Heart Lab Flashcards
(75 cards)
1
Q
Difference between human and sheep heart
A
- Sheep has 3 vena cava’s - left anterior (smaller)
- left posterior
- right anterior (larger))
2
Q
What separates the 3 vena cava?
A
Fat pads
3
Q
Left and right anterior vena cava drain:
A
Head and forelegs
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
5
Q
Dorsal view of sheep heart:
A
- Dorsal interventricular sulcus is straight
- More vessels in dorsal view
- flatter than ventral side
6
Q
What colour is the atria?
A
Dark red
7
Q
Great arteries appearance:
A
- Shrouded with fat
- Cream-coloured wall
- Pulmonary trunk is most ventral
8
Q
What makes up the apex of the heart?
A
Left ventricle
9
Q
Appearance of aorta
A
Large and white
10
Q
Interaction between pulmonary trunk and aorta
A
They half twist around each other, reversing positions as they continue away from the heart
11
Q
What is the ligamentum arteriosum?
A
- Remnant of ductus arteriosus
- Fibrous bridge
12
Q
Brachiocephalic trunk:
A
Supplies the arm and the brain
13
Q
Posterior vena cava drain:
A
Posterior of sheep
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
15
Q
Atria internal wall:
A
Smooth - allows for smooth laminar flow
16
Q
Auricle internal wall:
A
Irregular due to bundles of muscle fibres crossing over like a woven basket.
They’re trabeculated
17
Q
Function of trabeculae:
A
To aid contraction
18
Q
What are the tendinous cords made of?
A
Fibrous connective tissue
19
Q
What is in the RV but not in the LV?
A
Moderator band that crosses from the septum to the ventricular wall
20
Q
What is the function of the moderator band:
A
Made of purkinje fibres, aids in conduction
21
Q
When is the mitral valve open?
A
Ventricular filling and atrial contraction
22
Q
When is the mitral valve closed?
A
Isovolumetric ventricular filling, ventricular ejection, and isovolumetric ventricular relaxation
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
24
Q
Where do cardiac veins drain into
A
Left anterior vena cava
25
Fossa ovalis
- remnant structure of foreman ovale
- Between right and left atrium, interatrial septum
- translucent
26
What happens when the papillary muscles rupture?
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
27
What could cause a rupture of the papillary muscles?
- Myocardial infarction
- Bacterial or viral infection
- Ischemia
28
Why don't the outlet valves need chordae tendinae?
No place to attach
They use their cup/pocket shape structure to be closed via the pressure of blood
Their shape gives strength
29
What did the foramen ovale do?
- 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
30
What did the ductus arteriosus do?
Allowed a shunt of blood to pass from the pulmonary trunk to the aorta, again because fetus has no need for pulmonary circuit.
31
What causes closure of foramen ovale?
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
What causes closure of ductus arteriosus?
Smooth muscle constriction after birth
33
What happens if ductus arteriosus doesn't close
- 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
In the sheep heart, blood that enters the coronary arteries has just passed through the:
aortic valve
35
Compare the left side of the sheep heart with the right
- 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
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
right atrium
37
What is in the right atrium and close to the interatrial septum
Fossa ovalis
38
What is a fibrous bridge linking the pulmonary trunk to the aorta
Ligamentum arteriosum
39
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)
Moderator band
40
The tricuspid valve gets what sort of blood?
Deoxygenated
41
The pulmonary valve gets what sort of blood?
Deoxygenated
42
The mitral valve gets what sort of blood?
oxygenated
43
The aortic valves get what sort of blood
oxygenated
44
What do papillary muscles do during systole
contract
45
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
Interatrial
right
left
left
46
The ligamentum arteriosum is a remnant of a large fetal vessel called the ____ ____. This vessel carries blood from the ____ ____ to the ____
Ductus arteriosus
Pulmonary trunk
aorta
47
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
aorta
pulmonary trunk
larger
48
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:
Papillary muscles
49
In the sheep heart, one of the four heart valves has only two flaps or cusps.
When closed this valve prevents blood flow from:
the left ventricle to the left atrium
50
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:
right atrium
51
Which structure is made of white fibrous CT
chordae tendinae
52
interventricular septum has
cardiac muscle
53
Chordae tendinae has:
dense regular fibrous connective tissue
54
Auricles have:
cardiac muscle
55
Moderator band has:
modified cardiac muscle
56
Pericardium, out to in layers
fibrous pericardium
parietal pericardium
serous fluid
visceral/epicardium pericardium
57
Heart wall layers
epicardium
myocardium
endocardium
58
For blood to enter either atrium, what must the vessels/atrium do to ensure the filling of the atrium?
the atrium pressure must be below 5/8mmHg
59
Right ventricle
- pressure range
- wall thickness
2-27mmHg
| Thin wall
60
Left ventricle
- pressure range
- wall thickness
5-120mmHg (5x as RV)
| 3x thicker than RV
61
What has no mechanical function in the heart?
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
How many heart sounds?
Two, one from the atrioventricular valves and the 2nd one from the semilunar valves
63
Which heart sound does the tricuspid valve contribute to?
first: when the tricuspid valve closes, the first heart sound is made
64
The semilunar valve has _ leaflets
3
65
When is the mitral valve open?
ventricular relaxation
66
When is the mitral valve active?
During systole when it's contracting
67
When is the aortic valve open?
during ventricular contraction or systole
68
Which heart sound does the aortic valve contribute to?
The second one
69
What is the first division of the aorta?
The coronary arteries
70
Peak pressure in the aorta:
120 mmHg (lowest 80 mmHg)
71
Is there coronary Ostia in the pulmonary trunk?
No, only in the aortic valve
72
The posterior end of a sheep is equivalent to the _____ or ____ surface of a human.
Inferior or caudal
73
The dorsal surface of a sheep is equivalent to the _____ or ____ surface of a human.
posterior or dorsal
74
The anterior surface of a sheep is equivalent to the _____ or ____ surface of a human.
superior or cranial
75
The ventral surface of a sheep is equivalent to the _____ or ____ surface of a human.
anterior or ventral
