The Internal Heart

Question 1

Why are there anatomical differences between the 4 Chambers of heart?

Answer 1

They all function differently and arise from different structures during embryonic development.

Question 2

What structures are in the right atrium?

Answer 2

Interatrial septum
Fossa ovalis
Crista terminalis (with pectinate muscles)

Question 3

What separates the two atria?

Answer 3

Interatrial septum

Question 4

What is the fossa ovalis?

Answer 4

Depression in the interatrial septum
Remnant of the foetal foramen ovale

Question 5

What does the foramen ovale do?

Answer 5

In fetus it shunts oxygenated blood from the right atrium to the left atrium, bypassing the lungs

Question 6

What is the crista terminalis?

Answer 6

A muscular ridge separating smooth wall of posterior right atria from anterior ridged (pectinate muscles) muscular wall

Question 7

What are pectinate muscles?

Answer 7

Muscles in muscular ridged wall of (right?) atria. Extend into right auricle

Question 8

Name of the right atrioventricular valve

Answer 8

Tricuspid valve

Question 9

Do atria contract?

Answer 9

Only to fully empty
Most of the flow is passive

Question 10

What structures are in the right ventricle?

Answer 10

Interventricular septum
Trabeculae carneae
Papillary muscles
Chords tendinae
Moderator band

Question 11

What separates the two ventricles?

Answer 11

The inerventricular septum

Question 12

What are the muscular ridges on the internal wall of the right ventricle?

Answer 12

Trabeculae carneae

Question 13

What are the papillary muscles? What is their function?

Answer 13

Modified regions of trabeculae carneae
They project into the lumen of the ventricle

Prevent backwards leaking of valves

Question 14

What are the chordae tendinae?

Answer 14

Fibrous cords which connect tip of papillary muscles to tricuspid valve

Question 15

What is the mitral valve?

Answer 15

Left atrio-ventricular valve, bicuspid valve

Question 16

What is the moderator band?

Answer 16

connects interventricular septum to one of the papillary muscles (Modified region of trabeculae carneae)

Question 17

What does the pulmonary trunk bifurcate into?

Answer 17

Left and right pulmonary artery

Question 18

How does the left atrium differ from the right?

Answer 18

It doesn’t, apart from valve and vessel types and names.

Still smooth posterior wall with pectinate muscles on anterior wall

Question 19

What are the first branches from the aorta?

Answer 19

Coronary arteries

Question 20

What prevents backflow of blood into the left ventricle?

Answer 20

Aortic valve

Question 21

What structures does the left ventricles contain?

Answer 21

Trabeculae carneae
Papillary muscles
Chordae tendineae
(interventricular septum)

Question 22

How do the left and right ventricles differ?

Answer 22

Left ventricle has a thicker wall
Left ventricle has no moderator band (i think? or a fake one?)

Question 23

What occurs in terms of pressure and valves during ventricular systole?

Answer 23

Pressure rises in ventricles so Pventricles > Patria
Tricuspid and mitral valves close
Blood flows into pulmonary trunk and aorta

Question 24

How are chordae tendineae and papillary muscles essential for valve functioning?

Answer 24

Papillary muscles contract as ventricles contract
Tense the chords so they pull on valve cusps and prevent eversion into atria