Exam 3: Circulatory System: Heart Flashcards
2 pathways of circulation
pulmonary: deoxygenated blood directed to lungs for gas exchange
systemic: oxygenated blood directed to organs and tissues of body to undergo gas exchange and transport of various materials/nutrients
bronchial circulation
blood vessels feeding bronchi and trachea - tissues of the lungs
carry blood away from heart
carry blood to heart
allow for exchange between blood and tissues
artery
vein
capillary
right side vs left side of heart
right side: collects and pumps deoxygenated blood
left side: collects and pumps oxygenated blood
embryonic development of heart
-begins in third week when diffusion no longer sufficient
-heart begins as tube, by looping to the right it starts to form pockets which become the chambers
-septum formation between chambers begins at end of the 4th week but may not complete until birth
atria separate by 5th week
separation of ventricles 6th/7th week
coronary sinus
collects all of the blood returning and feeding the heart muscle - need blood vessels to go on outside of heart to feed the muscle, not the chambers
chordae tendinae
attach AV valves to the floor of the ventricle
papillary muscles
raised muscles that attach to chordae tendinae - help it slam shut
ligamentum arteriosum
only remnant you have left from when fetus and blood went straight from the RV to the aorta bc oxygen was retrieved from the placenta, not the lungs
atrioventricular valves prevent backflow of
blood from ventricles to the atrium
semilunar valves prevent backflow from
pulmonary trunk and aorta in the ventricles
S1 heart sound
“lub”
closing of the AV valves
prevents backflow into atria while ventricles contracting
S1 marks beginning of ventricular systole
S2 heart sound
“dub”
closing of semilunar valves
prevents backflow from aorta and pulmonary artery while ventricles are relaxing to fill
S2 marks beginning of ventricular diastole
how to drain deoxygenated blood?
interventricular sulcus at front of heart runs between the ventricles
great cardiac vein comes up and goes around drains on backside - posterior cardiac vein
middle cardiac vein comes up and fuses with coronary sinus
into cardiac vein and then sinus and then RA
Feeding the heart
systemic circulation LV to aorta
1st muscles off aorta before arch: R coronary artery and L coronary artery
Right coronary artery
goes around coronary sulcus
posterior descending arteries feed back of eart
2 branches of the Left coronary artery
- left anterior descending artery (LAD) : widow maker, if block in this you can detect on ECG and trace, this is the main artery for feeding!!!!! it goes down the interventricular sulcus
- left circumflex: small, feeds posterior regions
outermost toughest layer of the heart
fibrous pericardium
2 parts of the serous pericardium
secretes serous fluid filtered from plasma - keeps friction low in heart
parietal pericardium: lines inside fibrous portion
visceral pericardium (epicardium): surface of heart
protective layers of heart if get inflammation or bleeding
fluid impairs ability of heart to function
fibrous pericardium is tough and does not give which makes it harder for heart to relax and fill
how are cardiac muscle cells connected to eachother
intercalated discs
each cell is capable of automaticity because of…
hyperpolarization activated cyclic nucleotide (HCN) channels in the cell membrane
when hyperpolarized you are opening a bunch of channels - constantly filling and contracting
the rapid depolarizing cells become the _____ of the heart
pacemaker
ectopic pacemakers
dangerous to heart function
regions that can cause contractions if the signals from the pacemaker (SA node) are blocked
funny channel
the decrease in membrane potential to -60 activates different population of channels
dropping to -60 triggers cAMP which activates funny channels to open allowing Na+ enter the cells
starts conduction cycle and sets pace
aka pacemaker current
electrical conduction and pacemakers
conductive pathway begins at -60
allows influx of Na into cell until threshold use
at threshold Ca channels open causing influx and depolarization
influx channels close and K+ channels open and K goes out
when membrane potential returns to -60 K channels close, Na open
no RMP
surrounding muscle tissue has RMP of _____
-90 and conducts action potential via Na flow through gap junctions
SA node depolarizes and has three tracts down RA to atrial ventricular node
bacchmans bundle goes to LA
delay in conduction between atria and ventricles
gives time for ventricles to fill
purkinje fibers
bundle of hiss divides into right and left bundle branches ad they go into purkinje fibers
they branch into th muscular walls of ventricles ; start depolarization for contraction
is the conductive tissue in the heart cardiac or nerve tissue
cardiac
the atrial conduction system consists of
3 internodal tracts
Bachmans bundle
the ventricular conduction system consists of
bundle of his
left and right bundle branches
purkinje fibers
the SA node sets the
normal sinus rhythm
overdrive suppression
bc the SA node depolarizes faster it activates other conductive tissue suppressing their slower pace from being expressed
sympathetic neurons
release NE targeting B1 receptors in SA node
increases rate, force, sensitivity to depolarization
parasympathetic neurons
releas Ach targeting cholinergic receptors in SA and AV nodes
decreases rate, force, sensitivity
