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Thursday, October 09, 2008

Which of the following is the correct order for Pathway a sperm

Question 18
Which of the following is the correct order for Pathway a sperm
a.       Straight tubules à Rete testis à Efferent tubules
b.      Rete Tubules à Efferent Tubules à Straight Tubule
c.       Efferent Tubule à Rete Testis à Straight Tubules
d.      Straight Tubule à Efferent Tubules à Rete Tubules
a) Straight tubules à Rete testis à Efferent tubules
Gray’s Anatomy 38th Edition Page 1849. Diagram 14.2
The actual path is seminiferous tubules à Straight tubules à Rete Testis à Efferent ductile à Tail of epididymis à Deferent duct
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.
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.

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