Chapter 19 PowerPoint Flashcards
What is coronary circulation?
The Blood Supply to the Heart
= Coronary circulation
supplies blood to muscle tissue of heart
coronary arteries and cardiac veins
Coronary arteries:
Which two?
Originate?
Causes blood to flow into them?
left and right
originate at aortic sinuses
high blood pressure, elastic rebound forces blood through coronary arteries between contractions
Coronary arteries?
branches of the ascending aorta that supply blood to the heart; the left coronary artery feeds the left
side of the heart, the left atrium and ventricle, and the interventricular septum; the right coronary artery feeds the
right atrium, portions of both ventricles, and the heart conduction system
What does the right coronary artery supply blood to?
Right Coronary Artery
Supplies blood to:
right atrium
portions of both ventricles
cells of sinoatrial (SA) and atrioventricular nodes
What two branches of RCA?
marginal arteries (surface of right ventricle)
posterior interventricular artery
Marginal artery?
branches of the right coronary artery that supply blood to the superficial portions of the right
ventricle
Posterior interventricular artery?
(also, posterior descending artery) branch of the right coronary artery that runs
along the posterior portion of the interventricular sulcus toward the apex of the heart and gives rise to branches that
supply the interventricular septum and portions of both ventricles
What does the left coronary artery supply blood to?
Left Coronary Artery
supplies blood to:
left ventricle
left atrium
interventricular septum
Two branches of LCA?
Circumflex artery
Anterior interventricular artery
What are the five cardiac veins and what do the drain/empty into?
great cardiac vein
Drains blood from area of anterior interventricular artery into coronary sinus
anterior cardiac veins
empty into right atrium
posterior cardiac vein, middle cardiac vein, and small cardiac vein
empty into great cardiac vein or coronary sinus
Describe CAD?
Coronary artery disease (CAD)
areas of partial or complete blockage of coronary circulation
cardiac muscle cells need a constant supply of oxygen and nutrients
reduction in blood flow to heart muscle produces a corresponding
reduction in cardiac performance
reduced circulatory supply, coronary ischemia, results from partial or complete blockage of coronary arteries
reduced circulatory supply, ____ ____, results from partial or complete blockage of coronary arteries
Coronary ischemia
What is classified as a heartbeat?
a single contraction of the heart
the entire heart contracts in series
1st, the atria
then the ventricles
What are the two types of cardiac muscle cells?
Conducting system
controls and coordinates heartbeat
Contractile cells
produce contractions that propel blood
Cardiac Muscle Tissue
Intercalated discs
interconnect cardiac muscle cells:
secured by ____
linked by ____ ____
convey force of contraction
propagate action potentials
Cardiac Muscle Tissue
Intercalated discs
interconnect cardiac muscle cells:
secured by desmosomes
linked by gap junctions
convey force of contraction
propagate action potentials
What is a unique feature of cardiac muscle?
Intercalated discs interconnecting cardiac muscle cells
Intercalated disc?
hysical junction between adjacent cardiac muscle cells; consisting of desmosomes, specialized
linking proteoglycans, and gap junctions that allow passage of ions between the two cells
4 characteristics of cardiac muscle cells?
small size
single, central nucleus
branching interconnections between cells
intercalated discs
The Cardiac Cycle
Begins with action potential at ____ ____
transmitted through ____ ____
produces action potentials in cardiac muscle cells (____ ____)
The Cardiac Cycle
Begins with action potential at SA node
transmitted through conducting system
produces action potentials in cardiac muscle cells (contractile cells)
Electrocardiogram (ECG or EKG)?
electrical events in the cardiac cycle can be recorded on an electrocardiogram
the ____ ____ is a system of specialized cardiac muscle cells
initiates and distributes electrical impulses that stimulate contraction
the Conducting System is a system of specialized cardiac muscle cells
initiates and distributes electrical impulses that stimulate contraction
What is automaticity?
Cardiac muscle tissue contracts automatically
What is the conducting system?
a system of specialized cardiac muscle cells that
initiates and distributes electrical impulses that stimulate contraction
Autorhythmicity?
ability of cardiac muscle to initiate its own electrical impulse that triggers the mechanical contraction
that pumps blood at a fixed pace without nervous or endocrine control
3 structures of the conducting system and there location?
Sinoatrial (SA) node – wall of right atrium
Atrioventricular (AV) node – junction between atria and ventricles
Conducting cells – throughout myocardium
Conducting Cells
interconnect ____ and ____ nodes
distribute stimulus through ____
in the atria they form ____ ____
in the ventricles the form ____ ____ and the ____ ____
Conducting Cells
interconnect SA and AV nodes
distribute stimulus through myocardium
in the atria they form internodal pathways
in the ventricles the form AV bundle and the bundle branches