Chapter 21 The Heart part 2 Flashcards
What is the coronary circuit?
A series of arteries and veins that supply & drain the myocardium of the heart.
2 major arteries in the coronary circuit?
Left and Right coronary arteries
Located at the base of the ascending aorta - inside the Coronary sulcus
The Right coronary artery supplies blood to…
Right atrium
Right ventricle & portions of the left ventricle
Conduction system
What is the conduction system of the heart?
SA node (sinoatrial node) AV node (atrioventricular node)
What is the pacemaker of the heart
SA node
The Left coronary artery supplies blood to…
Left atrium
Left ventricle & can supply to the right ventricle if necessary
The Coronary arteries begin at the Anterior or Posterior portions of the heart
Anterior
The Left Coronary Artery divides into?
Anterior/ Posterior Interventricular Artery
Circumflex Artery
The anterior interventricular artery branches off of what
Off the left coronary artery
The posterior interventricular artery branches off of what
off the right coronary artery
What brings deoxygenated blood from the myocardium into the right atrium?
Coronary Sinus
Cardiac cells that regulate heart rate & are found in the sinoatrial node are called what?
Nodal cells
The beginning of the conduction system is called?
Sinoatrial Node (SA node)
T/F Nodal cells have a higher threshold & they contract first setting the normal rate of contraction
False
Nodal cells do contract first setting the normal rate of contraction, but they have a LOWER THRESHOLD
What do parasympathetic neurons do?
They slow the rate of depolarization & lower the heart rate
What do Sympathetic neurons do?
They increase the rate of polarization & increase the heart rate
T/F Parasympathetic neurons increase the rate of depolarization & increase the heart rate
False.
They do the opposite
What is autorythmicity?
The ability of cardiac muscle cells to contract on its own without neural or hormonal stimulation
Systole? increased or decreased pressure?
Contraction
Increased pressure
Diastole? increased or decreased pressure
Relaxation
Reduced pressure
What is the pathway of conduction of the heart i.e. what starts the electrical impulse and follow its route.
SA node – AV node – Bundle of His – Purkinje fibers
What is the P wave?
Depolarization or Contraction of the Atria
What is the QRS wave?
Depolarization of the ventricles
What is the T wave?
Repolarization or Relaxation of the Ventricles
T/F The majority of the time, the atria is in diastole?
True
What causes the AV valve to close?
The PRESSURE of the blood NOT the contraction of the papillary muscles
What produces the Lupp sound of the heart?
Closure of the AV valves
What produces the Dupp sound of the heart?
Closure of the Semilunar valves
The anterior and posterior interventricular sulci mark the position of which internal heart structure? A) bicuspid and tricuspid valves B) semilunar valves C) fossa ovalis D) interventricular septum
D
Which of the following vessels is a branch of the left coronary artery?
A) left posterior ascending artery
B) circumflex artery
C) posterior interventricular artery
D) left subclavian artery
B
All cardiac veins empty into the \_\_\_\_\_\_, which then empties into the \_\_\_\_\_\_. A) coronary sinus; left atrium B) coronary sinus; right atrium C) great cardiac vein; right atrium D) great cardiac vein; left atrium
B
The coronary sinus is a(n) ______ located in the ________.
A) vein; posterior atrioventricular sulcus
B) vein; posterior interventricular sulcus
C) artery; anterior atrioventricular sulcus
D) artery; interatrial septum
A
The Purkinje fibers are found in which layer of the heart wall?
A) endocardium
B) epicardium
C) fibrous pericardium
D) myocardiumD
Intercalated discs include these structures:
A) gap junctions, desmosomes, interdigitating folds
B) gap junctions, tight junctions, t-tubules
C) gap junctions, desmosomes, t-tubules
D) sarcoplasmic reticulum, interdigitating folds
A
Which of the following parts of the cardiac conduction system is correctly matched with its location?
A) AV bundle (bundle of His) - upper part of interatrial septum
B) AV node - left atrium in the inferior interventricular septum
C) Purkinje fibers - epicardium of the ventricles
D) SA node - right atrium near the opening of the superior vena cava
D
In which choice are the components of the cardiac conduction system listed in the correct sequence?
A) SA node, AV bundle, AV node, Purkinje fibers
B) SA node, AV node, AV bundle, Purkinje fibers
C) AV node, AV bundle, SA node, Purkinje fibers
D) AV node, SA node, Purkinje fibers, AV bundle
B
Damage to cells of the AV bundle would prevent the cardiac impulse from reaching the
A) SA node
B) atria
C) AV node
D) ventricles
D
Conduction of the cardiac impulse is slowed as it passes through the AV node. This allows time for the
A) ventricles to start contracting before the atria finish contracting.
B) atria to contract completely before the ventricles start to contract.
C) SA node to catch up.
D) last ventricular contraction to finish.
B
Because of the distribution of the cardiac impulse by the conduction system, ventricular contraction begins
A) in the semilunar valves and then pushes blood toward the interventricular septum
B) in the papillary muscles and causes the atrioventricular valves to open
C) in the superior part of the ventricles and pushes blood toward the apex
D) at the apex of the heart and pushes blood toward the semilunar valves
D
Which component of a myocardial cell allows it to electrically stimulate adjoining cells?
A) gap junctions
B) t-tubules
C) desmosomes
D) sarcoplasmic reticulum
A
An electrocardiogram actually records
A) the contraction and relaxation of the myocardium
B) electrical changes that occur in the myocardial cells.
C) blood flow through the heart.
D) changes in pressure in the left ventricle.
B
Which of the following components of an ECG is not correctly matched with the corresponding event occurring in the heart?
A) P wave - atrial depolarization
B) PR interval - AV node conduction
C) QRS complex - ventricular depolarization
D) T wave - atrial repolarization
D
If the SA node is damaged, which part of the heart is most likely to take over as a pacemaker? A) atrial myocardial cells B) AV nodal cells C) Purkinje fibers D) ventricular myocardial cell
B
In which choice are the components of the heart placed in correct order of decreasing intrinsic rhythm? A) SA node, AV node, Purkinje cells B) SA node, Purkinje cells, AV node C) AV node, SA node, Purkinje cells D) Purkinje cells, AV node, SA node
A
If lines were drawn on a typical ECG recording showing where atrial and ventricular systole begin and end, then the ventricular systole would be seen as beginning during a ____ and ending during the next ____.
A) P wave; QRS complex
B) PR segment; T wave
C) QRS complex; T wave
D) T wave; P wave
C
In an ECG taken from a person who has no SA node activity, which component will not appear?
A) P wave
B) QRS complex
C) ST segment
D) T wave
A
Contraction of a ventricular chamber is called?
systole
The atrioventricular valves open when pressure in the
A) superior and inferior vena cavae.
B) left atrium.
C) right ventricle.
D) aorta.
C
The alternate contraction and relaxation of the atria and ventricles are referred to as the…
Cardiac cycle
While the atria of the heart are in systole
A) the ventricles are also in systole.
B) the atrioventricular valves are closed.
C) blood is being pumped into the aorta and pulmonary trunk.
D) blood is being pumped into the ventricles.
D
During ventricular diastole
A) pressure in the atria exceeds pressure in the ventricles and the atrioventricular valves open
B) pressure in the ventricles eventually exceeds pressure in the arteries and the semilunar valves open.
C) the atria contract and pump blood into the ventricles
D) no blood enters the arteries
B
Pressure in the ventricles would be highest during
A) atrial diastole
B) atrial systole
C) ventricular diastole
D) ventricular systole
D
In which choice must the first event occur before the second event for normal cardiac activity during one cardiac cycle?
A) the atria contract and pump blood into the ventricles
B) the ventricles contract and pump blood into the blood vessels
C) both atria and ventricles are relaxed
D) the ventricles contract but ventricular pressure is lower than arterial pressure
C
The semilunar valves close at the beginning of
A) atrial systole
B) atrial diastole
C) ventricular systole
D) ventricular diastole
D
