Heart II Flashcards
what are the coronary arteries known as?
-they’re known as being the first branches of the aorta
how many branches does the right coronary artery divide into?
-two branches
right coronary artery components
- marginal branch
- posterior interventricular(PCA) branch
marginal branch of right coronary artery
-supplies myocardium of the inferior wall of both ventricles
posterior interventricular branch of right coronary artery
-travels in sulcus on posterior side to supply posterior wall of both ventricles
how many branches does the left coronary artery divide into?
-two branches
left coronary artery components
- anterior interventricular branch
- circumflex branch
anterior interventricular branch of left coronary artery
- aka left anterior descending(LAD) or widowmaker
- supplies interventricular septum and anterior wall of both ventricles
circumflex branch of left coronary artery
-supplies left atrium and posterior-lateral left ventricle
venous drainage
-three main veins (great, small, and middle) drain blood into coronary sinus which empties into the right atrium
electrical conduction system of the heart types
- primary (intrinsic) regulating system
- secondary (extrinsic) regulating system
primary (intrinsic) regulating system function
- stimulates cardiac muscle fibers to contract w/o need for any direct stimulus from nervous system
- composed of specialized muscle tissue that generates and distributes required electrical impulses throughout heart
secondary (extrinsic) regulating system function
- alters heart rates through ANS control to meet immediate needs of the body
- ex: when exercising
intrinsic conduction system components
- sinoatrial(SA) node
- atrioventricular node
- atrioventricular bundle of His
- purkinje fibers
sinoatrial(SA) node location
- aka ‘pacemaker’ of the heart
- collection of specialized “conducting cells” located in wall of right atrium
sinoatrial(SA) node function
- initiates heartbeat
- sends message to left atrium
atrioventricular node
- sends message to the bundle of His
- receives message from SA node located in right atrium
atrioventricular bundle of His
- tract located in IV septum
- transmits message to purkinje fibers
what is a tract?
-collection of conduction fiber
purkinje fibers
- located in walls of the ventricles
- conducts impulse to myocardium
- results in ventricular contraction
extrinsic control system
- controlled through ANS pathways
- alters heart rate to meet needs of body
extrinsic control system components
- sympathetic stimulation
- parasympathetic stimulation
sympathetic stimulation
- release of norepinephrine
- acts on SA node
- increases heart rate and strength of contraction
parasympathetic stimulation
- inhibitory (vagus CN X)
- releases acetylcholine
- decreases heart rate
cardiac cycle
- refers to one complete heartbeat
- SA node initiates each cycle
- occurs 70 times per minute
as the atria contacts, what does this do in the heart?
-it forces blood into both ventricles
systole in cardiac cycle
- ventricles contract**
- AV valves close and through SLV blood is ejected from the heart
diastole in cardiac cycle
- ventricles relax
- AV valves open and SLV valves close
- blood has filled atria which are awaiting the signal from SA node to begin next cardiac cycle
which occurs first, systole or diastole?
-systole, then diastole
what occurs during an EKG?
- impulse transmission through conduction system generates electrical currents that may be detected on body’s surface
- each portion of cardiac cycle produces different electrical impulses which can be recorded on a graph as deflection waves
“lubb-dubb” heart sounds
-sounds made by vibrations as the valves close
auscultation
- act of listening to sounds within the body
- usually performed with the use of a stethoscope
first heart sound
- “lubb”
- closure of AV values (ventricular contraction)
second heart sound
- “dubb”
- closure of semilunar valve (ventricular relaxation)
where is it best to listen to heart sounds?
-adjacent to the anatomical location of the valve(auscultatory areas)
auscultatory areas components
- aortic area
- pulmonic area
- tricuspid area
- bicuspid area
aortic area
- aortic semilunar valve
- 2nd intercostal space, right side
pulmonic area
- pulmonic semilunar valve
- 2nd intercostal space, left side
tricuspid area
- right AV valve
- 5th intercostal space
- to the right of the sternum
bicuspid area
- left AV valve
- 5th intercostal space
- to the left ot the sternum, near apex of heart
