Heart anatomy Flashcards
anatomical location of heart
thoracic region
inferior mediastinum
medially between the lungs
above the diaphragm
what surface is right ventricle
antieror/ sternoncostal
what surface is left atrium
posterior/base
what surface is left and right ventricles
inferior/diaphragmatic
what surface is the right atrium
right pulmonary
what surface is the left ventricle
left pulmonary
2 layers that surround the hear
fibrous pericardium (outer)
serous pericardium (inner)
fibrous pericardium (outer) role
thick connective tissue
protects heart and maintains its position
serous pericardium (inner) role
helps to lubricate heart
layers of 2 layers serous pericardium (inner)
parietal = fused to fibrous pericardium
visceral (epicardium) = fused to heart
pericardial cavity
lies between the parietal and visceral layers of the serous pericardium
serous fluid
reduced friction when heart contracts
where is serous fluid released
mesothelium
where is serous fluid released
mesothelium
where is fat around heart
associated with epicardium
auricles
thin walled
increase collecting capacity of the atria
sulci (sulcus)
contain major coronary blood vessels
coronary sulcus, Anterior interventriclar sulcus, posterior inter ventricular sulcus
coronary sulcus
between atria and ventricles
anterior inter ventricular sulcus
between 2 ventricles on anterior heart surface
posterior inter ventricular sulcus
between 2 ventricles on posterior heart surface
wall of the heart layers
epicardium (superficial)
myocardium (middle) - left thicker than right
endocardium (deepest)
interatrial septum
between 2 atria
oval shaped depression (fossa ovals) remnant of foramen ovale
atrioventricular septum
between atria and ventricles
4 openings = valves are present at openings
cardiac skeleton
dense connective tissue surrounding the openings and point of attatchment for heart valves
interventricular septum
between 2 ventricles
thicker than intertribal septum
atria
left and right
receives blood from connecting vessels
valves between atria and ventricles
right - tricuspid
left - bicuspid
pectinate muscle in atria
right = pectinate muscle on anterior surface and auricle
left = pectinate in auricle only
where does atria receive blood from
right = inferior and superior vena cave
left - pulmonary veins
walls of ventricles are lined with
trabecular carneae
valve between ventricle and vessel
right = pulmonary valve between right ventricle and pulmonary trunk
left = aortic valve between left ventricle and aorta
features of right and left ventricle
right = trabecular carneae
3 papillary muscles
left = trabecular carneae
2 papillary muscle
myocardium thicker than right ventricle
features of the valves in the heart
4 valves
2 AV
2 SL
composed of flaps/cusps = made of fibrous connective tissue
situated in openings of heart
unidirectional flow of blood
closing of valves generates heart sounds
AV valves
between atria and ventricles
close at start of ventricular contraction
produce first heart sound
tricuspid valve
between right atrium and ventricle
3 cusps/leaflets
bicuspid/mitral valve
between left atrium and ventricle
2 cusps/leaflets
chord tendinea
thin, strong inelastic fibrous cords
extend from free edges of valve cup to papillary muscles
papillary muscles
5 in total
on interior surface of ventricle
attach to valve cusps via chord tendinea
3 = tricuspid valave
2 = mitral vavle
purpose of chordae/papillary muscle complex
support for AV valves
prevents prolapsing of valve into atrium when ventricle contracts
SL valves
between ventricles and arteries
close at beginning of ventricular relaxation
second heart sound
no papillary muscle or chord tendineae associated with these valves
pulmonary valve
between right ventricle and pulmonary trunk
3 flaps
aortic valve
between left ventricle and aorta
3 flaps (some have 2)
2 main coronary arteries
left and right coronary artery
left coronary artery
80% of blood to heart tissue
supplies left atrium, most of left ventricle and Interventricular septum
left anterior descending and left circumflex branches
right coronary artery
along coronary sulcus
supplies right t ventricle, right atrium , SA, AV node , inter ventricular septum and inferior part of the left ventricle
posterior inter ventricular artery
coronary veins
drains deoxygenated blood from myocardium to right atrium
e.g vena cave, great cardiac vein, small cardiac vein, coronary sinus, middle cardiac vein, anterior cardiac vein, great cardiac vein
coronary sinus
most of veins come together into coronary sinus -> right atrium
anterior cardiac and small veins directly drain into cardiac chambers
nerve supply to heart
sympathetic and parasympathetic stimulation
through cardiac plexus located at the base of the heart
Vagus nerve
parasympathetic
decreases HR
Sympathetic cardiac nerve
increase HR and force of contraction
conduction system of the heart
- SA node
- AV node
- bundle of his
- purkinje fibres
sinoatrial node
- junction of superior vena cave and right atrium
- specialised myocardial conducting cells
- main pacemaker of heart
atrioventricular node
inferior portion of right atrium within AV septum
myocardial conducting cells
slowing of impulse to allow full atrial contraction
purkinjie fibres
conducts impulses to ventricular contractile fibres
small pause before AV node transmits the impulse to AV bundle
his allows the atrial cadiomyoctes to complete contraction and pump blood into ventricles before the inpluse is transmitted to the ventircular cells
heart conduction steps
- SA node depolarises
- impulse spreads through the atria to AV node via internal pathways
- AV node provides a slowing of impulse to allow full atrial contraction
- impulse proceeds down atrio-ventriclar bundle and its right and left bundle branches to apex of heart
- purkinjie fibres conduct impulse to ventricular contractile fibres
- ventricles contract
ventricular diastole steps
- ventricles and atria relax
- all valves closed
- blood enters right and left atrium
- blood pools in atria
- pressure in atrium exceeds pressure in ventricles mitral and tricuspid valves open
- SL valves still closed
- blood flows into relaxed ventricle
- SA node fires causing atrial contraction
- ejects residual blood into ventricles
- ventricular filling finishes
- impulse travels through AV node -> atrioventricular bundle -> purkinje fibres
ventricular systole steps
-ventricular contraction begins
-pressure in ventricles exceeds corresponding atrial pressure
-closure of AV valves
-when ventricular pressure exceeds pressure in —-connecting arteries
-SL valves open
-blood ejected into corresponding arteries
(right - pulmonary trunk, left - aorta)
-pressure changes result in closure of SL valves at –end of systole
4 valves we can hear when examining
aortic
pulmonary
tricuspid
mitral
heart sound 1
Lub
signals the start of systole
corresponds with closure of AV (mitral and tricuspid) valves
heart sound 2
dub
signals Strat of diastole
correspond with closure of semolina (aortic and pulmonary) valves
ECG
records electrical signalling of heart
involved placement of electrodes over chest and on each limb
P wave on ECG
electrical signal from SA node desolate atria
atrial contraction starts just after start of P wave
PR interval
start of P wave to attract of QRS complex
electrical signal passes from atria to ventricles
QRS complex
electrical signal depolarises ventricles
ventricular contraction starts near peak of R wave
T wave
ventricles repolarise
following depolarisation - ventricles relax
QT interval
beginning of QRS complex to end of T wave
time taken for ventricles to depolarise and depolarise (ventricles contract and relax)
blood pressure
pressure against the walls of arteries
what measure does blood pressure record
systolic = peak in arterial pressure during systole
diastolic = represents minimum arterial pressure during diastole
healthy BP
120/80 mmHg
hypertension BP
140/90 mmHg
many levels of hypertension - heart attack, stroke, renal disease
hypotension BP
90/60 mmHg
many levels of hypertension - heart attack, stroke, renal disease
chest x ray provides info about the
shape of the heart
size of the heart
cardiothoracic ratio
presence of abnormalities (calcification)
normal cardiothoracic ratio
0.42-0.5
enlarged cardiothoracic ratio
> 0.5
tetralogy of fallot
congenital heart condition
infant born with it
structural cardiac abnormalities = calcified lesion
upturned apex
right ventricular hypertrophy or enlargement
boot shaped heart
echocardiogram
ultrasound scan
size and structure of heart
movement of heart valves, septum, walls of heart chambers
doppler ECHO = speed and direction of blood flow
dextrocardia
heart on wrong side of the body
coronary disease
narrow of coronary arteries due to atherosclerosis
myocardium supplied by affected artery becomes ischemia
what can coronary disease cause
angina (narrowing of artery / arteries results in symptoms upon exertion )
actor coronary syndrome (heart attack)
treatment of coronary disease
severity and patients clinical condition
some interventions involve the coronary arteries themselves
angioplasty
occlusion in artery = mechanicaly widened with a balloon
stent (wire mesh) inserted at site of occlusion to maintain patency
coronary artery bypass graft
when there is widespread CAD (triple vessel disease)
blockages = coronary arteries are bypassed with harvested venous or arterial vessels from patients body
common vessels used as grafts
left internal mammary artery and saphenous vein
atrioventricular block/ heart block
- delay/ disturbance of transmission of electrical impulse from atria to ventricles
impairment in heart conduction system at the level of the AV node or below
first degree heart block
prolonged PR interval
delayed conduction of impulse from atrium to ventricle
no symptoms
second degree heart block
not all p waves are followed by QRS complex
regular patter (2:1, 3:1)
intermittent conduction of atrial signal to ventricles
can range from asymptomatic to haemodynamic instability
third degree heart block
p waves are never related to the QRS complex
absence of AV node conduction
atria and ventricles conduct independent of each other
range from fatigue / chest pain / syncope to haemodynamic instability
treatment of heart block
sometimes don’t require treatment = sometimes have serves damage to their conduction system - more severe arrhythmias = may require a pacemaker
valvular heart disorders
dysfunction of heart valves
benign to fatal
various cause (cognenital, infection, trauma)
any valve affected
some more common than others (mitral , aortic)
patients have heart murmur - dependent on type of valvular disease
2 main categories of valvular heart disorders
valvular stenosis
valvular insufficiency/regurgitation
valvular stenosis
heart valve does not fully open
stiff or fused leaflets = valves not fully opening
limits blood flow out of the atria or ventricle
heart has to pump with increased force to push blood through stenotic valve
weekend heart resulting in heart failure
aortic vavle stenosis cause
age related calcification
associated with ejection systolic murmur
ventricular insufficiency (regurgitation)
valve does not close tightly
some blood leaks backwards across the valve
less blood exits heart if severe insufficiency
heart has to work harder to compensate for blood regurgitating back
Leaky valve = does not close tightly = backward leaking = heart has to work harder to make up for it = mitral regurgitation
can lead to heart failure
mitral regurgitation causes
various causes
mitral vale prolapse, rheumatic fever, coronary heart disease
pan systolic murmur
patent foramen ovale
in the foetus - foramen ovale directs blood flow directly from the right to the left atrium
bypassing the pulmonary circulation
following birth of foramen ovale closes (fossa ovals)
failure of closure = patent foramen ovale - small intertribal shunt
often asymptomatic = may have faint systolic murmur
ventricular septal defect
incomplete development of interventriculr septum
various types depending on part of septum affected
results in a shunt between right and left ventricles
what does size and location determine
- amount and direction of blood shunted
- symptoms of affected individual = often have pansystolic murmur
what 4 structural abnormalities are in tetralogy of fallot
congenital heart disease
1. ventricular septal defect
2. pulmonary stenosis (narrowing)
3. misplaced aorta
4. ventricular hypertrophy (thicker)
symptoms of tetralogy of fallot
hyper cyanotic episodes when crying or feeding
loud systolic ejection murmur
