anatomy of the anal canal Flashcards
what is the final part of the GI tract?
the anal canal
where does the anal canal start and end ?
- starts at end of rectum
- ends at anus
within what structure is the anal canal contained in?
the anal triangle (posterior half of perineum)
how does the anal canal control defecation?
with 2 sphincters
- internal
- external
which anal sphincter is made of skeletal muscle, which of smooth muscle?
which is controlled voluntarily/involuntarily?
internal sphincter
-smooth muscle
- involuntary
external sphincter
- skeletal muscle
- voluntary
(same way round as bladder sphincters)
name the line that divides the superior 2/3 of the anal canal from the inferior 1/3.
the pectinate line
ie. denate line
is the anal canal part of the hindgut?
the superior 2/3 (above pectinate line) is
is the superior anal canal encircled by the internal and external sphincters?
yes
encircled by both
is the inferior anal canal encircled by the internal and external anal sphincters?
no
only by external
what is the arterial supply of the superior anal canal?
HINDGUT
- inferior mesenteric artery
(superior rectal branches)
what is the venous drainage of the superior anal canal?
HINDGUT
- portal vein
what is the nervous innervation of the superior anal canal?
inferior hypogastric plexus
sympathetic - sympathetic trunk
parasympathetic fibres - pelvic splanchnic nerves
what is the arterial supply of the inferior anal canal?
- middle and inferior rectal arteries
which originate from the internal iliac arteries.
what is the venous drainage of the inferior anal canal?
direct to IVC
what is the nervous innervation of the inferior anal canal?
pudendal nerve.
