Lab 3: Heart

Question 1

Distinguish between superior and inferior.

Answer 1

S: toward the head or the upper part of a structure
I: away from the head or the lower part of the structure

Question 2

What are two other names for superior?

Answer 2

Cephalic or cranial

Question 3

What is another name for inferior?

Answer 3

Caudal

Question 4

What is meant by anterior and posterior?

Answer 4

A: nearer to or at the front of the body
P: nearer to or at the back of the body

Question 5

What is ventral also known as in humans? What about 4 legged animals?

Answer 5

Humans: Anterior

4-legged: Inferior

Question 6

What is meant by medial and lateral?

Answer 6

M: nearer tot he midline
L: farther from the midline

Question 7

What is meant by intermediate?

Answer 7

Between two structures

Question 8

What is meant by ipsilateral and contralateral?

Answer 8

I: on the same side of the body as another structure
C: on the opposite side of the body from another structure

Question 9

What is meant by proximal and distal?

Answer 9

P: nearer to the attachment of a limb to the trunk , nearer to the origination of a structure.
D: Farther from the attachment of a limb to the trunk, farther from the origination of a structure.

Question 10

What is meant by superficial and deep? What are two other terms for this?

Answer 10

External: Toward or on the surface of the body
Internal: Away from the surface of the body

Question 11

How does the sheep heart differ from the human heart?

Answer 11

Size: sheep heart is smaller
Shape of the atria
In sheep, venous blood is drained from the head and forelegs to the heart via two anterior (large right and small left), whereas in humans, there is only one superior vena cava. The shape of the right atrium is influenced by the entry of these large vessels.

Question 12

What are the similarities of the sheep heart and the human heart?

Answer 12

Internal features of the adult sheep heart and human sheep heart are very similar.

Question 13

What do each of the following directional terms of humans correspond with in a sheep?

• Superior or Cranial
• Inferior or Caudal
• Anterior or Ventral
• Posterior and Dorsal

Answer 13

• Anterior or Cranial
• Posterior or Cranial
• Ventral
• Dorsal

Question 14

What forms the apex of the heart?

Answer 14

The larger LV

Question 15

What does the groove running diagonally across the ventricles represent?

Answer 15

The position of the septum separating RV and LV.

Marks the course of one of the coronary arteries and a cardiac vein.

Question 16

Which vessel is most ventral?

Answer 16

The pulmonary trunk

Question 17

What is the ligamentum arteriosum?

Answer 17

A fibrous bridge linking the pulmonary trunk to the aorta.

Question 18

Which is the base of the heart?

Answer 18

The broad end of the heart.

Question 19

What are the two parts of the atria? Describe the walls of each.

Answer 19

The main part has a smooth internal wall.
The second part, the atrial appendage (auricle), has an irregular internal surface on which bundles of muscle fibres cross each other in the same way that a basket is woven together (trabeculated).

Question 20

What are the tendinous cords placed in tension by?

Answer 20

The papillary muscles on the inside wall of the ventricles

Question 21

What traverses the right ventricle from wall to wall?

Answer 21

A slender bridge, the moderator band.

Question 22

What is the moderator band made of? What is it’s function?

Answer 22

Muscle. It has no mechanical function in the action of the heart, and contains modified cardiac muscle fibers (Purkinje fibres) which are part of the heart’s conduction system.

Question 23

Where are the openings of the coronary arteries located?

Answer 23

Just inside the aortic valve flaps.

Question 24

Where do the cardiac veins drain into?

Answer 24

The right atrium

Question 25

What is another name for the Fossa ovalis?

Answer 25

Foramen ovale

Question 26

What is the purpose of the foramen ovale?

Answer 26

Allows blood to cross from the right atrium to the left in the sheep fetus.

Question 27

What are the three indicators that we are looking at the sheep heart in a ventral view?

Answer 27

1) Great arteries visible 2) Auricles of atria seen (pointy ends) 3) Interventricular sulcus/groove is diagonal

Question 28

What is the first external outlet of the aorta? Where does blood from this outlet go to?

Answer 28

Brachiocephalic aorta | Head and arms

Question 29

What indicates a dorsal view?

Answer 29

A vertical sulcus

Question 30

what are found just behind the valves of the aorta?

Answer 30

Coronary ostia - the openings to the coronary arteries

Question 31

What is the moderator band an extension of?

Answer 31

Conduction system. It acts as a short cut for the impulse.

Question 32

From where to where does the moderator band extend?

Answer 32

From IVS to the outermost papillary muscle

Question 33

What is the fossa ovalis a remnant of?

Answer 33

The foramen ovale

Question 34

What causes the heart sounds? Where are heart sounds heard?

Answer 34

Turbulence created in the blood causes heat sounds. In the direction of flow of blood

Question 35

Describe the flow of blood and the pressures in a fetus before birth.

Answer 35

10% of blood from the RV goes to the lungs which are filled with water so are at high pressure so this reduces the flow of blood back to the LA. 90% of blood from the RV goes to the systemic capillaries. The mother's blood also contributes to this, so the pressure of blood returning to the RA is much higher than that returning to the LA. Blood flows form RA to LA.

Question 36

What is the foramen ovale?

Answer 36

A hole in the interatrial septum

Question 37

What is the function of the foramen ovale?

Answer 37

Allows blood to cross from RA to LA

Question 38

What does the foramen ovale have on the left side of the septum?

Answer 38

A flap valve

Question 39

The ligamentum arteriosum is a remnant of a large fetal vessel called the _________ ___________. This vessel carried blood from the ___________ _______ to the _______.

Answer 39

Ductus arteriosus Pulmonary trunk Aorta

Question 40

Why does the flap valve of the foramen ovale close at birth?

Answer 40

RA flow decreases due to the loss of of the umbilical cord. LA flow increases. Pressure in the LA is thus greater than the RA and the valve closes.

Question 41

What process causes the formation of the fossa ovalis?

Answer 41

The valve flap becomes sealed by the growth of the connective tissue around its edges.

Question 42

What does the ductus arteriosus close due to the action of?

Answer 42

Contraction of the smooth muscle

Question 43

What would happen if the ductus arteriosus remained open (patent) after birth?

Answer 43

There would be a large shunt of blood from the aorta to the pulmonary trunk. The volume of the blood reaching the lungs would thus be larger.