A&P 2 Ch.18: The Heart

chordae tendineae

"heart strings" are tiny white collagenic cords that anchor the cusps to the ventricular walls. They originate from the papillary muscles.

Which term describes an area of the heart conduction system where the impulse is delayed for 0.1 sec?

AV node

Stroke Volume (SV)

Amount of blood ejected by one contraction of the heart Cardiac output (CO) is the amount of blood pumped out by each ventricle in 1 minute. It is the product of heart rate (HR) in beats per minute and stroke volume (SV) in ml per beat. Stroke volume is defined as the volume of blood pumped out by one ventricle with each beat. In general, stroke volume correlates with the force of ventricular contraction.

ESV (end systolic volume)

Amount of blood in the ventricle at the end of contraction

Cardiac Output (CO)

Amount of blood pumped out by each ventricle in 1 minute Cardiac output (CO) is the amount of blood pumped out by each ventricle in 1 minute. It is the product of heart rate (HR) in beats per minute and stroke volume (SV) in ml per beat. Stroke volume is defined as the volume of blood pumped out by one ventricle with each beat. In general, stroke volume correlates with the force of ventricular contraction.

What is the purpose of the chordae tendineae?

Anchor the AV valves in the closed position

The coronary arteries receive blood from the _______.

Aorta

What valve separates left ventricle and aorta?

Aortic semilunar valve

The superior chambers of the heart are called the __________.

Atria

What makes the heart valves open and close?

Blood pressure

Papillary muscles

Enlarged muscles in ventricles that are attached to chordae tendinae.

Which of the following factors gives the myocardium its high resistance to fatigue?

Large number of mitochondria in the cytoplasm

Blood exits left atrium through

Mitral (bicuspid) valve

Failure of which heart valve would allow blood to move from the left ventricle to the left atrium?

Mitral (bicuspid) valve

Atrial depolarization

P wave

What muscles prevent the atrioventricular valves from everting during ventricular contraction?

Papillary muscles

Aortic semilunar valve

Prevents backflow of blood into the left ventricle

Pulmonary semilunar valve

Prevents backflow of blood into the right ventricle

The left atrium receives blood from which of the following structure(s)?

Pulmonary Veins

Blood exits right ventricle through

Pulmonary semilunar valve

Blood exits the right ventricle through?

Pulmonary semilunar valve

Ventricular depolarization

QRS wave

Identify the correct sequence of blood flow through the chambers of the heart.

Right atrium, right ventricle, lungs, left atrium, left ventricle

Which is the correct sequence of layers in the heart wall, starting with the outer layer

Right atrium, right ventricle, lungs, left atrium, left ventricle

The normal pacemaker of the heart is the __________.

SA node

Which term describes an area of the heart conduction system with the fastest depolarizing pacemaker cells?

SA node

sequence of current flow through the intrinsic conduction system of the heart

SA node, AV node, AV bundle, right and left bundle branches, subendocardial conducting network

Ventricular repolarization

T wave

Stroke volume

The amount of blood ejected from the heart in one contraction. (end diastolic volume - end systolic volume)

Preload

The degree to which cardiac muscle cells are stretched just before they contract Preload controls stroke volume. In a normal heart, the higher the preload, the higher the stroke volume. This relationship between preload and stroke volume is called the Frank-Starling law of the heart.

What part of the heart is considered the systemic circuit pump?

The left ventricle

Which of the following valves is most often faulty in the heart?

The mitral (bicuspid) valve

Serous pericardium

Thin, slippery, two-layered membrane Deep to the fibrous pericardium is the serous pericardium, a thin, slippery, two-layer serous membrane that forms a closed sac around the heart. Its parietal layer lines the internal surface of the fibrous pericardium. At the superior margin of the heart, the parietal layer attaches to the large arteries exiting the heart, and then turns inferiorly and continues over the external heart surface as the visceral layer, also called the epicardium ("upon the heart"), which is an integral part of the heart wall.

What valve separates right atrium and right ventricle?

Tricuspid valve

Which of the following is a difference between cardiac muscle and skeletal muscle?

Unlike skeletal muscle cells, cardiac muscle has gap junctions between cells (that allow them to be autorhythmic).

EDV (end diastolic volume)

amount of blood collected in a ventricle during diastole

The P wave of an electrocardiogram represents __________.

atrial depolarization

The __________ are attached to the AV valve flaps.

chordae tendineae

The second heart sound (the 'dup' of 'lub-dup') is caused by the __________.

closure of the semilunar valves Auscultating (listening to) the thorax with a stethoscope will reveal two sounds during each heartbeat. These heart sounds, often described as lub-dup, are associated with the heart valves closing. First heart sound is caused by closing of AV valves. Second heart sound is caused by closing of SL valves.

Systole

contraction

The vessels that carry oxygen to the myocardium are called __________.

coronary arteries

The cells of the myocardium behave as a single, coordinated unit called a __________.

functional syncytium

The interventricular septum forms a dividing wall between the __________.

left and right ventricles

Freshly oxygenated blood is delivered to the __________ and then it passes into the __________ to be pumped to the entire body.

left atrium; left ventricle

When the mitral valve closes, it prevents the backflow of blood from the __________.

left ventricle into the left atrium

Diastole

relaxation

During pulmonary circulation, blood leaves the __________.

right ventricle and moves to the lungs

The role of the atrioventricular node (AV node) is to __________.

slow down impulses so that the atria can contract to fill the adjacent ventricles with blood

Cardiac output is __________.

the amount of blood pumped out of each ventricle in one minute

The absolute refractory period refers to the time during which __________.

the muscle cell is not in a position to respond to a stimulus of any strength

pulmonary circulatory system

the system of blood vessels that carries deoxygenated blood to the lungs and oxygenated blood back to the heart

systemic circulatory system

the system of blood vessels that carries oxygenated blood to the tissues of the body and deoxygenated blood back to the heart

The __________ nerve carries parasympathetic fibers to the sinoatrial (SA) node.

vagus

The trabeculae carneae are located in the __________.

ventricles Together the ventricles make up most of the volume of the heart. The right ventricle forms most of the heart's anterior surface and the left ventricle dominates its posteroinferior surface. Irregular ridges of muscle called trabeculae carneae mark the internal walls of the ventricular chambers. Other muscle bundles, the papillary muscles, which play a role in valve function, project into the ventricular cavity.