus on the posterior surface of the heart. The coronary sinus empties the deoxygenated blood directly into the right atrium where it joins deoxygenated from the body.

The right side of the heart pumps deoxygenated blood into __________.

pulmonary arteries

Which of the following vessels delivers oxygen-poor blood to the lungs?

pulmonary arteries

What structure receives blood from the venae cavae?

right atrium

Of the coronary vessels listed, which one receives blood first?

right coronary artery

the myocardium not the right side of the heart receives blood supply from ....

right coronary artery - The right coronary artery travels inferiorly and laterally along the right atrioventricular sulcus, where it gives off several branches that supply the right atrium and ventricle

Which chamber of the heart exits into the pulmonary trunk?

right ventricle The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk to be distributed to the lungs.

what is this structure?

sarcoplasmic reticulum. - The SR stores and releases calcium ions to promote cardiac contractio

Name the irregular ridges of muscle lining the ventricles that are not indirectly to the atrioventricular values.

trabeculae carneae Trabeculae carneae are the small elevated ridges of muscle arranged in a web type fashion found in both the right and left ventricles.

Identify the right atrioventricular valve

tricuspid valveIt separates the right atrium from the right ventricle.

T of F: The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human.

true In both the sheep and human, the brachiocephalic artery is the first major vessel to exit the arch of the aorta. Further branching of the brachiocephalic artery and the arch of the aorta differs between a sheep and a human.

T or f; Blood on the right never mixes with blood on the left, once the heart is fully developed

true Once fetal modifications (i.e. foramen ovale, ductus arteriosus) close following delivery of the infant, blood on the right side of the heart should not mix with blood on the left side of the heart.