Lecture 6

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Question 1 of 33

Why are ventricular inlets larger than outlets?
Filling is passive and a larger outlet allows for quicker filling – ejection active.

Question 1 of 33

Question 2 of 33

What is the wall thickness ratio RV : LV?
3:1 (4-5mm – 15mm).

Question 2 of 33

Question 3 of 33

What is the peak pressure ration RV : LV?
5:1 (27mm Hg – 12-mm Hg).

Question 3 of 33

Question 4 of 33

Are the semilumn valves open or closed during ventricular filling?
Closed.

Question 4 of 33

Question 5 of 33

Why do inlets have chordae tendinae and the outlets don’t?
Inlets larger and have anchor points (papillary muscles).

Question 5 of 33

Question 6 of 33

What forms the right border?
Right atrium.

Question 6 of 33

Question 7 of 33

What forms the inferior border?
Right ventricle.

Question 7 of 33

Question 8 of 33

What forms the left border?
Left ventricle.

Question 8 of 33

Question 9 of 33

What forms the superior border?
Base of heart (valves).

Question 9 of 33

Question 10 of 33

What reduces the friction during heart movement?
Pericardium.

Question 10 of 33

Question 11 of 33

What are the layers in order from the heart outwards? (3)
Visceral pericardium, parietal pericardium, fibrous pericardium.

Question 11 of 33

Question 12 of 33

What type of cells comprise the semous membranes of internal organs?
Mesothelial.

Question 12 of 33

Question 13 of 33

What layer of the heart has two names?
Visceral pericardium / epicardium.

Question 13 of 33

Question 14 of 33

What is pericarditis?
Inflammation of the pericardial space due to fluid build-up (infection, damage, rupture).

Question 14 of 33

Question 15 of 33

Between which layers is the pericardial space?
Visceral pericardium / parietal pericardium.

Question 15 of 33

Question 16 of 33

Which outlet/inlet has an incomplete fibrous ring?
RA

Question 16 of 33

Question 17 of 33

What are the problems with an enlarged heart? (3)
Small lumen, inflexible cardiac tissue, decreased blood supply to heart.

Question 17 of 33

Question 18 of 33

What causes an enlarged heart?
Aortic stenosis (scarring of valve tissue, narrowing of aortic valve).

Question 18 of 33

Question 19 of 33

What happens after a myocardial infarction through macrophage cleanup?
Macrophages cleanup dead tissue before fibroblasts can repair – rupture.

Question 19 of 33

Question 20 of 33

Where does the blood leak into?
Pericardial space.

Question 20 of 33

Question 21 of 33

How does the fibrous pericardium affect the heart’s ability to fill during cardiac tamponade?
Does not expand as pericardial space fills – puts pressure on heart.

Question 21 of 33

Question 22 of 33

What functions do the fibrous rings have? (2)
Maintain valve shape, insulate ventricles from atria.

Question 22 of 33

Question 23 of 33

Where is the SA node situated?
At the junction of SVC and Atrium (R).

Question 23 of 33

Question 24 of 33

How many times does the SA node depolarise / repolarise?
60 – 100 p/m.

Question 24 of 33

Question 25 of 33

Through which structure do the ventricles receive action potential.
AV node.

Question 25 of 33

Question 26 of 33

What does the AV node connect to?
AV bundle (bundle of His)

Question 26 of 33

Question 27 of 33

What does this bundle divide into?
L & R bundle branches.

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Question 28 of 33

What do these divide into?
Purkinje fibres.

Question 28 of 33

Question 29 of 33

What are the differences between myocytes and purkinje fibres? (4)
Purkinje fibres : fatter, conduct AP’s, weaker contractility, not branched.

Question 29 of 33

Question 30 of 33

What is the speed of action potential through Atria?
0.5 m/s.

Question 30 of 33

Question 31 of 33

What is the speed of action potential conduction through AV node?
0.05 m/s.

Question 31 of 33

Question 32 of 33

What is the delay of action potential from Atria to Ventricle?
100 m/s.

Question 32 of 33

Question 33 of 33

What is the speed of action potential through AV Bundle / perkinje fibres.
5 m/s.

Question 33 of 33