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