The heart Flashcards
the heart is located
in mediastinum between second and 5th rib
Pericardium
fluid filled buffer where heart sits, reduces friction anchors to surrounding structures
visceral layer of pericardium
secrets paricardial fluid, direct layer of pericardium on surface of heart
Parietal layer of pericardium
outter layer
Epicardium
viscleral layer of pericardium
myocardium
muscle part of heart
endocardium
squamous layer of endothelium
pericarditis
creaking sound, inflammation of pericardium
pericardial friction rub
creaking noise
cardiac tamponade
excess fluid sometimes compresses heart
cardiac skeleton
crisscrossing, interlacing, layer of conective tissue - non conductive tissure, help contains electrical spread of electrical activity
right side of the heart
receives blood from the body - doxygenated
pulmonary circuit
right side of heart, pumps blood to lungs then to left side
left side of heart
receives oxygenated blood from lungs, pumps to body tissues via systemic circuit
pulmonary arteries go to the
lungs
pulmonary artery is the only artery that contains
deoxygenated blood
pulmonary veins are one of the only veins that contain
oxygenated blood
largest artery in the body
aeorta
systemic circuit
left side of the heart
two superior chambers that receive blood
atria
two inferior chmabers that pump blood out
ventricles
interatrial septum
seperates atria
Fossa ovalis
remnant of foramen ovale of fetal heart
interventricular septum
seperates ventricels
auricles
flaps that increase atrial volume, extension of atrial
three veins empty into right atrium
superior vena cava, inferior vena cava and coronary sinus
Blood that comes in from the head and superior cavities enter in the heart through the
superior vena cava
blood from lower extremenies/ anywhere from below the heart
inferior vena cava
vein that pumps blood from the heart itslef
coronary sinus
right ventricle v left ventricle
right is anterior, left is posteroinferior
trabeculae carnea
irregular ridges of muscle walls, meaty
papillary muscles
pull on chordae tendinea attached to valves to keep them shut
vintricles are the …. of the heart
pumps
right ventricle pumps blood into
pulmonary trunk/lungs
left ventricle
pumps blood into aorta (largest artery in the body) throughout the entire body
which ventricle has a thicker wall/myocardium
left ventricle
purpose of the fibrous skeleton
insulator (not conductive) divides atria and ventricles, prevents signaling from getting from the atria to the ventricle too soon, allowing ventricle to fill up.
heart valves open and close in response to
pressure
heart valves ensure what type of blood flow through the heart
unidirectional
where are the atrioventricular valves located between atria and ventricles
atrioventricular valve
atrioventricular valve on right side of heart
tricuspid valve (3 cusps)
atrioventricular valve on the left side of heart
mitral valve/bicuspid valve
chordae tendineae anchor
cusps to papillary muscles, hold valves flaps closed
semilunar SL valves
prevent backflow into ventricles when ventricles relax, open and close in response to pressure
names of two SL valves
aortic semilunar valve and pulmonary semilunar valve
incompetent valve
valve doesnt close all the way
valvular stenosis
valve doesnt open all the way
Pulmonary circuit with valves
right atrium–>tricuspid valve –>right ventricle–>pulmonary semilunar valve –>pulmonary trunk —>pulmonary arteries—> lungs—>pulmonary veins –>left atrium
Systemic circuit
left atrium–>mitral valve–>left ventricle—>aortic semilunar valve–>aorta–systemic circulation
Coronary sinus
largest vein in the heart where all the blood collects
full blood circuit
superior and inferior vena cava–>right atrium–>right ventricle –>pulmonary trunk –>lungs –>four pulmonary veins –>left atrium–>left ventricle —>aorta
what type of circulation is pulmonary circuit
short, low-pressure circulation
what type of circulation is systemic circuit
long, high friction circulation
what is the coronary circulation
hearts own blood supply
which side of the body receives most of the blood supply
left ventricle, when relaxed
arteries aries from
base of aorta
coronary sinus drains into
right atrium
left coronary artery branches
anterior interventricular artery and circumflex - supplies left part of the heart
right coronary artery branches
right marginal artery and posterior interventricular artery supplies right atrium and right ventricle
heart is aerobic or anerobic
aerobic but occasion uses anerobic energy
angiogram
test where you can see how blood flows
angina pectoris
chest pain because of blood deficiency
myocardial infarction
heart attack due to prolonged coronary blockage
differences in heart muscle and skeletal muscle
heart cells are shorter, no terminal systema, only 1 nucleus,
Intercalated discs
Juctions between cells - anchor cardiac cells
intercalated discs are made of
desmosomes and gap junctions
gap junctions allow ions to
pass from cell to cell; electrically couple adjacent cells
3 differences between heart and skeletal muscle
1) heart has no need for nervous system stimulation 2)cadimyocutes contact as unit or none do, 3) long absolute refractory period, prevents tentanic contactions
Depolirization is due to BLANK influx through channels
CA while heart is NA
Pacemaker potential is stimulated by
sympathetic increase
pacemaker cells are also called
autorhythmic cells
3 parts of action potential
pacemaker potential, depolarization, repolirization
Pacemaker potential
repolarization closes K+ channels and opens slow Na+ channels
depolarization
Ca channels open –>huge influx –>rising phase of action potential
repolarization
K+ channels open –>efflux of K+
3 similarities among cardiac and skeletal muscle
1)depolarization opens few voltage-gated fast NA+ channels in sarcolemma 2)depolarization wave down t tubules —>sr to release CA 3)excitation-contraction coupling occurs (CA2 binds to troponin, filaments slide)
pacemaker of the heart
Sinoatrial node (SA)
sinus rhythm
the average rhythm generated by the SA node at 75X a minute
if SA node quits working, what takes place
atrioventricular node
Internodal pathway
the stimulation of depolarization from the SA node to the AV node
Bundle of HIS is also known as the
AV bundle
Conductive system of the heart pathway
SA node –>AV node–>AV bundle/bundle of HIS–> bundle branches –>subendocardial conducting network /purkinje fibers —>cardiac muscle
arrhythmias
irregular heart rhythms
fibrillation
rapid, irregular contractions, circulation ceases, brain death
Ectopic focus
abnormal pacemaker
junctional rhytm
when AV node takes over, 40-60 beats
extrasystole
premature contraction
ectopic focus - from caffeine, drugs etc
sets high heart rate
heart block
signal from SA node doesn’t get through to AV node leading to ventricles beating at their own rate, causes artificial pacemaker
cardiac center in the brain
medulla oblongata
what is cardioacceleratory center
sympathetic pathway to accelerate heart
cardioinhibitory center
vagus nerve to heart
ECG/EKG
measures electrical activity of the heart
P wave
depolarization SA node –> atria
QRS complex
ventricular depolarization and atrial repolarization
T wave
ventricular repolarization
3 waves of an EKG
p wave, QRS complex, T wave
following depolarization
contraction, at the R
when the SA nod eis nonfunction
p waves are absent
systole
contraction
diastole
relaxation
with atrial systole (contraction), there is ventricular
diastole (relaxation)
with ventricular systole (contraction) there is atrial
diastole (relaxation)
during atrial systole
atrial pressure increases
to push valves open pressure in the ventricle needs to
overcome the pressure in the atrial
S1 sound occurs
right after atrial contract and valves are closed, closing AV valves - pushing blood down into ventricles
S2 sound occurs
when the blood tries to come back in and the valves close — ventricular ejection OR backflow of blood in aorta nad pulmonary trunk closes SL valves
stroke volume
how much blood is pumped out
how 100% blood reaches ventricles
80% passively flows, 20% atrial systole occurs delivering remaining 20%
EDV- end diastolic volume
volume of blood in each ventricle at end of ventricular diastole
Isovolumetric contraction phase
all 4 valves are closed, pressure is building but hasnt pumped it out
ejection phase
blood being squirted out through vessels
ESV (end systolic volume)
volume of blood remaining in each ventricle after systole
Start with e – end with e–
end diastolic volume, end systolic volume
Isovolumetric relaxation
early diastole, ventricles relax, atria relaxed and filling
when atrial pressure exceeds that in ventricles –>
AV valves open, cycle beings again at step 1
Cardiac output
volume of blood pumped by each ventrice in one minute
CO= blank X blank
heart rate (# beats per minute) X stroke volume (volume of blood pumped out by one ventricle with each beat
normal CO
5.25 L per minute
cardiac reserve
difference between resting and maximal CO
CO blank in trained athletes
increases
SV= blank - blank
EDV (what you start with in the ventricles) - ESV (what you end with in the ventricles)
3 main factors that affect SV
preload, contractility and afterload
EDV is affected by
length of ventricular diastole and venous pressure
ESV is affected
by arterial BP and fore of ventricular contraction.
preload (1 affect of SV)
degree of stretch of cardiac muscle cells before the contract (frank starling law of heart)
venous return
most important factor stretching cardiac muscle, amount of blood returning to heart
contractility
contraile strength at given muscle length, independent of muscle stretch and EDV, increased by sympathetic stimulation.
positive inotropic agents
increase contractility
negative inoropic agents
decrease contractility
afterload
pressure ventricles must overcome to eject blood, increased by hypertension –> decreasing SV
3 phases of cardiac cycle
1) Ventricular filling 2) Ventricular systole 3) Isovolumetric relaxation
Two factors that control heart rate
positive or negative chronotropic agents
Positive chronotopic agents
sympathetic nervous system
negative chronotopic agents
parasympathetic nervous system
cardiac output in influenced by
stroke volume and heart rate
tachycardia
abnormally fast, over 100 beats per minute
bradycardia
heart rate slower than 60 beats per minute
endurance training may lead to increased efficiency by:
increased stroke volume and decreased heart reate
congestive heart failure
cardiac output is low, not getting enough o2 and nutrients to your heart.
pulmonary congestion
left heart failure, everything backs up in lungs
peripheral congestion
ride side fails, blood pools in body organs and edema
foramen ovale (hole)
connects two atria , remnant is fossa ovalis
ductus arteriosus
connect pulmonary trunk to aorta
P-R interval
beginning of atrial excitation to beginning of ventricular excitation
S-T Segment
entire ventricular myocardium depolarized
Q-T interval
Beginning of ventricular depolarization through ventricular repolarization
