Flashcards in Lab 3: Heart Deck (43):
Distinguish between superior and inferior.
S: toward the head or the upper part of a structure
I: away from the head or the lower part of the structure
What are two other names for superior?
Cephalic or cranial
What is another name for inferior?
What is meant by anterior and posterior?
A: nearer to or at the front of the body
P: nearer to or at the back of the body
What is ventral also known as in humans? What about 4 legged animals?
What is meant by medial and lateral?
M: nearer tot he midline
L: farther from the midline
What is meant by intermediate?
Between two structures
What is meant by ipsilateral and contralateral?
I: on the same side of the body as another structure
C: on the opposite side of the body from another structure
What is meant by proximal and distal?
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.
What is meant by superficial and deep? What are two other terms for this?
External: Toward or on the surface of the body
Internal: Away from the surface of the body
How does the sheep heart differ from the human heart?
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.
What are the similarities of the sheep heart and the human heart?
Internal features of the adult sheep heart and human sheep heart are very similar.
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
- Anterior or Cranial
- Posterior or Cranial
What forms the apex of the heart?
The larger LV
What does the groove running diagonally across the ventricles represent?
The position of the septum separating RV and LV.
Marks the course of one of the coronary arteries and a cardiac vein.
Which vessel is most ventral?
The pulmonary trunk
What is the ligamentum arteriosum?
A fibrous bridge linking the pulmonary trunk to the aorta.
Which is the base of the heart?
The broad end of the heart.
What are the two parts of the atria? Describe the walls of each.
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).
What are the tendinous cords placed in tension by?
The papillary muscles on the inside wall of the ventricles
What traverses the right ventricle from wall to wall?
A slender bridge, the moderator band.
What is the moderator band made of? What is it's function?
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.
Where are the openings of the coronary arteries located?
Just inside the aortic valve flaps.
Where do the cardiac veins drain into?
The right atrium
What is another name for the Fossa ovalis?
What is the purpose of the foramen ovale?
Allows blood to cross from the right atrium to the left in the sheep fetus.
What are the three indicators that we are looking at the sheep heart in a ventral view?
1) Great arteries visible
2) Auricles of atria seen (pointy ends)
3) Interventricular sulcus/groove is diagonal
What is the first external outlet of the aorta? Where does blood from this outlet go to?
Head and arms
What indicates a dorsal view?
A vertical sulcus
what are found just behind the valves of the aorta?
Coronary ostia - the openings to the coronary arteries
What is the moderator band an extension of?
Conduction system. It acts as a short cut for the impulse.
From where to where does the moderator band extend?
From IVS to the outermost papillary muscle
What is the fossa ovalis a remnant of?
The foramen ovale
What causes the heart sounds? Where are heart sounds heard?
Turbulence created in the blood causes heat sounds. In the direction of flow of blood
Describe the flow of blood and the pressures in a fetus before birth.
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.
What is the foramen ovale?
A hole in the interatrial septum
What is the function of the foramen ovale?
Allows blood to cross from RA to LA
What does the foramen ovale have on the left side of the septum?
A flap valve
The ligamentum arteriosum is a remnant of a large fetal vessel called the _________ ___________. This vessel carried blood from the ___________ _______ to the _______.
Why does the flap valve of the foramen ovale close at birth?
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.
What process causes the formation of the fossa ovalis?
The valve flap becomes sealed by the growth of the connective tissue around its edges.
What does the ductus arteriosus close due to the action of?
Contraction of the smooth muscle