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
Internodal pathway?
specialized conductile cells within the atria that transmit the impulse from the SA node
throughout the myocardial cells of the atrium and to the AV node
Prepotential:
AKA?
What is it?
gradually ____ toward threshold
____ node depolarizes first, establishing heart rate
Prepotential
also called pacemaker potential
resting potential of conducting cells
gradually depolarizes toward threshold
SA node depolarizes first, establishing heart rate
SA node generates ____-____ action potentials per minute
____ stimulation slows heart rate
AV node generates ____-____ action potentials per minute
SA node generates 80–100 action potentials per minute
parasympathetic stimulation slows heart rate
AV node generates 40–60 action potentials per minute
SA node:
Where?
Contains what type of cells?
Connected to what?
What does it begin?
The Sinoatrial (SA) Node:
in posterior wall of right atrium
contains pacemaker cells
connected to AV node by internodal pathways
begins atrial activation (Step 1)
AV node:
Where?
What does it receive?
What does it do?
What begins after?
The Atrioventricular (AV) Node:
in floor of right atrium
receives impulse from SA node (Step 2)
delays impulse (Step 3)
atrial contraction begins
AV bundle:
Where?
What does it do?
Where does it carry the impulse?
The AV Bundle:
in the septum
carries impulse to left and right bundle branches
which conduct to Purkinje fibers (Step 4)
and to the moderator band
which conducts to papillary muscles
Purkinje fibers:
Where?
What ends here?
What begins here?
distribute impulse through ventricles (Step 5)
atrial contraction is completed
ventricular contraction begins
The Electrocardiogram (ECG or EKG):
a recording of ____ events in the heart
obtained by ____ at specific body locations
abnormal patterns diagnose ____
The Electrocardiogram (ECG or EKG):
a recording of electrical events in the heart
obtained by electrodes at specific body locations
abnormal patterns diagnose damage
Five steps of heart contractions
- SA node begins atrial activation
- AV node receives impulse
- AV node delays impulse
- AV bundle –> bundle branches –> purkinje fibers
- Purkinje fibers distribute impulse through ventricles
SA node?
known as the pacemaker, a specialized clump of myocardial conducting cells located in the
superior portion of the right atrium that has the highest inherent rate of depolarization that then spreads throughout
the heart
Pacemaker cells?
cluster of specialized myocardial cells known as the SA node that initiates the sinus rhythm
AV node?
lump of myocardial cells located in the inferior portion of the right atrium within the
atrioventricular septum; receives the impulse from the SA node, pauses, and then transmits it into specialized
conducting cells within the interventricular septum
AV bundle?
(also, bundle of His) group of specialized myocardial conductile cells that transmit the
impulse from the AV node through the interventricular septum; form the left and right atrioventricular bundle
branches
Left and right bundle branches?
The left bundle branch conducts impulses to the left ventricle, and the right bundle branch conducts impulses to the right ventricle
ECG?
Electrocardiogram (ECG) surface recording of the electrical activity of the heart that can be used for diagnosis of
irregular heart function; also abbreviated as EKG
Features of a ECG and what occurs at those features?
P wave
atria depolarize
QRS complex
ventricles depolarize
T wave
ventricles repolarize
P–R interval
from start of atrial depolarization
to start of QRS complex
Q–T interval
from ventricular depolarization
to ventricular repolarization
Bradycardia?
abnormally slow HR
Tachycardia?
abnormally fast HR
Ectopic pacemaker?
abnormal cells
generate high rate of action potentials
bypass conducting system
disrupt ventricular contractions
Purkinje fibers distribute the stimulus to the ____ cells, which make up most of the muscle cells in the heart
resting potential
of a ventricular cell about ____ mV
of an atrial cell about ____ mV
Purkinje fibers distribute the stimulus to the contractile cells, which make up most of the muscle cells in the heart
resting potential
of a ventricular cell about –90 mV
of an atrial cell about –80 mV
Two types of refractory periods?
Absolute refractory period
Relative refractory period?
What is the absolute refractory period?
long
cardiac muscle cells cannot respond
What is the relative refractory period?
short
response depends on degree of stimulus
The cardiac cycle:
What is it?
What two phases does it include?
the period between the start of one heartbeat and the beginning of the next
includes both contraction and relaxation
Two (2) phases:
within any one chamber
Systole (contraction)
Diastole (relaxation)
Systole?
Contracting
period of time when the heart muscle is contracting
Diastole?
Relaxation
period of time when the heart muscle is relaxed and the chambers fill with blood
Blood Pressure
in ____ chamber:
rises during ____
falls during ____
blood flows from ____ to ____ pressure
controlled by timing of contractions
directed by ____-____ ____
Blood Pressure
in any chamber:
rises during systole
falls during diastole
blood flows from high to low pressure
controlled by timing of contractions
directed by one-way valves
Cardiac Cycle and Heart Rate
@ ____ beats per minute (bpm)
cardiac cycle lasts about ____ msec
Cardiac Cycle and Heart Rate
@ 75 beats per minute (bpm)
cardiac cycle lasts about 800 msec
When heart rate increases
all phases of cardiac cycle ____, particularly ____
When heart rate increases
all phases of cardiac cycle shorten, particularly diastole
4 phases of the cardiac cycle?
Atrial systole
Atrial diastole
Ventricular systole
Ventricular diastole
Atrial systole:
atrial contraction begins
right and left ____ ____ are open
Atria eject blood into ventricles
filling ventricles
Atrial systole ends
____ ____ close
ventricles contain maximum blood volume
known as ____-____ ____ (____)
Atrial systole:
atrial contraction begins
right and left AV valves are open
Atria eject blood into ventricles
filling ventricles
Atrial systole ends
AV valves close
ventricles contain maximum blood volume
known as end-diastolic volume (EDV)
End-diastolic volume (EDV)?
(also, preload) the amount of blood in the ventricles at the end of atrial systole just prior
to ventricular contraction
Ventricular Systole
Ventricles contract and build pressure
____ valves close causing ____ ____
Ventricular ejection
ventricular pressure exceeds vessel pressure opening the____ ____ and allowing blood to leave the ventricle
amount of blood ejected is called the ___ ____ (____)
Ventricular Systole
Ventricles contract and build pressure
AV valves close causing isovolumetric contraction
Ventricular ejection
ventricular pressure exceeds vessel pressure opening the semilunar valves and allowing blood to leave the ventricle
amount of blood ejected is called the stroke volume (SV)
Isovolumetric contraction?
(also, isovolumetric contraction) initial phase of ventricular contraction in which tension and
pressure in the ventricle increase, but no blood is pumped or ejected from the heart
Ventricular ejection?
second phase of ventricular systole during which blood is pumped from the ventricle
Stroke volume (SV)?
amount of blood pumped by each ventricle per contraction; also, the difference between EDV and
ESV
Ventricular systole:
Ventricular pressure falls
____valves close
ventricles contain ____-____ ____ (____), about ____ percent of end-diastolic volume
Ventricular systole:
Ventricular pressure falls
semilunar valves close
ventricles contain end-systolic volume (ESV), about 40 percent of end-diastolic volume
Ventricular Diastole
ventricular pressure is higher than atrial pressure
____ heart valves are closed
ventricles relax (____ relaxation)
Atrial pressure is higher than ventricular pressure
AV valves open
passive _____ filling
passive ____ filling
Ventricular Diastole
ventricular pressure is higher than atrial pressure
all heart valves are closed
ventricles relax (isovolumetric relaxation)
Atrial pressure is higher than ventricular pressure
AV valves open
passive atrial filling
passive ventricular filling
8 Phases of the cardiac cycle?
- Atrial systole-contraction begins
- Atrial systole-blood ejected into ventricles
- Atrial systole ends
- Ventricular systole-ventricles contract and build pressure
- Ventricular systole-ventricular ejection
- Ventricular systole-ventricular pressure falls
- Ventricular diastole-ventricles relax
- Ventricular diastole-ventricles passively fill
