Circulation, chambers, conducting system Flashcards
What are the 3 cusps of the aortic valve?
- anterior
- left posterior
- right posterior - non-coronary artery associated cusp
What are the branches of the Right Coronary ARtery
- synoatrial 60%
- marginal
- avinode
- Posterior Interventricular (descending artery) (85%)
What are the branches of the left coronary artery
- circumflex
- anterior interventricular branch
- sinoatrial node (40%)
Do the arteries anastomose?
No. only at the capillary level, but not sufficient to supply the heart if a major artery is blocked.
Which artery maintains the electrical signal to the heart?
the Right coronary artery
The coronary sinus opens into what part of the heart?
the right atrium
What are the tributaries to the coronary sinus?
the great cardiac vein, the middle cardiac vein, and the small cardiac vein
Where do the small veins of the heart drain?
They drain where they are- so yes sometimes unoxegenated blood is flowing into the left side of the heart, but it’s miniscule in comparison to the remainder of the blood coming from the pulmonary veins, so it’s insignificant
What are the veins of the heart?
oblique cardiac vein
great cardiac vein
coronary sinus
anterior cardiac vein
middle cardiac vein
small cardiac vein
what is the thickest walled chamber?
The Left Ventricle
Why do valves open and close?
Valves open due to the increased pressure on one side of the cusp
What is the texture of the anterior wall of the right atrium? How about the posterior wall?
anterior wall = rough - pectinate muscles
posterior wall = smooth- sinus venosus
what separates the rough anterior surface of the right atrium from the smooth posterior surface of the right atrium?
the “Crista Terminalis”
What valve sits between the right atrium and the right ventricle?
Tricuspid valve
What is the “fossa ovalis”?
embryological foramen ovale - which sits in the right atrium and allowed blood to move from the right atrium to the left atrium
What is it called when the fossa ovalis fails to close during development?
Atrial Septal Defect
What are the ridges called in the ventricles?
Trabeculations (latin for slab)
What muscles make up part of the wall of the ventricle?
papillary muscles - connected to atrioventricular valves by chordae tendineae
What is the purpose of Chordae Tendineae?
“heart strings” they prevent the valves from opening backwards under systolic pressure - note that these cords do NOT pull the valve shut, they passively restrict their motion
What are the three cusps of the tricuspid valve?
anterior
septal
posterior
What are the two atrioventricular valves?
Tricuspid and mitral (bicuspid) valves
What are the two semilunar valves?
pulmonary and aortic valves- they are located between the ventricles and their corresponding arteries
What are the two cusps of the bicuspid/Mitral valve?
anterior and posterior cusps
The atrioventricular valves close at the start of what type of contraction?
systole contraction or ventricular contraction
during what action do the semilunar valves close?
They close at the beginning of ventricular relaxation (diastole)
What are the three cusps of the pulmonary valve?
two anterior and one posterior
what are the cusps of the aortic valve?
one anterior and two posterior (one of which is non-coronary)
what is aortic stenosis?
Aortic stenosis refers to narrowing of the aortic valve, restricting the flow of blood leaving the heart. The main three causes are:
Age-related calcification
Congenital defects
Most commonly a bicuspid aortic valve, which predisposes the valve to calcification later in life.
Rheumatic fever
which heart section is most posterior?
The left Atrium
an enlarged left atrium can effect what other structure?
it can interfere with the esophagus- so you can diagnose an enlarged left atrium with a barium swallow
What are trabeculae Carneae?
part of the right/left ventricle, they give the chamber a sponge like appearance
they consist of ridges, bridges and pillars (papillary muscle)
Are the Atria and ventricles separated?
yes, by fibrous tissue
Describe the conduction of electrical signals through the heart
sinoatrial node starts the signal - contracts the atrium,
then the atrioventricular node (which has been delayed to allow for atrial contraction) causes the ventricles to contract
what is the single most useful way to determine normal functioning of the heart?
Take a damn pulse for goodness sake
what are the parts of the conduction system?
- sinoatrial node
- atrioventricular node
- bundle of His (right and left branches)
- purkinje fibres
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the only electrical path from the atria to the ventricles is via what structure?
the bundle of His
how long does the atrioventricular node delay the electrical signal?
0.12-0.2 seconds to allow the atria to contract before the ventricles
What are the borders of the heart on surface anatomy?
remember 3,6 - 2,5
3rd CC
6th CC
2nd CC
5th ICS
What is the definition of the apex
the lowest most lateral point on the chest wall where you can feel the heart beating-
Normally in the 5th intercostal space in midclavicular line
What are the surface anatomy positions of the valves?
pulmonary = 3rd CC
aoritc = 3rd ICS
Mitral = 4th CC
Tricuspid = 4th ICS
Where can you listen to the valves of the heart?
Pulmonary = 2nd ICS left of sternum
Aortic = 2nd ICS right of sternum
Mitral = 5th left ICS MCL
Tricuspid = 5th ICS Left of sternum
What size should the heart not surpass normally?
It shouldn’t be any larger than 1/2 of the diameter of the chest
What is Stenosis?
narrowing of the valve
What is ‘regurgitation’ related to valves?
regurgitation= problem with valve closing - furthermore leaking blood into the heart
