The Internal Heart Flashcards
Why are there anatomical differences between the 4 Chambers of heart?
They all function differently and arise from different structures during embryonic development.
What structures are in the right atrium?
Interatrial septum
Fossa ovalis
Crista terminalis (with pectinate muscles)
What separates the two atria?
Interatrial septum
What is the fossa ovalis?
Depression in the interatrial septum
Remnant of the foetal foramen ovale
What does the foramen ovale do?
In fetus it shunts oxygenated blood from the right atrium to the left atrium, bypassing the lungs
What is the crista terminalis?
A muscular ridge separating smooth wall of posterior right atria from anterior ridged (pectinate muscles) muscular wall
What are pectinate muscles?
Muscles in muscular ridged wall of (right?) atria. Extend into right auricle
Name of the right atrioventricular valve
Tricuspid valve
Do atria contract?
Only to fully empty
Most of the flow is passive
What structures are in the right ventricle?
Interventricular septum
Trabeculae carneae
Papillary muscles
Chords tendinae
Moderator band
What separates the two ventricles?
The inerventricular septum
What are the muscular ridges on the internal wall of the right ventricle?
Trabeculae carneae
What are the papillary muscles? What is their function?
Modified regions of trabeculae carneae
They project into the lumen of the ventricle
Prevent backwards leaking of valves
What are the chordae tendinae?
Fibrous cords which connect tip of papillary muscles to tricuspid valve
What is the mitral valve?
Left atrio-ventricular valve, bicuspid valve
What is the moderator band?
connects interventricular septum to one of the papillary muscles (Modified region of trabeculae carneae)
What does the pulmonary trunk bifurcate into?
Left and right pulmonary artery
How does the left atrium differ from the right?
It doesn’t, apart from valve and vessel types and names.
Still smooth posterior wall with pectinate muscles on anterior wall
What are the first branches from the aorta?
Coronary arteries
What prevents backflow of blood into the left ventricle?
Aortic valve
What structures does the left ventricles contain?
Trabeculae carneae
Papillary muscles
Chordae tendineae
(interventricular septum)
How do the left and right ventricles differ?
Left ventricle has a thicker wall
Left ventricle has no moderator band (i think? or a fake one?)
What occurs in terms of pressure and valves during ventricular systole?
Pressure rises in ventricles so Pventricles > Patria
Tricuspid and mitral valves close
Blood flows into pulmonary trunk and aorta
How are chordae tendineae and papillary muscles essential for valve functioning?
Papillary muscles contract as ventricles contract
Tense the chords so they pull on valve cusps and prevent eversion into atria
