800 Questions Anatomic Sciences_pag42

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Answers: 10-18 27
It is also semilunar, and separates the right
ventricle from the pulmonary arteries. 
14. The correct answer is A. Blood supply to the
lateral wall of the left ventricle is via the left
circumflex artery. The coronary arteries are
the first branches of the aorta, and fill during
the diastole stage of the heart cycle. 
Answer B is incorrect. The right coronary
artery branches off as the acute marginal and
posterior descending arteries. 
Answer C is incorrect. The left anterior
descending artery provides blood supply to
the anterior wall of left ventricle and inter-
ventricular septum.
Answers D and E are incorrect. Such vascu-
lature supplies blood to the posterior and
inferior walls of the left ventricle, as well as
the entire right ventricle and atrioventricular
node.
Note that the left coronary artery to branch
from the aorta is the left main coronary
artery, which subsequently gives off the cir-
cumflex (blood supplied to the lateral wall of
the left ventricle) and left descending arteries.
15. The correct answer is B. The vagus nerve
travels through the posterior portion of the
inferior mediastinum. It contains the thoracic
duct, descending aorta, azygous vein, hemi-
azygous vein, esophagus, vagus nerves,
splanchnic nerves, and lymph nodes. Within
the thorax, between and medial to the lungs,
lies an area termed the mediastinum, which
is divided into a superior and inferior portion. 
Answer A is incorrect. The superior medi-
astinum contains the following: thoracic
duct, ascending and descending aorta, aortic
arch (and branches), superior vena cava, bra-
chiocephalic veins, thymus (childhood), tra-
chea, esophagus, cardiac nerve, and left
recurrent laryngeal nerve. 
Answer C is incorrect. The anterior medi-
astinum (subdivision of the inferior medi-
astinum) contains the thymus, connective tis-
sue, lymph nodes, and branches of internal
thoracic artery. 
Answer D is incorrect. The middle medi-
astinum (subdivision of the inferior medi-
astinum) contains the pericardium, heart,
roots of great vessels, and phrenic nerve. 
16. The correct answer is D. Oxygenated blood
bypasses the pulmonary circulation by a
communication in the fetal heart called the
foramen ovale. This opening connects the
right atrium to the left atrium. Blood, there-
fore, is oxygenated by the mother and enters
the fetal heart by way of the inferior vena
cava. The blood is then shunted from the
right to left atrium, where it proceeds to
flow through the left ventricle, and subse-
quently out through the aorta to supply the
fetal head. Prostaglandins, as well as inspi-
ration, help to close the foramen ovale
upon birth.
Answers A, B, C, and E are incorrect.Oxy-
genated blood does not bypass the pulmonary
circulation via these routes. 
17. The correct answer is B. The fossa ovalis,
which lies on the atrial septum (separating
the right and left atria) is the adult remnant
of the fetal foramen ovale. Its upper margin is
the anulus ovalis. 
Answer A is incorrect. The crista terminalis
lies between the vena cavae openings, and is
a vertical ridge which represents the sinus
venosus and fetal heart. 
Answer C is incorrect. The sulcus terminalis,
a vertical groove lying externally on the right
atrium, represents the internal location of the
crista terminalis. 
Answer D is incorrect. The right auricle is
an appendage of the right atrium.
Answer E is incorrect. The atrial appendage
serves as a connection (in concert with the
crista terminalis) of the pectinate muscula-
ture of the right atrium. 
18. The correct answer is C. The ductus arterio-
sus connects the pulmonary artery to the
aorta, thus assisting in the pumping of blood
throughout the fetal vasculature. 
Anatomic Sciences
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