Heart Lab Flashcards

1
Q

Difference between human and sheep heart

A
  • Sheep has 3 vena cava’s - left anterior (smaller)
  • left posterior
  • right anterior (larger))
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2
Q

What separates the 3 vena cava?

A

Fat pads

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3
Q

Left and right anterior vena cava drain:

A

Head and forelegs

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4
Q

Ventral view of sheep heart:

A
  • Ventral interventricular sulcus is on 45 degree angle
  • Aorta is to the sheep’s left (our right)
  • pulmonary trunk is the most ventral
  • ventral side is rounder than the flatter dorsal side due to the spine
  • ligamentum arteriosum is only visible in ventral view
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5
Q

Dorsal view of sheep heart:

A
  • Dorsal interventricular sulcus is straight
  • More vessels in dorsal view
  • flatter than ventral side
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6
Q

What colour is the atria?

A

Dark red

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7
Q

Great arteries appearance:

A
  • Shrouded with fat
  • Cream-coloured wall
  • Pulmonary trunk is most ventral
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8
Q

What makes up the apex of the heart?

A

Left ventricle

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9
Q

Appearance of aorta

A

Large and white

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10
Q

Interaction between pulmonary trunk and aorta

A

They half twist around each other, reversing positions as they continue away from the heart

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11
Q

What is the ligamentum arteriosum?

A
  • Remnant of ductus arteriosus

- Fibrous bridge

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12
Q

Brachiocephalic trunk:

A

Supplies the arm and the brain

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13
Q

Posterior vena cava drain:

A

Posterior of sheep

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14
Q

Cross-section of the base of the heart:

A
  • Dorsal: Right ventricle opening and left ventricle opening
  • Central: aorta
  • Most-ventral: pulmonary trunk
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15
Q

Atria internal wall:

A

Smooth - allows for smooth laminar flow

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16
Q

Auricle internal wall:

A

Irregular due to bundles of muscle fibres crossing over like a woven basket.
They’re trabeculated

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17
Q

Function of trabeculae:

A

To aid contraction

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18
Q

What are the tendinous cords made of?

A

Fibrous connective tissue

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19
Q

What is in the RV but not in the LV?

A

Moderator band that crosses from the septum to the ventricular wall

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20
Q

What is the function of the moderator band:

A

Made of purkinje fibres, aids in conduction

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21
Q

When is the mitral valve open?

A

Ventricular filling and atrial contraction

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22
Q

When is the mitral valve closed?

A

Isovolumetric ventricular filling, ventricular ejection, and isovolumetric ventricular relaxation

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23
Q

Aortic valve open view

A
  • Brachiocephalic trunk opening superior to valve flaps
  • 3 valve cusps (semilunar shape)
  • 2 coronary ostia (openings to coronary arteries) just behind valve flaps
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24
Q

Where do cardiac veins drain into

A

Left anterior vena cava

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25
Q

Fossa ovalis

A
  • remnant structure of foreman ovale
  • Between right and left atrium, interatrial septum
  • translucent
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26
Q

What happens when the papillary muscles rupture?

A

Inlet valves can no longer close; as the tension the papillary muscle provided to keep the chordae teninae tight is gone so the flaps shoot upwards when ventricular pressure exceeds atrial pressure

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27
Q

What could cause a rupture of the papillary muscles?

A
  • Myocardial infarction
  • Bacterial or viral infection
  • Ischemia
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28
Q

Why don’t the outlet valves need chordae tendinae?

A

No place to attach
They use their cup/pocket shape structure to be closed via the pressure of blood
Their shape gives strength

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29
Q

What did the foramen ovale do?

A
  • Let blood flow from RA to LA because fetus had no need for pulmonary circuit as placenta of mother supplied oxygenated blood
  • flap is on the left side
  • in fetus the pressure is opposite
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30
Q

What did the ductus arteriosus do?

A

Allowed a shunt of blood to pass from the pulmonary trunk to the aorta, again because fetus has no need for pulmonary circuit.

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31
Q

What causes closure of foramen ovale?

A

After birth the left side pressure increases and as the RA starts being used and blood goes to the lungs pressure decreases, forcing th valve closed.

Connective tissue growth seals the flap

32
Q

What causes closure of ductus arteriosus?

A

Smooth muscle constriction after birth

33
Q

What happens if ductus arteriosus doesn’t close

A
  • The shunt bridge is called patent
  • shunt of blood from the aorta to the pulmonary trunk (as pressure gradients reverse after birth)
  • Volume reaching the lung increases
  • if this occurs for too long we get hypertopy of right side leading to eventual reversal of flow
  • greater blood flow to the lungs than to the systemic circuit
34
Q

In the sheep heart, blood that enters the coronary arteries has just passed through the:

A

aortic valve

35
Q

Compare the left side of the sheep heart with the right

A
  • aortic valve - pulmonary valve
  • mitral valve - tricuspid valve
  • left and right pulmonary veins - right anterior, left anterior, and posterior vena cavae)
  • thick-walled ventricle - thin-walled ventricle
36
Q

Cardiac veins drain into the _____, their openings are very small, but they can be found by slitting open lengthwise the small left anterior vena cava and searching inside the wall of the vessel

A

right atrium

37
Q

What is in the right atrium and close to the interatrial septum

A

Fossa ovalis

38
Q

What is a fibrous bridge linking the pulmonary trunk to the aorta

A

Ligamentum arteriosum

39
Q

Traversing the right ventricle from wall to wall is a slender bridge that is made of muscle, not connective tissue.
It has no mechanical function in the action of the heart and actually contains modified cardiac muscle fibers (Purkinje fibers)

A

Moderator band

40
Q

The tricuspid valve gets what sort of blood?

A

Deoxygenated

41
Q

The pulmonary valve gets what sort of blood?

A

Deoxygenated

42
Q

The mitral valve gets what sort of blood?

A

oxygenated

43
Q

The aortic valves get what sort of blood

A

oxygenated

44
Q

What do papillary muscles do during systole

A

contract

45
Q

The foramen ovale of the fetal heart is a hole in the ____ septum. It allows blood to cross from the ____ atrium to the ___. It has a flap valve on the ___ side of the septum

A

Interatrial
right
left
left

46
Q

The ligamentum arteriosum is a remnant of a large fetal vessel called the ____ ____. This vessel carries blood from the ____ ____ to the ____

A

Ductus arteriosus
Pulmonary trunk
aorta

47
Q

If the ductus arteriosus remains open after birth, the result would be a large shunt of blood from the ____ to the ____ ___.

In that case, the volume of blood reaching the lungs would be _____ than normal

A

aorta
pulmonary trunk
larger

48
Q

During your dissection of the sheep’s heart, you used scissors to remove the apex of the heart.
Among the structures cut with the scissors were the:

A

Papillary muscles

49
Q

In the sheep heart, one of the four heart valves has only two flaps or cusps.
When closed this valve prevents blood flow from:

A

the left ventricle to the left atrium

50
Q

A chamber of the sheep’s heart is entered by three thin-walled vessels of unequal size.
The chamber has a valve at its outlet but no inlet valve.
The wall of the chamber is partly smooth and partly trabeculated.
When alive, the blood in the chamber would be a dark red/blue in colours.
This chamber is the:

A

right atrium

51
Q

Which structure is made of white fibrous CT

A

chordae tendinae

52
Q

interventricular septum has

A

cardiac muscle

53
Q

Chordae tendinae has:

A

dense regular fibrous connective tissue

54
Q

Auricles have:

A

cardiac muscle

55
Q

Moderator band has:

A

modified cardiac muscle

56
Q

Pericardium, out to in layers

A

fibrous pericardium
parietal pericardium
serous fluid
visceral/epicardium pericardium

57
Q

Heart wall layers

A

epicardium
myocardium
endocardium

58
Q

For blood to enter either atrium, what must the vessels/atrium do to ensure the filling of the atrium?

A

the atrium pressure must be below 5/8mmHg

59
Q

Right ventricle

  • pressure range
  • wall thickness
A

2-27mmHg

Thin wall

60
Q

Left ventricle

  • pressure range
  • wall thickness
A

5-120mmHg (5x as RV)

3x thicker than RV

61
Q

What has no mechanical function in the heart?

A

The moderator band
It has no mechanical function in the action of the heart, and actually contains modified cardiac muscles (Purkinje fibers) which are part of the heart’s conduction system.

62
Q

How many heart sounds?

A

Two, one from the atrioventricular valves and the 2nd one from the semilunar valves

63
Q

Which heart sound does the tricuspid valve contribute to?

A

first: when the tricuspid valve closes, the first heart sound is made

64
Q

The semilunar valve has _ leaflets

A

3

65
Q

When is the mitral valve open?

A

ventricular relaxation

66
Q

When is the mitral valve active?

A

During systole when it’s contracting

67
Q

When is the aortic valve open?

A

during ventricular contraction or systole

68
Q

Which heart sound does the aortic valve contribute to?

A

The second one

69
Q

What is the first division of the aorta?

A

The coronary arteries

70
Q

Peak pressure in the aorta:

A

120 mmHg (lowest 80 mmHg)

71
Q

Is there coronary Ostia in the pulmonary trunk?

A

No, only in the aortic valve

72
Q

The posterior end of a sheep is equivalent to the _____ or ____ surface of a human.

A

Inferior or caudal

73
Q

The dorsal surface of a sheep is equivalent to the _____ or ____ surface of a human.

A

posterior or dorsal

74
Q

The anterior surface of a sheep is equivalent to the _____ or ____ surface of a human.

A

superior or cranial

75
Q

The ventral surface of a sheep is equivalent to the _____ or ____ surface of a human.

A

anterior or ventral