Ch 66; Anal

Question 1

The anal canal is ___ in length, the posterior wall being longer than the
anterior

Answer 1

The anal canal is 3 to 4 cm in length, the posterior wall being longer than the
anterior

Question 2

Perianal carcinomas are arbitrarily
considered to be cancers arising from the skin within a __radius of the anal
verge

Answer 2

Perianal carcinomas are arbitrarily
considered to be cancers arising from the skin within a 5-cm radius of the anal
verge

Question 3

At the anal verge, the skin
blends with a pale-colored zone, sometimes called the ___, lined by modified
squamous epithelium that lacks hair or glandular structures

Answer 3

At the anal verge, the skin
blends with a pale-colored zone, sometimes called the pecten, lined by modified
squamous epithelium that lacks hair or glandular structures

Question 4

The major lymphatic pathways flow to three lymph node systems. The
perianal skin, the anal verge, and the canal distal to the dentate line drain
predominantly to the ____, with some communication to
the femoral nodes and to the external iliac systems.

Answer 4

The major lymphatic pathways flow to three lymph node systems. The
perianal skin, the anal verge, and the canal distal to the dentate line drain
predominantly to the superficial inguinal nodes, with some communication to
the femoral nodes and to the external iliac systems.

Question 5

Lymphatics from around and
above the dentate line flow with those from the distal rectum to the ____

Answer 5

Lymphatics from around and
above the dentate line flow with those from the distal rectum to the internal
pudendal, hypogastric, and obturator nodes of the internal iliac systems.

Question 6

The
proximal canal drains to the ____.

Answer 6

The
proximal canal drains to the perirectal and superior hemorrhoidal nodes of the
inferior mesenteric system.

Question 7

The veins draining the inferior parts of the anal canal plexuses
communicate with the ____, and those from the superior canal flow predominately to the
_____

Answer 7

The veins draining the inferior parts of these plexuses
communicate with the systemic venous system via the internal pudendal and
internal iliac veins, and those from the superior canal flow predominately to the
inferior mesenteric vein and then to the portal system

Question 8

The smooth muscle of the internal sphincter is supplied by
parasympathetic fibers from the _____sacral segments as well
as sympathetic fibers from the hypogastric plexus.

Answer 8

The smooth muscle of the internal sphincter is supplied by
parasympathetic fibers from the second, third, and fourth sacral segments as well
as sympathetic fibers from the hypogastric plexus.

Question 9

The voluntary control of the external sphincter is via

Answer 9

internal rectal nerve