Heart Lecture

Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?

AV node - AV node slows down the impulse giving the atria time to contract before the ventricles contract

Which of the following structures receives the depolarization wave from the atria and passes impulses onto the ventricles?

AV node - The AV node receives the depolarizing wave from the atria and delays and coordinates that distribution to the ventricles.

Trace the pathway of stimulation through the heart. Name these pathways of stimulation in the correct order.

AV node, AV bundle, interventricular septum, subendocardial conducting network - This is the correct order of stimulation of the heart muscle. The signal to the AV node would begin in the SA node.

Describe afterload.

Back pressure exerted by arterial blood. - Afterload refers to the back pressure exerted by arterial blood, or the pressure that must be overcome for the ventricles to eject blood.

True or False Arterial blood supply to heart muscle is continuous whether the heart is in systole or diastole.

False

True or False The right side of the heart is considered the systemic circuit pump.

False - The right side of the heart pumps deoxygenated (oxygen-poor) blood into the pulmonary circuit of the lungs to be re-oxygenated. For this reason, the right side of the heart is considered the pulmonary circuit pump. The left side of the heart pumps blood into the systemic circuit, which serves the tissues of the body, and is therefore considered the systemic circuit pump.

Which of the following would decrease stroke volume? -increasing afterload -increasing contractility -increasing sympathetic stimulation -increasing preload

Increasing afterload decreases stroke volume.

Contraction of the atria results from which wave of depolarization on the ECG tracing?

P wave - P wave represents atrial depolarization, which leads to atrial contraction

part of the conduction system that initiates the depolarizing impulse, which spreads throughout the heart

SA node - SA Node spontaneously depolarizes, causing the wave of depolarization that spreads through the rest of the conduction system and heart

True or False Anastomoses among coronary arterial branches provide collateral routes for blood delivery to the heart muscle.

True

True or False As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve.

True

True or False If blood volume decreased dramatically due to massive bleeding, the autonomic nervous system will attempt to maintain cardiac output by increasing the heart rate.

True

True or False If the aorta and pulmonary trunk were switched, oxygen rich blood would be pumped from the left ventricle to the lungs.

True

True or False The left side of the heart pumps the same volume of blood as the right.

True

True or False The myocardium receives its blood supply from the coronary arteries.

True

True or False Tissues damaged by myocardial infarction are replaced by fibrous connective tissue.

True

The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________.

angia pectoris

Blood enters the left and right coronary arteries directly from which vessel or chamber?

aorta

Prevents backflow into the left ventricle.

aortic semilunar valve

The P wave on an electrocardiogram represents __________.

atrial depolarization

Which of the following is NOT part of the intrinsic conduction system of the heart? -bundle branches -atrioventricular (AV) valve -atrioventricular (AV) node -sinoatrial (SA) node

atrioventricular (AV) valve

During the period of ventricular filling, ________.

blood flows mostly passively from the atria through the atrioventricular (AV) valves into the ventricles

Which of the following receive(s) blood during ventricular systole? -aorta only -pulmonary arteries only -pulmonary veins only -both the aorta and pulmonary trunk

both the aorta and pulmonary trunk

The foramen ovale ________.

connects the two atria in the fetal heart

What does the ECG wave tracing represent?

electrical activity of the heart - the ECG waves show the depolarization and repolarization in various areas of the heart

What is the innermost layer of the heart?

endocardium - endocardium lines the inside of the heart; Its surface is composed of simple squamous epithelium

Which of the following would increase cardiac output? -decreased cytoplasmic calcium concentration during contraction -epinephrine -high blood pressure -parasympathetic stimulation

epinephrine - Sympathetic stimulation leads to the release of epinephrine and norepinephrine, both of which increase heart rate and increase contractility, which increases stroke volume. Increasing heart rate and stroke volume increases cardiac output.

True or False An electrocardiogram (ECG) provides direct information about valve function.

false

Which heart chamber receives oxygenated blood from the lungs?

left atrium

Which heart chamber receives blood from the pulmonary veins?

left atrium - left atrium receives oxygenated blood from the pulmonary veins

Which chambers of the heart contain oxygenated blood?

left atrium and ventricle

Which chamber of the heart sends oxygenated blood directly to the systemic circuit via the aorta? Failure in a particular structure of the heart tends to cause a backup of blood in the lungs, known as pulmonary congestive heart failure. Failure of which structure of the heart would lead to such a backup?

left ventricle

Which chamber pumps oxygenated blood out the aorta to the systemic circuit?

left ventricle - pumps oxygenated blood out the aorta to the entire body (systemic circuit)

Prevents backflow into the left atrium. Atrioventricular (AV) valve with two flaps.

mitral (bicuspid) valve

blockage in the right marginal artery would most likely cause a _________.

myocardial infarction in the lateral right side of the heart - The right marginal artery branches from the right coronary artery to nourish the lateral areas of the right ventricle. A blockage in this vessel could damage this area.

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

myocardium - myocardium is composed of cardiac muscle and a dense network of connective tissue

What separates the parietal and visceral pericardium?

pericardial cavity - pericardial cavity separates the parietal and visceral pericardium; cavity contains serous fluid that lubricates the visceral and parietal membranes

Branch of right coronary artery

posterior interventricular artery - although an anastomosis with the circumflex artery meets with it near its origin

Exercise results in skeletal muscles compressing veins which encourages blood to return to the heart. In this scenario, which of the following is correct? -venous return decreases -end diastolic volume (EDV) decreases -preload increases -stroke volume decreases

preload increases

Prevents backflow into the right ventricle.

pulmonary semilunar valve

Which vessel of the heart receives blood from the right ventricle?

pulmonary trunk

NOT a vessel that brings blood directly into the right atrium

pulmonary vein

vessels that deliver (oxygenated) blood to the left atrium of the heart

pulmonary veins

The presence of an incompetent tricuspid valve would have the direct effect of causing ______.

reduced efficiency in the delivery of blood to the lungs - The tricuspid valve separates the right atrium and the right ventricle. It must remain tightly closed during ventricular contraction so blood can be pumped out of the ventricle and into the pulmonary arteries.

The receiving chambers of the heart include the ________.

right & left atria

The right tricuspid valve prevents backflow of blood from the right ventricle into the __________. Into which chamber of the heart do the superior vena cava, inferior vena cava, and coronary sinus return deoxygenated blood?

right atrium

Which chamber receives blood from the superior and inferior vena cavae?

right atrium - the right atrium receives unoxygenated blood from the systemic circuit

Which heart chamber pumps unoxygenated blood out the pulmonary trunk?

right ventricle - pumps unoxygenated blood out the pulmonary trunk to the lungs

What is the quiescent period?

total heart relaxation - During each cardiac cycle there is a period of time in which both the atria and ventricles are relaxed (in diastole) at the same time; this is called the quiescent period.

What valve is located between the right atrium and ventricle? Prevents backflow into the right atrium. Atrioventricular (AV) valve with three flaps.

tricuspid valve

The heart is actually (one, two, or three) pumps?

two - the right side of the heart pumps to/from the lungs (pulmonary circuit) and the left side of the heart pumps to/from the rest of the body (the systemic circuit).

What does the QRS wave of the electrocardiogram (ECG) represent?

ventricular depolarization - Ventricular depolarization is represented by the QRS complex of an ECG.

What does the QRS complex represent in the ECG wave tracing?

ventricular depolarization - represents depolarization in the ventricles, which have greater mass than the atria

order of the intrinsic conduction system in the order that a depolarizing impulse travels during a normal heartbeat

1. SA node ( Internodal pathways ) 2. AV node 3. AV bundle 4. Bundle branches 5. Purkinje fibers

1. What causes heart sounds? 2. The first heart sound (the "lub" of the "lub-dub") is caused by __________. 3. The second heart sound (the "dup" of the "lub-dub") is caused by __________.

1a. heart valve closure 2b. closure of the atrioventricular valves 3c. closure of the semilunar valves

Calculate the stroke volume if the end diastolic volume (EDV) is 135 mL/beat and the end systolic volume (ESV) is 60 mL/beat.

75 mL/beat - The SV is calculated by subtracting the ESV from the EDV. You are comparing the volume of the ventricle at its fullest to its emptiest.