A&P Chapter 17
The anatomy of the intrinsic conduction system causes contraction of the ventricles to begin at the apex and move superiorly. Why is this important?
so blood is forced upward, toward the semilunar valves
What two values are needed in order to calculate cardiac output (CO) for a ventricle?
stroke volume (SV) and heart rate (HR)
carries oxygen-poor venous blood from above the diaphragm from areas of the upper body and extremities into the right atrium.
superior vena cava
The capillaries receiving blood flow from the left side of the heart are the
systemic capillaries
The vessels that deliver oxygen to the tissues of the body are part of the
systemic circuit
How much blood is pumped from each ventricle during the ventricular ejection phase
70 ml
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 of these structures conduct(s) action potentials the slowest?
AV node
true or false... 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.
A damaged atrioventricular (AV) bundle or atrioventricular (AV) node will primarily affect the length of the _____
P-R interval
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.
A person notices his or her heart beat because he or she senses blood being pumped by the heart. Excessive caffeine intake can lead to irregular heart rhythms (arrhythmias) that patients perceive as "skipped beats." Given that caffeine is a stimulant, which of the following mechanisms best explains the reason for the feeling that the heart skipped a beat?
Purkinje fibers initiate spontaneous action potentials, which cause the ventricles to contract early.
Which of the following can be used to measure heart rate?
R-R interval
Which part of the intrinsic conduction system normally initiates the depolarizing impulse that causes a heartbeat?
SA node
True or False...... 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.
Which of the following decreases heart rate? a) epinephrine b) norepinephrine c) acetylcholine d) cortisol
acetylcholine
The vessel that carries oxygen-rich blood to tissues is the
aorta
the complete blood flow pathway
aorta to smaller systemic arteries to systemic capillaries to systemic veins to right atrium through the tricuspid valve
Prevents backflow into the left ventricle.
aortic semilunar valve
The structure that is located anatomically between the aorta and the left ventricle is the
aortic semilunar valve
the base of the heart is located where?
at the top of the heart
The P wave on an electrocardiogram (ECG) represents the depolarization of cells in the _______
atria
Which hormone decreases cardiac output by decreasing blood volume and preload?
atrial natriuretic peptide s
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.
Identify the valve found between the left atrium and left ventricle.
bicuspid (mitral) valve The atrioventricular valve on the left is the bicuspid valve. The mitral valve is also called the mitral valve.
Autorhythmicity in the heart is the responsibility of _
cardiac pacemaker cells
The cusps of the atrioventricular valves attach to the papillary muscles via the
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.
Inotropic agents affect _
contractility
carries oxygen-poor venous blood of the coronary circulation into the right atrium.
coronary sinus
The right side of the heart receives
deoxygenated blood from the systemic circuit
The cranial cavity is a subdivision of the ___
dorsal cavity
What largely determines preload?
end diastolic volume (EDV)
what largely determines preload?
end-diastolic volume (EDV)
The inner lining of the heart.
endocardium
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.
Serous layer covering the heart muscle.
epicardium
The visceral pericardium is also known as the _____
epicardium
the visceral pericardium is the same as ____
epicardium
High-pressured blood in the ventricles __________.
forces the semilunar valves open
The heart is located __
in the mediastinum
The apex of the heart is _
inferior
carries oxygen-poor venous blood from below the diaphragm from the areas of the lower body and extremities into the right atrium.
inferior vena cava
Blood returning from the lungs enters the ____
left atrium
Which heart chamber receives blood from the pulmonary veins?
left atrium
The cardiac chamber with the thickest wall is the _
left ventricle
Which chamber pumps oxygenated blood out the aorta to the systemic circuit?
left ventricle
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.
Atrioventricular (AV) valve with two flaps.
mitral (bicuspid) valve
Prevents backflow into the left atrium.
mitral (bicuspid) valve
The structure that prevents backflow of blood into the left atrium is the
mitral (bicuspid) valve
Heart muscle.
myocardium
Is the moderator band is found on both the right and left side of the heart.
no, 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.
The outermost layer of the serous pericardium.
parietal layer
Name the ridged bundles of muscle found projecting inside the right atrium.
pectinate muscles
During what part of the action potential will calcium ions enter the contractile cell?
plateau phase
The degree of stretch experienced by the sarcomeres in the ventricle cells before they contract is called __
preload
What is the function of the valves in the heart?
prevent backflow of blood through the heart
Identify the valve located at the exit of the right ventricle
pulmonary semilunar valve
Prevents backflow into the right ventricle.
pulmonary semilunar valve
Blood that leaves the right ventricle enters the
pulmonary trunk
Which vessel is guarded by a semilunar valve at its base?
pulmonary trunk
Which of the following vessels carries oxygenated blood? a) pulmonary artery b) pulmonary vein c) superior vena cava d) pulmonary trunk
pulmonary vein
What vessel(s) deliver oxygenated blood to the left atrium?
pulmonary veins
What valve prevents the backflow of blood from the right ventricle into the right atrium?
right atrioventricular (tricuspid) valve
Which chamber receives blood from the superior and inferior vena cavae?
right atrium
Which heart chamber pumps unoxygenated blood out the pulmonary trunk?
right 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.The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk to be distributed to the lungs.
The right and left atria depolarize and contract following the arrival of the action potential from the _____
sinoatrial (SA) node
What normally serves as the pacemaker of the entire heart?
sinoatrial (SA) node
Name the needle like ridges of muscle lining the ventricles.
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.
Atrioventricular (AV) valve with three flaps.
tricuspid valve
Identify the right atrioventricular valve.
tricuspid valve
Prevents backflow into the right atrium.
tricuspid valve
Blood in the right atrium should travel next past the _____
tricuspid valve then into the right ventricle
True or False.....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.
the heart is actually (one, two, or three) pumps?
two
Both the left and right atria receive blood from
veins
Blood from the systemic circuit returns to the heart via the _
vena cava