The artery to the ductus deferens is a branch of

Question 19

The artery to the ductus deferens is a branch of

a.       Inferior epigastric artery

b.      Superior Epigastric Artery

c.       Superior Vesical Artery

d.      Cremasteric Artery

Answer

c) Superior Vesical Artery

Reference

Gray’s Anatomy 38^th Edition Page 1559

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Discussion

Each internal iliac artery, about 4 cm long, begins at the common iliac bifurcation, level with the lumbosacral intervertebral disc and anterior to the sacro-iliac joint; it descends posteriorly to the superior margin of the greater sciatic foramen, dividing here into: an anterior trunk, which continues in the same line towards the ischial spine; and a posterior trunk, passing back to the foramen.

Explanation

Ä     Superior Vesical Artery supplies many branches to the vesical fundus; from one the artery to the ductus deferens occasionally starts and accompanies the ductus to the testis, anastomosing with the testicular artery. Others supply the ureter. The beginning of the superior vesical artery is the proximal, patent section of the fetal umbilical artery.

Ä     Often arising with the middle rectal, Inferior Vesical Artery supplies the vesical fundus, prostate, seminal vesicles and lower ureter. Prostatic branches communicate across the midline. The inferior vesical may sometimes provide the artery to the ductus deferens.

Comments

In the fetus the internal iliac artery is twice the size of the external and is the direct continuation of the common iliac. It ascends on the anterior abdominal wall to the umbilicus, converging on its fellow. Having traversed the opening, the two arteries, now umbilical, enter the umbilical cord, coil round the umbilical vein and ultimately ramify in the placenta. At birth, when placental circulation ceases, only the pelvic segment remains patent as the internal iliac artery and part of the superior vesical, the remainder becoming a fibrous medial umbilical ligament raising the peritoneal medial umbilical fold from the pelvis to the umbilicus. In males, the patent part usually gives off an artery to the ductus deferens.

Tips

The remnant of the fetal left umbilical vein is the ligamentum teres of the liver; the obliterated umbilical arteries form the medial umbilical ligaments, enclosed in peritoneal folds of the same name; and the partially obliterated remains of the urachus persist as the median umbilical ligament.

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Explanation

The actual path is seminiferous tubules à Straight tubules à Rete Testis à Efferent ductile à Tail of epididymis à Deferent duct

Comments

Ä     As Highly coiled parts of the seminiferous tubules reach the lobular apices they are less convoluted, assume an almost straight course and unite into 20–30 larger but short straight ducts (tubuli recti), about 0.5 mm in diameter.

Ä     Straight seminiferous tubules enter the fibrous tissue of the mediastinum testis, ascending backwards as a close network (the rete testis) of anastomosing tubes lined by a flat epithelium.

Ä     At the upper pole of the mediastinum, 12–20 efferent ductules (ductuli efferentes) perforate the tunica albuginea to pass from the testis to the epididymis. They are at first straight, becoming enlarged and very convoluted and forming conical lobules of the epididymis, which make up its head (caput).

Ä     Each epididymal lobule is a convoluted duct, 15–20 cm in length. Opposite the lobular bases the ducts open into a single duct of the epididymis, whose coils form the epididymal body (corpus) and tail (cauda). With the coils unravelled the tube measures more than 6 metres, increasing in thickness as it approaches the epididymal tail, where it becomes the deferent duct.

Ä     The coils are held together by bands of fibrous connective tissue. The epididymal body and tail are thus a single tube.

Tips

Ä     Efferent ductules are lined by two types of epithelial cell: tall columnar ciliated cells, their cilia beating towards the epididymis, and shorter non-ciliated cells containing conspicuous lysosomes and shown to be actively endocytic. External to the epithelium, the ductules are surrounded by a thin circular coat of smooth muscle.